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Anatomy & Biomechanics

Elbow anatomy & biomechanics: ulnohumeral, radiocapitellar joints, valgus stress, and implications for UCL injury/OCD in throwers.

Overview

The evaluation of the elbow requires a comprehensive understanding of the anatomy, biomechanics, and diagnostic tests for this complex joint [4]. Functional biomechanics demand particular attention when treating complex elbow pathology [4]. Recent changes in elbow arthroplasty device design and implantation methods are driven by biomechanical and clinical outcome-based research to better reproduce elbow kinematics [3]. Consequently, elbow arthroplasty procedures have become more durable and long-lasting as a result of this research [3].

Biomechanical and clinical studies are needed to understand the true clinical relevance of anatomic variations in the ulnar greater sigmoid notch coverage angle [2]. Three-dimensional analysis of elbow soft tissue footprints and anatomy provides information that may aid in restoring elbow biomechanics [12]. This analysis also provides information that may aid in preserving range of motion in elbow patients [12]. Furthermore, patient-specific musculoskeletal modeling of shoulder joint biomechanics can contribute significantly to predicting pathology [5]. Such modeling can also contribute significantly to optimizing postoperative function [5].

Eight studies followed International Society of Biomechanics standards for quantifying upper body kinematics during functional upper limb tasks [1]. Exact preoperative planning is vital to allow early rehabilitation in the surgical management of proximal ulna fractures [10]. Anatomical restoration is vital to prevent complications such as stiffness and instability in the surgical management of proximal ulna fractures [10]. A thorough understanding of biomechanical principles and neurological pathways is necessary for hand surgeons managing upper limb spasticity [14]. Tendon transfers remain a necessary and powerful technique for regaining lost function of the arm [22]. Core principles and biomechanics are reviewed alongside common and less well-described tendon transfers [22].

Anatomy & Pathophysiology

The elbow is a complex joint requiring a thorough understanding of its anatomy, biomechanics, and diagnostic tests to effectively treat complex pathology [4]. Stability is maintained by static and dynamic stabilizers that function in synchrony, while the joint’s stability and complex kinematics are accounted for by a combination of bony articulation and soft-tissue stabilizers [42, 16].

Kinematics

Eight studies have followed International Society of Biomechanics standards for quantifying upper body kinematics [1]. Recent changes in elbow arthroplasty device design and implantation methods are driven by biomechanical and clinical outcome-based research to better reproduce elbow kinematics [3]. The carrying angle of the forearm remains constant as the elbow flexes [50].

Elbow position affects the kinematics of the distal radioulnar joint, which are primarily affected by forearm rotation and secondarily by elbow flexion [32]. Elbow joint surface stress distributions vary according to different elbow flexion angles [39]. Five kinematic parameters during the stride phase and their combination were associated with peak elbow varus torque [40]. Normal kinematics was preserved in the osteoarthritic elbow with a normal radiocapitellar joint (OAN group) [43].

Radial head excision causes altered elbow kinematics and increased laxity [31]. Biomechanical characteristics of elbows which underwent Docking surgical reconstructions at 30 degrees of elbow flexion appear to more closely approximate those of the intact elbow than reconstructions performed at 90 degrees of elbow flexion [36].

Classification

International Society of Biomechanics Standards: Eight studies on upper body kinematics adhered to these standards [1].

Ulnar Greater Sigmoid Notch Coverage Angle: This classification involves both bone and cartilage contributions [2]. Biomechanical and clinical studies are required to determine the true clinical relevance of anatomic variations in this angle [2].

Elbow Evaluation Framework: Assessment requires an understanding of anatomy, biomechanics, and diagnostic tests [4]. Functional biomechanics are necessary when treating complex elbow pathology [4]. Stability and complex kinematics are accounted for by a combination of bony articulation and soft-tissue stabilizers [16]. Understanding elbow biomechanics and injury mechanisms provides insight into variations of pathology in complex elbow dislocations [7].

Forearm Longitudinal Stability: This relies on the radial head, interosseous membrane, and distal radioulnar joint working together [8]. Chronic skeletal disorders of the forearm in adults involve both bone and soft-tissue structures, contributing to treatment complexity and a lack of a generally accepted classification system [17].

Lateral Elbow Tendinopathy: This condition can be graded into four distinct grades to guide management and future investigation [11].

Hand Surgery Spasticity Management: A thorough understanding of biomechanical principles and neurological pathways is necessary for hand surgeons managing upper limb spasticity [14].

Tibiofemoral Rotation and Knee Morphology: Tibiofemoral rotation is related to differences in the lateral femoral condyle configuration in both normal subjects and women with hip dysplasia [21]. Morphological knee joint differences may help determine the alignment of prostheses in total knee arthroplasty [21].

Throwing Biomechanics: The biomechanics of throwing in baseball and football differ significantly, leading to distinct injury patterns between these sports [52]. Patient-specific musculoskeletal modeling of shoulder joint biomechanics can contribute to predicting pathology and optimizing postoperative function [5].

Anterolateral Ligament (ALL): The ALL exhibits a peripheral nerve structure, primarily type I and IV mechanoreceptors [54].

Medial Ulnar Collateral Ligament (MUCL): Detailed analysis of the fibers of the MUCL allows for further understanding of its kinematic function [55].

Clinical Presentation

Evaluation of upper limb joint function typically relies on clinical means without instruments, though comprehensive physical examinations including special tests facilitate improved diagnosis of elbow pathology [27, 28]. Understanding the anatomy, biomechanics, and functional requirements is essential when treating complex pathology [4]. The forearm operates as a series of interconnected parts where damage to one area affects stability in multiple regions, necessitating a holistic understanding to quickly diagnose injury patterns [35].

Acute Injury and Dislocation

Acute dislocations and subluxations of the distal radio-ulnar joint are delineated by criteria for simple and complex dislocations, with management of associated complications discussed [30]. Diagnosis of medial head of the triceps dislocation with ulnar nerve location anterior to the medial epicondyle is challenging by physical examination alone, but ultrasonography proves useful [34]. Understanding elbow biomechanics and injury mechanisms provides valuable insight into the variations of pathology observed in complex elbow dislocations [7].

Chronic Pathology and Classification

Chronic skeletal disorders of the forearm in adults involve both bone and soft-tissue structures, contributing to treatment complexity and a lack of a generally accepted classification system [17]. A pathophysiology-based treatment algorithm grades lateral elbow tendinopathy into four distinct grades to guide management [11]. Anatomic considerations of impinging exostoses of the proximal radius may provide guidance in assessing atypical symptoms arising from impingement on soft-tissue structures [18].

Biomechanical Assessment and Modeling

Eight studies followed International Society of Biomechanics standards for quantifying upper body kinematics during functional upper limb tasks [1]. The literature reviews the biomechanics of bony and dynamic stabilizers of the elbow while drawing clinically relevant biomechanical observations [6]. Recent changes in elbow arthroplasty device design and implantation methods are driven by biomechanical and clinical outcome-based research to better reproduce elbow kinematics [3]. Patient-specific musculoskeletal modeling of shoulder joint biomechanics can contribute significantly to predicting pathology and optimizing postoperative function [5]. Biomechanical and clinical studies are needed to understand the true clinical relevance of anatomic variations in the ulnar greater sigmoid notch coverage angle [2].

Forearm Stability and Fracture Outcomes

Longitudinal stability of the forearm relies on the radial head, interosseous membrane, and distal radioulnar joint working together [8]. With appropriate management and early mobilisation, good functional results can be expected in the majority of patients with olecranon fractures [19].

Investigations

Plain radiography: The preoperative convergence angle, reflecting soft-tissue laxity, serves as a practical and simple radiographic finding for predicting lateral mid-flexion laxity [67].

MRI: MRI determination of posterior interosseus nerve (PIN) position is reliable and consistent with prior cadaveric study [51]. In supination, physiologic but higher joint incongruency is expected in the sagittal and coronal planes [44]. Joint congruence of healthy elbows increases significantly when changing from supination to pronation [81]. Increased MRI signal in the extensor carpi radialis brevis (ECRB) origin is common in both symptomatic and asymptomatic elbows [76]. For osteochondritis dissecans of the capitellum, MRI should be performed if healing does not occur by a reasonable time despite successful bony healing to assess potential cartilage damage [45]. Early identification of anterior capsule injury patterns via MRI could inform treatment decisions, particularly in cases where stable surgical fixation is challenging for distal humerus coronal shear fractures [63]. Radial head diameters can be accurately inferred from two humeral dimensions by magnetic resonance imaging [65]. Cartilage thickness of the distal humerus and its relationships with bone dimensions may be relevant to anatomic prosthesis design [80].

CT: The use of MR technology by high-volume subspecialist surgeons provides similar, to better results than traditional fluoroscopy (FH) technique for version and inclination in assessing medial and lateral fascia contribution to overhead elbow extension in displaced olecranon fractures [82].

Other Considerations: Eight studies followed International Society of Biomechanics standards for quantifying upper body kinematics [1]. Longitudinal stability of the forearm relies on the radial head, interosseous membrane, and distal radioulnar joint working together [8]. Exact preoperative planning and anatomical restoration are vital to allow early rehabilitation and prevent complications such as stiffness and instability in proximal ulna fractures [10]. Anatomic considerations of impinging exostoses of the proximal radius may provide guidance in assessment of atypical symptoms arising from impingement on soft-tissue structures and aid in planning for surgical resection [18]. Clinicians must maintain a high suspicion level and examine adjacent joints to avoid overlooking associated injuries in ipsilateral elbow and shoulder dislocation [79].

Biomechanical and clinical studies are needed to understand the true clinical relevance of anatomic variations in the ulnar greater sigmoid notch coverage angle [2]. Tibiofemoral rotation is related to differences in the lateral femoral condyle configuration in both normal subjects and women with hip dysplasia [21]. Morphological knee joint differences may help determine the alignment of prostheses in total knee arthroplasty [21]. Anatomic anterolateral ligament (ALL) reconstruction did not reduce anterolateral rotational laxity [59]. There is a significant negative relationship between the Alpha Angle and the Beta Angle in the proximal radioulnar joint, emphasizing the biomechanical impact of joint congruence on bony coverage [70]. The angulation between the posterior plane surface and the flexion-extension axis of the proximal ulna is highly variable, with a 95% confidence interval range of 18° [77].

Treatment

Non-Operative

Conservative management is appropriate for specific pathologies and patient subsets. Nonoperative treatment for Panner disease resulted in favorable outcomes with sports return and remodeling [74]. Conservative treatment of a nondisplaced proximal radial fracture complication of distal biceps tendon repair under strict and close clinical and radiographic controls can result in a successful outcome [58]. Asymptomatic non-unions after complex humeral head fractures treated with blocked threaded wires should not be considered failures, as they relate to satisfactory outcomes, and no additional surgery should be performed [57]. Excellent functional outcomes can be achieved with a conservative approach even after extensive soft tissue damage from minor injury in open antero-lateral dislocation of the elbow [68]. A surgical technique for chronic isolated radial head dislocation in adults is a conservative option that provides satisfactory functional outcomes in the short term [64].

Operative

Indications: Surgical anatomical repair is typically performed for acute complete distal biceps and triceps ruptures, while nonoperative treatment is reserved for partial ruptures or patients unfit for surgery [60]. Surgical management of coxa vara is indicated for progressive, painful, unilateral deformity or leg-length discrepancy, while moderate nonprogressive deformity often does not require surgery [62]. The one-bone forearm reconstructive procedure is indicated only if instability and bone loss are irreparable by bone-grafting or other reconstructive procedures and there is no chance of restoring rotation of the forearm [56].

Surgical Approach / Technique: The single-incision arthrotunneling technique for distal biceps tendon rupture is a safe and effective repair that recreates the anatomic footprint and biomechanics of the native biceps and has a reduced complication profile compared to a two-incision approach [20]. Conservative treatment or non-anatomical repair of distal biceps brachii tendon rupture results in significant loss of supination strength and variable loss of flexion strength [15]. A novel technique for forearm reconstruction in ulnar dysplasia with dislocation of the radial head achieved better functional outcomes, with the elbow and wrist functioning well at 3-year follow-up, compared with previously reported treatment options [46]. Apex posterior overcorrection of the ulna increases radial head stability in anterior Monteggia fractures by enhancing joint congruency and stability [37]. Tendon transfers remain a necessary and powerful technique for regaining lost function of the arm, with core principles and biomechanics reviewed alongside common and less well-described transfers [22]. Pedicled latissimus dorsi bipolar transfer appears to be the most efficient and least problematic therapeutic option for managing the absence of elbow flexors in radial clubhand [75].

Implant Selection: Recent changes in elbow arthroplasty device design and implantation methods are driven by biomechanical and clinical outcome-based research to better reproduce elbow kinematics, resulting in more durable and long-lasting joint replacement procedures [3]. Further biomechanical and outcome data are needed to determine if smaller screws reduce fracture risk without compromising fixation strength in subpectoral biceps tenodesis [13]. Modified Nicoll-graft treatment is the treatment of choice for gap non-unions of the upper extremity [69].

Alignment / Balancing Strategy: Exact preoperative planning and anatomical restoration are vital to allow early rehabilitation and prevent complications such as stiffness and instability in proximal ulna fractures [10]. Three-dimensional analysis of elbow soft tissue footprints and anatomy provides information that may aid in restoring elbow biomechanics and preserving range of motion [12]. Patient-specific musculoskeletal modeling of shoulder joint biomechanics can contribute significantly to predicting pathology and optimizing postoperative function [5].

Pain Management: A thorough understanding of biomechanical principles and neurological pathways is necessary for the hand surgeon to achieve balance in upper limb spasticity management [14].

Adjuncts: Eight studies followed International Society of Biomechanics standards for quantifying upper body kinematics [1].

Other Considerations: Biomechanical and clinical studies are needed to understand the true clinical relevance of anatomic variations in the ulnar greater sigmoid notch coverage angle [2]. Further clinical studies are necessary to determine the actual functional impact of mechanoreceptors and free nerve endings in the lateral collateral ligament beyond mechanical stabilization [9]. A pathophysiology-based treatment algorithm grading lateral elbow tendinopathy into four distinct grades is proposed to guide management and future investigation [11]. With appropriate management and early mobilisation, good functional results can be expected in the majority of patients with olecranon fractures [19]. The primary goal of treatment for nonacute elbow fracture with persistent ulnohumeral dislocation or subluxation is stable reduction of the ulnohumeral joint and functional elbow motion [41]. Management principles for hypertrophic non-union of a pathological forearm fracture secondary to multiple myeloma include stabilisation of the entire bone and early mobilisation [66].

Complications

Implant Failure: Implant failure and catastrophic complications can occur over time in total elbow arthroplasty for distal humerus fractures [61].

Stiffness / Arthrofibrosis: Exact preoperative planning and anatomical restoration are vital to prevent complications such as stiffness and instability in the surgical management of proximal ulna fractures [10]. Anatomical restoration of the trochlea is important for restoring elbow function and preventing varied, mostly minor complications in intercondylar fractures of the humerus [72].

Aseptic Loosening: Understanding normal and degenerative anatomy is necessary to prevent complications such as glenoid loosening or cuff failure in anatomic and reverse shoulder arthroplasty [73].

Other Considerations: The single-incision arthrotunneling technique for distal biceps tendon rupture has a reduced complication profile compared to a two-incision approach [20]. Further biomechanical and outcome data are needed to determine if smaller screws reduce fracture risk without compromising fixation strength in subpectoral biceps tenodesis [13].

Recovery

Light activity (weeks): Evidence does not specify a week range for light activity or desk work.

Full activity (months): Evidence does not specify a month range for full activity or return to sport.

Complete recovery / outcome plateau (months): Satisfactory function is observed at the 2.5-year follow-up for customized treatment using a custom-made 3D-printed prosthesis for grade II chondrosarcoma of the proximal ulna [71].

Rehabilitation protocol: The time for evolution of juvenile osteochondritis of the radial head appeared to be about two years [83]. Open reduction of interposed tissues in irreducible isolated anteromedial radial head dislocation due to ruptured anterior capsule and annular ligament can result in a good functional outcome, at least in the short term [84].

Functional milestones: Evidence does not specify validated PROM trajectories or outcome-measure benchmarks.

Other Considerations: Eight studies followed International Society of Biomechanics standards for quantifying upper body kinematics [1]. Biomechanical and clinical studies are needed to understand the true clinical relevance of anatomic variations in the ulnar greater sigmoid notch coverage angle [2]. Recent changes in elbow arthroplasty device design and implantation methods are driven by biomechanical and clinical outcome-based research to better reproduce elbow kinematics, resulting in more durable and long-lasting joint replacement procedures [3]. Patient-specific musculoskeletal modeling of shoulder joint biomechanics can contribute significantly to predicting pathology and optimizing postoperative function [5]. The article reviews the literature surrounding the biomechanics of bony and dynamic stabilizers of the elbow while drawing clinically relevant biomechanical observations [6]. Longitudinal stability of the forearm relies on the radial head, interosseous membrane, and distal radioulnar joint working together [8]. Further clinical studies are necessary to determine the actual functional impact of mechanoreceptors and free nerve endings in the lateral collateral ligament beyond mechanical stabilization [9]. Conservative treatment or non-anatomical repair of a ruptured distal tendon of the biceps brachii results in significant loss of supination strength and variable loss of flexion strength [15]. At time zero, ulnar collateral ligament reconstruction (UCLR) has inferior biomechanical properties compared with the native intact ligament [23]. The identification of particular, concerning high-risk biomechanical factors in those who have had UCLR was more common and identifiable versus controls [24]. Radiocapitellar replacement remains a new technology requiring further long-term follow-up before general recommendations can be made [78]. The study evaluated the time-zero biomechanical performance of UCL docking reconstruction with and without an internal brace compared to native UCL properties [85].

Key Evidence

  • [L4] Eight studies followed International Society of Biomechanics standards for quantifying upper body kinematics. (10.1016/j.jelekin.2018.02.011)
  • [L5] Biomechanical and clinical studies are needed to understand the true clinical relevance of these anatomic variations. (10.1016/j.jse.2015.06.006)
  • [L5] Recent changes in device design and implantation methods are driven by biomechanical and clinical outcome-based research to better reproduce elbow kinematics, resulting in more durable and long-lasting joint replacement procedures. (10.1302/2058-5241.2.160064)
  • [L5] Patient-specific musculoskeletal modeling of shoulder joint biomechanics can contribute significantly to predicting pathology and optimizing postoperative function. (10.1016/j.jseint.2024.04.006)
  • [L5] This article reviews the literature surrounding the biomechanics of bony and dynamic stabilizers of the elbow while drawing clinically relevant biomechanical observations. (10.1016/j.jhsa.2020.01.016)
  • [L4] Understanding elbow biomechanics and the injury mechanism provides valuable insight into the variations of pathology that may be observed. (10.5435/jaaos-d-14-00023)
  • [L4] The review outlines the integrated anatomy and biomechanics of the forearm unit, emphasizing that longitudinal stability relies on the radial head, interosseous membrane, and distal radioulnar joint working together, and discusses current diagnostic and treatment options. (10.1111/j.1758-5740.2012.00207.x)
  • [L5] However, further clinical studies are necessary to determine the actual functional impact beyond mechanical stabilization. (10.1016/j.jse.2025.04.005)
  • [L5] Exact preoperative planning and anatomical restoration are vital to allow early rehabilitation and prevent complications such as stiffness and instability. (10.1302/2058-5241.4.180022)
  • [L5] The authors propose a pathophysiology-based treatment algorithm grading tendinopathy into four distinct grades to guide management and future investigation. (10.1177/2325967116670635)
  • [L5] This study provides the upper extremity surgeon with information that may aid in restoring elbow biomechanics and preserving range of motion in these patients. (10.1016/j.jse.2014.05.003)
  • [L5] Further biomechanical and outcome data are needed to determine if smaller screws reduce fracture risk without compromising fixation strength. (10.1016/j.arthro.2017.06.003)
  • [L5] A thorough understanding of biomechanical principles and neurological pathways is necessary for the hand surgeon. (10.1177/17531934261434453)
  • [L4] Conservative treatment or non-anatomical repair results in significant loss of supination strength and variable loss of flexion strength. (10.2106/00004623-198567030-00011)
  • [L5] This article discusses the basic anatomy of the elbow and the biomechanics of this joint, noting that a combination of bony articulation and soft-tissue stabilizers accounts for the elbow's stability and complex kinematics. (10.1016/j.csm.2004.06.008)
  • [L4] The anatomic considerations illustrated by these two cases may provide guidance in assessment of atypical symptoms arising from impingement on soft-tissue structures and aid in planning for surgical resection. (10.1016/j.xrrt.2021.01.001)
  • [Paper] With appropriate management and early mobilisation good functional results can be expected in the majority of patients. (10.1016/j.injury.2008.12.013)
  • [L5] The single-incision arthrotunneling technique is a safe and effective repair that recreates the anatomic footprint and biomechanics of the native biceps and has a reduced complication profile compared to a two-incision approach. (10.1177/17585732211034818)
  • [L3] These morphological knee joint differences may help determine the alignment of prostheses in total knee arthroplasty. (10.1186/s12891-019-2737-3)
  • [L5] Tendon transfers remain a necessary and powerful technique for regaining lost function of the arm, with core principles and biomechanics reviewed alongside common and less well-described transfers. (10.1016/j.hcl.2016.05.001)
  • [L1] At time zero, UCLR has inferior biomechanical properties compared with the native intact ligament. (10.1177/23259671251407657)
  • [L3] The identification of particular, concerning high-risk biomechanical factors in those who have had UCLR was more common and identifiable versus controls. (10.1177/2325967124s00346)
  • [L5] This article provides evidence that evaluation of upper limb joint function may be performed without the use of instruments and using only clinical means to diagnose in most cases. (10.1016/s0749-0712(03)00029-5)
  • [L5] A comprehensive approach to the physical examination of the elbow, including special tests, may facilitate improved diagnosis of elbow pathology. (10.5435/jaaos-d-16-00622)
  • [L5] This instructional course lecture reviews the anatomy, biomechanics, diagnosis, and treatment of acute dislocations and subluxations of the distal radio-ulnar joint, delineating criteria for simple and complex dislocations and discussing management of associated complications. (10.2106/00004623-199506000-00017)
  • [L5] Radial head excision causes altered elbow kinematics and increased laxity. (10.2106/00004623-200408000-00018)
  • [L5] Elbow position affects the kinematics of the distal radioulnar joint, which are primarily affected by forearm rotation and secondarily by elbow flexion. (10.1016/j.jhsa.2009.04.025)
  • [L4] Diagnosis by physical examination was challenging, but ultrasonography proved useful for diagnosis. (10.1016/j.jhsa.2019.03.005)
  • [Paper] The forearm operates as a series of interconnected parts where damage to one can affect stability in multiple areas, and physicians need a holistic understanding of these components to quickly diagnose the proper injury patterns before the condition worsens. (10.1016/j.hcl.2020.06.001)
  • [L5] Biomechanical characteristics of elbows which underwent Docking surgical reconstructions at 30 degrees of elbow flexion appear to more closely approximate those of the intact elbow than reconstructions performed at 90 degrees of elbow flexion. (10.1016/j.arthro.2013.07.111)
  • [L5] This biomechanical study demonstrates that specific angular corrections enhance joint congruency and stability. (10.1016/j.jhsa.2025.10.010)
  • [L5] Elbow joint surface stress distributions vary according to different elbow flexion angles. (10.1186/s13018-014-0060-0)
  • [L4] Five kinematic parameters during the stride phase and their combination were associated with peak elbow varus torque. (10.1177/2325967120968068)
  • [L5] The primary goal of treatment is stable reduction of the ulnohumeral joint and functional elbow motion. (10.2106/jbjs.m.00817)
  • [L5] The elbow consists of static and dynamic stabilizers that function in synchrony to prevent elbow instability. (10.1016/j.jhsa.2016.11.025)
  • [L4] Normal kinematics was preserved in the osteoarthritic elbow with a normal radiocapitellar joint (OAN group). (10.1016/j.jhsa.2013.02.006)
  • [L4] When evaluating an MRI in supination, one should be aware that in sagittal and coronal plane a physiologic but higher joint incongruency can be expected. (10.1016/j.jse.2023.02.099)
  • [Case_report] The authors recommend performing an MRI if healing does not occur by a reasonable time despite successful bony healing to assess potential cartilage damage. (10.1007/s00402-005-0018-0)
  • [L4] Compared with previously reported treatment options, this surgery achieved better functional outcomes, with the elbow and wrist functioning well at 3-year follow-up. (10.1177/17531934221095919)
  • [L5] The carrying angle of the forearm remains constant as the elbow flexes. (10.2106/00004623-198163040-00003)
  • [L4] MRI determination of PIN position is reliable and consistent with prior cadaveric study. (10.1016/j.arthro.2020.12.118)
  • [L5] The biomechanics of throwing in baseball and football differ significantly, leading to distinct injury patterns between sports. (10.1177/23259671251407244)
  • [L2] There is no significant biomechanical advantage of one UCL reconstruction technique over another. (10.1016/j.arthro.2014.04.057)
  • [L5] The ALL exhibits a peripheral nerve structure, primarily type I and IV mechanoreceptors. (10.1016/j.arthro.2019.05.023)
  • [L5] Detailed analysis of the fibers of the MUCL allows for further understanding of its kinematic function. (10.1177/2325967118762750)
  • [L4] Asymptomatic non-unions should not be considered as failures as they are related to satisfactory outcomes, and no additional surgery should be performed. (10.1016/j.jse.2021.03.067)
  • [Case_report] In this case, a successful outcome was obtained with conservative treatment of a nondisplaced fracture under strict and close clinical and radiographic controls. (10.1016/j.jse.2019.11.038)
  • [L5] Anatomic ALL reconstruction did not reduce anterolateral rotational laxity. (10.1177/2325967116s00027)
  • [Paper] Surgical anatomical repair is typically performed in acute complete ruptures, while nonoperative treatment is reserved for partial ruptures or patients unfit for surgery. (10.1016/j.injury.2013.01.003)
  • [L4] Although outcomes are generally satisfactory in the short to midterm, implant failure and catastrophic complications can occur over time. (10.1016/j.hcl.2015.06.008)
  • [L5] Surgical management is indicated for progressive, painful, unilateral deformity or leg-length discrepancy, while moderate nonprogressive deformity often does not require surgery. (10.5435/00124635-199803000-00003)
  • [L4] Early identification of anterior capsule injury patterns via MRI could inform treatment decisions, particularly in cases where stable surgical fixation is challenging. (10.5397/cise.2024.00955)
  • [L4] This surgical technique is a conservative option that provides satisfactory functional outcomes in the short term. (10.1016/j.otsr.2021.102829)
  • [L3] Radial head diameters can be accurately inferred from 2 humeral dimensions by magnetic resonance imaging. (10.1016/j.jhsa.2020.11.027)
  • [Case_report] Management principles remain the same with stabilisation of the entire bone and early mobilisation being appropriate. (10.1186/1749-799x-5-26)
  • [L4] The preoperative convergence angle, reflecting soft-tissue laxity, can be a practical and simple radiographic finding for predicting lateral mid-lexion laxity. (10.1007/s00167-021-06846-8)
  • [Case_report] This case highlights that excellent functional outcomes can be achieved with a conservative approach even after extensive soft tissue damage from minor injury. (10.1186/1471-2474-3-1)
  • [L4] The authors state this method is their treatment of choice for gap non-unions of the upper extremity. (10.2106/00004623-198163020-00007)
  • [L4] This study describes anatomical structures of the PRUJ and highlights a significant negative relationship between the Alpha Angle and the Beta Angle, emphasizing the biomechanical impact of joint congruence on bony coverage. (10.1016/j.xrrt.2026.100695)
  • [Case_report] Satisfactory function is seen at the 2.5-year follow-up. (10.1016/j.jseint.2020.07.008)
  • [L4] While complications were varied and mostly minor, the study demonstrates that anatomical restoration of the trochlea is important for restoring elbow function. (10.2106/00004623-198567020-00008)
  • [L5] Understanding normal and degenerative anatomy is necessary to restore joint function and prevent complications such as glenoid loosening or cuff failure. (10.1302/2058-5241.6.210014)
  • [L4] Nonoperative treatment for Panner disease resulted in favorable outcomes in 7 patients. (10.1177/23259671251372617)
  • [L4] This therapeutic option appears to be the most efficient and least problematic in the management of the absence of elbow flexors in radial clubhand. (10.1016/j.jse.2015.01.021)
  • [L4] Increased MRI signal in the ECRB origin is common in symptomatic and in asymptomatic elbows. (10.1016/j.jse.2016.01.033)
  • [L5] The angulation between the posterior plane surface and the FE axis is highly variable (95% CI range: 18°). (10.1016/j.jseint.2024.10.016)
  • [Paper] Radiocapitellar replacement remains a new technology requiring further long-term follow-up before general recommendations can be made. (10.1016/j.hcl.2011.01.006)
  • [Case_report] Clinicians must maintain a high suspicion level and examine adjacent joints to avoid overlooking associated injuries. (10.1016/j.jse.2019.04.038)
  • [L4] These findings may be relevant to anatomic prosthesis design. (10.1016/j.jse.2016.10.012)
  • [L4] Joint congruence of healthy elbows on MRI increased significantly when changing from supination to pronation. (10.1177/03635465251330152)
  • [L5] This study shows that the use of MR technology by high-volume subspecialist surgeons provides similar, to better results than traditional FH technique for version and inclination. (10.1016/j.jse.2023.02.085)
  • [Case_report] Open reduction of interposed tissues can result in a good functional outcome, at least in the short term. (10.1177/17585732211039459)
  • [L5] The study evaluated the time-zero biomechanical performance of UCL docking reconstruction with and without an internal brace compared to native UCL properties. (10.1016/j.jse.2019.04.061)

See Also

References

[1] Use of optical motion capture for the analysis of normative upper body kinematics during functional upper limb tasks: A systematic review. Journal of Electromyography and Kinesiology. 2018. DOI: 10.1016/j.jelekin.2018.02.011

[2] The ulnar greater sigmoid notch “coverage angle”: bone and cartilage contribution. Magnetic resonance imaging anatomic study on 78 elbows. Journal of Shoulder and Elbow Surgery. 2015. DOI: 10.1016/j.jse.2015.06.006

[3] Current concepts in elbow arthroplasty. EFORT Open Reviews. 2017. DOI: 10.1302/2058-5241.2.160064

[4] Chapter 26 Anatomy, Biomechanics, Physical Examination, and Imaging of the Elbow. 2020.

[5] Modeling the future of shoulder arthroplasty. JSES International. 2025. DOI: 10.1016/j.jseint.2024.04.006

[6] Elbow Biomechanics: Bony and Dynamic Stabilizers. The Journal of Hand Surgery. 2020. DOI: 10.1016/j.jhsa.2020.01.016

[7] Management of Complex Elbow Dislocations. Journal of the American Academy of Orthopaedic Surgeons. 2015. DOI: 10.5435/jaaos-d-14-00023

[8] Re: ‘Longitudinal instability of the forearm: anatomy, biomechanics, and treatment considerations’. Shoulder & Elbow. 2012. DOI: 10.1111/j.1758-5740.2012.00207.x

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[10] Fractures of the proximal ulna: current concepts in surgical management. EFORT Open Reviews. 2019. DOI: 10.1302/2058-5241.4.180022

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