Disabled Throwing Shoulder 2021 Update: Part 1-Anatomy and Mechanics.

The purpose of this article is to provide updated information for sports health care specialists regarding the Disabled Throwing Shoulder (DTS). A panel of experts, recognized for their experience and expertise in this field, was assembled to address and provide updated information on several topics that have been identified as key areas in creating the DTS spectrum. Each panel member submitted a concise presentation on one of the topics within these areas, each of which were then edited and sent back to the group for their comments and consensus agreement in each area. Part 1 presents the following consensus conclusions and summary findings regarding anatomy and mechanics, including: 1) The current understanding of the DTS identifies internal impingement, resulting from a combination of causative factors, as the final common pathway for the great majority of the labral pathoanatomy; 2) intact labral anatomy is pivotal for glenohumeral stability, but its structure does not control or adapt well to shear or translational loads; 3) the biceps plays an active role in dynamic glenohumeral stability by potentiating "concavity compression" of the glenohumeral joint; 4) the ultimate function of the kinetic chain is to optimize the launch window, the precise biomechanical time, and position for ball release to most effectively allow the ball to be thrown with maximum speed and accuracy, and kinetic chain function is most efficient when stride length is optimized; 5) overhead throwing athletes demonstrate adaptive bony, capsular, and muscular changes in the shoulder with repetitive throwing, and precise measurement of shoulder range of motion in internal rotation, external rotation, and external rotation with forearm pronation is essential to identify harmful and/or progressive deficits. LEVEL OF EVIDENCE: Level V, expert opinion.

Management of disorders of the rotator cuff: proceedings of the ISAKOS upper extremity committee consensus meeting.

The goal of this article is to consolidate the International Society of Arthroscopy, Knee Surgery & Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee's (UEC's) current knowledge on rotator cuff disease and management, as well as highlight key unresolved issues. The rotator cuff is an anatomically complex structure important for providing glenohumeral function and stability as part of a closed chain system. Current consensus suggests rotator cuff injuries are most accurately diagnosed, at levels similar to diagnosis by magnetic resonance imaging, with a combination of cuff- and impingement-specific clinical tests. Updates in the understanding of acromion morphology, the insertional anatomy of the rotator cuff, and the role of suprascapular nerve release may require changes to current classification systems and surgical strategies. Although initial management focuses on nonoperative protocols, discussion continues on whether surgery for isolated impingement is clinically more beneficial than rehabilitation. However, clear indications have yet to be established for the use of single- versus double-row repair because evidence confirms neither is clinically efficacious than the other. Biceps tenodesis, however, in non-isolated cuff tears has proven more successful in addressing the etiology of shoulder pain and yields improved outcomes over tenotomy. Data reviewing the benefits of tendon transfers, shoulder prostheses, and mechanical scaffolds, as well as new research on the potential benefit of platelet-rich plasma, pluripotential stem cells, and gene therapies, will also be presented.

Managing Scapular Dyskinesis.

Scapular dyskinesis, the impairment of optimal scapular position and motion, is common in association with shoulder injury. A comprehensive evaluation process can show the causative factors and lead to effective treatment protocols. The complexity of scapular motion and the integrated relationship between the scapula, humerus, trunk, and legs suggest a need to develop rehabilitation programs that involve all segments working as a unit rather than isolated components. This is best accomplished with an integrated rehabilitation approach that includes rectifying deficits in mobility, strength, and motor control but not overtly focusing on any one area.

Neuromuscular adaptations in shoulder function and dysfunction.

Neuromuscular activity, organized in coordinated patterns, forms the basis of task-specific function in sports and exercise. The content and extent of these patterns may be variable, but include elements of activation/inhibition, co-activation, concentric/eccentric activation, proximal-to-distal activation, plyometric activation, and preactivation stiffness. They may be based on inherent neuromuscular architecture, but are commonly affected by positive or negative adaptations to imposed functional demands. Positive neuromuscular adaptations improve the efficiency of performing the task, which can result in less energy expenditure, maximum force delivered to the task, and protection of involved joints from excessive loads/motions, and improve the effectiveness of task performance. They frequently result from specific training in task mechanics and optimal conditioning of the neuromuscular structures involved in the task. Negative neuromuscular maladaptations can affect the efficiency of performing the task, increase energy expenditure and loads, decrease the effectiveness of task performance, and can be associated with clinical presentation of injury symptoms. They can result from overload, injury, and/or limited recovery. This chapter will focus specifically on shoulder joint function to provide examples of positive adaptations and negative maladaptations. It will then provide guidelines for clinical evaluation, treatment of clinical injury, and training/conditioning, based on understanding the neuromuscular activation.

Kinetic chain contributions to elbow function and dysfunction in sports.

The elbow functions in throwing and other athletic activities as a link in the kinetic chain of force development, regulation, and transfer. Efficient function, with maximal performance and minimal injury risk, requires optimum activation of all the link in the kinetic chain. Injury is often associated with alterations in force production or regulation capabilities in links that may be distant to the site of injury. Evaluation of injured athletes should include screening examinations for these areas, and treatment and conditioning should also include these areas.

Clinical utility of traditional and new tests in the diagnosis of biceps tendon injuries and superior labrum anterior and posterior lesions in the shoulder.

BACKGROUND: Clinical tests are a key element in diagnosing shoulder lesions. PURPOSE: This study examined the clinical utility of traditional and new examination tests, the upper cut for biceps injuries, and the modified dynamic labral shear for superior glenoid labral lesions. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 2. METHODS: A total of 325 consecutive patients who were seen for shoulder pain underwent a standardized clinical testing battery. Six clinical tests that have been previously reported in the literature (Yergason's, Speed's, bear hug, belly press, O'Brien's, and anterior slide) and 2 new examination tests (upper cut and modified dynamic labral shear) were performed. Clinical examination findings were correlated with findings in those who came to surgery (101 patients). Sensitivity, specificity, accuracy, positive/negative predictive value, and positive/negative likelihood ratio were calculated for each test. A binary logistic regression analysis was used to determine which tests produced the most significant findings. RESULTS: For biceps disease, the bear hug and upper cut were most sensitive (0.79 and 0.73, respectively), whereas the belly press and Speed's test were most specific (0.85 and 0.81, respectively). The upper cut was most accurate (0.77) and produced the highest positive likelihood ratio (3.38). For labral injury, the modified dynamic labral shear demonstrated sensitivity of 0.72, specificity of 0.98, accuracy of 0.84, and a positive likelihood ratio of 31.57. A binary logistic regression analysis revealed that the combination of the upper cut and Speed's tests were significantly better at detecting biceps lesions (P = .021, R(2) = .400) than other tests, whereas labral lesions were best identified by combination of the modified dynamic labral shear and O'Brien's maneuvers (P = .045, R(2) = .641). CONCLUSION: The new tests are helpful additions to the clinical examination for shoulder injury. The modified dynamic labral shear test demonstrates high scores for clinical utility and exhibits a high likelihood ratio, indicating a significant probability of affecting the clinical decision, which should moderately or significantly improve the diagnostic conclusion and allow the clinician to be more efficient in making an accurate diagnosis.

Rehabilitation of the athlete's shoulder.

Optimal shoulder function is achieved through segmental activation along the kinetic chain. Alterations within the kinetic chain often contribute to shoulder injury. Therefore, a multi-factorial approach to shoulder rehabilitation, where the causes of shoulder pain as well as site of symptoms, should be implemented.