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Tendons, Ligaments and Muscles

Hand/wrist tendon, ligament, and muscle injuries: acute repair principles, chronic tendinopathy management, and anatomical considerations.

128 citationsUpdated Oct 2026

Overview

Tendon and ligament pathology nomenclature can mislead understanding of both the condition and its management [1]. Clinical evaluations of disruption are relatively subjective and lack high intraobserver and interobserver reliability, meaning the "50% rule" should not be considered an exact rule in medical science [2]. Biomechanical healing varies significantly by tissue type; after 20 weeks, tendon transfers reach 60% of control mechanical strength, whereas tendon grafts reach only 20% [11, 12]. The width of the palmaris longus tendon may limit repair success [19], while partial pulley excision up to 50% is supported to facilitate exposure and repair [146].

Primary tendon repair is permissible only when strict criteria are met, including early presentation, minimal contamination, and favorable wound conditions [30]. When these criteria are not met, secondary repair via tendon graft is recommended [30]. Recent repair and motion protocols lead to over 80% good or excellent outcomes after Zone 2 repair, with an infrequent need for tenolysis [56]. Repair of both flexor digitorum profundus and flexor digitorum superficialis tendons is slightly more preferable based on increased grip strength, though superficialis repair is not mandatory in acute Zone 2B injuries [63]. Secondary reconstruction remains an important technique for complicated flexor tendon injuries or those that have failed primary repair [144].

Graft harvesting options include the palmaris longus, which can be harvested with minimal scarring [32], and the plantaris tendon, which offers a clinical advantage due to stable surgical availability across human populations compared to the high ethnicity-based variability of the palmaris longus [141]. Standardized methods of measurement and recording are needed for valid comparisons of results after flexor tendon repair [138]. Novel repair techniques, including barbed suture, should be tested cyclically in a manner that closely mimics in vivo conditions during postoperative rehabilitation before clinical adoption [149]. More stringent criteria, such as Tang's criteria, are necessary as results move toward more ideal functional outcomes, and surgeon expertise should always be considered when comparing outcomes [142].

Anatomy & Pathophysiology

Osseous Architecture and Kinematics

The hand and wrist skeleton comprises 27 bones, 19 of which are long bones [39]. The hand is organized into five rays, each forming a polyarticulated chain of metacarpals and phalanges [39]. The wrist possesses three axes of movement, permitting the hand to be positioned in any spatial configuration for grasping [39]. In the sagittal plane, the thumb metacarpal makes an angle of approximately 45 degrees with the second metacarpal [39]. The transverse axis of the palm forms an acute angle of approximately 75 degrees with the longitudinal axis [39]. Epiphyseal plates are located at the proximal ends of the phalanges and the first metacarpal, and at the distal ends of the other metacarpals [39]. The index metacarpal is the most firmly fixed, while the fifth metacarpal has a range of flexion–extension of approximately 20 degrees [77]. The metacarpophalangeal joints serve as the keystones of the longitudinal arches of the hand [77]. Volar plates prevent hyperextension at the metacarpophalangeal joints and are interconnected by the transverse interglenoid ligament [77]. The axes of flexion are arranged such that flexion of all metacarpophalangeal and proximal interphalangeal joints causes the fingers to converge toward the scaphoid [85].

Extrinsic Musculature and Tendon Anatomy

Extrinsic extensors run through six fibroosseous retinacular compartments at the wrist level [38]. Compartment contents: - First compartment: abductor pollicis longus and extensor pollicis brevis [38]. - Second compartment: extensor carpi radialis longus and extensor carpi radialis brevis [38]. - Third compartment: extensor pollicis longus, which turns abruptly radialward about Lister tubercle [38]. - Fourth compartment: extensor indicis proprius lying deep to the four tendons of the extensor digitorum communis [38]. - Fifth compartment: extensor digiti quinti [38]. - Sixth compartment: extensor carpi ulnaris tendon [38].

The extensor digitorum communis tendons of the middle, ring, and little fingers are tethered together by juncturae tendinum over the dorsum of the hand proximal to the metacarpophalangeal joint [38]. Sagittal bands stabilize the digital extensor tendons over the midline of the metacarpophalangeal joint [38]. Rupture or attenuation of the sagittal band fibers allows the extrinsic extensor tendon to sublux to the ulnar side of the metacarpal head, causing ulnar deviation of the finger [38].

The flexor digitorum profundus originates from the proximal ulna and the interosseous membrane [81]. The flexor digitorum superficialis has a radial head originating from the proximal shaft of the radius and a humeral ulnar head originating from the medial humeral epicondyle and coronoid process of the ulna [81]. The flexor digitorum superficialis tendon bifurcates around the flexor digitorum profundus at the beginning of the A2 pulley [81]. The flexor digitorum superficialis tendon slips reunite distally at the Camper chiasm, with approximately half of the fibers staying on the ipsilateral side and half crossing to the contralateral side [81]. The flexor pollicis longus originates from a radial head on the proximal radius and interosseous membrane, and an accessory head on the coronoid process of the ulna and medial epicondyle of the humerus [81]. The tenosynovial sheath of the flexor pollicis longus is continuous with the radial bursa, and the sheath to the little finger is continuous with the ulnar digital bursa [81]. In some patients, the radial and ulnar bursae communicate, allowing a horseshoe abscess to spread between the thumb and little finger [81]. The fibroosseous tunnel of the digital flexor sheath consists of annular pulleys providing mechanical stability and cruciate pulleys providing flexibility [81]. The A2 and A4 pulleys are the most essential in maintaining the mechanical advantage of the flexor tendons [81]. Within the fibroosseous tunnel, tendon vascularity is supplied via the vincula system, specifically the vinculum longus and brevis [81].

Intrinsic Musculature

There are seven interosseous muscles in the hand: four dorsal and three volar [74]. The dorsal interossei are abductors, while the volar interossei are adductors [74]. The middle finger has two dorsal interossei and no volar interossei because the central axis of the hand lies within it [74]. Each dorsal interosseous muscle, with the exception of the third, has two muscle heads: a superficial head and a deep head [74]. The superficial head of the dorsal interosseous muscles abducts and weakly flexes the proximal phalanx [74]. The deep head of the dorsal interosseous muscles forms a lateral band that flexes and weakly abducts the proximal phalanx while extending the middle and distal phalanges [74]. The volar interossei have only one muscle head and do not insert onto the proximal phalanx [74]. The abductor digiti quinti and flexor digiti quinti brevis are structurally and functionally similar to the superficial and deep heads of the dorsal interossei, respectively [74]. The opponens digiti quinti arises from the pisohamate ligament and the hook of the hamate and inserts onto the ulnar side of the diaphysis of the fifth metacarpal [74].

Extensor Mechanism Biomechanics

The extensor mechanism at the proximal interphalangeal joint is a trifurcation of the extensor tendon into the central slip and two lateral bands [168]. The central slip inserts into the base of the middle phalanx, while the lateral bands pass on either side of the proximal interphalangeal joint to insert into the distal phalanx [168]. Simultaneous extension of the proximal and distal interphalangeal joints depends on the balanced lengths of the central slip and the two lateral bands [168]. Dorsal migration of the lateral bands during proximal interphalangeal joint extension is attributed to the elastic quality of the triangular ligament [168]. Extension of the maximally flexed distal phalanges is actively initiated by motor forces [106].

Gliding Mechanisms and Soft Tissue

In unrestricted areas with a straight tendon trajectory, tendons are surrounded by paratenon and areolar connective tissue [82]. In narrow crowded areas, the gliding mechanism is assured by the synovial sheath, which is surrounded by fibrous sheaths that act as pulleys [82]. Synovial sheaths on the dorsal aspect are present only at the level of the wrist [82]. The dorsal skin becomes fragile in old age due to thin epidermis and dearth of connective and elastic tissue in the dermis [83]. Flexion of the fingers produces a significant lengthening of the dorsal skin, with an average increase of 3 cm in the middle finger from extension to full flexion [83]. The dorsal and palmar areas of skin are independent due to a system of adhesions anchoring their common boundary to the underlying plane [83]. The superficial palmar fascia covers a triangular area of the central palm, with the proximal corner facing directly proximal [84]. The palmaris longus tendon terminates in continuity with the fibers of the proximal corner of the superficial palmar fascia when present [84]. Fibers dorsal to the digital neurovascular bundle are collectively called Cleland ligament, and those palmar to the bundle are called Grayson ligament [84]. The subdermal fascial layer bordering the web spaces forms the distal first web space ligament between the thumb and index finger [84].

Vascular Anatomy

The "princeps pollicis" artery is the terminal branch of the radial artery that crosses the first intermetacarpal space [78]. In anatomical studies, only 15% of dissections of the palmar arteries of the thumb fall into the classical "typical" category [78]. The dorsal arteries of the thumb originate from palmar arteries at the level of the first metacarpal and head distally on the side of the two distal phalanges [78].

Tendon and Ligament Pathophysiology

Tendons are load-bearing structures that transmit forces from muscle to bone, with a hierarchical collagen structure interlaced with non-fibrillar proteins [33]. Tenocytes sense loads from the extracellular matrix and modulate it, making loading essential for tendon homeostasis [33]. After tendon degeneration leads to rupture, healing does not effectively restore the native structure and function of the tendon even after secure surgical repair [33]. Tendinopathy is defined as a form of tendinosis (degeneration) rather than tendonitis (inflammation) [181]. It is characterized by mucoid degeneration, fat infiltration, calcification, and alterations in collagen architecture and alignment [181]. The histopathologic changes of tendinopathy are consistent across tendons from different anatomic sites [181]. Disruption to the flexor pulley system of the thumb is an infrequent but devastating injury that can lead to significant compromise in strength and function [43]. The estimated lengths of principal ligaments stabilizing the thumb carpometacarpal joint change substantially during thumb motions in vivo [95]. Finger flexor tendon forces are a complex function of finger joint motions and fingertip forces, with the relationship between tip and tendon force being nonlinear during dynamic activities [93]. The predominance of specific mechanoreceptors in flexor tendons indicates that position sense and kinetic activities of the fingers are well-served [94].

Classification

Ligament Injury Grading

Ligament injuries are generally classified into three grades: I, II, and III [9]. Grade I corresponds to a mild sprain [9]. Grade II corresponds to a moderate sprain or partial tear [9]. Grade III corresponds to a complete ligament tear [9]. Avulsion of the ligament from its bony insertion is an additional type of ligament injury distinct from grades I–III [9].

Flexor Tendon Zone I (Leddy and Packer)

Zone I flexor tendon injuries are defined as the region from the FDP tendon to the insertion of the FDS tendon [155]. Leddy and Packer classified subtypes of zone I avulsion injuries to help guide management [155]. Type I involves retraction of the proximal stump of the FDP to the palm [155]. In Type I injuries, both vincula are disrupted and the tendon retracts proximal to the synovial sheath, rendering it devoid of nutrition [155]. Repair for Type I injuries should proceed within 7 days to avoid tendon contracture and necrosis [155]. Type I trauma has the worst prognosis of all zone I injuries [155]. Type II avulsions involve tendon retraction to the level of the proximal interphalangeal (PIP) joint, sometimes with a small fleck of bone [155]. Type II avulsions may be successfully repaired within 6 weeks of injury [155]. Type III avulsions are characterized by large bony fragments that prevent the tendon from retracting past the distal edge of the A4 pulley [155]. Direct repair for Type III avulsions may be possible for up to 6 weeks [155]. Type IV and Type V injuries were added to the Leddy and Packer classification subsequently [155]. Type IV injuries involve fracture and avulsion of the FDP tendon from the fracture fragment [155]. Type IV injuries require fixation of the fragment followed by repair of the tendon [155].

Extensor Tendon Zones

A simpler classification system for extensor tendon zones has been proposed to align with current treatment strategies, such as conservative splinting for closed injuries and strong surgical repair for open injuries [60]. A classification of extensor tendon zones based on the presence of the extensor retinaculum is suggested as preferable to those based on the wrist joint [143]. Classification based on the extensor retinaculum simplifies treatment discussion and aligns with flexor tendon zoning [143]. Tang's simplified classification is expected to enhance the accuracy of operative evaluations and provide valuable insights into surgical outcomes for anatomically diverse extensor tendon injuries [134]. Future studies are needed to validate the effectiveness of Tang's simplified classification [134]. A survey of views in a hand surgery department suggests that a revisit of popular extensor tendon zone classification systems may be necessary for future clinical practice and communication among surgeons [119].

Accessory and Anomalous Structures

An additional category (Type 3) has been proposed to the Türker classification system to encompass rare findings of two radial-sided accessory extensor tendons in the same individual [118]. The origin, insertion, and location of an unusual variation of extensor digitorum brevis manus differ from those previously reported, preventing placement into current classifications [132]. An analysis of the embryologic development of the extensor muscle mass with phylogenetic comparisons is presented to underscore the clinical relevance of anomalous extensors [59].

Other Classifications

A modification to the most prevalent classification system for sagittal band injuries has been described to guide treatment and allow standardization in documenting and describing injuries [156]. The anterior bundle, posterior bundle, and common tendon of the ulnar collateral ligament of the elbow can each be classified into an independent form and an unclear form [151].

Clinical Presentation

Ligaments

Ligaments function to restrict joint motion and stabilize joints [9]. Injuries are classified into three grades: Grade I corresponds to a mild sprain, Grade II to a moderate sprain or partial tear, and Grade III to a complete ligament tear [9]. An additional injury type is avulsion of the ligament from its bony insertion [9]. The metacarpophalangeal joints of the ulnar four digits are most vulnerable to injury with forces directed ulnarly and dorsally [48]. The radial collateral ligaments are stronger, more oblique in their long axis, and have an origin closer to the articular surface of the metacarpal head than their ulnar counterparts, particularly for the index and long fingers [48]. The scaphotrapezial ligament consists of three distinct fascicles, including a deep fascicle that attaches 3.3 mm from the most distal point of the scaphoid [126].

Tendons

Normal tendons do not rupture except at the musculotendinous junction or tendon insertion, typically due to excessive weight application when the muscle is holding at maximum power [47]. The pathophysiology of tendinosis is characterized by degenerative rather than inflammatory changes, with susceptibility related to activity and age [125]. Consequently, extensor carpi radialis brevis pathology is more accurately described as a tendinopathy or tendinosis rather than a tendinitis [121]. Intra-tendinous foreign bodies are not rare, with 53 cases (5.6%) found from 931 operative specimens [51]. Pulley rupture or insufficiency presents a diagnostic and therapeutic dilemma owing to the overall rarity of the injury and the lack of comparative clinical studies describing its diagnosis, treatment, and outcome [23]. The "50% rule" for tendon and ligament disruption should not be considered an exact rule in medical science because clinical evaluations are relatively subjective and lack high intraobserver and interobserver reliability [2]. Perhaps the most appropriate term for intramuscular tendon pathology should not include 'tendon' as it misleads understanding of both the pathology and its management [1].

Muscles

The mean length of lumbrical muscle discontinuity was 1.1 mm (0.2) [16]. Symptoms from lumbrical muscle tears resolve after conservative therapy, with recovery taking longer in more severe injuries where there is musculotendinous discontinuity [16]. In the unusual circumstance when persistent intermetacarpal pain is accompanied by incomplete composite digital flexion, the diagnosis of tethered and ruptured lumbrical muscle should be considered [53].

Diagnostic Findings and Imaging

Ultra-sonography provides a new ability to study the complex anatomical structures of the hand, with the technique being quick and simple to perform [6]. The application of colour Doppler imaging (CDI) for flexor tendon pathology in the hand is satisfactory and promising, though further development is necessary to optimize images and quantitative aspects of moving structures [14]. Active and passive movement of tendons and muscles can be successfully visualized using colour Doppler ultrasound [45]. The use of ultrasound in the treatment of musculoskeletal disorders is based on empirical experience but lacks substantial support in controlled studies [26]. In cases where pain is pronounced and the patient is not cooperative for preoperative examination, ultrasonography can be conducted to assess the continuity of the tendon [115]. If doubt persists after ultrasonography, an MRI is performed to assess tendon continuity [115].

The Biceps Provocation Test (BPT) appears to be highly accurate in the clinical diagnosis of distal biceps tendon pathology [116]. MRI is the gold standard to evaluate for hamstring injury, but it should be reserved for patients in whom a complete rupture is suspected or who do not respond to conservative management [52]. Sitting pain is common in proximal hamstring tears, but functional pain (stairs, hiking, sprinting) is a more specific finding for hamstring pathology rather than other causes of buttock pain [52].

Patients with extensor carpi ulnaris tendinitis or stenosing tenosynovitis usually report a gradual, insidious onset of ulnar-sided wrist pain over the course of weeks to months [117]. Pain in extensor carpi ulnaris tendinitis is generally worsened with activity and may be elicited with resisted radial deviation or active ulnar deviation against resistance [117]. A positive extensor carpi ulnaris synergy test in the absence of other positive examination maneuvers for intra-articular pathology correctly identified ten of eleven patients with isolated extensor carpi ulnaris tendinitis and correctly ruled out extensor carpi ulnaris tendinitis in all twenty-one patients with a negative test [117]. The extensor carpi ulnaris synergy test is performed with the patient’s elbow on the examination table, flexed at 90° and in full supination, while the examiner palpates the extensor carpi ulnaris and the patient abducts the thumb against resistance [117]. In a series of fifty-four consecutive patients reviewed over a two-year period, a positive extensor carpi ulnaris synergy test in the absence of other positive examination maneuvers for intra-articular pathology correctly identified ten of eleven patients with isolated extensor carpi ulnaris tendinitis [117].

Patient evaluation for medial gastrocnemius proximal tendon avulsion begins with a thorough clinical examination to check for tenderness to palpation of the MGT and gastrocnemius tubercle, knee range-of-motion differences, strength deficits, and stability of the knee [131]. Radiographic imaging for medial gastrocnemius proximal tendon avulsion should include lower extremity long-standing views to assess alignment bilaterally and magnetic resonance imaging to assess for any MGT or possible meniscal pathology [131].

Specific Clinical Presentations

Triggering of the lateral slip of the extensor mechanism on a Bouchard’s node is a rare case where physiological treatment preserves tendon balance, with no recurrence of symptoms at 10-month follow-up [7]. An isolated constriction of the tendon sheath of extensor digiti minimi can cause triggering of the little finger [127]. Triggering can be caused by an untreated partially-cut flexor tendon, providing another mechanical cause for triggering and an example of the complication after an unrepaired partially-cut flexor tendon [49]. A lesion causing increased diameter of the tendon results in a loss of pull-through of the tendon at the A1 pulley of the flexor sheath, causing "congenital" trigger thumb [122]. Ulnar subluxation of the extensor tendons in elderly osteoarthritic females is a neglected diagnosis where successful centralisation of operatively treated extensor tendons provides relief of symptoms [10].

A 30-year-old right-handed woman presented with fifth-digit pain and a prominent lump on her right wrist, denying specific injury but endorsing a 6-month history of pain and symptomatology [129]. Sharp pain occurred with immediate onset following extension of the fifth digit in a patient with anomalous extensor digiti minimi [129]. The patient reported that her small finger felt as though it was snapping over the dorsal aspect of the fifth metacarpal [129]. Magnetic resonance imaging of the right wrist showed prominent thickening of the extensor digiti minimi tendon within the wrist extensor region localized at the level of the distal ulnar styloid [129]. Initial plain films demonstrated a possible marginal osteophyte at the base of the fifth metacarpal on the right wrist when compared to the left wrist [129].

Release of the flexor retinaculum permits the tendon to move smoothly in its track, but the prognosis is guarded as the tendon is weakened in partial rupture of the flexor hallucis longus tendon [15]. The symptoms of congenital shortening of the flexor digitorum profundus muscle resolved completely after the affected tendon was transected and sutured to the adjacent FDP tendon under appropriate tension [114]. For late-stage cases of congenital flexion deformity with an aberrant origin of the flexor digitorum profundus, both local release and a thorough muscle sliding were preferred [4]. The injury suffered by a patient with complete avulsion of a tendon of flexor digitorum profundus from its myotendinous junction would be seen to be an extreme form of muscle strain injury [28].

Extensor tendon injuries are common and early recognition and treatment are key to the management of such injuries [13]. The closer look at data for primary single-finger flexor tendon repairs showed miscellaneous and often even unclear reasons for tendon ruptures, making the definition of one major cause, such as two-strand repairs, impossible [8]. Across large claims-based cohorts, testosterone replacement therapy (TRT) in adult males is associated with higher odds of tendon and ligament injuries, with estimates of similar magnitude at one and two years where both were reported [27].

Investigations

Plain radiography: Plain radiographs are important in the assessment of patients presenting with closed flexor tendon rupture [191]. In shoulder pathology, the radiographic appearance of a bone fragment beneath the humeral head is a valuable sign for avulsion of the subscapularis tendon [189].

MRI: Magnetic resonance imaging was helpful in diagnosing a displaced ulnar collateral ligament in two cases and an intraligamentous injury in another case [172]. MRI might be worth considering in revision cases, as 43% of those cases with clinical signs of olecranon bursitis had previous surgery [179]. In Dupuytren’s disease, MRI assessment is hindered by the resolution of current equipment, orientation issues due to multiplanar deformities of the fingers, and lack of intraoperative availability [90]. However, MRI is probably most useful in identifying additional pathology such as flexor tendon bowstringing in Dupuytren’s disease [90]. Regarding lumbrical injuries, MRI located musculotendinous disruption in the fourth lumbrical muscle in eight of the 10 Grade III cases and in the third lumbrical muscle in two [16]. Additionally, magnetic resonance imaging indicates that the donor site after autologous osteochondral mosaicplasty is resurfaced with fibrous tissue [194].

Ultrasound: Diagnostic medical ultrasound provides a new ability to study the complex anatomical structures of the hand, with the technique being quick and simple to perform [6]. Colour Doppler ultrasound application for flexor tendon pathology in the hand is considered satisfactory and promising, though further development is necessary to optimize images and quantitative aspects of moving structures [14]. Colour Doppler ultrasound has been used to successfully visualize active and passive movement of tendons and muscles [45]. Ultrasound is superior to MRI for dynamic evaluation of stenosing synovitis of the extensor pollicis longus tendon [174]. In the context of lumbrical injuries, ultrasound located injuries in the fourth lumbrical muscle in 23 of the 32 Grade II cases and in the third lumbrical muscle in nine [16]. An 8-MHz Doppler tone assessment may be used to identify superficially displaced neurovascular bundles when Dupuytren cords lie beneath soft fleshy prominences, but false-negatives are possible [90].

Other Considerations: The '50% rule' should not be considered an exact rule in medical science because clinical evaluations of tendon and ligament disruption are relatively subjective [2]. A careful physical examination is essential to direct care and future testing if indicated, as diagnostic tests such as imaging and serum laboratory studies can be expensive, time consuming, and often nonspecific [37]. Patients often have difficulty accurately describing their symptoms and may incorrectly attribute pathology to a perceived deficit [37]. Closed rupture of the flexor tendon should be recognized as a complication in patients with asymptomatic Kienböck disease [191]. The possibility of tendon entrapment should be considered in juxta-epiphyseal fractures of the proximal phalanx [5]. Angulation greater than 20 degrees at the proximal interphalangeal joint is abnormal and indicates a loss of collateral ligament integrity [195]. The extensor tendon reserve was 2 to 6 mm, and the sagittal bands became tight at the limits of this reserve [193]. Tendon cross-sectional area correlated well with the physiological cross-sectional area of associated muscles [190].

Treatment

Non-Operative

Conservative management remains the primary approach for most closed extensor tendon injuries in the acute phase [145]. For proximal hamstring tendon ruptures, nonoperative management with delayed reconstruction is an option for low-demand patients [68]. Patients with chronic sagittal band injuries or those failing nonoperative management may benefit from surgical exploration [171].

Operative

Indications: Surgical intervention is indicated for chronic extensor tendon injuries [145], complete collateral ligament ruptures to prevent prolonged disability [36], and acute proximal hamstring tendon ruptures in patients desiring return to sports [68]. Primary tendon repair for flexor tendons is permissible only when strict criteria are met, including early presentation, minimal contamination, and favorable wound conditions; otherwise, secondary repair via tendon graft is recommended [30]. Surgical treatment is the treatment of choice for ruptures of the tendo achillis in more active patients due to significantly better functional results and a lower incidence of reruptures compared to non-surgical treatment [62]. Tendon lengthening and transfer are indicated for neuromuscular disorders, nerve injuries, and congenital or traumatic lesions [139].

Surgical Approach / Technique: For Zone 2 flexor tendon injuries, recent repair and motion protocols consistently achieve over 80% good or excellent outcomes with infrequent need for tenolysis [56]. Repair of the flexor digitorum superficialis together with flexor digitorum profundus is not mandatory for acute Zone 2B injuries, although repairing both is slightly more preferable based on increased grip strength [63]. A fingertip winding suture technique provides a strong tendon-to-bone attachment for Zone I flexor tendon repair [3]. Tendon grafts will tolerate early motion therapy if the proximal and distal tenorrhaphy junctures are strong enough [120]. For late-stage cases of congenital flexion deformity with aberrant origin of the flexor digitorum profundus, both local release and a thorough muscle sliding were preferred [4]. In juxta-epiphyseal fractures of the proximal phalanx, the possibility of tendon entrapment should be considered [5].

For extensor tendon repairs in zones V and VI, relative motion extension plus and relative motion extension only are used interchangeably depending on surgeon preferences and patient/tendon factors [61]. Available biomechanical studies have validated controlled motion as biomechanically sound utilizing contemporary repair techniques [42]. A new technique to shorten extensor tendons has been used with good results in patients with lengthening of an extensor tendon with extensor deficit due to unrecognized or inadequately treated damage [175]. Extensor tendon salvage and reconstruction using a tendon from an unsalvageable finger may be a reasonable remedy for reconstruction of tendon loss or gaps in zone I [163].

For ligament reconstruction, the double superficialis tenodesis technique for the unstable proximal interphalangeal joint uses local tissues and provides stability without sacrificing range of motion [34]. The advantage of the tendon used for repair in ulnar instability of the metacarpophalangeal joint of the thumb is the tightness with which it can be sutured to achieve maximum stability [58]. A flexor carpi radialis to palmaris longus tendon transfer for spontaneous rupture of the flexor carpi radialis tendon is simple to perform and requires uncomplicated post-operative management [170]. The technique for harvest of palmaris longus tendon allows the tendon to be harvested with minimal scarring [32]. Published clinical results for the contralateral C7 transfer have demonstrated significant improvements in upper limb function, confirming the procedure's safety and efficacy, with donor site morbidity that is typically mild and transient [130].

Rehabilitation Protocols: The frequency of controlled passive motion in postoperative tendon management protocols is a significant factor in accelerating the healing response regarding tensile properties [166]. In clinical studies of repaired flexor tendons, the duration of the daily controlled passive-motion interval is a significant variable, with increased frequency providing superior clinical results with respect to IP motion [166]. Patients treated with the LEAF protocol are advised to spend three to five minutes each hour performing the controlled exercise [166]. Surgical repair of complete proximal hamstring tendon avulsions with a nonbracing rehabilitation protocol for patients over 40 years demonstrated intact repairs with no reruptures [158].

Implant Selection: Both techniques provided excellent short- to mid-term clinical and functional outcomes for distal biceps tendon repair using cortical button with or without interference screw [31]. The placement of a K-wire across the trapezial void is as effective as tendon interposition or ligament reconstruction in creating a trapezial space in the short term, with no significant difference between the 1-year follow-up trapezial space ratios of the three treatment groups [55].

Other Considerations: The width of the PL tendon may limit the success of the repair when comparing Pulvertaft suture to step-cut suture [19]. Disruption to the flexor pulley system of the thumb is an infrequent but devastating injury that can lead to significant compromise in both strength and function [43]. Reduplication of the extensor carpi ulnaris tendon is the rule, not the exception, occurring in 52% of hands [150]. The authors propose a simpler classification system for extensor tendon zones to align with current treatment strategies, such as conservative splinting for closed injuries and strong surgical repair for open injuries [60]. A repair using the tendo achillis itself has been suggested for defects in the tendo achillis [54].

Complications and Risk Factors

Mechanical Complications and Entrapment: Triggering is a complication that can occur after an unrepaired partially-cut flexor tendon [49]. Triggering of the lateral slip of the extensor mechanism on a Bouchard’s node is a rare cause of triggering [7]. A physiological treatment for triggering caused by a Bouchard's node preserves tendon balance, with no recurrence of symptoms noted at 10-month follow-up [7]. Ulnar subluxation of the extensor tendons in elderly osteoarthritic females is a neglected diagnosis [10]. There was successful centralisation of all seven operatively treated extensor tendons with relief of symptoms in all cases of ulnar subluxation [10].

Tendon and Ligament Rupture: After tendon degeneration leads to rupture, healing does not effectively restore the native structure and function of the tendon even after apparently secure surgical repair [33]. Even after clinically successful flexor tendon autograft, tendons may still be at risk of degeneration and rupture a decade or more after reconstruction [64]. Clinical outcome following rotator cuff repair was compromised by tendon retearing and increased fatty infiltration of the infraspinatus muscle [152]. The closer look at data from primary single-finger flexor tendon repairs showed miscellaneous and often even unclear reasons for tendon ruptures, making the definition of one major cause, such as two-strand repairs, impossible [8]. Completely ruptured collateral ligaments frequently result in prolonged disability when treated non-operatively [36]. Surgical repair of fourteen fingers with complete rupture of the collateral ligament yielded satisfactory results with restored joint stability and pain relief [36].

Infection and Fibrosis: The unnecessary recourse to a first stage using a silicone rod for flexor tendon reconstruction can result in infection, scar, and dense fibrosis developing, which can compromise or prevent successful grafting [153].

Functional Deficits and Sensory Changes: Release of the flexor retinaculum for partial rupture of the flexor hallucis longus tendon permits the tendon to move smoothly in its track, but the prognosis is guarded as the tendon is weakened [15]. Sixteen of 34 patients continued to suffer from cold sensitivity at a mean of 10.6 years after zone 2 flexor tendon repair [165]. A significant decrease in the excursion efficiency of the flexor tendons was demonstrated when the wrist was in the flexed position [136].

Systemic and Hormonal Risk Factors: Testosterone replacement therapy in adult males is associated with higher odds of tendon and ligament injuries, with estimates of similar magnitude at one and two years where both were reported [27]. Estrogen decreases stiffness in tendons and ligaments, which can decrease power and increase the risk of catastrophic ligament injury [154].

Surgical Technique Limitations: Proximal hamstring tendon repair is associated with an overall complication rate of 15.4%, including a 4.6% rate of major complications [124]. The disadvantages of the modified 69 blade for tenolysis are that it is a very sharp blade and requires careful use to prevent fraying of the tendon [137].

Biological and Experimental Data: Understanding the biology and organization of the native tendon and the process of morphogenesis of tendon tissue is necessary to improve current treatment modalities [17]. After 20 weeks, the mechanical strength of the tendon transfers had reached 60% of the controls and that of the tendon grafts 20% of the controls in an experimental study of tendon implantation into bone [11, 12]. The healing period for Grade III lumbrical muscle injuries was significantly longer than in the two other sub-groups (P < 0.001) [16].

Ligament Classification and Outcomes: Ligament injuries are generally classified into three grades: I, II, and III, where Grade I corresponds to a mild sprain, grade II corresponds to a moderate sprain/partial tear, and grade III corresponds to a complete ligament tear [9]. Patients with early surgical treatment for collateral ligament rupture of metacarpophalangeal joints regained full or nearly full motion within a mean period of 11 weeks and most of them with no residual laxity [57]. Chronic ulnar collateral ligament injuries are traditionally managed with tendon graft ligament reconstruction or tendon transfers, though evidence is limited to case reports and retrospective series [35]. Injured ulnar collateral ligaments were naturally stable after reduction and did not need surgical repair in arthroscopic findings of the thumb metacarpophalangeal joint [169]. Surgical reconstruction of the PIP joint collateral ligament in chronic instability in a high performance athlete is believed to be critical for normal joint biomechanical approximation, allowing the patient to resume a career of professional basketball [46].

Recovery

Light activity (weeks): The evidence does not specify a distinct week range for light activity such as desk work or driving. However, patients regained full or nearly full motion within a mean period of 11 weeks following early surgical treatment for collateral ligament rupture of metacarpophalangeal joints [57].

Full activity (months): The mechanical strength of tendon transfers reached 60% of controls after 20 weeks [11, 12]. In contrast, the mechanical strength of tendon grafts reached only 20% of controls after 20 weeks [11, 12]. Acute repair is recommended for patients desiring return to sports following proximal hamstring tendon rupture [68]. Nonoperative management with delayed reconstruction is an option for low-demand patients following proximal hamstring tendon rupture [68].

Complete recovery / outcome plateau (months): The evidence does not provide a specific month range for the complete recovery or outcome plateau phase.

Rehabilitation protocol: Release of the flexor retinaculum permits the tendon to move smoothly in its track [15]. Studies point to increasing tendon function after rehabilitation [182].

Functional milestones: Most patients had no residual laxity following early surgical treatment for collateral ligament rupture of metacarpophalangeal joints [57]. Surgical repair of fourteen fingers with complete rupture yielded satisfactory results with restored joint stability and pain relief [36]. Forty-seven (96 per cent) of the forty-nine shoulders had a good clinical result after distal release of the contracture [178].

Other Considerations: The prognosis is guarded following release of the flexor retinaculum because the tendon is weakened [15]. In cases of tendon graft, there is concern over extension lag of the MP joint [18]. The time to surgery should be considered in cases of tendon graft [18]. There appears to be some recurrence of hyper-extension with time following volar tenodesis for swan-neck deformity [184]. Papers with longer follow-up tend to have poorer results following volar tenodesis for swan-neck deformity [184].

Key Evidence

• [L5] Perhaps the most appropriate term for the pathology should not include ‘tendon’ as it misleads our understanding of both the pathology and its management. [1] (10.1136/bjsports-2017-098834)
• [L5] The authors agree that the '50% rule' should not be considered an exact rule in medical science because clinical evaluations of tendon and ligament disruption are relatively subjective and lack high intraobserver and interobserver reliability. [2] (10.1016/j.arthro.2011.10.003)
• [L5] Finally, it provides a strong tendon-to-bone attachment thus yielding a good functional outcome. [3] (10.1097/bth.0000000000000167)
• [Case_report] For late-stage cases, both local release and a thorough muscle sliding were preferred. [4] (10.1016/j.jhsa.2008.04.013)
• [L5] In both situations, the possibility of tendon entrapment should be considered. [5] (10.1016/s0266-7681(98)80152-6)
• [L4] Ultra-sonography provides a new ability to study the complex anatomical structures of the hand, with the technique being quick and simple to perform. [6] (10.1016/0266-7681(90)90133-o)
• [L4] The authors describe a rare case of triggering caused by a Bouchard's node and propose a physiological treatment that preserves tendon balance, noting no recurrence of symptoms at 10-month follow-up. [7] (10.1177/1753193410397860)
• [L4] The closer look at the data showed miscellaneous and often even unclear reasons for these tendon ruptures, making the definition of one major cause, such as two-strand repairs, impossible. [8] (10.1177/17531934231200159)
• [L4] There was successful centralisation of all seven operatively treated extensor tendons with relief of symptoms in all cases. [10] (10.1016/j.jhsb.2006.08.003)
• [Paper] After 20 weeks, the mechanical strength of the tendon transfers had reached 60% of the controls and that of the tendon grafts 20% of the controls. [11] (10.1016/0266-7681(87)90179-3)
• [Paper] After 20 weeks, the mechanical strength of the tendon transfers had reached 60% of the controls and that of the tendon grafts 20% of the controls. [12] (10.1016/0266-7681_87_90179-3)
• [L5] Extensor tendon injuries are common and early recognition and treatment are key to the management of such injuries. [13] (10.1016/j.hcl.2014.12.006)
• [L4] Although we conclude that the application of CDI flexor tendon pathology in the hand is satisfactory and promising we consider further development of the CDI necessary to optimize the images and the quantitative aspects of moving structures of the locomotor system. [14] (10.1016/s0266-7681(96)80048-9)
• [L4] Release of the flexor retinaculum permits the tendon to move smoothly in its track, but the prognosis is guarded as the tendon is weakened. [15] (10.2106/00004623-197961010-00031)
• [L4] [16] (10.1177/1753193418765716)
• [L5] Understanding the biology and organization of the native tendon and the process of morphogenesis of tendon tissue is necessary to improve current treatment modalities. [17] (10.1016/j.jhsa.2007.09.007)
• [L4] In cases of tendon graft, the time to surgery should be considered, and there is concern over extension lag of MP joint. [18] (10.1186/s12891-022-05815-7)
• [L5] The width of the PL tendon may limit the success of the repair. [19] (10.1016/j.hansur.2017.11.004)
• [L5] Pulley rupture or insufficiency is a diagnostic and therapeutic dilemma owing to the overall rarity of the injury as well as the lack of comparative clinical studies describing its diagnosis, treatment, and outcome. [23] (10.1016/j.jhsa.2012.07.021)
• [L4] The use of ultrasound in the treatment of musculoskeletal disorders is based on empirical experience but lacks substantial support in controlled studies. [26] (10.1177/175899830000500202)
• [L4] Across large claims-based cohorts, TRT in adult males is associated with higher odds of tendon and ligament injuries, with estimates of similar magnitude at one and two years where both were reported. [27] (10.1177/2325967126s00289)
• [L5] The injury suffered by our patient would be seen to be an extreme form of muscle strain injury. [28] (10.1016/0020-1383(95)00139-5)
• [L5] Primary tendon repair is permissible only when strict criteria are met, including early presentation, minimal contamination, and favorable wound conditions; otherwise, secondary repair via tendon graft is recommended. [30] (10.2106/00004623-195941040-00001)
• [L3] Both techniques provided excellent short- to mid-term clinical and functional outcomes. [31] (10.1177/17585732261441889)
• [L4] This technique allows the tendon to be harvested with minimal scarring. [32] (10.1016/0266-7681(93)90008-4)
• [L5] [33] (10.1002/jor.22869)
• [L4] The technique has the advantage of using local tissues and of providing stability without sacrificing range of motion. [34] (10.1016/s0363-5023(78)80040-9)
• [L4] Chronic UCL injuries are traditionally managed with tendon graft ligament reconstruction or tendon transfers, though evidence is limited to case reports and retrospective series. [35] (10.1016/j.jhsa.2011.06.004)
• [L4] Completely ruptured collateral ligaments frequently result in prolonged disability when treated non-operatively, whereas surgical repair of fourteen fingers with complete rupture yielded satisfactory results with restored joint stability and pain relief. [36] (10.2106/00004623-196749020-00009)
• [L4] In addition, available biomechanical studies concerning finger extension strength, tendon repair strength, tendon shortening, resultant loss of motion, and gliding capability have validated controlled motion as biomechanically sound utilizing contemporary repair techniques. [42] (10.1197/j.jht.2005.01.006)
• [Paper] Disruption to the flexor pulley system of the thumb is an infrequent but devastating injury that can lead to significant compromise in both strength and function. [43] (10.1097/bth.0000000000000253)
• [L4] We have examined and successfully visualized active and passive movement of tendons and muscles using colour Doppler ultrasound. [45] (10.1016/s0266-7681(98)80183-6)
• [L5] We believe this is critical for normal joint biomechanical approximation, and we believe these points better allowed our patient to resume a career of professional basketball. [46] (10.1097/bth.0b013e3181efa215)
• [L4] [48] (10.1016/s0363-5023(79)80072-6)
• [L5] It provides another mechanical cause for triggering of a partial tendon laceration and yet another example of the complication of triggering after an unrepaired partially-cut flexor tendon. [49] (10.1016/0266-7681(89)90159-9)
• [L3] These procedures should be considered in symptomatic patients with chronic tears that are not amenable to primary repair. [50] (10.1177/23259671251383094)
• [L4] Intra-tendinous foreign bodies are not rare; in our patients we have found 53 cases (5.6%) from 931 operative specimens. [51] (10.1016/0266-7681(89)90022-3)
• [Paper] [52] (10.1016/j.eats.2019.11.022)
• [L5] We suggest that in the unusual circumstance when persistent intermetacarpal pain is accompanied by incomplete composite digital flexion, the diagnosis of tethered and ruptured lumbrical muscle be considered. [53] (10.1016/s0363-5023(96)80109-2)
• [L4] A repair using the tendo achillis itself has been suggested. [54] (10.2106/00004623-195638010-00011)
• [L1] There was no significant difference between the 1-year follow-up trapezial space ratios of the three treatment groups, suggesting that the placement of a K-wire across the trapezial void is as effective as tendon interposition or ligament reconstruction in creating a trapezial space in the short term. [55] (10.1053/jhsu.2001.27761)
• [L5] Recent repair and motion protocols lead to remarkably more reliable repairs, with over 80% good or excellent outcomes achieved rather consistently after Zone 2 repair along with infrequent need of tenolysis. [56] (10.1177/17531934211053757)
• [L4] Patients regained full or nearly full motion within a mean period of 11 weeks and most of them with no residual laxity. [57] (10.1053/jhsu.2003.50048)
• [L4] Its advantage is the tightness with which the tendon used for repair can be sutured to achieve maximum stability. [58] (10.1016/s0266-7681(85)80035-8)
• [L5] An analysis of the embryologic development of the extensor muscle mass with phylogenetic comparisons between species of the animal kingdom is presented to underscore the clinical relevance of these anomalous extensors. [59] (10.1053/jhsu.1999.0449)
• [L5] The authors propose a simpler classification system for extensor tendon zones to align with current treatment strategies, such as conservative splinting for closed injuries and strong surgical repair for open injuries. [60] (10.1177/17531934241274112)
• [L4] RME plus and RME only are used interchangeably depending on surgeon preferences and patient/tendon factors. [61] (10.1016/j.jht.2019.12.016)
• [L3] Surgical treatment is the treatment of choice and should be recommended for more active patients due to significantly better functional results and a lower incidence of reruptures compared to non-surgical treatment. [62] (10.2106/00004623-197658070-00015)
• [L3] Although repair of both flexor digitorum profundus and flexor digitorum superficialis tendons is slightly more preferable based on increased grip strength, the repair of the flexor digitorum superficialis together with flexor digitorum profundus is not mandatory. [63] (10.1177/1753193420932446)
• [L4] Even after clinically successful flexor tendon autograft, tendons may still be at risk of degeneration and rupture a decade or more after reconstruction. [64] (10.1177/15589447221131846)
• [L3] Acute repair is recommended for patients desiring return to sports, while nonoperative management with delayed reconstruction is an option for low-demand patients. [68] (10.1177/2325967113s00061)
• [Paper] During dynamic activities, the relationship between tip and tendon force was nonlinear and often remained elevated when the finger was moving but with no applied force. [93] (10.1197/j.jht.2005.01.011)
• [L5] The predominance of these two mechanoreceptors indicates that position sense and kinetic activities of the fingers are well-served, as evidenced in hand movements. [94] (10.1016/0266-7681(89)90134-4)
• [L4] The estimated lengths of principal ligaments stabilizing the CMC joint change substantially during thumb motions in vivo. [95] (10.1016/j.jhsa.2010.11.007)
• [L5] The experiments disclosed that extension of the maximally flexed distal phalanges was actively initiated by motor forces. [106] (10.1016/s0266-7681(85)80009-7)
• [L4] The symptoms resolved completely after the affected tendon was transected and sutured to the adjacent FDP tendon under appropriate tension. [114] (10.1016/j.jhsa.2006.10.006)
• [L3] [115] (10.1177/17531934221074514)
• [L2] The BPT appears to be highly accurate in the clinical diagnosis of distal biceps tendon pathology. [116] (10.1016/j.jhsa.2020.12.012)
• [L4] [117] (10.2106/jbjs.rvw.n.00070)
• [L4] The authors propose an additional category (Type 3) to the Türker classification system to encompass rare findings of two radial-sided accessory extensor tendons in the same individual, which were not previously represented in existing classifications. [118] (10.1016/j.jhsg.2023.10.005)
• [L4] Based on the results of this survey, a revisit of the popular extensor tendon zone classifications systems may be necessary for future clinical practice and communication among surgeons. [119] (10.1177/17531934241253137)
• [L5] Achieving consistent, satisfactory results remains an elusive goal, but recent studies demonstrate that tendon grafts will tolerate early motion therapy if the proximal and distal tenorrhaphy junctures are strong enough. [120] (10.1016/j.jhsa.2015.04.016)
• [L5] The lesion caused increased diameter of the tendon resulting in a loss of pull-through of the tendon at the Al pulley of the flexor sheath. [122] (10.1016/s0266-7681(96)80141-0)
• [L1] Proximal hamstring tendon repair is associated with an overall complication rate of 15.4%, including a 4.6% rate of major complications. [124] (10.1177/2325967123s00208)
• [L5] The scaphotrapezial ligament consists of three distinct fascicles, including a deep fascicle that attaches 3.3 mm from the most distal point of the scaphoid. [126] (10.1016/j.jhsa.2025.09.010)
• [L5] An isolated constriction of the tendon sheath of extensor digiti minimi caused triggering of the little finger. [127] (10.1016/0266-7681(94)90139-2)
• [L4] [129] (10.1016/j.jhsg.2023.04.010)
• [L5] Published clinical results have demonstrated significant improvements in upper limb function, confirming the procedure's safety and efficacy, with donor site morbidity that is typically mild and transient. [130] (10.1177/17531934251314640)
• [L5] [131] (10.1016/j.eats.2025.103849)
• [L5] The origin, insertion, and location of the muscle differ from those previously reported; with these anatomic features, the muscle variation cannot be placed into the current classifications. [132] (10.1016/s0363-5023(98)80108-1)
• [L5] Tang's simplified classification is expected to enhance the accuracy of operative evaluations and provide valuable insights into surgical outcomes for anatomically diverse extensor tendon injuries, though future studies are needed to validate its effectiveness. [134] (10.1177/17531934251326850)
• [L5] A significant decrease in the excursion efficiency of the flexor tendons was demonstrated when the wrist was in the flexed position. [136] (10.1016/s0363-5023(96)80300-5)
• [L5] The disadvantages are that it is a very sharp blade and requires careful use to prevent fraying of the tendon. [137] (10.1016/s0363-5023(83)80138-5)
• [L4] The study suggests a need for one standard method of measurement and recording, if a comparison of results after flexor tendon repair is to be of value. [138] (10.1016/s0266-7681(85)80018-8)
• [L5] Tendon lengthening and transfer are indicated for neuromuscular disorders, nerve injuries, and congenital or traumatic lesions. [139] (10.1016/j.otsr.2014.07.033)
• [L1] The surgical availability of the PM tendon was found stable across human populations; a clinical advantage when compared to the high variability of PL ethnicity-based frequency. [141] (10.1142/s2424835519500280)
• [L5] The authors agree that more stringent criteria, such as Tang's criteria, are necessary as results move toward more ideal functional outcomes, and that surgeon expertise should always be considered when comparing outcomes. [142] (10.1177/1753193416634602)
• [L5] The author suggests that a classification of extensor tendon zones based on the presence of the extensor retinaculum is preferable to those based on the wrist joint, as it simplifies treatment discussion and aligns with flexor tendon zoning. [143] (10.1177/17531934241232066)
• [L5] Secondary reconstruction remains an important and useful technique for complicated flexor tendon injuries or those that have failed primary repair. [144] (10.1016/j.jhsa.2007.08.018)
• [L5] Most closed extensor tendon injuries can be treated conservatively in the acute phase, but chronic injuries often require operative intervention. [145] (10.1016/j.csm.2014.09.005)
• [L5] These data support the clinical practice of partial pulley excision, up to a limit of 50%, to facilitate exposure and tendon repair. [146] (10.1016/j.jhsa.2004.04.014)
• [L4] We describe a technique for flexor tendon retrieval that eliminates the need for proximal incisions. [148] (10.1016/s0363-5023(05)80025-5)
• [Letter] The authors advocate that novel flexor tendon repair techniques, including barbed suture, should be tested cyclically in a manner that closely mimics in vivo conditions during postoperative rehabilitation before clinical adoption. [149] (10.1016/j.jhsa.2015.02.034)
• [L5] The author states that reduplication of the extensor carpi ulnaris tendon is the rule, not the exception, occurring in 52% of hands. [150] (10.1016/s0363-5023(87)80080-1)
• [L5] These results suggest that the anterior bundle, posterior bundle, and common tendon each can be classified into an independent form and an unclear form. [151] (10.1177/2325967120952415)
• [L2] Clinical outcome was compromised by tendon retearing and increased fatty infiltration of the infraspinatus muscle. [152] (10.1177/23259671231196875)
• [L4] [153] (10.1177/1753193415575985)
• [L5] Estrogen improves muscle mass and strength and increases collagen content in connective tissues, but decreases stiffness in tendons and ligaments, which can decrease power and increase the risk of catastrophic ligament injury. [154] (10.3389/fphys.2018.01834)
• [L5] [155] (10.5435/jaaos-d-16-00316)
• [L4] This review provides a contemporary perspective on sagittal band injuries and describes a modification to the most prevalent classification system to guide treatment and allow standardization in documenting and describing injuries. [156] (10.1016/j.jhsa.2021.09.011)
• [L4] Surgical repair of complete proximal hamstring tendon avulsions with a nonbracing rehabilitation protocol for patients .40 years demonstrated intact repairs with no reruptures. [158] (10.1177/23259671251326604)
• [L4] Extensor tendon salvage and reconstruction using a tendon from an unsalvageable finger may be a reasonable remedy for reconstruction of tendon loss or gaps in zone I, offering advantages over other traditional techniques in certain cases. [163] (10.1016/j.jhsa.2014.01.029)
• [L3] [165] (10.1054/jhsb.1998.0175)
• [L4] [166] (10.1197/j.jht.2005.03.001)
• [L5] [168] (10.2106/00004623-197254040-00003)
• [L4] Injured UCL ligaments were naturally stable after reduction and did not need surgical repair. [169] (10.1177/1753193418790502)
• [L4] This tendon transfer is simple to perform and requires uncomplicated post-operative management. [170] (10.1142/s242483551672019x)
• [L4] Patients with chronic injuries or those failing nonoperative management may benefit from surgical exploration. [171] (10.1177/1558944719895622)
• [L4] Magnetic resonance imaging was helpful in diagnosing a displaced ulnar collateral ligament in two cases and an intraligamentous injury in the other. [172] (10.1016/0363-5023(89)90203-7)
• [L4] They emphasize that ultrasound is superior to MRI for dynamic evaluation and that surgical release is a viable treatment to prevent tendon rupture. [174] (10.1016/j.jhsa.2011.02.004)
• [L4] This technique has been used with good results in four patients who had lengthening of an extensor tendon with extensor deficit due to unrecognized or inadequately treated damage. [175] (10.1016/s0266-7681(05)80021-x)
• [L3] Forty-seven (96 per cent) of the forty-nine shoulders had a good clinical result after distal release of the contracture. [178] (10.2106/00004623-199802000-00010)
• [L4] They suggest that MRI might be worth considering in revision cases, as 43% of those cases with clinical signs of olecranon bursitis had previous surgery. [179] (10.1016/j.arthro.2014.11.005)
• [L5] [181] (10.1002/jor.20646)
• [L4] The present scoping review shows contradictory results regarding tendon-related outcomes although studies point to increasing tendon function after rehabilitation. [182] (10.1186/s12891-025-08734-5)
• [L4] There appears to be some recurrence of hyper-extension with time so that papers with longer follow-up tend to have poorer results. [184] (10.1142/s0218810417300030)
• [Case_report] Avulsion of the subscapularis tendon may be more common than literature suggests, and the radiographic appearance of a bone fragment beneath the humeral head is a valuable sign. [189] (10.2106/00004623-198769090-00024)
• [L5] This study reports that tendon cross-sectional area correlated well with the physiological cross-sectional area of associated muscles. [190] (10.1016/0266-7681(91)90130-g)
• [Case_report] Closed rupture of the flexor tendon should be recognized as a complication in patients with asymptomatic Kienböck disease, and plain radiographs are important in the assessment of patients presenting with closed flexor tendon rupture. [191] (10.1177/1558944718795511)
• [L5] The extensor tendon reserve was 2 to 6 mm, and the sagittal bands became tight at the limits of this reserve. [193] (10.1016/s0363-5023(98)80054-3)
• [L4] However, magnetic resonance imaging indicates that the donor site is resurfaced with fibrous tissue. [194] (10.1177/0363546507306465)
• [L5] Angulation greater than 20 degrees is abnormal and indicates a loss of collateral ligament integrity. [195] (10.1016/0363-5023(93)90345-4)

See Also

• Flexor tendon repair

References

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