Clinicians › Shoulder
Ligaments & Soft Tissue
Glenohumeral and coracoclavicular ligamentous injuries, focusing on HAGL lesions and their role in anterior instability and preoperative diagnostic challenges.
Overview¶
Soft-tissue and ligamentous pathology in the shoulder and acromioclavicular joint requires precise identification of all contributing bony and soft-tissue factors to select an adequate repair or reconstruction strategy [2, 4]. Surgical indications are driven by patient functional demands, activity level, and the specific pattern of instability [2, 3]. For recurrent anterior instability, nonsurgical treatment is often insufficient, particularly in contact athletes where isolated soft-tissue procedures carry a high failure rate [30]. The ideal candidate for an isolated soft-tissue procedure presents with minimal glenoid bone loss of 13.5% [14]. In recurrent posterior instability, nonsurgical treatment is successful in most cases, but surgical intervention is indicated when conservative management fails and requires accurate definition of the instability pattern [3]. Revision procedures in children and adolescents often necessitate an escalation of surgical complexity, as simply repeating the index procedure typically results in poor outcomes [4].
Anatomic reconstruction is the cornerstone of effective treatment, aiming to replicate normal ligament function and return tissues to their anatomic locations [59, 6]. Arthroscopic techniques offer the advantage of preserving native anatomy, maintaining joint integrity, and allowing for alternative interventions if failure occurs [62]. The crucial advantage of arthroscopic suture repair is its capacity for a real anatomic repair and physiological tensioning of ligamentous restraints [32]. Biologic soft-tissue reconstruction techniques provide robust time zero strength and a diminished complication profile [15]. For acromioclavicular joint separation, an arthroscopy-assisted all-suture adjustable system emphasizes flexible, anatomic ligament reconstruction, showing early results of stability and accelerated rehabilitation without common hardware complications [1].
Treatment guidelines emphasize anatomic dissection, identification of responsible lesions, and early postoperative range of motion [59]. There is no one procedure that fits all patients; surgeons must individualize their approach based on bone changes, soft tissue quality, activity requirements, and surgical experience [29]. Achieving the best result for recurrent anterior instability depends on a procedure that allows observation of joint surfaces, provides anatomical repair, maintains range of motion, and has low rates of complications and recurrence [28]. Unanimous consensus exists on relative indications for nonoperative management and labral repair in posterior instability, as well as steps to minimize complications [48]. Further studies involving more subjects with long-term results are needed to guide future surgical indications for posterior bone block techniques in young contact athletes [221].
Anatomy & Pathophysiology¶
Glenohumeral Joint & Ligaments¶
The glenohumeral joint is a ball-and-socket articulation where the large humeral head contacts, rather than sits within, the small glenoid cavity [82]. The glenoid is a convex, shallow structure shaped like an inverted pear, with subchondral bone that is relatively flat; articular concavity is augmented by cartilage and a circumferential labrum [70, 73]. The glenoid averages 5° of retroversion relative to the scapular body axis [73]. The radius of curvature of the glenoid articular surface is 2 to 3 mm larger than that of the humeral head [82].
The humeral head is spherical with a diameter of 37 to 57 mm and a radius of curvature of approximately 25 mm, which is slightly larger in men than in women [70, 82]. The articular surface is covered by cartilage over an arc of approximately 160 degrees [82]. Version and inclination vary across literature: the head averages 29.8 degrees of version (range, 10 to 55 degrees) and is inclined approximately 130 degrees to the shaft [70]; alternatively, it is described as averaging 19° of retroversion and 41° of inclination (neck-shaft angle) [73], or a neck-shaft angle of 135 degrees with 30 degrees of retroversion [71]. The superior margin of the humeral head articular surface lies 8 to 10 mm superior to the top of the greater tuberosity [82, 70]. The bicipital groove, located between the greater and lesser tuberosities, serves as a pathway for the long head of the biceps tendon, with its distal aspect internally rotated relative to the proximal portion [70].
Stability of the glenohumeral joint relies on both static and dynamic stabilizers [82]. Static stabilizers include articular congruity, the glenoid labrum, concavity-compression, negative intra-articular pressure, and the glenohumeral capsule and ligaments [73]. Dynamic stabilizers comprise the rotator cuff and biceps tendon [73]. The rotator cuff stabilizes the joint via compression [73]. The fibrocartilaginous glenoid labrum deepens the socket by 50%, providing up to 50% of marginal glenoid socket depth and acting as a bumper to translation [73, 85]. Combined with the glenoid articular surface, the labrum creates a socket approximately 9 mm deep superoinferiorly and 5 mm deep anteroposteriorly [83]. Including the labrum increases the glenoid surface coverage to 75% of the humeral head vertically and 57% horizontally [83].
The rotator interval is defined medially by the base of the coracoid, superiorly by the supraspinatus tendon, and inferiorly by the subscapularis tendon [73]. It contains the coracohumeral ligament, the superior glenohumeral ligament, and the intra-articular portion of the long head of the biceps tendon [73]. Laxity of this interval results in inferior laxity (the sulcus sign), while contracture is seen in adhesive capsulitis [73].
Specific ligaments provide position-dependent restraint: * Coracohumeral ligament: A thick band of fibrous tissue extending from the coracoid process along the capsule to the tuberosities between the supraspinatus and subscapularis tendons [83]. It is deep to the cuff insertion and blends with the capsule and supraspinatus tendon to form part of the biceps sheath roof [83]. A 1-cm wide thickening extends posteriorly from its coracoid origin to the posterior margin [83]. It restricts external rotation in adduction and acts as a static restraint to inferior and posterior translation in adduction and external rotation [73]. * Superior glenohumeral ligament: A primary static restraint against anterior translation with the arm at the side [73]. It is the primary restraint to inferior humeral subluxation at 0 degrees of abduction and the primary stabilizer to anterior and posterior stress in that position [83]. Together with the coracohumeral ligament, it forms a pulley restraining medial subluxation of the long head of the biceps tendon [73]. * Middle glenohumeral ligament: A primary static restraint against anterior translation with the arm in external rotation and 45° of abduction [73]. It limits external rotation in the lower and middle ranges of abduction but has little effect at 90 degrees of abduction [83]. This ligament is absent in up to 30% of shoulders [85]. * Inferior glenohumeral ligament: Composed of a thick anterior band, a less thick posterior band, and a thinner intervening axillary pouch, creating a hammock-type sling [83]. The anterior band is the primary static restraint against anterior-inferior dislocation in 90° of abduction and external rotation [73]. The posterior band is the primary static restraint against posterior-inferior translation in internal rotation and adduction [73]. With external rotation, the hammock slides anteriorly and superiorly, tightening the anterior band and fanning out the posterior band; internal rotation produces the opposite effect [83]. The anteroinferior glenohumeral ligament complex is the main stabilizer to anterior and posterior stresses when the shoulder is abducted 45 degrees or more [83].
In healthy adult shoulders, ligamentous structures are not fully elongated in many positions but function as restraints at the extremes of motion [125].
Anatomic variants include the sublabral foramen (anterosuperior) and the Buford complex, characterized by the absence of the anterosuperior labrum and a cordlike middle glenohumeral ligament [85]. The capsule extends from the glenoid rim laterally toward the surgical neck of the humerus, blending with rotator cuff tendons [77]. The posteromedial metaphysis, part of the physis, and the epiphysis are intracapsular in the proximal humerus, while a large part of the physis is extracapsular and susceptible to traumatic injury [77]. The physis is irregularly shaped with its apex on the posteromedial portion [77]. The periosteum is thicker and stronger posteromedially than anterolaterally, explaining the tendency of proximal humeral metaphyseal fracture fragments to penetrate the thin anterolateral periosteum [77].
The subscapular bursa lies between the subscapularis tendon and the scapular neck, communicating with the joint cavity between the superior and middle glenohumeral ligaments [74]. It protects the subscapularis tendon as it passes under the coracoid base and over the scapular neck, and is linked to the coracoid by a suspensory ligament [74]. In 28% of specimens, subscapular bursae merged with subcoracoid bursae to form a unique wide bursa [74]. This bursa often houses loose bodies and is a region where synovitis may be most intense, with villi projecting into the joint cavity [74]. DePalma described six types of anterior capsule recesses, which are variations in the opening of the subscapularis bursa [74]: * Type 1 (30.2%): One synovial recess above the middle glenohumeral ligament [74]. * Type 2 (2.0%): One synovial recess below the middle glenohumeral ligament [74]. * Type 3 (40.6%): One recess above and one below the middle glenohumeral ligament [74]. * Type 4 (9.0%): One large recess above the inferior ligament, with the middle glenohumeral ligament absent [74]. * Type 5 (5.1%): The middle glenohumeral ligament manifested as two small synovial folds [74]. * Type 6 (11.4%): No synovial recesses, with all ligaments well defined [74].
DePalma noted that if the capsule arises at the labrum or glenoid border, few recesses are present; if it begins farther medially on the scapula or glenoid neck, recesses are larger and more numerous [74]. He believed these recesses result in a thin, weakened anterior capsule that may predispose the shoulder to instability [74]. The rotator interval is also defined as the region between the superior border of the subscapularis and the anterior border of the supraspinatus, including the superior, coracohumeral, and middle glenohumeral ligaments [74]. Plancher and colleagues found the average area of the rotator interval to be 20.96 mm [74]. Dynamic testing shows that subscapularis and supraspinatus dimensions and the total rotator interval area decrease significantly with internal rotation and open with external rotation [74]. Imbrication procedures are performed with the arm in a neutral position to avoid loss of motion or insufficient tightening [74].
A soft tissue sheath consistently covers the long head of the biceps tendon to the proximal margin of the pectoralis major tendon, contributing to the roof of the bicipital tunnel [74]. The fibro-osseous bicipital tunnel consists of three distinct zones: * Zone 1: The traditional bony bicipital groove, beginning at the articular margin and ending at the distal margin of the subscapularis tendon [74]. * Zone 2: Extends from the distal margin of the subscapularis tendon to the proximal margin of the pectoralis major tendon; this "no man's land" is not viewable from arthroscopy above or subpectoral exposure below [74]. * Zone 3: Distal to the proximal margin of the pectoralis major tendon, representing the subpectoral region [74].
Tendon anatomy includes the infraspinatus and supraspinatus tendons joining approximately 15 mm proximal to insertion, making them difficult to separate by blunt dissection [83]. The infraspinatus and teres minor fuse near their musculotendinous junctions [83]. The supraspinatus and subscapularis tendons join as a sheath surrounding the biceps tendon at the entrance of the bicipital groove, with the supraspinatus forming the roof and the subscapularis forming the floor [83].
Acromioclavicular & Sternoclavicular Joints¶
The acromioclavicular (AC) joint is a diarthrodial joint serving as a primary link between the axial skeleton and the upper extremity [63]. It is a small plane/gliding joint with an interposed fibrocartilaginous disk [73, 85]. The AC joint is movable in all planes and is not a rigid structure, possessing both dynamic and static stabilizers [63]. The complex ligamentous structure is critical to normal shoulder girdle function [63]. The main ligaments are superior, inferior, anterior, and posterior, with the primary function of reinforcing the joint capsule [63]. The posterior and superior AC ligaments are considered the strongest [85].
Static stabilizers of the AC joint include the AC and coracoclavicular (CC) ligaments [63]. The superior and posterior AC ligaments are the primary stabilizers to anterior and posterior (horizontal) translation of the clavicle [73]. The CC ligaments, comprising the medial conoid and lateral trapezoid, are the primary stabilizers to superior (vertical) translation of the distal clavicle [73]. The trapezoid ligament is located approximately 25 mm from the AC joint, while the conoid ligament is located approximately 45 mm away, is posteromedial, and is stronger [85]. Dynamic stabilizers include the deltoid and trapezoid muscles [63].
The normal AC joint translates 4 to 6 mm in the anterior, posterior, and superior planes under 70-N loads [63]. It accommodates rotary motion of 5° to 8° during scapulothoracic motion and 40° to 45° with shoulder abduction and elevation [63]. The trapezoid and conoid ligaments have unique functions in normal shoulder kinematics due to their anatomic attachments [108]. Scapular and clavicular kinematics are affected in AC separation models [114]. Injuries to AC joint structures do not exist in isolation but within the context of the AC joint complex's effect on scapulohumeral rhythm [193]. Pathoanatomy of AC and/or CC ligament injury can affect scapulohumeral rhythm by decoupling the claviscapular segment, altering suspensory and guidance mechanisms, disrupting the AC joint rotational axis, and altering scapular motion [193]. Because scapulohumeral rhythm and AC joint motion are 3D functions, individual injuries in any part of the system can result in 3D dysfunction [193].
The sternoclavicular (SC) joint is the only true diarthrodial articulation between the upper appendicular and axial skeletons [73]. It has double gliding with an articular disc [85]. The posterior SC joint capsule and ligaments are the primary stabilizers to anterior and posterior translation of the medial clavicle [73]. The posterior sternoclavicular ligament is the strongest and primary restraint to anteroposterior instability [85]. The SC joint rotates 30 degrees with shoulder motion [85].
The superior shoulder suspensory complex (SSSC) provides a stable connection between the scapula and the axial skeleton [73]. It is a bone–soft-tissue ring providing a stable connection of the glenoid and scapula to the clavicle [79]. The SSSC is composed of four bony landmarks—distal clavicle, acromion, coracoid process, and glenoid neck—and the supporting ligamentous complexes of the AC joint and the CC ligaments [79]. Specifically, it comprises the glenoid, coracoid process, coracoclavicular ligaments, distal clavicle, AC joint, and acromion [73]. The superior strut of the SSSC comprises the middle clavicle, while the inferior strut comprises the lateral scapular border/spine of the scapula [73].
Classification¶
Acromioclavicular Joint¶
Rockwood: This system classifies acromioclavicular (AC) joint injuries based on the degree and direction of disrupted anatomy [43]. Type I is defined by 0% to <10% superior displacement of the distal clavicle [20]. Type II presents when the affected side differs by 10% to ≤25% [20]. Type III dislocation is characterized by a coracoclavicular distance (CCD) of >25% to ≤100% [20]. A CCD of >100% compared with the contralateral side indicates a type V separation [20]. The modified Rockwood classification system includes deltotrapezial fascial injury in the grading of ACJ injuries [206].
New AC Instability Classification: This system defines Group 1 as having a CCD ≤30%, which includes all Rockwood type I, type II, and borderline low-grade type III patients [20]. Group 2 is defined as having a CCD >30%, representing high-grade AC joint dislocations including all Rockwood type V patients and the majority of Rockwood type III patients [20].
Other Considerations: The spectrum of acromioclavicular injury ranges from sprain to disruption of the AC ligaments, which are typically injured first, and the coracoclavicular ligaments, which are disrupted with more significant force [43]. High-grade acromioclavicular injuries were always based on additional structural damage to the coracoclavicular ligaments [167]. The AC and CC ligaments are the static stabilizers of the acromioclavicular joint, whereas the deltoid and trapezoid muscles are the dynamic stabilizers [63]. The anatomic orientation of the native coracoclavicular ligaments is highly variable in the sagittal plane [214].
Glenohumeral Instability¶
Proposed All-Inclusive Classification: A proposed classification system for shoulder instability challenges previous systems by being all-inclusive and recognizing that more than one pathology can occur in an individual shoulder [41].
Frequency-Aetiology-Direction-Severity Classification: A new classification system for shoulder instability categorizes instability based on frequency, aetiology, direction, and severity [153].
Chronologic Posttraumatic Anterior Instability Classification: A chronologic classification of posttraumatic anterior shoulder instability is based on dynamic pathophysiologic reasoning rather than cataloging complex descriptions of multiple arthroscopic findings [7]. The dynamic progression of labral and ligamentous lesions in posttraumatic anterior shoulder instability suggests a time-dependent, recurrence-dependent worsening of pathology [7]. In a substantial number of patients with a long-standing history of instability, classification of anteroinferior labroligamentous lesions was impossible at arthroscopy because of scar tissue formation and advanced degenerative changes [9].
Other Considerations: Strains in the anteroinferior glenohumeral capsule under subluxation were generally not oriented along major ligamentous bands [42]. Anatomic identification of the type of capsular insertion, split versus broad, is pivotal to the success of an inferior capsular shift [180]. The coracohumeral ligament is more capsular than ligamentous based on its histologic features [18]. The coracoacromial ligament is considered a continuum of the glenohumeral capsule, rather than a typical ligament [159]. Five main types of coracoacromial ligaments were identified, with no statistical correlation found between the ligament type and rotator cuff degeneration [207].
Diagnostic Imaging and Assessment¶
Imaging Accuracy: Ultrasound was wrong in six cases and radiography in 24 cases when comparing grades of acromioclavicular joint injuries against MRI [24]. In 17 cases, ultrasound showed a grade 3 injury suggestive of ruptured coracoclavicular ligaments, which was confirmed on MRI, whilst radiography had given grade 2 [24].
Assessment Principles: It is important to identify all contributing pathoanatomic soft-tissue and bone factors and to take into account the patients' functional demands and activity level for selection of the adequate revision repair procedure [2]. All bony and soft tissue pathology should be identified and assessed in recurrent anterior shoulder instability, with an understanding that simply repeating the steps of the index procedure typically results in poor outcomes [4]. A comprehensive clinical approach emphasizing the evaluation of the extent of the anatomic injury and understanding its mechanical consequences regarding shoulder and arm function is a key in the development of guidelines for operative or non-operative treatment protocols [11]. By integrating recurrence status, bone loss, soft tissue injury and sport type, the 2024 ESSKA–ESA consensus provides a clinically valuable framework for individualized decision-making in traumatic anterior shoulder instability [56].
Clinical Presentation¶
General Assessment & Pathophysiology¶
A comprehensive clinical approach emphasizing the evaluation of the extent of the anatomic injury and understanding its mechanical consequences regarding shoulder and arm function is a key in the development of guidelines for developing operative or non-operative treatment protocols and for establishing outcomes of the treatment protocols [11]. The dynamic progression of labral and ligamentous pathology in dislocation and subluxation disorders suggests a time-dependent, recurrence-dependent worsening [7]. Non-traumatic shoulder instability's aetiologies and clinical manifestations are multifactorial [49]. Shoulder anatomy is particularly complex and requires a thorough knowledge by the orthopedic surgeon, with anatomical variants that should not be confounded with pathological findings [23]. Different anatomical lesions can be found depending on the type of instability and the functional requirements of the patient, so the surgical procedures must be carefully chosen to achieve optimal outcomes when treating shoulder instability [23]. A detailed assessment of soft tissue injury is mandatory as it influences surgical outcomes, with various non-operative and operative options available based on patient characteristics [13]. All bony and soft tissue pathology should be identified and assessed, with an understanding that simply repeating the steps of the index procedure typically results in poor outcomes, and often an ' escalation ' of surgical complexity is required at the time of revision [4]. Nonsurgical treatment is successful in most cases of recurrent posterior shoulder instability, but surgical intervention is indicated when conservative treatment fails, requiring accurate definition of the instability pattern and addressing all soft-tissue and bony injuries [3]. Surgery for posterior shoulder instability focuses on correcting either bony and/or soft tissue anatomy to increase the stability of the joint [25]. Soft-tissue stabilization alone may not be sufficient in patients who present with substantial bone loss to the posterior glenoid and/or the anterior humeral head [46]. Only soft tissue repair without considering the bone defect could be promising in patients with posterior shoulder instability and only a labral tear [47]. The biomechanical stabilization effect of combined AC ligaments and deltotrapezoid fascia injuries is questionable due to quantitatively small differences [8]. Rotator cuff disease, shoulder instability, and associated lesions are common pathologic conditions of the shoulder involving soft tissues [135]. Minor or occult shoulder instability can present as an intra-articular pathology with extra-articular subacromial impingement symptoms [142]. By treating the intra-articular pathology in minor or occult shoulder instability, the extra-articular symptoms can be relieved in the vast majority of patients [142]. The authors propose a classification system for shoulder instability which challenges previous systems by being all inclusive and recognises that more than one pathology can occur in an individual shoulder [41]. Extensive labral lesions can occur even in patients with few previous dislocations, and clinical outcomes can be excellent with appropriate treatment [137]. Patients searching the internet for information regarding shoulder labral pathology often look for facts regarding the diagnosis and management of their conditions [141]. The severity of the capsulo-labral damage and the modality of repair are the main causes of postoperative lack of range of motion in anterior traumatic instability [149]. Postoperative ossifications of the AC joint ligaments are common, but seem to have no influence on the clinical results [147].
Anterior Instability¶
The indications for an isolated soft-tissue procedure in anterior shoulder instability are now narrower; the ideal candidate presents with minimal glenoid bone loss (13.5%) [14]. Age less than 22 years old, ligamentous laxity, the presence of an off-track lesion, and a concomitant SLAP tear were significantly associated with revision failure in anterior shoulder instability [21]. If patients demonstrate symptomatic instability after arthroscopic soft tissue stabilization without evidence of labral retears on imaging scans, an anterior capsular tear should be considered as a possible factor for recurrence [45]. Surgeons should have a heightened suspicion for posterior and combined anteroposterior labral pathology when performing arthroscopic stabilization procedures in young, active individuals [144]. Athletes with an initial instability injury and primary soft-tissue pathology may return to sport within 3 weeks, while those with bone loss, recurrent instability, or an inability to perform sport-specific drills are candidates for surgical stabilization [138]. In cases where significant bony pathology is excluded, the arthroscopic labroplasty procedure has been most successful in restoring joint stability [146]. Bone loss of 20% is a relative indication for a bone augmentation procedure in anterior shoulder instability [145]. Open operative treatment for anterior shoulder instability includes indications such as bone loss, soft tissue deficiencies, and some revision situations [27]. This procedure has the advantages of being an anatomic reconstruction that addresses bony and soft tissue instability [5].
Posterior Instability¶
It is essential to show subtle capsulolabral and ligamentous findings that reduce joint stability in posterior shoulder instability [37].
Acromioclavicular (AC) Joint¶
The clinical evaluation of acute AC joint injury was deferred for 7 to 14 days after injury to minimize the acute pain and swelling and to allow recovery of arm motion [19]. The clinical examination for AC joint injuries consisted of 3 clinical parts—the AC joint examination, the scapular evaluation, and the glenohumeral examination—and also included imaging [19]. The AC joint was palpated for point tenderness and crepitus on motion, and ligament instability was evaluated by manual manipulation of the clavicle and acromion in the inferior-superior and anterior-posterior directions [19]. Increased translation, compared with the uninvolved side, was considered a positive finding for AC joint ligament instability [19]. A positive finding for dynamic AC joint stability was noted if the acromion could be observed to displace around the clavicle with arm motion in flexion and abduction [19]. The clinical history and specific physical examination tests, mainly the modified dynamic labral shear test, were used to identify labral injury associated with AC joint injuries [19]. The spectrum of AC joint injury ranges from sprain to disruption of the AC ligaments, which are typically injured first, and the coracoclavicular (CC) ligaments, which are disrupted with more significant force [43]. The Rockwood classification system is currently almost universally used and is based on the degree and direction of disrupted anatomy [43]. According to the RW classification, the diagnosis of type I was established when 0% to <10% superior displacement of the distal clavicle was found [20]. If the affected side differed by 10% to≤25%, RW type II was present [20]. An RW type III dislocation was defined as a CCD of >25% to≤100% [20]. A CCD of >100% compared with the contralateral side indicated an RW type V separation [20]. A new classification of AC joint instability defined 2 groups that reached the widest and most significant difference in all clinical scoring systems by setting the cutoff at a 30% difference in the CCD compared with the contralateral side [20]. Group 1, with a CCD≤30%, included all RW type I, type II, and borderline lowgrade type III patients (n ¼ 4, 22.2%) [20]. Group 2, defined as having a CCD > 30%, represented the high-grade AC joint dislocations, including all RW type V patients and the majority of the RW type III patients (n 14, 77.8%) [20]. In cases of AC joint ligament disruption, the distal clavicle was displaced posterosuperiorly and overlapping with the acromion was less or nullified [20]. Horizontal translation in AC joint dislocations was graded as none, partial translation, or complete translation [20]. Natural anatomical reconstruction of the CC ligaments has excellent potential to replicate the function of normal ligaments, achieving both maximum therapeutic efficacy and patient satisfaction [6]. Its emphasis on flexible, anatomic ligament reconstruction, combined with favorable early results showing stability, accelerated rehabilitation, and an absence of common hardware complications, positions it as a viable alternative to overcome the drawbacks of established methods [1]. Surgical treatment of high-grade acromioclavicular (AC) joint separations has become analogous to ligament reconstructions elsewhere in the body with the goal being restoration of the native anatomy [44]. Circumferential access to the base of the coracoid is essential to reconstruct the coracoclavicular ligament complex [44]. An arthroscopically assisted reconstruction offers the advantage of less soft tissue dissection and superior visualization to the base of the coracoid [44]. All patients improved subjectively with regard to pain and function at a minimum followup of 3 months (mean, 5 months; range, 3-18 months) in a study of arthroscopically assisted AC joint reconstruction [44]. A total of 16 studies reporting on 327 CC ligament reconstruction procedures were included in a systematic review, with 11 studies (253 cases) reporting a minimum follow-up of 5 years and 5 studies (74 cases) reporting a minimum follow-up of 10 years [10]. Of the included studies in the CC ligament reconstruction systematic review, 2 were level III studies, and 14 were level IV studies [10]. The median sample size was 19 patients (range, 8-50 patients) in the CC ligament reconstruction systematic review [10]. Most studies in the CC ligament reconstruction systematic review originated from the United States (n = 4 [25%]), followed by Germany (n = 2 [13%]), the United Kingdom (n = 2 [13%]), and Japan (n = 2 [13%]) [10]. Europe and Asia were the most-represented continents in the CC ligament reconstruction systematic review, each accounting for 38% of the included studies (n = 6) [10]. According to the MINORS criteria, noncomparative studies had a mean score of 12/16, and comparative studies had a mean score of 16/24, indicating moderate quality of evidence for both study types in the CC ligament reconstruction systematic review [10]. Given that all of the stabilizing structures of the AC joint—the CC ligaments, the AC joint capsule, the deltotrapezial fascia, and the bony articulation—were intact in a case of voluntary dislocation, the senior author did not want to disrupt these structures and selected to augment the intact ligaments with an arthroscopic AC joint reconstruction/ augmentation technique [133]. In a case of voluntary AC joint dislocation, a diagnostic arthroscopy revealed no intra-articular pathology and no labral tear, in contrast with the MRI report [133].
Imaging & Diagnostic Evaluation¶
In a substantial number of patients with a long-standing history of instability, classification of lesions was impossible at arthroscopy because of scar tissue formation and advanced degenerative changes in the labroligamentous complex [9]. MRI or MR-Arthrogram are the best methods for evaluating soft tissue quality, specifically assessing capsular volume, labral ring integrity and labral tissue degeneration (size and signal) (Grade B) [134]. Evaluation of soft tissue quality should also consider medical records (including the time from dislocation and the number of dislocation episodes), the mechanism of injury and the clinical examination (Grade D) [134]. In older adults, the most critical soft tissue lesion is the rotator cuff tear, and the most effective method for evaluating rotator cuff quality is MRI [134]. Ultrasound can also be used to evaluate rotator cuff quality in older adults, but the results depend on the user's experience (Grade B) [134]. The ultrasound, MRI and radiography results were in agreement in 24 of the 47 cases in a study comparing imaging modalities for AC joint injuries [24]. In the other 23 cases of the AC joint imaging comparison study, one of the three imaging techniques had a different grade than the others [24]. Ultrasound was wrong in six cases and radiography in 24 cases in the AC joint imaging comparison study [24]. MRI should not be the imaging modality of first choice for AC joint injuries, but could be useful to clinically assess low-grade injuries that have not settled to exclude higher-grade injury or if there are associated glenohumeral soft tissue injuries [43]. Radiographs are crucial to confirming the diagnosis after dislocation, traumatic or otherwise, and at least 2 views are required to prove a dislocation [39]. After reduction, MRA is used to assess for soft tissue injury in glenoid avulsion of the glenohumeral ligaments [39]. Imaging would show disruption of the capsular fibers with possible extravasation of contrast through the deficiency in glenoid avulsion of the glenohumeral ligaments [39]. MRA can be limited in its clarity and, in the case of a GAGL lesion, may not clearly delineate the separation of the glenohumeral ligaments from the intact labrum, leading to a misdiagnosis of an anterior capsulolabral injury [39]. Because of the possible limitations of MRA, diagnostic arthroscopy with proper portal placement becomes integral to identifying this often-missed pathology in glenoid avulsion of the glenohumeral ligaments [39]. Patients who present with glenohumeral instability undergo a standardized workup including a detailed history and physical as well as advanced imaging to critically assess soft tissues and glenoid bone loss [145]. The exact degree of glenoid bone loss is calculated in each patient and, in conjunction with history and physical examination, used to determine eligibility for the outlined procedure [145]. This article is a review of the evaluation and treatment of rotator cuff pathology, covering anatomy, pathophysiology, clinical presentation, physical examination, and diagnostic testing [38]. This article reviews the pathoanatomy, recognition, and management of shoulder instability in the patient with hypermobile Ehlers-Danlos syndrome, emphasizing the need for a multidisciplinary approach and special considerations due to severe instability and connective tissue abnormalities [139]. This review offers a comprehensive overview of tears of the latissimus dorsi and teres major, including their indications, surgical and nonoperative approaches, and associated outcomes [151].
Investigations¶
Plain radiography: Standardized plain films are almost always sufficient to garner the information needed for shoulder imaging, and there is information that can be gathered from properly taken plain films that cannot be obtained from CT scans [35]. The purpose of imaging is to help establish the diagnosis, determine the severity of the pathoanatomy, assist in surgical planning, and enable the surgeon to illustrate the condition of the shoulder to the patient [35]. Unless a specific research protocol is in place, the temptation to “overimage” should be resisted, obtaining only the scans or reconstructions that are necessary for the care of the patient [35]. At least two X-ray views should be obtained for shoulder imaging: an anteroposterior view in the plane of the glenoid and an axillary projection with the arm in abduction to show the relationship of the humeral head to the glenoid [89]. The standard shoulder radiographic series should include a true AP view in the scapular plane, an AP view, an axillary view, and a scapular Y view [102]. The first key radiographic view is the anteroposterior (AP) view in the plane of the scapula taken so that the x-ray beam passes through the glenohumeral joint [35]. The AP view in the plane of the scapula shows the superoinferior position of the humeral head relative to the glenoid, presence of osteophytes, narrowing of the joint space, degree of medial displacement of the humerus, quality of bone, presence of loose bodies, and humeral head collapse or deformity [35]. The second key radiographic view is the axillary view taken with the arm in the functional position of elevation in the plane of the scapula [35]. The axillary view is referred to as the “truth view” because it demonstrates the glenohumeral relationships in the functional position of elevation [35]. The axillary view is a necessary view in the evaluation of glenohumeral joint instability and enables determination of the humeral head position in the glenoid fossa [102]. The axillary view may detect occult, locked posterior shoulder dislocation in a patient who exhibits a lack of passive external rotation [102]. The standardized axillary view enables measurement of posterior subluxation or “functional decentering” that is not evident in images taken with the arm at the side [35]. The degree of posterior subluxation can be measured as the position of the center of the humeral head in relation to the plane of the scapula, the position of the center of the humeral head in relation to the glenoid face, or the point of contact of the humeral articular surface on the glenoid articular surface [35]. The point of contact of the humeral articular surface on the glenoid articular surface reflects the degree of centering of the net humeral joint reaction force on the glenoid [35]. Malcentering of the joint reaction force leads to posterior instability, posterior glenoid wear, and “rocking horse” loosening of prosthetic glenoid components [35].
Special radiographic views are indicated for specific pathologies. The Zanca view is a special radiographic view indicated for the acromioclavicular joint, performed as an AP with 10° cephalic tilt centered over the AC joint [102]. The West Point view is a special radiographic view indicated for anterior glenoid bone loss, performed with the patient prone and the involved shoulder raised above table level [102]. The Stryker notch view is a special radiographic view indicated to evaluate Hill-Sachs lesions after dislocation [102]. The apical oblique view is a special radiographic view indicated to evaluate for glenoid rim fracture in instability [102]. Focal cortical bone loss at the inferior aspect of the glenoid appears to be a new radiographic sign of damage to the anterior capsular mechanism [205]. For acromioclavicular dislocations, post-traumatic radiography includes bilateral anteroposterior stress views with a 10-kg axial load and bilateral stress views according to Alexander [20]. The coracoclavicular distance (CCD) is measured as the interspace between the inferior cortex of the clavicle and the highest part of the coracoid, parallel to the spine [20]. The normal coracoclavicular distance is 1.1 to 1.3 cm [102]. In a new classification of AC joint instability, a cutoff at a 30% difference in the CCD compared with the contralateral side defined two groups that reached the widest and most significant difference in all clinical scoring systems [20]. Group 1 of the new AC joint instability classification includes patients with a CCD ≤30%, comprising all RW type I, type II, and borderline low-grade type III patients [20]. Group 2 of the new AC joint instability classification includes patients with a CCD >30%, representing high-grade AC joint dislocations including all RW type V patients and the majority of RW type III patients [20]. Distal clavicle translation on bilateral Alexander views is graded as none, partial translation, or complete translation in cases of AC joint ligament disruption [20].
For proximal humerus fractures, the Neer trauma series consists of an AP view, a lateral view in the scapular plane, and a Velpeau modified axillary view [93]. The lateral radiograph in the scapular plane is the tangential Y-view of the scapula [93]. The combination of the three views in the Neer trauma series allows evaluation of the shoulder joint in three separate perpendicular planes [93]. The axillary view in the Neer trauma series is important for evaluating the glenoid articular surface and the relationship of the humeral head anteriorly and posteriorly [93].
CT: CT imaging is frequently used to evaluate fractures of the shoulder, assess for bony lesions in recurrent instability cases, or for preoperative templating for shoulder arthritis [99]. CT with three-dimensional reconstructions is the advanced imaging study of choice for determining the extent of glenoid bone loss in the setting of shoulder instability [102]. Three-dimensional sagittal CT scans allow for optimal evaluation of displaced glenoid fractures [102]. Three-dimensional sagittal CT scans show anterior glenoid bone deficiency in the setting of shoulder instability [102]. Despite the advantages of MRI in the detection of soft tissue damages in recurrent anterior shoulder instability, CT imaging proved to be more important for glenoid defects [183]. Accurate imaging and assessment of the size and relations of bone defects are crucial for further treatment planning in bony-mediated shoulder instability [218]. Appropriate preoperative imaging is essential for detection and quantification of osseous abnormalities, and treatment decisions should be guided by the extent of osseous deficiency and patient-specific factors [202]. Advanced imaging modalities are essential for identifying associated lesions, and bony reconstruction procedures should be considered for patients with significant glenoid bone loss or recurrent instability after soft tissue reconstruction [148]. CT scans may offer a few degrees of increased precision in the measurement of glenoid version, but this precision does not necessarily improve the quality of the surgery or the clinical outcome [35]. CT scans have the disadvantage of being taken with the arm in the adducted position, unlike the axillary truth view [35].
MRI: MRI is useful to identify osteonecrosis of the humeral head, or a bone tumour [89]. MRI is the modality of choice for evaluating the rotator cuff, biceps, and subacromial/subdeltoid bursa [99]. MRI can identify labral tears and rotator cuff tears, although the accuracy for these is enhanced by combining the scan with arthrography [89]. T1-weighted MRI can reveal Hill-Sachs lesions and is often used with magnetic resonance (MR) arthrograms to provide a more detailed picture of the joint surfaces [99]. T2-weighted MRI provides better visualization of full thickness rotator cuff tears [99]. Traditional magnetic resonance imaging (MRI) is a diagnostic tool to complement both physical examination and standard radiographs in the management of patients with anterior shoulder instability [96]. MRI is utilized for evaluation of soft tissues, which can be performed with high contrast and spatial resolution [96]. The acquired multi-planar imaging of MRI allows for the detailed evaluation of the glenoid, labrum, joint capsule, and rotator cuff in different planes [96]. MR accuracy in identifying labral and rotator cuff tears in the literature ranges from 70% to 100% [96]. MRI is a valid imaging tool to diagnose and measure osseous lesions of the shoulder in adolescents [220]. Careful history and physical examination are critical in the diagnosis of HAGL lesions, with MRI being the best imaging study [231].
MR Arthrography: MR arthrography (MRA) refers to MRI of a joint that has been injected with an intra-articular contrast agent such as diluted gadolinium or saline solution [96]. The contrast material for MRA is injected prior to MRI by fluoroscopic or ultrasound guidance under strict aseptic technique [96]. By distending the joint capsule, the cartilage, ligaments, and labrum are outlined with contrast, increasing the sensitivity for detecting tears and other lesions [96]. MR arthrography is considered the benchmark for evaluation for labral tears and rarely is indicated for evaluation of rotator cuff pathology [99]. When MRI or MR arthrography is contraindicated, CT arthrography is indicated [99]. In the acute dislocation setting, a joint effusion with distension of the joint may outline structures similarly, making the arthrogram unnecessary [96]. MRA has proven utility by increasing both sensitivity and specificity in detecting injuries to the capsulolabral–ligamentous complex as compared to traditional MRI [96]. In a meta-analysis of 6 studies including 4,667 shoulders, MRA had greater diagnostic test accuracy for the detection of glenoid labral lesions than MRI, with MRA sensitivity of 88% and specificity of 93% versus MRI sensitivity of 76% and specificity of 87% [96]. With standard MRI or MRA, the shoulder is routinely positioned in neutral or partial external rotation, but other alternative positions can be used to increase the sensitivity for detecting labroligamentous injuries [96]. Abduction and external rotation (ABER) of the arm is an alternative position utilized to increase the sensitivity and specificity for detecting anteroinferior labroligamentous injury [96]. Limited ROM or pain may prohibit patients from performing the ABER provocative maneuver [96]. Schreinemachers et al. found that full routine MRI or MRA examination had similar accuracy as the ABER sequence in evaluating the anteroinferior labral–ligamentous complex [96]. Tian et al. found that the sensitivity of MRA with the ABER position for detecting anteroinferior labral lesions was significantly higher than that of the MRA in neutral position and more effective in identifying Perthes lesions [96]. MRAs can demonstrate a patulous capsule on the coronal, sagittal, and axial imaging in patients with multidirectional instability (MDI) [96]. MRAs can be helpful in evaluating lesions of the rotator interval and other associated findings that may ultimately affect the eventual surgical plan [96]. The presence of glenoid dysplasia, increased capsular cross-sectional area, and increased glenoid retroversion have all been found to be associated with increased posterior labral tears and symptomatic instability [96]. Glenoid retroversion was significantly increased in patients with symptomatic posterior labral tears, but there was no significant association between instability and increased humeral head subluxation [96]. The diagnosis of multidirectional instability (MDI) is a clinical one, and the need for expensive and/or invasive imaging should be weighed against the information that will be gained from these studies [96]. Identification of critical radiographic variables on magnetic resonance arthrography assists in the accurate diagnosis and management of clinically significant posterior shoulder instability [230]. The sensitivity, specificity, and reliability of magnetic resonance arthrogram for detecting Kim's lesions in posterior shoulder instability are substantial, while the interobserver reliability of Kim's classification is fair [211]. After reduction of a dislocation, MRA is used to assess for soft tissue injury, showing disruption of the capsular fibers with possible extravasation of contrast through the deficiency [39]. Because of the possible limitations of MRA, diagnostic arthroscopy with proper portal placement becomes integral to identifying GAGL pathology [39]. Careful interpretation of MR arthrograms and thorough diagnostic arthroscopy are essential to identify posterior humeral avulsion of the glenohumeral ligaments [189]. Substantial tears of the anterior capsule in cases of recurrent anterior shoulder instability can be diagnosed by arthro-CT [233]. MDCT arthrography showed better accuracy than MR arthrography in the detection of osseous, cartilage, and labroligamentous injuries related to anterior shoulder instability [235]. Axial T2-weighted MRI of the shoulder with intra-articular contrast shows anterior labral pathology, with contrast fluid leaking between the glenoid bone and the labral tissue consistent with a labral tear [102].
Ultrasonography: Ultrasound is a simple and accurate test for identifying rotator cuff tears and calcific tendinitis [89]. Ultrasonography is a low-cost alternative to MRI and arthrography for evaluating both skeletal and soft-tissue structures of the shoulder [99]. Ultrasonography can provide immediate, real-time visualization of the rotator cuff, biceps tendon, and calcific deposits [99]. Ultrasound can be useful in guiding injections or barbotage (aspirating calcific deposits in the rotator cuff) [89]. Ultrasonography can be used to measure the subacromial space and detect atrophy of rotator cuff muscles [99]. As a result of providing images in real-time, ultrasonography can evaluate impingement in various positions and motions [99]. Ultrasonography is highly operator dependent and is not as useful for evaluating labral tears or rotator cuff tears that are very small or larger than 3 cm [99]. The most commonly performed joint examination using ultrasonography is the shoulder examination, and accuracy depends on the skill of the scanner operator and an awareness of pitfalls that are encountered [87]. In a comparison of radiography, ultrasound, and MRI for acromioclavicular joint injuries, the results were in agreement in 24 of the 47 cases [24]. In the comparison of radiography, ultrasound, and MRI for acromioclavicular joint injuries, ultrasound was wrong in six cases and radiography in 24 cases [24]. In 17 cases of acromioclavicular joint injury, ultrasound showed a grade 3 injury suggestive of ruptured coracoclavicular ligaments, which was confirmed on MRI, whilst radiography had given grade 2 [24]. Coronal ultrasonographic images can visualize intact and torn supraspinatus tendons [102]. The sensitivity of ultrasonography for the detection of full-thickness rotator cuff tears is 98% [102]. The specificity of ultrasonography for the detection of full-thickness rotator cuff tears is 80% [102]. The positive predictive value of ultrasonography for the detection of full-thickness rotator cuff tears is 90% [102]. The negative predictive value of ultrasonography for the detection of full-thickness rotator cuff tears is 95% [102]. The accuracy of ultrasonography for the detection of full-thickness rotator cuff tears is 94% [102]. The sensitivity of MRI for the detection of full-thickness rotator cuff tears is 100% [102]. The specificity of MRI for the detection of full-thickness rotator cuff tears is 68% [102].
Other Considerations: Coronal T2-weighted MRIs of the shoulder can visualize normal rotator cuff insertion, partial-thickness rotator cuff tears, full-thickness nonretracted rotator cuff tears, and massive retracted rotator cuff tears [102]. Sagittal T1-weighted MRIs of the shoulder can visualize normal infraspinatus musculature and fatty infiltration of the infraspinatus muscle [102]. Axial T2-weighted MRI of the shoulder and chest can show a complete tear of the pectoralis major tendon [102]. Axial T2-weighted MRI of the shoulder can show medial dislocation of the biceps tendon, empty bicipital groove, and subscapularis tear [102].
Treatment¶
Non-Operative¶
Nonoperative management is the accepted standard for low-grade acromioclavicular (AC) joint injuries (types I and II) [53]. For type III AC joint injuries, literature indicates no significant difference between operative and nonoperative treatment, with one specific study showing no strength difference at 2-year follow-up [53]. A review of 2000 patients with type III AC joint injuries showed satisfactory outcomes for nonoperative versus operative treatment to be 87% and 88%, respectively [53]. Consequently, there is a slight trend toward initial conservative management for type III AC joint injuries [53]. At a minimum 5-year follow-up, patients with successful non-operative treatment for type III-V ACJ injuries achieved similar clinical outcomes compared to those who were converted to anatomic coracoclavicular ligament reconstruction (ACCR) [174]. The author urges clinicians to err on the conservative side when possible until better evidence defines when surgery is necessary for unstable acromioclavicular injuries [164].
For posterior shoulder instability, nonsurgical treatment is successful in most cases, but surgical intervention is indicated when conservative treatment fails [3]. However, nonoperative treatment is commonly unsuccessful in active patients with posterior shoulder instability, and surgical stabilization can be considered in patients who do not respond [132]. Conservative therapies for posterior shoulder instability include guided rehabilitation focusing on strengthening exercises and range of motion [152]. Patients with a chief complaint of pain were much more likely to succeed with nonoperative treatment of posterior shoulder labral tears, while those with instability were more likely to undergo surgical management [55].
Regarding anterior shoulder instability, recent studies continue to demonstrate a role for nonoperative treatment in the successful long-term management of anterior glenohumeral instability [165]. Treatment algorithms have traditionally included a period of non-operative management in all patients, however young athletic patients may often benefit from early operative treatment [140]. In a survey of 32 NHL team physicians, 28 preferred nonoperative management for the treatment of initial anterior shoulder dislocations with isolated soft tissue injuries [177]. Data suggests conservative management is highly effective for patients whose goal is to return to the same level of sport in the next season, calling into question routine fixation for first-time dislocators [178]. While nonoperative treatment is associated with faster return to play, operative management is associated with fewer recurrent instability events, greater time between recurrent instability events, and greater career longevity in NFL athletes [168]. Primary non-operative management is a prominent risk factor for recurrence of shoulder instability [51]. Level II evidence suggests that recurrence is lower in patients managed with surgical as compared with conservative management for shoulder instability [176].
Specific protocols exist for other injuries. Following nonsurgical management of type V AC injuries, most patients are able to return to work but have limited functional outcome scores [160]. A specific non-operative protocol exists for the in-season management of AC injuries to quickly and safely return athletes to play [150]. A Rockwood type V injury can be treated conservatively using an AC joint brace for six weeks in combination with a restrictive physiotherapy program [170]. Conservative treatment can be used as the first-line therapy for secondary frozen shoulder after traumatic anterior shoulder instability, followed by effective arthroscopic mobilization when conservative treatment fails [156]. Mild ligamentous sprains (grade I) of the sternoclavicular (SC) joint are stable and are always treated conservatively with ice and immobilization in a sling for 1 to 2 weeks, followed by early range-of-motion exercises [163]. Grade II SC joint sprains require a longer course of immobilization (3 to 6 weeks) in a sling or a soft figure-of-eight bandage, and a full recovery can be expected [163]. Anterior SC joint dislocations (grade III sprain) are considered unstable injuries, and if identified within 48 hours of initial dislocation, the treatment of choice is a closed reduction [163]. In non-massive rotator cuff ruptures, an intensive reparative process coming up from the subacromial bursa may have a protective role if the bursa is left on the suture [169].
Operative¶
Indications: Surgical intervention for recurrent posterior shoulder instability is indicated when conservative treatment fails, requiring accurate definition of the instability pattern and addressing all soft-tissue and bony injuries [3]. High-grade ACJ disruptions (types IV-VI) are managed surgically through a variety of procedures ranging from simple plate and screw fixation to more complex procedures involving ligament repair, transfer, and reconstruction [53]. The failure rate in contact athletes with recurrent anterior shoulder instability using a soft tissue procedure alone is high [30]. It is important to identify all contributing pathoanatomic soft-tissue and bone factors and to take into account the patients' functional demands and activity level for selection of the adequate revision repair procedure for recurrent anterior shoulder instability [2]. Repair and reconstruction indications should be properly assessed on patients to ensure functions returned to their pre-injury state which is important for athletes' return to sports [61]. By integrating recurrence status, bone loss, soft tissue injury and sport type, the 2024 ESSKA–ESA consensus provides a clinically valuable framework for individualized decision-making for traumatic anterior shoulder instability [56].
Surgical Approach / Technique: The goals of surgical treatment of ACJ injuries are anatomic reduction and restoration of normal arthrokinematics to minimize complications including pain, loss of reduction, arthrosis, and decreased extremity function [53]. Surgical options for ACJ disruptions can be performed through both open and/or newer arthroscopically assisted techniques, underscoring the lack of consensus about the ideal management of these injuries [53]. An arthroscopy-assisted all-suture adjustable system for anatomic reduction of AC joint separation emphasizes flexible, anatomic ligament reconstruction and has shown favorable early results showing stability, accelerated rehabilitation, and an absence of common hardware complications [1]. Treatment of AC dislocation by synthetic ligament reconstruction gave satisfactory results, notably in terms of recovery of strength, but evolution is not risk-free with onset of significant early osteolysis [22]. Biologic soft-tissue reconstruction techniques for the floating clavicle (ipsilateral AC and SC joint dislocation) offer robust time zero strength and a diminished complication profile [15]. Combined anatomic reconstruction of both AC and CC ligaments using nylon tape provides overall 88.2% satisfaction, 94% radiologic reduction, and a low complication rate [185]. Comparable subjective outcomes after surgical treatment of AC joint instability were reported for all modalities, with relatively low unplanned reoperation rates [186]. An arthroscopically assisted technique using a subacromial approach to pass suture material and a tendon graft around the coracoid offers the advantage of less soft tissue dissection and superior visualization to the base of the coracoid compared to traditional open approaches [44]. In a preliminary series of 10 patients undergoing arthroscopically assisted coracoclavicular ligament reconstruction for high-grade AC separation, all patients improved subjectively with regard to pain and function at a minimum followup of 3 months (mean, 5 months; range, 3-18 months) [44]. Future surgical approaches for AC joint reconstruction should systematically evaluate and address both CC ligament-mediated vertical stability and AC ligament-mediated horizontal stability to optimize clinical outcomes [187]. The biomechanical differences in stabilization effect of combined AC ligaments and deltotrapezoid fascia (DTF) injuries were quantitatively small, so that the clinical relevance of the DTF's stabilization effect is questionable [8]. Protection of the repair with a sling for 6 weeks significantly improved functional and anatomical results in the surgical treatment of chronic acromioclavicular dislocations [65].
For anterior instability, there is no one procedure that fits all patients with anterior instability; surgeons should individualize their approach based on patients' bone changes, soft tissue quality, activity requirements, and surgical experience to maximize success and reduce complications [29]. Achieving the best result for any particular patient depends on the procedure that allows observation of the joint surfaces, provides the anatomical repair, maintains range of motion, and can be applied with low rates of complications and recurrence [28]. Regardless of which procedure is chosen by a surgeon, the treatment should follow guidelines taught by Rowe: anatomic dissection, identification and repair of the lesions responsible for the instability, returning tissues to their anatomic locations, and early postoperative range of motion [59]. A comprehensive clinical approach emphasizing the evaluation of the extent of the anatomic injury and understanding its mechanical consequences regarding shoulder and arm function is a key in the development of guidelines for developing operative or non-operative treatment protocols [11]. Long-term clinical studies demonstrate good clinical outcomes of patients operated with a Mason–Allen labral repair for recurrent anterior shoulder instability [16]. Arthroscopic ligamentoplasty is advantageous in preserving the patient's native anatomy, maintaining joint integrity, and allowing for alternative interventions in case of failure [62]. The crucial advantage of arthroscopic suture repair as a primary or even as a revision technique for shoulder instability is based on its capacity of a real anatomic repair and of a physiological tensioning of the ligamentous restraints with respect to its course [32]. Arthroscopic soft tissue stabilization combined with selected augmentations provided good clinical outcomes for competitive collision athletes, characterized by low rates of recurrence and complication, a high rate of return to sports, and good shoulder function [155]. Soft tissue stabilization combined with selective augmentation procedures for shoulder instability in collision athletes demonstrated satisfactory outcomes with low recurrence rate [166]. Soft tissue stabilization combined with selective augmentation procedures for traumatic shoulder instability in collision athletes demonstrated satisfactory outcomes with extremely low recurrence rate [179]. In a case series with 1 year follow-up, 20 patients who underwent arthroscopic labrum repair with the addition of a dermal allograft for anterior shoulder instability had a significant improvement in outcome scores, and excellent incorporation of the graft as seen on MRI [33]. Arthroscopic anatomic glenoid reconstruction using distal tibial allograft for recurrent anterior shoulder instability has the advantages of being an anatomic reconstruction that addresses bony and soft tissue instability [5]. The arthroscopic transfer of the long head of the biceps brachii for anterior shoulder instability is indicated for patients younger than 45 years with specific activity requirements or capsule-ligament insufficiency, and for patients 45 years or older with combined SLAP lesions [54]. Capsular reconstruction has emerged as an option for the management of instability with poor quality or absent capsular tissue [175]. Recurrent instability does not vary by region but occurs more frequently following soft-tissue compared to bony stabilization procedures [17].
For posterior instability, operative treatment can be divided into two broad groups: soft-tissue repair and osseous stabilization [152]. Unanimous consensus was reached on relative indications for nonoperative management and labral repair, as well as steps to minimize complications for labral repair in posterior shoulder instability [48]. Overall, 77% of statements reached unanimous or strong consensus, covering patient history evaluation, prognostic factors for nonoperative management, and Bankart repair steps in anterior shoulder instability [52]. This case demonstrates a clear indication for the usefulness of diagnostic and therapeutic arthroscopy in the situation of soft tissue instability complicating a previously successful total shoulder arthroplasty [58].
Implant Selection: In the surgical treatment of acute type-V AC injuries using a Dacron graft, the coracoclavicular ligaments are never sutured or reconstructed, and the torn muscle attachments of the deltoid and trapezius muscles are carefully repaired [162].
Alignment / Balancing Strategy: Surgery for acute type-V acromioclavicular injuries in athletes is performed within 24 h of injury with the patient under general anesthesia [162].
Pain Management: No specific analgesic regimens are detailed in the provided evidence.
Adjuncts: No specific adjunctive technologies are detailed in the provided evidence.
Setting of Care: No specific setting of care data is provided in the evidence.
Revision: Noncompliance with immobilization, rehabilitation, or return to activity restrictions constitutes a fairly common and preventable cause of recurrent instability following arthroscopic stabilization [172]. Several investigators have found higher failure rates in patients inadequately immobilized postoperatively, serving to justify current protocols recommending 3 to 6 weeks of immobilization for arthroscopic stabilization [172]. Rarely, patients are permitted to return to sport before 3 months after arthroscopic stabilization surgery, with contact or collision athletes usually restricted for 4 to 6 months after surgery [172]. Regarding immediate postoperative protocol for revision shoulder instability surgery using distal tibial allograft and osteochondral allograft, the patient is to remain non-weightbearing on the affected upper extremity with no active range of motion of the shoulder for 2 weeks [173]. Patients undergoing revision shoulder instability surgery with allografts are immobilized in an Ultra Sling at all times but allowed to come out of the sling for elbow range of motion [173].
Other Considerations: Postoperative protocols vary by procedure. Postoperatively for acute type-V AC injury surgery using a Dacron graft, the extremity is protected in a broad arm sling for 6 weeks, with isometric and pendulum exercises started a few days after surgery and active mobilization allowed after 6 weeks [162]. Patients undergoing endoscopically assisted reconstruction of acute AC joint dislocation using a synthetic ligament are immobilized for 4 weeks with the elbow against the body in a light removable sling, with passive hanging movements authorized beginning the 1st postoperative day [161]. Patients undergoing AC joint reconstruction with 360-degree control are immobilized in a neutral sling for 2 weeks, with passive and active-assisted mobilization commenced immediately postoperatively and active mobilization permitted from 2 weeks without restriction [158]. No weight-bearing is allowed on the affected extremity during the first 4-week period after AC joint reconstruction with 360-degree control, with light strengthening beginning at 4 weeks and return to full activities including contact sport as early as 6 weeks [158]. Rehabilitation for anatomic coracoclavicular ligament reconstruction involves wearing an abduction sling fulltime for 6 weeks with only pendulum exercises allowed, initiating range of motion exercises at 6 weeks postoperatively, and beginning strengthening exercises at approximately 3 months [171]. The arm is placed in a sling for comfort for a few days after radiofrequency capsular shrinkage for voluntary shoulder instability, with motion allowed avoiding extremes in all directions for the first 6 weeks [136]. Proprioceptive physiotherapy is initiated within the first week after surgery for radiofrequency capsular shrinkage for voluntary shoulder instability [136]. In a systematic review of 16 studies reporting on 327 CC ligament reconstruction procedures, 11 studies (253 cases) reported a minimum follow-up of 5 years and 5 studies (74 cases) reported a minimum follow-up of 10 years [10]. The median sample size in the systematic review of CC ligament reconstruction was 19 patients (range, 8-50 patients) [10]. According to MINORS criteria, noncomparative studies in the CC ligament reconstruction systematic review had a mean score of 12/16, and comparative studies had a mean score of 16/24, indicating moderate quality of evidence for both study types [10].
Complications¶
Anterior Shoulder Instability¶
Recurrent Instability: Recurrent instability occurs more frequently following soft-tissue stabilization procedures compared to bony stabilization procedures [17]. Long-term results of arthroscopic Bankart repair suggest higher than optimal recurrence and revision rates, especially in patients younger than 23 years old, despite using modern suture anchor and capsular tightening techniques [209]. A history of multiple instability episodes prior to presentation is the greatest predictor of recurrent instability and failure of nonoperative treatment [67]. The failure rate is high when treating recurrent anterior shoulder instability in contact athletes with a soft tissue procedure alone [30].
Risk Factors: Age less than 22 years old, ligamentous laxity, the presence of an off-track lesion, and a concomitant SLAP tear are significantly associated with revision failure after arthroscopic anterior stabilization [21]. Characteristics related to a history of instability, including age <20 years at the first instability episode, a larger number of dislocations, and ≥2 years between the first dislocation and surgery, are risk factors for the development of an off-track Hill-Sachs lesion [68]. Poor quality of the soft tissues surrounding the glenohumeral joint, whether caused by multiple previous operations, multiple subluxation or dislocation episodes, or an underlying connective tissue disorder, has the potential to threaten the success of any shoulder stabilization procedure [192].
Clinical Course: The dynamic progression of labral and ligamentous pathology suggests a time-dependent, recurrence-dependent worsening in dislocation and subluxation disorders [7]. Patients with hyperlaxity and instability are more likely to experience episodes of recurrent subluxation than they are to have recurrent dislocation [192]. In a study of Australian Rules Football players, instability-related complications occurred only in the capsulolabral group, and the incidence increased with time [181]. The most disabling failures in open stabilization occurred when internal fixation was performed too soon after soft-tissue healing [190]. An age of at least 30 years at the time of diagnosis and surgical intervention are identified as risk factors for developing symptomatic arthritis at long-term follow-up after posterior shoulder instability [69].
Acromioclavicular Joint¶
Hardware and Graft Complications: Treatment of acromioclavicular dislocation by synthetic ligament reconstruction carries a risk of significant early osteolysis [22]. AC joint reconstruction with the LARS system has a surgical revision rate of 8.5% at long-term follow-up [60]. A case report documented distal clavicle tunnel widening after coracoclavicular ligament reconstruction with a semitendinous autograft tendon, with no definite detrimental effect on functional outcome at more than 2 years' follow-up [57]. An Arthroscopy-Assisted All-Suture Adjustable System for acromioclavicular joint separation showed an absence of common hardware complications in early results [1].
Surgical Strategy: Coracoclavicular ligament augmentation is recommended to decrease complications for Rockwood type V acromioclavicular separation treated by hook plate [191]. Biologic soft-tissue reconstruction techniques for the floating clavicle offer a diminished complication profile [15]. Double disruptions of the superior shoulder suspensory complex create an unstable anatomic situation with adverse long-term consequences including delayed union, malunion, nonunion, impingement, decreased strength, fatigue muscle discomfort, neurovascular compromise, and degenerative joint disease [182].
General Soft Tissue & Ligament Considerations¶
Anatomical Variants: Anatomical variants should not be confounded with pathological findings when treating shoulder instability [23]. No long-term disability results from the loss of the coraco-acromial ligament from its normal site [50].
Recovery¶
Anterior Shoulder Instability¶
Other Considerations: Long-term outcome data for the Bankart procedure indicate that the most common patient complaints are decreased range of motion and intermittent pain, rather than recurrent instability [200]. In professional football players, surgical stabilization restores the rate and timing of instability to that of players with no prior history of instability [239]. Following repair of humeral and glenoid detachment of the anterior inferior glenohumeral ligament, no patients experienced instability after an average follow-up of 26 months [222]. At long-term follow-up of 17 years, a high rate of poor outcomes was observed following nonoperative management of anterior shoulder instability [198]. The combination of arthroscopic remplissage and classic Bankart repair for recurrent anterior shoulder instability with engaging Hill–Sachs lesions has long-term outcomes in terms of recurrence rate and does not significantly influence the range of motion of the shoulder [194]. In a case series with 1 year follow-up, 20 patients who underwent arthroscopic labrum repair with the addition of a dermal allograft had a significant improvement in outcome scores and excellent incorporation of the graft as seen on MRI [33].
Acromioclavicular Joint¶
Other Considerations: An arthroscopy-assisted all-suture adjustable system for anatomic reduction of acromioclavicular joint separation showed favorable early results including stability, accelerated rehabilitation, and an absence of common hardware complications [1]. Natural anatomical reconstruction of the coracoclavicular ligaments has excellent potential to replicate the function of normal ligaments, achieving both maximum therapeutic efficacy and patient satisfaction [6]. Biologic soft-tissue reconstruction techniques for the floating clavicle offer robust time zero strength and a diminished complication profile [15]. Treatment of acromioclavicular dislocation by synthetic ligament reconstruction gave satisfactory results in terms of recovery of strength, but evolution is not risk-free with the onset of significant early osteolysis [22]. Acromioclavicular joint reconstruction with the LARS achieves good-to-excellent clinical and functional outcomes at long-term follow-up with a surgical revision rate of 8.5% [60]. Coracoclavicular reconstruction using a semitendinosus tendon graft provides a satisfactory result in revision cases by replicating the course of the original coracoclavicular ligaments [66]. The addition of a semitendinosus graft to a suture reconstruction concept provides long-term stability to the reconstruction of the coracoclavicular ligamentous complex [212]. Excellent results were obtained and maintained over long-term follow-up for continuous loop double endobutton reconstruction for acromioclavicular joint dislocation [215]. The short-term follow-up of 15 patients treated with minimally invasive coracoclavicular ligament augmentation using a flip button/polydioxanone repair revealed excellent radiologic and clinical results, with no subluxations or dislocations of the acromioclavicular joint noted [237]. Although follow-up periods were less than 1 year, all patients treated with free tissue graft reconstruction of the acromioclavicular joint were satisfied with their surgery and demonstrated good reduction of the acromioclavicular joint on radiographs [238]. At a minimum 2-year follow-up period, four patients treated with acromioclavicular joint reconstruction using clavicular corticotomy showed the coracoclavicular interval improved by an average of 12.5 mm and restored to within 2 mm of the normal side on stress radiographs [240]. Early repairs of complete acromioclavicular dislocations within 3 weeks showed a trend for better results and return to sports or heavy labor compared to late reconstructions, though this was not statistically significant in the overall comparison [241]. A case of tunnel widening after coracoclavicular ligament reconstruction with a semitendinous autograft tendon noted no definite detrimental effect on the functional outcome at more than 2 years' follow-up [57].
Posterior Shoulder Instability¶
Other Considerations: Long-term follow-up demonstrates that nearly 40% of patients treated non-operatively for posterior shoulder instability eventually require surgery [208]. Patients who underwent surgery for posterior shoulder instability at any time point were at an increased risk of radiographic progression of arthritis at a minimum of 5 years of follow-up [236].
Key Evidence¶
- [L4] Its emphasis on flexible, anatomic ligament reconstruction, combined with favorable early results showing stability, accelerated rehabilitation, and an absence of common hardware complications, positions it as a viable alternative to overcome the drawbacks of established methods. [1] (10.1016/j.eats.2025.103906)
- [L5] It is important to identify all contributing pathoanatomic soft-tissue and bone factors and to take into account the patients' functional demands and activity level for selection of the adequate revision repair procedure. [2] (10.2106/jbjs.st.k.00023)
- [L5] Nonsurgical treatment is successful in most cases, but surgical intervention is indicated when conservative treatment fails, requiring accurate definition of the instability pattern and addressing all soft-tissue and bony injuries. [3] (10.5435/00124635-200608000-00004)
- [L4] Specifically, all bony and soft tissue pathology should be identified and assessed, with an understanding that simply repeating the steps of the index procedure typically results in poor outcomes, and often an ' escalation ' of surgical complexity is required at the time of revision. [4] (10.1007/s12178-020-09612-4)
- [L4] This procedure has the advantages of being an anatomic reconstruction that addresses bony and soft tissue instability. [5] (10.1177/0363546520960119)
- [L4] Natural anatomical reconstruction of the CC ligaments has excellent potential to replicate the function of normal ligaments, achieving both maximum therapeutic efficacy and patient satisfaction. [6] (10.1007/s00264-010-1124-3)
- [L3] [7] (10.1016/s1058-2746(99)90058-7)
- [L5] These differences were quantitatively small, so that the clinical relevance of the stabilization effect of combined AC ligaments and DTF injuries is questionable. [8] (10.1007/s00402-015-2389-1)
- [L2] In a substantial number of patients with a long-standing history of instability, classification of lesions was impossible at arthroscopy because of scar tissue formation and advanced degenerative changes in the labroligamentous complex. [9] (10.1148/radiol.2372041429)
- [L4] [10] (10.1177/03635465261457302)
- [L5] A comprehensive clinical approach emphasizing the evaluation of the extent of the anatomic injury and understanding its mechanical consequences regarding shoulder and arm function is a key in the development of guidelines for developing operative or non-operative treatment protocols and for establishing outcomes of the treatment protocols. [11] (10.1177/17585732221122335)
- [L5] A detailed assessment of soft tissue injury is mandatory as it influences surgical outcomes, with various non-operative and operative options available based on patient characteristics. [13] (10.1177/2325967121s00835)
- [Paper] The indications for an isolated soft-tissue procedure in anterior shoulder instability are now narrower; the ideal candidate presents with minimal glenoid bone loss (13.5%). [14] (10.2106/jbjs.rvw.26.00033)
- [L5] Biologic soft-tissue reconstruction techniques, such as those described in the present chronicle, offer robust time zero strength and a diminished complication profile. [15] (10.1016/j.eats.2023.01.006)
- [Paper] Long-term clinical studies demonstrate good clinical outcomes of patients operated with a Mason–Allen labral repair. [16] (10.1016/j.eats.2021.04.018)
- [L2] Recurrent instability does not vary by region but occurs more frequently following soft-tissue compared to bony stabilization procedures. [17] (10.1016/j.xrrt.2023.08.005)
- [L5] The coracohumeral ligament is more capsular than ligamentous based on its histologic features. [18] (10.1016/j.jse.2008.07.012)
- [L4] [19] (10.1016/j.arthro.2016.08.023)
- [L1] [20] (10.1016/j.jse.2020.10.026)
- [L3] Age less than 22 years old, ligamentous laxity, the presence of an off-track lesion, and a concomitant SLAP tear were significantly associated with revision failure. [21] (10.1016/j.arthro.2018.10.083)
- [L4] Treatment of ACD by synthetic ligament reconstruction gave satisfactory results, notably in terms of recovery of strength, but evolution is not risk-free with onset of significant early osteolysis. [22] (10.1016/j.otsr.2010.06.004)
- [L2] [24] (10.1007/s00330-016-4413-4)
- [L5] Surgery focuses on correcting either bony and/or soft tissue anatomy to increase the stability of the joint. [25] (10.1016/j.csm.2013.07.011)
- [L5] These include bone loss, softtissue deficiencies, and some revision situations. [27] (10.1197/j.jht.2005.04.011)
- [L4] Achieving the best result for any particular patient depends on the procedure that allows observation of the joint surfaces, provides the anatomical repair, maintains range of motion, and also can be applied with low rates of complications and recurrence. [28] (10.12998/wjcc.v2.i11.676)
- [L5] There is no one procedure that fits all patients with anterior instability; surgeons should individualize their approach based on patients' bone changes, soft tissue quality, activity requirements, and surgical experience to maximize success and reduce complications. [29] (10.1016/j.arthro.2017.09.028)
- [L5] The failure rate in these situations with a soft tissue procedure alone is high. [30] (10.1016/j.ocl.2014.09.005)
- [L3] Coracoclavicular ligament reconstruction is a relatively common and safe procedure in a physically active population. [31] (10.1177/2325967121s00708)
- [L4] The crucial advantage of arthroscopic suture repair as a primary or even as a revision technique is based on its capacity of a real anatomic repair and of a physiological tensioning of the ligamentous restraints with respect to its course. [32] (10.1016/s1058-2746(96)80315-6)
- [L4] In the case series with 1 year follow-up, 20 patients who underwent arthroscopic labrum repair with the addition of a dermal allograft had a significant improvement in outcome scores, and excellent incorporation of the graft as seen on MRI. [33] (10.1016/j.arthro.2024.11.027)
- [L5] It is essential to show subtle capsulolabral and ligamentous findings that reduce joint stability. [37] (10.1016/j.mric.2019.12.005)
- [L5] This article is a review of the evaluation and treatment of rotator cuff pathology, covering anatomy, pathophysiology, clinical presentation, physical examination, and diagnostic testing. [38] (10.1016/j.pop.2013.08.006)
- [Paper] [39] (10.1016/j.eats.2019.06.001)
- [L5] The authors propose a classification system, which challenges previous systems by being all inclusive and recognises that more than one pathology can occur in an individual shoulder. [41] (10.1016/j.cuor.2004.04.002)
- [Paper] Strains were generally not oriented along major ligamentous bands. [42] (10.1067/mse.2002.127093)
- [L1] [43] (10.1016/j.injury.2015.10.060)
- [L4] [44] (10.1007/s11999-007-0085-3)
- [L3] If patients demonstrate symptomatic instability after arthroscopic soft tissue stabilization without evidence of labral retears on imaging scans, an anterior capsular tear should be considered as a possible factor for recurrence. [45] (10.1177/2325967121995891)
- [L5] Soft-tissue stabilization alone may not be sufficient in patients who present with substantial bone loss to the posterior glenoid and/or the anterior humeral head. [46] (10.2106/jbjs.rvw.23.00243)
- [L4] Therefore, only soft tissue repair without considering the bone defect could be promising in this patient group. [47] (10.1016/j.jse.2023.06.032)
- [L5] Unanimous consensus was reached on relative indications for nonoperative management and labral repair, as well as steps to minimize complications for labral repair. [48] (10.1016/j.arthro.2024.04.035)
- [L5] Non-traumatic shoulder instability's aetiologies and clinical manifestations are multifactorial. [49] (10.1177/17585732251320070)
- [L4] No long term disability results from the loss of the coraco-acromial ligament from its normal site. [50] (10.1016/s0020-1383(80)80045-3)
- [L2] Primary non-operative management is a prominent risk factor for recurrence of shoulder instability. [51] (10.1136/bjsports-2016-096895)
- [L5] Overall, 77% of statements reached unanimous or strong consensus, covering patient history evaluation, prognostic factors for nonoperative management, and Bankart repair steps. [52] (10.1016/j.arthro.2021.07.022)
- [L4] [53] (10.1016/j.jse.2009.12.014)
- [Paper] The procedure is indicated for patients younger than 45 years with specific activity requirements or capsule-ligament insufficiency, and for patients 45 years or older with combined SLAP lesions. [54] (10.1016/j.eats.2017.07.009)
- [L3] Patients with a chief complaint of pain were much more likely to succeed with nonoperative treatment while those with instability were more likely to undergo surgical management. [55] (10.1093/milmed/usaa122)
- [L2] By integrating recurrence status, bone loss, soft tissue injury and sport type, the consensus provides a clinically valuable framework for individualized decision-making. [56] (10.1002/ksa.70497)
- [L5] The authors present a case of tunnel widening after CC ligament reconstruction with a semitendinous autograft tendon, noting no definite detrimental effect on the functional outcome at more than 2 years' follow-up. [57] (10.1016/j.jse.2005.02.019)
- [L5] This case demonstrates a clear indication for the usefulness of diagnostic and therapeutic arthroscopy in the situation of soft tissue instability complicating a previously successful total shoulder arthroplasty. [58] (10.1007/s11420-013-9373-5)
- [L5] Regardless of which procedure is chosen by a surgeon, the treatment should follow the guidelines taught by Rowe: anatomic dissection, identification and repair of the lesions responsible for the instability, returning tissues to their anatomic locations, and early postoperative range of motion. [59] (10.1177/03635465030310011001)
- [L4] AC joint reconstruction with the LARS achieves good-to-excellent clinical and functional outcomes at long-term follow-up with a surgical revision rate of 8.5%. [60] (10.1016/j.otsr.2018.02.010)
- [L5] Repair and reconstruction indications should be properly assessed on patients to ensure functions returned to their pre-injury state which is important for athletes' return to sports. [61] (10.1177/2325967121s00842)
- [L2] Arthroscopic ligamentoplasty is advantageous in preserving the patient's native anatomy, maintaining joint integrity, and allowing for alternative interventions in case of failure. [62] (10.1186/s13018-025-06422-7)
- [L4] [63] (10.1302/2058-5241.3.170027)
- [L3] Protection of the repair with a sling for 6 weeks significantly improved functional and anatomical results. [65] (10.1016/j.otsr.2015.09.002)
- [L4] Coracoclavicular reconstruction using a semitendinosus tendon graft provides a satisfactory result in revision cases by replicating the course of the original coracoclavicular ligaments. [66] (10.1016/j.jse.2006.10.009)
- [L3] A history of multiple instability episodes prior to presentation was the greatest predictor of recurrent instability and failure of nonoperative treatment and progression to surgery. [67] (10.1016/j.asmr.2023.03.014)
- [L3] Characteristics related to a history of instability (age <20 years at first instability episode, larger number of dislocations, ≥2 years between first dislocation and surgery) were found to be risk factors for the development of an off-track HS lesion. [68] (10.1177/23259671231213858)
- [L3] Although uncommon, an age of at least 30 years at the time of diagnosis and surgical intervention were identified as risk factors for developing symptomatic arthritis at long-term follow-up. [69] (10.1177/23259671221112973)
- [L5] The trapezoid and conoid ligaments have unique functions in normal shoulder kinematics because of their anatomic attachments. [108] (10.1016/j.arthro.2009.12.031)
- [L5] Scapular and clavicular kinematics were affected in AC separation models. [114] (10.1016/j.jse.2013.01.004)
- [L5] In healthy adult shoulders, ligamentous structures are not fully elongated in many positions but function as restraints at the extremes of motion. [125] (10.1186/1749-799x-7-29)
- [L4] Nonoperative treatment is commonly unsuccessful in active patients, and surgical stabilization can be considered in patients who do not respond. [132] (10.1177/1941738116672446)
- [Case_report] [133] (10.1016/j.jse.2019.03.039)
- [L2] [134] (10.1002/ksa.70336)
- [L4] [136] (10.1016/j.jse.2005.11.011)
- [L3] Extensive labral lesions can occur even in patients with few previous dislocations, and clinical outcomes can be excellent with appropriate treatment. [137] (10.1007/s00167-012-2045-z)
- [L5] Athletes with an initial instability injury and primary soft-tissue pathology may return to sport within 3 weeks, while those with bone loss, recurrent instability, or an inability to perform sport-specific drills are candidates for surgical stabilization. [138] (10.5435/jaaos-20-08-518)
- [L5] This article reviews the pathoanatomy, recognition, and management of shoulder instability in the patient with hypermobile Ehlers-Danlos syndrome, emphasizing the need for a multidisciplinary approach and special considerations due to severe instability and connective tissue abnormalities. [139] (10.1016/j.xrrt.2021.03.002)
- [L4] Treatment algorithms have traditionally included a period of non-operative management in all patients, however young athletic patients may often benefit from early operative treatment. [140] (10.1007/s12178-011-9092-9)
- [L4] Patients searching the internet for information regarding shoulder labral pathology often look for facts regarding the diagnosis and management of their conditions. [141] (10.1016/j.asmr.2024.100983)
- [L3] By treating the intra-articular pathology, the extra-articular symptoms can be relieved in the vast majority of patients. [142] (10.1007/s00167-011-1552-7)
- [L3] Surgeons should have a heightened suspicion for posterior and combined anteroposterior labral pathology when performing arthroscopic stabilization procedures in young, active individuals. [144] (10.1097/corr.0000000000001530)
- [Paper] [145] (10.1016/j.eats.2019.09.016)
- [L5] In cases where significant bony pathology is excluded, the arthroscopic labroplasty procedure has been most successful in restoring joint stability. [146] (10.1111/j.1758-5740.2010.00099.x)
- [L4] Postoperative ossifications of the AC joint ligaments are common, but seem to have no influence on the clinical results. [147] (10.1055/s-2008-1038577)
- [Paper] Advanced imaging modalities are essential for identifying associated lesions, and bony reconstruction procedures should be considered for patients with significant glenoid bone loss or recurrent instability after soft tissue reconstruction. [148] (10.1016/j.csm.2014.06.006)
- [L4] The severity of the capsulo-labral damage and the modality of repair are the main causes of postoperative lack of ROM. [149] (10.1016/s1058-2746(95)80139-1)
- [L4] This study represents a specific non-operative protocol for the in-season management of AC injuries to quickly and safely return athletes to play. [150] (10.1177/2325967117s00381)
- [L5] This review offers a comprehensive overview of these uncommon injuries, including their indications, surgical and nonoperative approaches, and associated outcomes. [151] (10.1016/j.xrrt.2025.05.015)
- [L4] [152] (10.2106/jbjs.rvw.n.00090)
- [L5] The system categorizes instability based on frequency, aetiology, direction, and severity. [153] (10.1136/bjsm.2009.071183)
- [L4] The treatment strategy of arthroscopic soft tissue stabilization combined with selected augmentations provided good clinical outcomes for competitive collision athletes, characterized by low rates of recurrence and complication, a high rate of return to sports, and good shoulder function. [155] (10.1177/03635465211003091)
- [L4] Conservative treatment can be used as the first-line therapy, followed by effective arthroscopic mobilization when conservative treatment fails. [156] (10.1016/j.jses.2019.10.100)
- [L4] [158] (10.1097/bte.0000000000000167)
- [L5] It is considered a continuum of the G-H capsule, rather than a typical ligament. [159] (10.1016/s1058-2746(95)80336-x)
- [L4] Following nonsurgical management of type V AC injuries, most patients are able to return to work but have limited functional outcome scores. [160] (10.5435/jaaos-d-16-00176)
- [L4] [161] (10.1016/j.otsr.2010.10.004)
- [L4] [162] (10.1007/bf00662287)
- [Paper] [163] (10.1016/s0278-5919(02)00112-6)
- [L5] The author urges clinicians to err on the conservative side when possible until better evidence defines when surgery is necessary. [164] (10.1016/j.arthro.2018.03.022)
- [L4] Recent studies continue to demonstrate a role for nonoperative treatment in the successful long-term management of anterior glenohumeral instability. [165] (10.1007/s12178-017-9432-5)
- [L4] Soft tissue stabilization combined with selective augmentation procedures for shoulder instability in collision athletes demonstrated satisfactory outcomes with low recurrence rate. [166] (10.1177/2325967119s00270)
- [L5] High-grade injuries were always based on additional structural damage to the coracoclavicular ligaments. [167] (10.1007/s00402-014-2045-1)
- [L3] Whereas nonoperative treatment is associated with faster return to play, operative management is associated with fewer recurrent instability events, greater time between recurrent instability events, and greater career longevity. [168] (10.1016/j.arthro.2020.12.225)
- [L4] In non-massive ruptures, an intensive reparative process is coming up from the bursa and leaving it on the suture may have a protective role. [169] (10.1016/s1058-2746(95)80182-0)
- [L4] [170] (10.1007/s00402-020-03630-0)
- [L4] [171] (10.1177/0363546516651613)
- [L5] [172] (10.1016/s0278-5919(05)70183-6)
- [L4] [173] (10.1016/j.eats.2021.12.013)
- [L4] At a minimum 5-year follow-up, patients with successful non-operative treatment for type III-V ACJ injuries achieved similar clinical outcomes compared to those who were converted to ACCR. [174] (10.1007/s00167-020-06159-2)
- [L5] Capsular reconstruction has emerged as option for the management of instability with poor quality or absent capsular tissue. [175] (10.1007/s12178-019-09569-z)
- [L2] Level II evidence suggests that recurrence is lower in patients managed with surgical as compared with conservative management. [176] (10.1197/j.jht.2004.02.010)
- [L4] Of the 32 NHL team physicians surveyed, 28 preferred nonoperative management for the treatment of initial anterior shoulder dislocations with isolated soft tissue injuries, while initial operative management was preferred by the same number of team physicians for any injuries with bony involvement. [177] (10.1177/23259671241271704)
- [L3] The data suggests conservative management is highly effective for patients whose goal is to return to the same level of sport in the next season, calling into question routine fixation for first-time dislocators. [178] (10.1177/2325967117s00284)
- [L4] Soft tissue stabilization combined with selective augmentation procedures for traumatic shoulder instability in collision athletes demonstrated satisfactory outcomes with extremely low recurrence rate. [179] (10.1177/2325967119s00192)
- [L5] Anatomic identification of the type of capsular insertion, split versus broad, is pivotal to the success of an inferior capsular shift (ICS). [180] (10.1016/j.jse.2004.04.014)
- [L3] Instability-related complications occurred only in the capsulabral group, and the incidence increased with time. [181] (10.1177/03635465211029022)
- [L5] Double disruptions of the SSSC create a very unstable anatomic situation with adverse long term healing and functional consequences (delayed union/malunion/nonunion; impingement; decreased strength and fatigue muscle discomfort; neurovascular compromise; degenerative joint disease). [182] (10.1016/s1058-2746(95)80217-7)
- [L3] Despite the advantages of MRI in the detection of soft tissue damages in recurrent anterior shoulder instability CT imaging proved to be more important for glenoid defects. [183] (10.1007/s00402-012-1656-7)
- [L4] Combined anatomic reconstruction of both AC and CC ligaments using nylon tape by the described technique provides overall 88.2% satisfaction, 94% radiologic reduction, and a low complication rate. [185] (10.1016/j.arthro.2012.02.001)
- [L1] Comparable subjective outcomes after surgical treatment of AC joint instability were reported for all modalities, with relatively low unplanned reoperation rates. [186] (10.1016/j.arthro.2018.01.016)
- [L5] Future surgical approaches should systematically evaluate and address both CC ligament-mediated vertical stability and AC ligament-mediated horizontal stability to optimize clinical outcomes. [187] (10.5397/cise.2025.00843)
- [Case_report] Careful interpretation of MR arthrograms and thorough diagnostic arthroscopy are essential to identify this rare lesion. [189] (10.1016/j.jse.2006.09.009)
- [L4] The most disabling failures occurred when internal fixation was performed too soon after soft-tissue healing, highlighting the importance of surgical judgment regarding timing. [190] (10.2106/jbjs.m.01524)
- [L3] Therefore, CC ligament augmentation is highly recommended to improve short-term outcomes and decrease complications for Rockwood type V AC separation treated by hook plate. [191] (10.1186/s12891-020-03726-z)
- [Paper] [192] (10.1016/j.csm.2017.12.001)
- [L5] [193] (10.5435/jaaos-d-24-00360)
- [L4] This combination has long-term outcomes in terms of the recurrence rate and does not significantly influence the range of motion of the shoulder. [194] (10.1007/s00167-018-5261-3)
- [L4] At long-term follow-up of 17 years, a high rate of poor outcomes was observed following nonoperative management of anterior shoulder instability. [198] (10.1016/j.jse.2021.07.016)
- [Paper] A long-term outcome report on the Bankart procedure found that the most common complaint of patients was not recurrent instability but decreased range of motion and intermittent pain. [200] (10.1016/s0278-5919(05)70182-4)
- [L5] Appropriate preoperative imaging is essential for detection and quantification of osseous abnormalities, and treatment decisions should be guided by the extent of osseous deficiency and patient-specific factors. [202] (10.2106/jbjs.j.00906)
- [L4] This pattern of bone loss, although small and uncommon, appears to be a new radiographic sign of damage to the anterior capsular mechanism. [205] (10.1016/1058-2746(92)90092-h)
- [L5] These findings validate the inclusion of deltotrapezial fascial injury being considered in the grading of ACJ injuries as outlined by the modified Rockwood classification system. [206] (10.1177/23259671221118943)
- [L4] Five main types of coracoacromial ligaments were identified, with no statistical correlation found between the ligament type and rotator cuff degeneration. [207] (10.1016/j.jse.2007.05.015)
- [L3] Long-term follow-up demonstrates that nearly 40% of patients treated non-operatively for posterior shoulder instability eventually require surgery. [208] (10.1177/2325967118s00098)
- [L4] Long-term results suggest higher than optimal recurrence and revision rates, especially in patients younger than 23 years old, despite using modern day suture anchor and capsular tightening techniques. [209] (10.1016/j.jisako.2023.03.343)
- [L4] The sensitivity, specificity, and reliability of magnetic resonance arthrogram for detecting these lesions are substantial, while the interobserver reliability of Kim's classification is fair. [211] (10.1016/j.arthro.2014.02.038)
- [L4] The addition of a semitendinosus graft to the previously reported suture reconstruction concept adds biologic fixation to the construct, thus providing long-term stability to the reconstruction of the coracoclavicular ligamentous complex. [212] (10.1016/j.arthro.2006.10.005)
- [L5] The anatomic orientation of the native coracoclavicular ligaments is highly variable in the sagittal plane. [214] (10.1016/j.jse.2019.11.034)
- [L4] Excellent results were obtained and maintained over long-term follow-up. [215] (10.1177/0363546515596409)
- [L4] Accurate imaging and assessment of the size and relations of bone defects are crucial for further treatment planning. [218] (10.1302/2058-5241.5.200049)
- [L4] Additionally, MRI is a valid imaging tool to diagnose and measure osseous lesions of the shoulder. [220] (10.1007/s00247-018-4318-2)
- [L5] Further studies involving more subjects with long-term results are needed to guide future surgical indications. [221] (10.1097/bte.0000000000000090)
- [L4] None of the patients has had instability after an average follow-up of 26 months. [222] (10.1016/s1058-2746(97)90064-1)
- [L4] The proposed mini-open technique provides adequate exposure of the base of the coracoid with minimal damage to the soft tissues surrounding the CC ligaments while ensures an excellent cosmetic result. [227] (10.1016/j.injury.2013.01.002)
- [L5] The authors believe the technique has advantages including efficient individualized plication, greater confidence in reduction of capsular laxity, and reduced risk to neurovascular structures due to control of soft tissue penetration depth. [228] (10.1016/j.eats.2025.103794)
- [L3] Identification of these critical radiographic variables on magnetic resonance arthrography assists in the accurate diagnosis and management of clinically significant posterior shoulder instability. [230] (10.1177/0363546516660076)
- [L5] Careful history and physical examination are critical in the diagnosis of HAGL lesions, with MRI being the best imaging study. [231] (10.5435/00124635-201103000-00001)
- [L4] Substantial tears of the anterior capsule in cases of RASI can be diagnosed by arthro-CT. [233] (10.1016/s1058-2746(95)80231-2)
- [L2] MDCT arthrography showed better accuracy than did MR arthrography in the detection of osseous, cartilage, and labroligamentous injuries related to anterior shoulder instability. [235] (10.2214/ajr.11.7251)
- [L3] Patients who underwent surgery at any time point were at an increased risk of radiographic progression of arthritis at a minimum of 5 years of follow-up. [236] (10.1016/j.arthro.2019.01.056)
- [L4] The short-term follow-up of 15 recently operated patients reveals excellent radiologic and clinical results, with no subluxations or dislocations of the acromioclavicular joint noted. [237] (10.1016/j.arthro.2006.12.015)
- [L4] Although the follow-up periods are less than 1 year, all patients are satisfied with their surgery and demonstrate good reduction of the AC joint on radiographs. [238] (10.1097/bte.0b013e31818a5dd9)
- [L3] Surgical stabilization appears to restore the rate and timing of instability to that of players with no prior history of instability. [239] (10.1177/1941738112472156)
- [L4] At a minimum 2-year follow-up period, in four patients the coracoclavicular interval was improved an average of 12.5 mm and was restored to within 2 mm of the normal side on stress radiographs. [240] (10.1016/s1058-2746(05)80068-0)
- [L4] Early repairs (within 3 weeks) showed a trend for better results and return to sports or heavy labor compared to late reconstructions, though this was not statistically significant in the overall comparison. [241] (10.1177/036354659502300313)
See Also¶
- Rotator Cuff
- Shoulder Instability
- Fractures
- Shoulder Arthritis
- Calcific Tendinitis
- Frozen Shoulder
- Total shoulder arthroplasty
- Internal Fixation
References¶
[1] An Arthroscopy‐Assisted All‐Suture Adjustable System for Anatomic Reduction of Acromioclavicular Joint Separation: N‐way Technique. Arthroscopy Techniques. 2025. DOI: 10.1016/j.eats.2025.103906
[2] Arthroscopic Capsulolabral Revision Repair for Recurrent Anterior Shoulder Instability. JBJS Essential Surgical Techniques. 2012. DOI: 10.2106/jbjs.st.k.00023
[3] Recurrent Posterior Shoulder Instability. Journal of the American Academy of Orthopaedic Surgeons. 2006. DOI: 10.5435/00124635-200608000-00004
[4] Management of Recurrent Anterior Shoulder Instability After Surgical Stabilization in Children and Adolescents. Current Reviews in Musculoskeletal Medicine. 2020. DOI: 10.1007/s12178-020-09612-4
[5] Arthroscopic Anatomic Glenoid Reconstruction Using Distal Tibial Allograft for Recurrent Anterior Shoulder Instability: Clinical and Radiographic Outcomes. The American Journal of Sports Medicine. 2020. DOI: 10.1177/0363546520960119
[6] Arthroscopically assisted anatomical coracoclavicular ligament reconstruction using tendon graft. International Orthopaedics. 2010. DOI: 10.1007/s00264-010-1124-3
[7] Evolution of lesions of the labrum-ligament complex in posttraumatic anterior shoulder instability: A prospective study. Journal of Shoulder and Elbow Surgery. 1999. DOI: 10.1016/s1058-2746(99)90058-7
[8] The biomechanical influence of the deltotrapezoid fascia on horizontal and vertical acromioclavicular joint stability. Archives of Orthopaedic and Trauma Surgery. 2016. DOI: 10.1007/s00402-015-2389-1
[9] Anterior Shoulder Instability: Accuracy of MR Arthrography in the Classification of Anteroinferior Labroligamentous Injuries. Radiology. 2005. DOI: 10.1148/radiol.2372041429
[10] Mid- to Long-term Outcomes of Coracoclavicular Ligament Reconstruction for Acromioclavicular Joint Dislocations: A Systematic Review of Studies With Minimum 5-Year Follow-up. The American Journal of Sports Medicine. 2026. DOI: 10.1177/03635465261457302
[11] Acromioclavicular joint injuries revisited: Pathoanatomy, pathomechanics, and clinical presentation. Shoulder & Elbow. 2022. DOI: 10.1177/17585732221122335
[13] Decision-Making in Anterior Shoulder Instability. Orthopaedic Journal of Sports Medicine. 2023. DOI: 10.1177/2325967121s00835
[14] Current Approaches to Arthroscopic Management of Anterior Shoulder Instability. JBJS Reviews. 2026. DOI: 10.2106/jbjs.rvw.26.00033
[15] The Floating Clavicle: Surgical Technique for Management of an Ipsilateral Acromioclavicular and Sternoclavicular Joint Dislocation. Arthroscopy Techniques. 2023. DOI: 10.1016/j.eats.2023.01.006
[16] Modified Mason–Allen Knot for Arthroscopic Complex Bankart Lesion Repair in Recurrent Anterior Shoulder Instability. Arthroscopy Techniques. 2021. DOI: 10.1016/j.eats.2021.04.018
[17] Global variations in treatment and outcomes reported for anterior shoulder instability: a systematic review of the literature. JSES Reviews, Reports, and Techniques. 2023. DOI: 10.1016/j.xrrt.2023.08.005
[18] An anatomic and histologic study of the coracohumeral ligament. Journal of Shoulder and Elbow Surgery. 2009. DOI: 10.1016/j.jse.2008.07.012
[19] Treatment of Symptomatic Acromioclavicular Joint Instability by a Docking Technique: Clinical Indications, Surgical Technique, and Outcomes. Arthroscopy. 2016. DOI: 10.1016/j.arthro.2016.08.023
[20] The ligamentous injury pattern in acute acromioclavicular dislocations and its impact on clinical and radiographic parameters. Journal of Shoulder and Elbow Surgery. 2021. DOI: 10.1016/j.jse.2020.10.026
[21] Risk Factors for Recurrent Shoulder Instability after Arthroscopic Revision Anterior Stabilization. Arthroscopy. 2018. DOI: 10.1016/j.arthro.2018.10.083
[22] Acute grade III and IV acromioclavicular dislocations: Outcomes and pitfalls of reconstruction procedures using a synthetic ligament. Orthopaedics & Traumatology: Surgery & Research. 2010. DOI: 10.1016/j.otsr.2010.06.004
[23] 360° Around Shoulder Instability. 2020.
[24] Ultrasound of the coracoclavicular ligaments in the acute phase of an acromioclavicular disjonction: Comparison of radiographic, ultrasound and MRI findings. European Radiology. 2016. DOI: 10.1007/s00330-016-4413-4
[25] Posterior Shoulder Instability in the Contact Athlete. Clinics in Sports Medicine. 2013. DOI: 10.1016/j.csm.2013.07.011
[27] Open Operative Treatment for Anterior Shoulder Instability: When and Why?. Journal of Hand Therapy. 2005. DOI: 10.1197/j.jht.2005.04.011
[28] Recurrent anterior shoulder instability: Review of the literature and current concepts. World Journal of Clinical Cases. 2014. DOI: 10.12998/wjcc.v2.i11.676
[29] Editorial Commentary: We Need to Customize Surgical Treatment When Treating Patients With Recurrent Anterior Shoulder Instability. Arthroscopy. 2018. DOI: 10.1016/j.arthro.2017.09.028
[30] The Latarjet-Patte Procedure for Recurrent Anterior Shoulder Instability in Contact Athletes. Orthopedic Clinics of North America. 2015. DOI: 10.1016/j.ocl.2014.09.005
[31] Poster 147: Operative Treatment of Acromioclavicular Injuries in the Military: Trends and Complications. Orthopaedic Journal of Sports Medicine. 2022. DOI: 10.1177/2325967121s00708
[32] Arthroscopic revision surgery in shoulder instability. Journal of Shoulder and Elbow Surgery. 1996. DOI: 10.1016/s1058-2746(96)80315-6
[33] Podium Presentation Title: Clinical Outcomes for Dermal Allograft Glenoid Augmentation for Anterior Shoulder Instability. Arthroscopy. 2025. DOI: 10.1016/j.arthro.2024.11.027
[35] Rockwood And Matsen S The Shoulder. Arthroscopic Management of Prearthritic and Arthritic Conditions of the Shoulder and the Postarthroplasty Shoulder > Radiographic Evaluation.
[37] Posterior Shoulder Instability. Magnetic Resonance Imaging Clinics of North America. 2020. DOI: 10.1016/j.mric.2019.12.005
[38] The Evaluation and Treatment of Rotator Cuff Pathology. Primary Care: Clinics in Office Practice. 2013. DOI: 10.1016/j.pop.2013.08.006
[39] Understanding the Glenoid Avulsion of the Glenohumeral Ligaments as a Cause of Shoulder Instability: Surgical and Postsurgical Management. Arthroscopy Techniques. 2019. DOI: 10.1016/j.eats.2019.06.001
[41] (ii) The classification of shoulder instability: new light through old windows!. Current Orthopaedics. 2004. DOI: 10.1016/j.cuor.2004.04.002
[42] Neer Award 2001: Nonrecoverable strain fields of the anteroinferior glenohumeral capsule under subluxation. Journal of Shoulder and Elbow Surgery. 2002. DOI: 10.1067/mse.2002.127093
[43] Is AC TightRope fixation better than Bosworth screw fixation for minimally invasive operative treatment of Rockwood III AC joint injury?. Injury. 2015. DOI: 10.1016/j.injury.2015.10.060
[44] A Modified Technique of Arthroscopically Assisted AC Joint Reconstruction and Preliminary Results. Clinical Orthopaedics & Related Research. 2008. DOI: 10.1007/s11999-007-0085-3
[45] Failure Rates After Revision Arthroscopic Stabilization for Recurrent Anterior Shoulder Instability Based on Anterior Capsulolabral Complex Conditions. Orthopaedic Journal of Sports Medicine. 2021. DOI: 10.1177/2325967121995891
[46] Management of Bone Loss in Posterior Glenohumeral Shoulder Instability. JBJS Reviews. 2024. DOI: 10.2106/jbjs.rvw.23.00243
[47] Does glenoid bone loss accompany posterior shoulder instability with only labral tear? A magnetic resonance imaging–based study. Journal of Shoulder and Elbow Surgery. 2023. DOI: 10.1016/j.jse.2023.06.032
[48] Posterior Shoulder Instability, Part I—Diagnosis, Nonoperative Management, and Labral Repair for Posterior Shoulder Instability—An International Expert Delphi Consensus Statement. Arthroscopy. 2024. DOI: 10.1016/j.arthro.2024.04.035
[49] Assessment and diagnosis of non-traumatic shoulder instability: A scoping review. Shoulder & Elbow. 2025. DOI: 10.1177/17585732251320070
[50] Disruption of the acromioclavicular joint: surgical anatomy and biological reconstruction. Injury. 1980. DOI: 10.1016/s0020-1383(80)80045-3
[51] Recurrence and return to play after shoulder instability events in young and adolescent athletes: a systematic review and meta-analysis. British Journal of Sports Medicine. 2016. DOI: 10.1136/bjsports-2016-096895
[52] Anterior Shoulder Instability Part I—Diagnosis, Nonoperative Management, and Bankart Repair—An International Consensus Statement. Arthroscopy. 2021. DOI: 10.1016/j.arthro.2021.07.022
[53] Arthroscopic stabilization of acromioclavicular joint dislocation using the AC graftrope system. Journal of Shoulder and Elbow Surgery. 2010. DOI: 10.1016/j.jse.2009.12.014
[54] Arthroscopic Transfer of the Long Head of the Biceps Brachii for Anterior Shoulder Instability. Arthroscopy Techniques. 2017. DOI: 10.1016/j.eats.2017.07.009
[55] Risk Factors for Failure of Nonoperative Treatment of Posterior Shoulder Labral Tears on Magnetic Resonance Imaging. Military Medicine. 2020. DOI: 10.1093/milmed/usaa122
[56] Age‐ and time‐specific management of traumatic anterior shoulder instability: The 2024 ESSKA–ESA Formal Consensus. Part 2: Treatment and return to sports. Knee Surgery, Sports Traumatology, Arthroscopy. 2026. DOI: 10.1002/ksa.70497
[57] Distal clavicle tunnel widening after coracoclavicular ligament reconstruction with semitendinous tendon: A case report. Journal of Shoulder and Elbow Surgery. 2006. DOI: 10.1016/j.jse.2005.02.019
[58] Shoulder Instability after Total Shoulder Arthroplasty: A Case of Arthroscopic Repair. HSS Journal®: The Musculoskeletal Journal of Hospital for Special Surgery. 2014. DOI: 10.1007/s11420-013-9373-5
[59] Open Repairs for the Treatment of Anterior Shoulder Instability. The American Journal of Sports Medicine. 2003. DOI: 10.1177/03635465030310011001
[60] The use of the LARS system in the treatment of AC joint instability – Long-term results after a mean of 7.4 years. Orthopaedics & Traumatology: Surgery & Research. 2018. DOI: 10.1016/j.otsr.2018.02.010
[61] Acromioclavicular Joint Problem in Athletes. Orthopaedic Journal of Sports Medicine. 2023. DOI: 10.1177/2325967121s00842
[62] Shoulder ligamentoplasty, arthroscopic Latarjet, dynamic anterior stabilization, and arthroscopic Trillat for the treatment of shoulder instability: a systematic review of original studies on surgical techniques. Journal of Orthopaedic Surgery and Research. 2025. DOI: 10.1186/s13018-025-06422-7
[63] Acromioclavicular joint injuries: diagnosis, classification and ligamentoplasty procedures. EFORT Open Reviews. 2018. DOI: 10.1302/2058-5241.3.170027
[65] Prognostic factors to succeed in surgical treatment of chronic acromioclavicular dislocations. Orthopaedics & Traumatology: Surgery & Research. 2015. DOI: 10.1016/j.otsr.2015.09.002
[66] Acromioclavicular reconstruction using autogenous semitendinosus tendon graft: Results of revision surgery in chronic cases. Journal of Shoulder and Elbow Surgery. 2007. DOI: 10.1016/j.jse.2006.10.009
[67] Patients Aged >50 Years With Anterior Shoulder Instability Have a Decreased Risk of Recurrent Dislocation After Operative Treatment Compared With Non‐Operative Treatment. Arthroscopy, Sports Medicine, and Rehabilitation. 2023. DOI: 10.1016/j.asmr.2023.03.014
[68] Association of Instability History and Off-Track Hill-Sachs Lesions in Anterior Shoulder Instability. Orthopaedic Journal of Sports Medicine. 2023. DOI: 10.1177/23259671231213858
[69] Patient Age and Surgical Intervention as Risk Factors for the Development of Osteoarthritis After Posterior Shoulder Instability: A Population-Based Study. Orthopaedic Journal of Sports Medicine. 2022. DOI: 10.1177/23259671221112973
[70] Rockwood And Matsen S The Shoulder. Shoulder and Elbow Specialty Clinic Workers’ Survey > ANATOMY.
[71] A Lange Medical Book Current Diagnosis Treatment In Orthopedics Fifth Edition. 2Musculoskeletal Trauma Surgery > SHOULDER AND ARM INJURIES.
[73] Aaos Comprehensive Orthopaedic Review 3. Anatomy of the Shoulder, Arm, and Elbow > I. Shoulder.
[74] Rockwood And Matsen S The Shoulder. Developmental Anatomy of the Shoulder and Anatomy of the Glenohumeral Joint > Bursae.
[77] Rockwood And Matsen S The Shoulder. Fractures, Dislocations, and Acquired Problems of the Shoulder in Children > FRACTURES OF THE PROXIMAL HUMERUS.
[79] Aaos Comprehensive Orthopaedic Review 3. Fractures of the Clavicle, Scapula, and Glenoid > I. Clavicular Fractures.
[82] Campbell S Operative Orthopaedics 4 Volume Set. RECONSTRUCTIVE PROCEDURES OF THE SHOULDER AND ELBOW IN ADULTS > ANATOMY AND BIOMECHANICS.
[83] Campbell S Operative Orthopaedics 4 Volume Set. ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION WITH BONE-PATELLAR TENDON-BONE GRAFT > SHOULDER INJURIES > ANATOMY AND BIOMECHANICS.
[85] Miller S Review Of Orthopaedics. Genetics of musculoskeletal conditions and abnormalities are summarized in Table 1.27 > UPPER EXTREMITY > SHOULDER.
[87] Orthopaedic Knowledge Update Sports Medicine 6. Diagnostic Ultrasonography and Ultrasonography-Guided Procedures > Annotated References.
[89] Apley And Solomon S Concise System Of Orthopaedics And Trauma. INVESTIGATION.
[93] A Lange Medical Book Current Diagnosis Treatment In Orthopedics Fifth Edition. 2Musculoskeletal Trauma Surgery > FRACTURES AND DISLOCATIONS AROUND THE SHOULDER.
[96] Rockwood And Green S Fractures In Adults. 29: Principles of Nonunion and Bone Defect Treatment > Magnetic Resonance Imaging and Arthrography.
[99] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Shoulder Anatomy and Biomechanics, Clinical Evaluation, Imaging > Clinical Evaluation > Imaging.
[102] Aaos Comprehensive Orthopaedic Review 3. Imaging of the Shoulder and Elbow > I. Shoulder.
[108] A Biomechanical Analysis of the Native Coracoclavicular Ligaments and Their Influence on a New Reconstruction Using a Coracoid Tunnel and Free Tendon Graft. Arthroscopy. 2010. DOI: 10.1016/j.arthro.2009.12.031
[114] Acromioclavicular joint ligamentous system contributing to clavicular strut function: a cadaveric study. Journal of Shoulder and Elbow Surgery. 2013. DOI: 10.1016/j.jse.2013.01.004
[125] In-vivo glenohumeral translation and ligament elongation during abduction and abduction with internal and external rotation. Journal of Orthopaedic Surgery and Research. 2012. DOI: 10.1186/1749-799x-7-29
[132] Posterior Shoulder Instability. Sports Health: A Multidisciplinary Approach. 2016. DOI: 10.1177/1941738116672446
[133] Voluntary acromioclavicular joint dislocation: a case report and literature review. Journal of Shoulder and Elbow Surgery. 2019. DOI: 10.1016/j.jse.2019.03.039
[134] Age‐ and time‐specific management of traumatic anterior shoulder instability: The 2024 ESSKA‐ESA formal consensus. Part 1: History taking, physical exam and imaging studies. Knee Surgery, Sports Traumatology, Arthroscopy. 2026. DOI: 10.1002/ksa.70336
[135] Chapter 24 Shoulder Instability, Rotator Cuff Disorders, Muscular Ruptures, Adhesive Capsulitis, Calcific Tendinitis. 2020.
[136] Radiofrequency capsular shrinkage for voluntary shoulder instability. Journal of Shoulder and Elbow Surgery. 2007. DOI: 10.1016/j.jse.2005.11.011
[137] Relationship between the extent of labral lesions and the frequency of glenohumeral dislocation in shoulder instability. Knee Surgery, Sports Traumatology, Arthroscopy. 2012. DOI: 10.1007/s00167-012-2045-z
[138] Management of Mid-season Traumatic Anterior Shoulder Instability in Athletes. Journal of the American Academy of Orthopaedic Surgeons. 2012. DOI: 10.5435/jaaos-20-08-518
[139] Management of shoulder instability in hypermobility-type Ehlers-Danlos syndrome. JSES Reviews, Reports, and Techniques. 2021. DOI: 10.1016/j.xrrt.2021.03.002
[140] Anterior shoulder instability: a review of pathoanatomy, diagnosis and treatment. Current Reviews in Musculoskeletal Medicine. 2011. DOI: 10.1007/s12178-011-9092-9
[141] Patients With Shoulder Labral Tears Search the Internet to Understand Their Diagnoses and Treatment Options. Arthroscopy, Sports Medicine, and Rehabilitation. 2024. DOI: 10.1016/j.asmr.2024.100983
[142] Minor or occult shoulder instability: an intra‐articular pathology presenting with extra‐articular subacromial impingement symptoms. Knee Surgery, Sports Traumatology, Arthroscopy. 2011. DOI: 10.1007/s00167-011-1552-7
[144] The Incidence of Posterior and Combined AP Shoulder Instability Treatment with Surgical Stabilization Is Higher in an Active Military Population than in the General Population: Findings from the US Naval Academy. Clinical Orthopaedics & Related Research. 2020. DOI: 10.1097/corr.0000000000001530
[145] Arthroscopic Technique for Bone Augmentation With Suture Button Fixation for Anterior Shoulder Instability. Arthroscopy Techniques. 2019. DOI: 10.1016/j.eats.2019.09.016
[146] Management of Anterior Shoulder Instability without Bone Loss: Arthroscopic and Mini-Open Techniques. Shoulder & Elbow. 2011. DOI: 10.1111/j.1758-5740.2010.00099.x
[147] Versorgung der Schultereckgelenksprengung mittels akromioklavikulärer und korakoklavikulärer FiberWire®-Cerclage. Zeitschrift für Orthopädie und Unfallchirurgie. 2008. DOI: 10.1055/s-2008-1038577
[148] Shoulder Instability in the Military. Clinics in Sports Medicine. 2014. DOI: 10.1016/j.csm.2014.06.006
[149] Factors affecting shoulder mobility in open and arthroscopic surgery for anterior traumatic instability. Journal of Shoulder and Elbow Surgery. 1995. DOI: 10.1016/s1058-2746(95)80139-1
[150] A Novel Non-operative Protocol for the Acute Management of In-season Acromioclavicular Separations. Orthopaedic Journal of Sports Medicine. 2017. DOI: 10.1177/2325967117s00381
[151] Approach to diagnosing and treating tears of the latissimus dorsi and teres major. JSES Reviews, Reports, and Techniques. 2025. DOI: 10.1016/j.xrrt.2025.05.015
[152] Posterior Shoulder Instability in Athletes. JBJS Reviews. 2015. DOI: 10.2106/jbjs.rvw.n.00090
[153] A new classification system for shoulder instability. British Journal of Sports Medicine. 2010. DOI: 10.1136/bjsm.2009.071183
[155] Arthroscopic Soft Tissue Stabilization With Selective Augmentations for Traumatic Anterior Shoulder Instability in Competitive Collision Athletes. The American Journal of Sports Medicine. 2021. DOI: 10.1177/03635465211003091
[156] Secondary frozen shoulder after traumatic anterior shoulder instability. JSES International. 2020. DOI: 10.1016/j.jses.2019.10.100
[158] Reconstruction of the Acromioclavicular Joint With 360-degree Control. Techniques in Shoulder & Elbow Surgery. 2019. DOI: 10.1097/bte.0000000000000167
[159] Coraco-acromial and coraco-humeral ligaments. Micro and macroscopic aspects. Journal of Shoulder and Elbow Surgery. 1995. DOI: 10.1016/s1058-2746(95)80336-x
[160] Functional Outcomes of Type V Acromioclavicular Injuries With Nonsurgical Treatment. Journal of the American Academy of Orthopaedic Surgeons. 2016. DOI: 10.5435/jaaos-d-16-00176
[161] Endoscopically assisted reconstruction of acute acromioclavicular joint dislocation using a synthetic ligament. Outcomes at 12 months. Orthopaedics & Traumatology: Surgery & Research. 2011. DOI: 10.1016/j.otsr.2010.10.004
[162] Surgical treatment of acute type-V acromioclavicular injuries in athletes. Archives of Orthopaedic and Trauma Surgery. 1993. DOI: 10.1007/bf00662287
[163] Treatment and results of sternoclavicular joint injuries. Clinics in Sports Medicine. 2003. DOI: 10.1016/s0278-5919(02)00112-6
[164] Editorial Commentary: Similar Outcomes Among Surgical Techniques for Unstable Acromioclavicular Injuries: Is There More to the Story?. Arthroscopy. 2018. DOI: 10.1016/j.arthro.2018.03.022
[165] The Epidemiology and Natural History of Anterior Shoulder Instability. Current Reviews in Musculoskeletal Medicine. 2017. DOI: 10.1007/s12178-017-9432-5
[166] Arthroscopic Soft Tissue Stabilization for Traumatic Anterior Shoulder Instability in Elite Collision Athletes: Is it Sufficient?. Orthopaedic Journal of Sports Medicine. 2019. DOI: 10.1177/2325967119s00270
[167] Acromioclavicular joint dislocations: radiological correlation between Rockwood classification system and injury patterns in human cadaver species. Archives of Orthopaedic and Trauma Surgery. 2014. DOI: 10.1007/s00402-014-2045-1
[168] Career Longevity and Performance After Shoulder Instability in National Football League Athletes. Arthroscopy. 2021. DOI: 10.1016/j.arthro.2020.12.225
[169] Subacromial bursa as a repairing factor at the rotator cuff pathology a histomorfologic study. Journal of Shoulder and Elbow Surgery. 1995. DOI: 10.1016/s1058-2746(95)80182-0
[170] Can an acute high-grade acromioclavicular joint separation be reduced and stabilized without surgery? A surgeon’s experience. Archives of Orthopaedic and Trauma Surgery. 2020. DOI: 10.1007/s00402-020-03630-0
[171] Medialized Clavicular Bone Tunnel Position Predicts Failure After Anatomic Coracoclavicular Ligament Reconstruction in Young, Active Male Patients. The American Journal of Sports Medicine. 2016. DOI: 10.1177/0363546516651613
[172] ARTHROSCOPIC SHOULDER INSTABILITY SURGERY. Clinics in Sports Medicine. 1999. DOI: 10.1016/s0278-5919(05)70183-6
[173] Revision Shoulder Instability Surgery After Failed Latarjet: Glenoid Reconstruction Using Distal Tibial Allograft and Humeral Head Reconstruction Using Osteochondral Allograft. Arthroscopy Techniques. 2022. DOI: 10.1016/j.eats.2021.12.013
[174] Conversion to anatomic coracoclavicular ligament reconstruction (ACCR) shows similar clinical outcomes compared to successful non‐operative treatment in chronic primary type III to V acromioclavicular joint injuries. Knee Surgery, Sports Traumatology, Arthroscopy. 2020. DOI: 10.1007/s00167-020-06159-2
[175] Innovative Approaches in the Management of Shoulder Instability: Current Concept Review. Current Reviews in Musculoskeletal Medicine. 2019. DOI: 10.1007/s12178-019-09569-z
[176] The effectiveness of rehabilitation for nonoperative management of shoulder instability: a systematic review. Journal of Hand Therapy. 2004. DOI: 10.1197/j.jht.2004.02.010
[177] Treatment of Initial Anterior Shoulder Instability in National Hockey League Players: A Survey of NHL Team Physicians. Orthopaedic Journal of Sports Medicine. 2024. DOI: 10.1177/23259671241271704
[178] Return to Sport as Outcome Measure for Shoulder Instability: Surprising Findings in Non-Operative Management in a High School Athlete Population. Orthopaedic Journal of Sports Medicine. 2017. DOI: 10.1177/2325967117s00284
[179] Arthroscopic Soft Tissue Stabilization for Traumatic Anterior Shoulder Instability in Elite Collision Athletes. Orthopaedic Journal of Sports Medicine. 2019. DOI: 10.1177/2325967119s00192
[180] An anatomic study of the humeral insertion of the inferior glenohumeral capsule. Journal of Shoulder and Elbow Surgery. 2005. DOI: 10.1016/j.jse.2004.04.014
[181] Return to Professional Australian Rules Football After Surgery for Traumatic Anterior Shoulder Instability. The American Journal of Sports Medicine. 2021. DOI: 10.1177/03635465211029022
[182] Double disruptions of the superior shoulder suspensory complex. Journal of Shoulder and Elbow Surgery. 1995. DOI: 10.1016/s1058-2746(95)80217-7
[183] The importance of CT for the pre-operative surgical planning in recurrent anterior shoulder instability. Archives of Orthopaedic and Trauma Surgery. 2012. DOI: 10.1007/s00402-012-1656-7
[185] Midterm Results of Combined Acromioclavicular and Coracoclavicular Reconstruction Using Nylon Tape. Arthroscopy. 2012. DOI: 10.1016/j.arthro.2012.02.001
[186] Acromioclavicular and Coracoclavicular Ligament Reconstruction for Acromioclavicular Joint Instability: A Systematic Review of Clinical and Radiographic Outcomes. Arthroscopy. 2018. DOI: 10.1016/j.arthro.2018.01.016
[187] Critical role of the acromioclavicular ligament in posterior stability: a paradigm shift in acromioclavicular joint reconstruction. Clinics in Shoulder and Elbow. 2025. DOI: 10.5397/cise.2025.00843
[189] Open treatment of posterior humeral avulsion of the glenohumeral ligaments: A case report and review of the literature. Journal of Shoulder and Elbow Surgery. 2007. DOI: 10.1016/j.jse.2006.09.009
[190] Is Open Stabilization Superior to Arthroscopic Stabilization for the Treatment of Recurrent Traumatic Anterior Shoulder Instability?. Journal of Bone and Joint Surgery. 2014. DOI: 10.2106/jbjs.m.01524
[191] Hook plate with or without coracoclavicular ligament augmentation in the treatment of acute acromioclavicular separation. BMC Musculoskeletal Disorders. 2020. DOI: 10.1186/s12891-020-03726-z
[192] Shoulder Instability. Clinics in Sports Medicine. 2018. DOI: 10.1016/j.csm.2017.12.001
[193] Effect of Acromioclavicular Joint Injuries on the Acromioclavicular Joint Complex and Scapulohumeral Rhythm: A Functional and Mechanical Perspective. Journal of the American Academy of Orthopaedic Surgeons. 2025. DOI: 10.5435/jaaos-d-24-00360
[194] Long‐term outcome of arthroscopic remplissage in addition to the classic Bankart repair for the management of recurrent anterior shoulder instability with engaging Hill–Sachs lesions. Knee Surgery, Sports Traumatology, Arthroscopy. 2018. DOI: 10.1007/s00167-018-5261-3
[198] Nonoperative management of anterior shoulder instability can result in high rates of recurrent instability and pain at long-term follow-up. Journal of Shoulder and Elbow Surgery. 2022. DOI: 10.1016/j.jse.2021.07.016
[200] OPEN SHOULDER INSTABILITY SURGERY. Clinics in Sports Medicine. 1999. DOI: 10.1016/s0278-5919(05)70182-4
[202] Recurrent Shoulder Instability: Current Concepts for Evaluation and Management of Glenoid Bone Loss. Journal of Bone and Joint Surgery. 2010. DOI: 10.2106/jbjs.j.00906
[205] Focal cortical bone loss at the inferior aspect of the glenoid: A new radiographic sign of anterior shoulder instability. Journal of Shoulder and Elbow Surgery. 1992. DOI: 10.1016/1058-2746(92)90092-h
[206] The Role of the Trapezius in Stabilization of the Acromioclavicular Joint: A Biomechanical Evaluation. Orthopaedic Journal of Sports Medicine. 2022. DOI: 10.1177/23259671221118943
[207] The coracoacromial ligament: The morphology and relation to rotator cuff pathology. Journal of Shoulder and Elbow Surgery. 2008. DOI: 10.1016/j.jse.2007.05.015
[208] Non-operative Management of Posterior Shoulder Instability: An Assessment of Survival and Predictors for Conversion to Surgery at 1 to 13 Years After Diagnosis. Orthopaedic Journal of Sports Medicine. 2018. DOI: 10.1177/2325967118s00098
[209] Arthroscopic Bankart Repair For Recurrent Anterior Shoulder Instability: Outcomes with Minimum 10-Year Follow-Up. Journal of ISAKOS. 2023. DOI: 10.1016/j.jisako.2023.03.343
[211] Arthroscopic and Magnetic Resonance Arthrogram Features of Kim's Lesion in Posterior Shoulder Instability. Arthroscopy. 2014. DOI: 10.1016/j.arthro.2014.02.038
[212] Arthroscopic Coracoclavicular Ligament Reconstruction Using Biologic and Suture Fixation. Arthroscopy. 2007. DOI: 10.1016/j.arthro.2006.10.005
[214] Sagittal orientation of coracoclavicular ligament reconstruction affects the stability of surgical repair. Journal of Shoulder and Elbow Surgery. 2020. DOI: 10.1016/j.jse.2019.11.034
[215] Continuous Loop Double Endobutton Reconstruction for Acromioclavicular Joint Dislocation. The American Journal of Sports Medicine. 2015. DOI: 10.1177/0363546515596409
[218] Clinical and radiological examination of bony-mediated shoulder instability. EFORT Open Reviews. 2020. DOI: 10.1302/2058-5241.5.200049
[220] Magnetic resonance imaging predictors of shoulder instability in adolescents. Pediatric Radiology. 2018. DOI: 10.1007/s00247-018-4318-2
[221] Management of Recurrent Posterior Shoulder Instability in a Young Contact Athlete Using a Posterior Bone Block Technique With Distal Tibia Osteochondral Allograft. Techniques in Shoulder & Elbow Surgery. 2017. DOI: 10.1097/bte.0000000000000090
[222] Humeral and glenoid detachment of the anterior inferior glenohumeral ligament: A cause of anterior shoulder instability. Journal of Shoulder and Elbow Surgery. 1997. DOI: 10.1016/s1058-2746(97)90064-1
[227] Management of acute acromioclavicular joint dislocation with a double-button fixation system. Injury. 2013. DOI: 10.1016/j.injury.2013.01.002
[228] “Pinch‐and‐Tuck” Arthroscopic Technique for Capsular Laxity in Posterior Shoulder Instability. Arthroscopy Techniques. 2025. DOI: 10.1016/j.eats.2025.103794
[230] Critical Findings on Magnetic Resonance Arthrograms in Posterior Shoulder Instability Compared With an Age-Matched Controlled Cohort. The American Journal of Sports Medicine. 2016. DOI: 10.1177/0363546516660076
[231] Humeral Avulsion of Glenohumeral Ligaments. American Academy of Orthopaedic Surgeon. 2011. DOI: 10.5435/00124635-201103000-00001
[233] Three cases of recurrent anterior shoulder instability secondary to capsular tears. Journal of Shoulder and Elbow Surgery. 1995. DOI: 10.1016/s1058-2746(95)80231-2
[235] Preoperative Imaging of Anterior Shoulder Instability: Diagnostic Effectiveness of MDCT Arthrography and Comparison With MR Arthrography and Arthroscopy. American Journal of Roentgenology. 2012. DOI: 10.2214/ajr.11.7251
[236] Nonoperative Management of Posterior Shoulder Instability: An Assessment of Survival and Predictors for Conversion to Surgery at 1 to 10 Years After Diagnosis. Arthroscopy. 2019. DOI: 10.1016/j.arthro.2019.01.056
[237] Minimally Invasive Coracoclavicular Ligament Augmentation With a Flip Button/Polydioxanone Repair for Treatment of Total Acromioclavicular Joint Dislocation. Arthroscopy. 2007. DOI: 10.1016/j.arthro.2006.12.015
[238] Free Tissue Graft Reconstruction of the Acromioclavicular Joint. Techniques in Shoulder & Elbow Surgery. 2008. DOI: 10.1097/bte.0b013e31818a5dd9
[239] Shoulder Instability in Professional Football Players. Sports Health: A Multidisciplinary Approach. 2013. DOI: 10.1177/1941738112472156
[240] A preliminary report of acromioclavicular joint reconstruction with clavicular corticotomy. Journal of Shoulder and Elbow Surgery. 1995. DOI: 10.1016/s1058-2746(05)80068-0
[241] Surgical Treatment of Complete Acromioclavicular Dislocations. The American Journal of Sports Medicine. 1995. DOI: 10.1177/036354659502300313