Diagnosis and Treatment of Shoulder Pain in the Overhead Athlete

Educational Objectives

The goal of this program is to improve the management of shoulder pain in overhead athletes. After hearing and assimilating this program, the clinician will be better able to:

1. Differentiate between natural adaptations in the throwing shoulder and shoulder pathology.
2. Use assessment tools to identify causes of shoulder pain.
3. Develop rehabilitation programs to treat shoulder pain in overhead athletes.

Summary

History: first treatment protocols were developed in 1888 for shoulder problems in baseball players; ossification of the posterior-inferior glenoid rim was noted in 1941; surgical procedures emerged for acquired anterior laxity in the 1970s and for anterior instability in the 1980s; internal impingement was first described in 1992; the concepts of the “SICK” scapula (scapular malposition, inferior medial border prominence, coracoid pain, scapular dyskinesis), posterior capsular contracture, and the importance of the kinetic chain to the throwing shoulder were formulated in 2003

Phases of throwing: windup — flexed elbow with forearm pronation; early cocking — when the ball is removed from the glove until the forward foot hits the ground; the shoulder is abducted and externally rotated; late cocking — the shoulder abducts further in maximal external rotation (ER), with elbow flexion 90 to 120 degrees and increased forearm pronation to 90 degrees; shoulder ER rapidly increases from 45 degrees to 170 degrees, with greatly increasing torque; acceleration — rapid internal rotation (IR) up to 80 degrees and adduction of the humerus, with rapid elbow extension; terminates with ball release; followthrough — excess kinetic energy dissipates with eccentric rotator cuff contraction; the posterior capsule absorbs ≥100% of the pitcher’s body weight, predisposing the shoulder to injury

Pathophysiology: throwing transfers energy from the lower extremities and core to the upper limbs; weakness in legs or trunk requires the shoulders to produce increased rotational velocity, creating heightened risk for injury; a pitcher with weakness in the kinetic chain places the throwing arm behind the trunk in ER, stressing the capsular labrum; normal adaptations — increased ER (10-20 degrees), decreased IR, possible increased humeral retroversion, and anterior laxity; treatment of natural adaptations may affect throwing ability

Clinical symptoms: deep, aching shoulder pain (noted in the late cocking or early acceleration phases), “dead” arm, reduced velocity, and poor recovery between games; anterior shoulder pain indicates pathology in the anterior labral capsule, biceps, or subscapularis; posterior shoulder pain indicates posterior labral tears, infraspinatus tears or posterior capsule contraction

Physical examination: inspect the shoulder from the anterior and posterior positions with adequate exposure; examine the scapular position at rest and through active range of motion; winging of the scapula indicates scapular dyskinesis; examine the full kinetic chain before obtaining imaging; scrutinize active and passive range of motion of the shoulder for glenohumeral internal rotation deficit (GIRD); the dominant arm should have the same arc of motion as the nondominant arm, with a slight shift into ER; the amount of IR lost in the dominant arm equals the amount of ER gained; GIRD is defined as >20 degrees of IR loss, compared with the contralateral side; evaluate rotator cuff strength; weakness in the rotator cuff may be indicative of a partial-thickness rotator cuff tear; assess for signs of internal or external impingement; perform load and shift assessment for anterior capsular laxity; inspect for multidirectional instability and presence of a sulcus sign; sulcus sign is more commonly seen in female overhead athletes; other examinations include apprehension relocation examination, O'Brien test, and tests for biceps pathology

Magnetic resonance imaging (MRI): the imaging modality of choice but indicated only after unsuccessful conservative treatment; MRI often reveals shoulder tears that are natural adaptations not requiring treatment; rehabilitation is recommended before obtaining MRI; Miniaci et al (2002) found labral tears in 79% of asymptomatic pitchers; Connor et al (2003) found rotator cuff tears in the dominant shoulder in 40% of asymptomatic athletes, all of whom remained asymptomatic after 5 yr; abnormal findings are expected on MRI of overhead athletes

Patterns of injury: superior labrum anterior-to-posterior (SLAP) tears are most common; the typical location is the posterior superior labrum; the undersurface of the rotator cuff often has partial thickness tearing at the junction of the supraspinatus and infraspinatus; anterior capsular laxity and contracture of the posterior capsule are common; anterior instability is less common; SLAP tears — the labrum is peeled back off the glenoid during ER of the shoulder; a “good” SLAP tear is a natural adaptation that allows velocity generation through ER; “bad” SLAP tears cause pain; SLAP tears with internal impingement result from contact between the posterosuperior rotator cuff and the posterior superior labrum; posterior rotator cuff tears — caused by eccentric forces generated during the deceleration phase of the throwing motion, contact between the rotator cuff and the labrum (ie, internal impingement), and increased contact between the rotator cuff and labrum resulting from posterior capsular contracture

Painful throwing shoulder: a combination of SLAP and rotator cuff tears; progression of natural adaptations to pathologic tears is unclear and likely multifactorial

Internal impingement: contact between the articular supraspinatus and infraspinatus and the posterior glenoid; typically occurs in the externally rotated and abducted (ABER) position;

GIRD: <20 degrees difference between the arms is not considered GIRD (established by Myers et al [2006] in a study on posterior capsular tightness); routine shoulder stretching slows or halts progression to GIRD

Posterior capsular contracture: may cause or worsen internal impingement, according to Grossman et al (2005); the sequence of pathology in shoulder injury is not clear

Glenohumeral retroversion: Crockett et al (2002) found that throwers had an increased humeral retroversion of 17 degrees and increased glenoid retroversion of 3 degrees in their dominant arm; these are adaptive changes that occur in early adolescence; incidence is likely to increase due to current trends in youth athletics

Anterior instability: no longer considered to be the cause of shoulder pathology; studies on reconstructive surgery developed in the 1990s to address anterior laxity found the procedure unsuccesful in allowing athletes to return to previous levels of prowess; focus has shifted to contributions of the kinetic chain to shoulder pathology

Rotator cuff impingement: a fatigued rotator cuff allows increased humoral head translation and causes internal impingement

Scapular dyskinesis: weakness of the trapezius, rhomboid, and serratus muscles creates excessive scapular protraction at rest and decreased retraction; resulting acromial elevation causes rotator cuff impingement; scapular rehabilitation strengthens the surrounding musculature to attain appropriate scapular positioning

Treatment: comprehensive rehabilitation program including posterior capsular stretching, scapular musculature and eccentric rotator cuff strengthening, correcting throwing motion mechanics, and strengthening the lower extremities and core; surgery is recommended only when an extensive rehabilitation program proves unsuccessful

SLAP repair surgery: the superior labrum has normal variations, including sublabial recesses, sublabial foramina, and the Buford complex, that must be differentiated from true pathology; a 1998 study of 102 SLAP repairs found 87% of surgeries produced excellent results; a 2001 study found 89% of players returned to play after a SLAP repair

2005 study: found that success depended on the cause of the SLAP tear, with surgery for traumatic injury more successful than that for overuse injury; the longer time to treatment for baseball players with chronic lesions may explain their inability to return to play at a high rate after a SLAP repair; resumption of repetitive throwing motion after surgery also may contribute to low success rates

SLAP repairs in an active population: a recent study reported a 31% failure rate

Other surgical treatments: biceps tenodesis — associated with a low rate of return to play in the overhead athlete; posterior capsular release — performed in tandem with rehabilitation; only considered in throwers who are recalcitrant to IR stretching; rate of return to play is low after isolated posterior capsule release; internal impingement surgery — no longer commonly performed; partial-thickness rotator cuff repairs — for <50% tear, debridement is recommended; for tears between 50% to 75%, transtendinous repair of the delaminated portion is recommended; tears >75% are converted to full-thickness tears and surgically repaired; 89% of patients had returned to play at 12 mo follow-up; another study found 8% of players (with prior surgery, mostly debridement) returned to a high level of pitching after open rotator cuff repair; the study concluded that more aggressive treatment of partial-thickness rotator cuff tears may be helpful; pitchers with a full-thickness rotator cuff tear are unlikely to return to play after repair

Readings

Burkhart SS, Morgan CD, Kibler WB. The disabled throwing shoulder: spectrum of pathology part III: the SICK scapula, scapular dyskinesis, the kinetic chain, and rehabilitation. Arthroscopy. 2003;19:641-661; doi: 10.1016/s0749-8063(03)00389-x; Chu SK, Jayabalan P, Kibler WB, et al. The kinetic chain revisited: new concepts on throwing mechanics and injury. PM R. 2016;8:S69-S77; doi: 10.1016/j.pmrj.2015.11.015; Connor PM, Banks DM, Tyson AB, et al. Magnetic resonance imaging of the asymptomatic shoulder of overhead athletes: a 5-year follow-up study. Am J Sports Med. 2003;31:724-727; doi: 10.1177/03635465030310051501; Crockett HC, Gross LB, Wilk KE, et al. Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers. Am J Sports Med. 2002;30:20-26; doi: 10.1177/03635465020300011701; DeFroda SF, Goyal D, Patel N, et al. Shoulder instability in the overhead athlete. Curr Sports Med Rep. 2018;17:308-314; doi: 10.1249/JSR.0000000000000517; Economopoulos KJ, Brockmeier SF. Rotator cuff tears in overhead athletes. Clin Sports Med. 2012;31:675-692; doi: 10.1016/j.csm.2012.07.005; Grossman MG, Tibone JE, McGarry MH, et al. A cadaveric model of the throwing shoulder: a possible etiology of superior labrum anterior-to-posterior lesions. J Bone Joint Surg Am. 2005;87:824-831; doi: 10.2106/JBJS.D.01972; Ide J, Maeda S, Takagi K. Sports activity after arthroscopic superior labral repair using suture anchors in overhead-throwing athletes. Am J Sports Med. 2005;33:507-514; doi: 10.1177/0363546504269255; Mazoué CG, Andrews JR. Repair of full-thickness rotator cuff tears in professional baseball players. Am J Sports Med. 2006;34(2):182-189. doi:10.1177/0363546505279916; Miniaci A, Mascia AT, Salonen DC, et al. Magnetic resonance imaging of the shoulder in asymptomatic professional baseball pitchers. Am J Sports Med. 2002;30:66-73; doi: 10.1177/03635465020300012501; Myers JB, Laudner KG, Pasquale MR, Bradley JP, Lephart SM. Glenohumeral range of motion deficits and posterior shoulder tightness in throwers with pathologic internal impingement. Am J Sports Med. 2006;34(3):385-391. doi:10.1177/0363546505281804; Reinold MM, Gill TJ. Current concepts in the evaluation and treatment of the shoulder in overhead-throwing athletes, part 1: physical characteristics and clinical examination. Sports Health. 2010;2:39-50; doi: 10.1177/1941738109338548; Reinold MM, Gill TJ, Wilk KE, et al. Current concepts in the evaluation and treatment of the shoulder in overhead throwing athletes, part 2: injury prevention and treatment. Sports Health. 2010;2:101-115; doi: 10.1177/1941738110362518; Tokish JM. Acquired and adaptive changes in the throwing athlete: implications on the disabled throwing shoulder. Sports Med Arthrosc Rev. 2014;22:88-93; doi: 10.1097/JSA.0000000000000015.

Disclosures

For this program, the following relevant financial relationships were disclosed and mitigated to ensure that no commercial bias has been inserted into this content: Dr. Werner is a consultant or speaker for Arthrex Inc. Members of the planning committee reported nothing to disclose.

Acknowledgements

Dr. Werner was recorded exclusively for Audio Digest using virtual teleconference software. Audio Digest thanks the speakers for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

OR450201

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.