Management of Shoulder Injuries in the Throwing Athlete

The Problem

Shoulder injuries in the throwing athlete present a unique challenge. The act of throwing itself subjects the shoulder to extremes of motion and stress. This can be amplified even further in high lever throwing athletes. The drive to succeed for many throwing athletes causes them to push their shoulders to near failure on a daily basis. The dominant shoulder is subjected to extreme positions and tremendous stresses as successful delivery requires transfer of the force generated from the legs and core of the body to the throwing arm, as well as precise coupling of scapulothoracic motion and glenohumeral joint rotation to achieve peak velocity and accuracy.

Alterations in the throwing motion due to overuse, muscle fatigue, and poor mechanics put the athlete at increased risk for a variety of pathologic conditions. These include capsular tightness, internal impingement, superior labrum anterior to posterior (SLAP) lesions, articular-sided partial rotator cuff tears, and even full thickness ruptures of the tendon. The pathomechanics that lead to these injuries are highly controversial; however, amongst the theories for causation, the principles of scapular dyskinesis and glenohumeral internal rotation deficit are often related to symptoms of internal impingement. These adaptations occur over time and to varying degrees, often enabling the athlete to succeed.

The diagnosis and treatment is no less confusing as many asymptomatic throwing athletes will often have findings by magnetic resonance imaging (MRI) and arthroscopy that in other contexts may be pathological; though, in the highly competitive overhead athlete the clinical significance of these findings is still debatable.

Most of these injuries are amenable to non-operative treatment encompassing rest and flexibility work, followed by disciplined rehabilitation programs to improve scapular kinetics and normalize glenohumeral range of motion. Surgery is indicated in cases where conservative non-operative treatment fails to relieve the athlete’s pain and get them back to the playing field.

Clinical Presentation

The throwing athlete who presents to the orthopaedic surgeon will often complain of posterior or deep shoulder pain exacerbated by the late cocking or early acceleration phase of throwing. The patient may report stiffness, weakness, or a decrease in velocity during the weeks leading up to presentation and will often be unable to cite a specific injury that caused the decline in performance. Throwers will rarely have any complaints of instability.

Diagnostic Workup

Classic physical exam findings

The first part of the exam should include inspection of the patient’s dominant and non-dominant shoulders noting any asymmetries. The dominant arm will often have hypertrophy of the shoulder girdle musculature in comparison to the other side. Note should be made of any wasting in the infraspinatus fossa. The static position of the scapula should be noted as in overhead athletes it often demonstrates a pathologic protracted position with medial border prominence and outward tilting as described by Burkhart. Palpation of the shoulder girdle will reveal tenderness over the coracoid from pectoralis minor tendonitis. Tenderness over the bicipital groove may be due to biceps tendonitis or a SLAP lesion. Laxity of the shoulder should be assessed and frequently reveals global laxity with a positive sulcus sign or increased anterior translation of the throwing arm.

Range of motion tests should be done with great detail. The dominant arm will show symmetric forward flexion and abduction of the shoulder. With the arm at the side the external rotation may be symmetric but there will be decreased internal rotation on the dominant side. While supine with the shoulder at 90 degrees of abduction in the scapular plane and the elbow in 90 degrees of flexion the throwing arm will have increased external rotation and decreased internal rotation; however, the total range of motion arc in this position should be similar.

A difference in glenohumeral internal rotation, in the above described supine position, of 20 degrees or a difference in total glenohumeral rotation of greater than 8 degrees is considered pathologic. Strength testing of the shoulder should be done to assess the integrity of the rotator cuff. Overhead athletes will often have asymmetric strength with decreased external rotation strength and increased internal rotation strength compared to the non-dominant side. Any signs of weakness in 90 degrees of abduction in the scapular plane or with external rotation should be concerning for a rotator cuff injury.

Provocative maneuvers should also be done to assess for any injuries to the rotator cuff or labrum. The patient should be tested for signs of impingement with the Hawkins or Neer test. The internal impingement relocation test can also be done with the patient supine in maximal external rotation and horizontal abduction to recreate the patient’s pain. If the patient has less pain with posterior pressure applied to the arm in the above position then the test is positive and indicative of internal impingement. Superior labrum anterior to posterior lesions should be suspected in patients with a positive O’Brien’s test. Biceps tendinopathy can be elicited with a Speed’s test or with groove pain in the 90/90 position with resisted internal rotation. Torso and lower limb flexibility should be assessed for strength and flexibility.

Imaging findings

Plain radiographs are the initial imaging modality of choice. A three-view series should be done at minimum consisting of standard anteroposterior (AP), true AP, and axillary views. The humeral head, glenoid, and glenohumeral joint should all be evaluated for abnormal morphology or fractures. The axillary view may demonstrate a Bennett lesion, commonly seen in throwing athletes, which is sclerosis of the posterior-inferior glenoid rim thought to be due to capsular traction. The greater tuberosity may also demonstrate sclerosis or cystic change from internal impingement. The acromioclavicular joint is also readily evaluated in these views and can be assessed for any injury or degenerative changes.

Magnetic resonance imaging is the most useful modality for evaluating the shoulder of the disabled throwing athlete. This can be performed with or without intra-articular contrast (MRI arthrogram). The interpretation of MRI findings in the disabled throwing athlete can be confusing as asymptomatic throwers have been shown to demonstrate adaptive changes such as increased humeral retroversion, glenoid changes, chronic SLAP tears, and partial thickness rotator cuff tears that would be considered a source of pain and disability under other circumstances.

In the symptomatic thrower the findings will often correlate with the history and physical exam; though, the exact nature of these injuries and exact nature by which they contribute to disability are not well understood. The posterior capsule may demonstrate a thickened appearance of the posterior inferior glenohumeral ligament consistent with glenohumeral internal rotation deficit (GIRD). These patients may also have associated posterior glenoid wear and sclerosis. Type 2 SLAP lesions are also associated with findings of GIRD.

In overhead athletes a common constellation of findings associated with posterosuperior impingement are posterosuperior labral injuries as well as partial articular-sided supraspinatus or infraspinatus tendinosis or tearing. In throwing athletes, it is especially important to always get a MRI with a specified abduction/external rotation (ABER) view to best demonstrate the abnormal posterior translation of the humeral head and abnormal contact between the greater tuberosity/rotator cuff and the superior labrum in this extreme position leading to symptoms of internal impingement. The articular-sided rotator cuff and superior labral injuries as well as injury or attenuation of the anterior inferior glenohumeral ligament are best seen with this view.

Special diagnostic tests

Electromyography and nerve conduction testing may be useful if muscle wasting or weakness cannot be explained by anatomic pathology. Potential sites of nerve injury, stretch, or compression can be elucidated using electrodiagnostic studies.

Non–Operative Management

Non–surgical care of shoulder dysfunction and injury in the throwing athlete can be very effective, and result in resolution and return to play. Shutting the athlete down from throwing activities for a variable period of time can be appropriate depending upon the degree of dysfunction. In patients with GIRD and scapular dyskinesis, non-operative management should focus on posterior capsule stretching and scapular rehabilitation.

A regimented program integrating scapular control and periscapular muscle strengthening should be employed under close supervision of a well-trained therapist once a full pain-free arc of motion can be accomplished. The thrower should have a disciplined posterior capsule maintenance stretching program with an emphasis on horizontal adduction of the arm and sleeper stretches on a daily basis.

Once the patient has a pain free arc, full range of motion, and strength the focus should move from flexibility and strengthening to kinematics of throwing with the final progression being to sport-specific activities before returning. A structured return to throw program is recommended not only to emphasize proper mechanics, but also to retrain muscles that have been rested from the throwing motion during the shutdown and rehabilitation period. Most throwing athletes with a symptomatic shoulder will respond with 4 to 6 weeks of a daily regimented program, but this can be very individualized.

Due to the high demands placed on the shoulder in high level throwing athletes, it is important for the athlete to continue their program throughout the season. For those who continue to worsen, have pain with daily activities, or have persistent motion deficits a further workup or surgery may be warranted.

The use of biologics (platelet rich plasma, stem cells, fat, etc.) remains controversial; further research is needed before surgeons can recommend for or against these treatments.

Indications for Surgery

The decision to proceed with surgery in the throwing athlete is based on the history and physical exam findings with correlating imaging and a failed course of non-operative treatment. In patients with the diagnosis of internal impingement who fail to improve after exhausting a full course of rehabilitation, a diagnostic arthroscopy with a plan to fix pathologic mechanical entities is warranted. Superior labrum anterior to posterior lesions may require repair. Partial thickness rotator cuff repairs may require debridement, but repair of what may be a natural adaptation of the athlete’s shoulder may be detrimental to the eventual return to play. Surgical repair should be considered in full thickness rotator cuff tears.

Surgical Technique

Necessary equipment/instrumentation

4 mm, 30 degree arthroscope
Motorized arthroscopic shaver
Radiofrequency ablation device

Patient set-up

For surgery the lateral decubitus position is preferred, but surgery can be done in the beach chair position. The endotracheal tube should be placed on the contralateral side of the operative shoulder and clear of any obstructions so that anesthesia has clear access to the airway. All bony prominences are adequately padded and non-operative extremities secured in a safe manner. The screen should be placed in a position so that the surgeon and assistant have unobstructed views. The tower and pump should be placed on the opposite side of the bed. The scrub assistant and table should be at the foot of the bed to allow easy passing of instruments.

Any number of devices may be used for traction of the operative arm. The preferred method of the authors is with the use of a pneumatic device that is positioned on the opposite side of the bed near the foot to provide the necessary abduction and joint distraction needed for visualization. This device also allows for dynamic examination of the shoulder during arthroscopy, to further demonstrate pathologic findings (i.e. peel back in SLAP lesions).

Step-by-step description of procedure

Exam under anesthesia

Once anesthesia has been properly administered the surgeon should perform another thorough physical exam to re-evaluate the patient’s range of motion and assess the stability of the shoulder.

Diagnostic arthroscopy

The procedure begins by first establishing a posterior portal that is positioned approximately 1 cm inferior and 2-3 cm medial to the posterior corner of the acromion. A #11 blade is used to make a 1 cm incision. The 30 degree arthroscope is then inserted into the joint through the posterior portal and a diagnostic arthroscopy should be performed in a systematic and stepwise fashion so that all components of the shoulder joint are adequately visualized.

The first step is assessment of the rotator interval and establishment of an anterior portal. This is made under direct visualization just above the subscapularis tendon. Once the portal is established, the entire joint is inspected starting with a full circumferential evaluation of the labrum, glenohumeral ligaments, glenoid and humeral head articular surfaces, long head of the biceps tendon, as well as the biceps-labral anchor. The intra-articular portion of the subscapularis tendon as well as the supraspinatus and infraspinatus tendons are scrutinized and probed to ensure integrity.

Rotator cuff tears

The most common rotator cuff lesions in throwing athletes are partial articular-sided injuries seen with internal impingement. The first step is to assess the quantity and quality of torn or delaminated rotator cuff tendon. This is done via the posterior portal, viewing the cuff from inside the glenohumeral joint. The tendon is debrided of its frayed edges using an anterior working portal. In general we use 14 mm as a reference for the insertional width of the rotator cuff tendons at the native footprint. Depending on the size of the tear the next step may vary.

If a partial tendon tear/delamination is accurately identified an 18-gauge spinal needle is passed through the most clinically compromised portion of the tendon from an accessory lateral portal. Via the spinal needle a monofilament suture is passed through the spinal needle and retrieved from the anterior portal within the joint. Once this is done the scope is then withdrawn from the joint and placed in the subacromial space. The subacromial space is thoroughly debrided of any bursal tissue to directly visualize the sub-acromial portion of the rotator cuff. The marking suture is identified and the cuff is probed to assess its integrity.

In general we use a 50 percent principle rule. If the articular-side is torn or delaminated less than 50% of the width and the bursal side is intact, then debridement is the definitive treatment. If the articular side is torn greater than 50% off the footprint and the bursal side integrity is poor then the cuff is taken down and repaired. The repair technique is accomplished using a posterior viewing portal, anterior portal for suture shuttling and a working lateral portal. For full-thickness tears the cuff is repaired in an all arthroscopic fashion using a double row technique.

Superior labrum anterior to posterior lesions

Surgical management of SLAP lesions is covered in a separate chapter.

Posterior capsular contracture

Posterior capsular tightness is rarely refractory to non-surgical care and stretching. In these cases, arthroscopic capsular release may be considered. Following standard diagnostic arthroscopy, including establishment of an anterior viewing portal, the arthroscope is placed through the viewing portal. The posterior capsulolabral structures can then be visualized. The original posterior rent in the capsule for the diagnostic portion of the arthroscopy can be used as a starting point. A cannula can be introduced to facilitate introduction of instruments. The release can be performed using arthroscopic scissors, meniscal resection instruments, motorized shaver, or radiofrequency ablation.

The capsule is incised a few millimeters posterior to the labrum, with care taken not to disrupt the labral tissue. The capsule is typically released from the level of the superior glenoid, inferiorly. Using the clock face model, this is from 11 o’clock (right shoulder) or 1 o’clock (left shoulder) down to the 6 o’clock position. Care must be taken releasing inferiorly, as the axillary nerve courses in close proximity to the inferior glenoid neck. Release should only include the capsule, avoiding injury to underlying structures. Manipulation under anesthesia may be done prior to or after release.

Pearls and Pitfalls of Technique

Rotator cuff repair/debridement

Avoid repair of partial thickness rotator cuff tears. This can result in over constraint of the shoulder.
Concurrent procedures (SLAP repair with rotator cuff repair) have a worse prognosis.
Superior labral lesions seen by MRI may not always be symptomatic in a throwing athlete and may be part of a spectrum of disease.

Posterior capsule release

Over release may result in glenohumeral instability.
Avoid axillary nerve injury inferiorly.
Manipulation under anesthesia prior to arthroscopy may lessen the need for surgical release, but also can obscure arthroscopic view due to bleeding.

Potential Complications

Complications seen after arthroscopy in the throwing athlete are similar to those of the general population. The most common adverse outcome encountered when treating the throwing athlete is failure to return to previous level of play. Specific complications of concern in the elite throwing population are an inability to return to play due to continued pain and stiffness, instability, and axillary neuropathy.

An inability to return to pre-injury level is most often seen in the instance of multiple concomitant injuries observed during arthroscopy and addressed at the time of surgery (i.e. SLAP repair and simultaneous infraspinatus repair). An inability to return to play may also result from overtreatment, such as with over-tightening of the rotator cuff or capsule, or laxity resulting from aggressive capsular release. Such over constraint or laxity may cause a decrease in performance.

Post–operative Rehabilitation

Rehabilitation post-operatively depends upon the pathology treated. In general, soft tissue repairs (rotator cuff, labrum) are treated with protected range of motion exercises for a period of 6 weeks, followed by more aggressive motion and strengthening exercises once the tissue has healed. Debridement and capsular release tissues can be treated with more aggressive range of motion exercises when post-surgical pain tolerance allows. Particularly in the case of capsular release, range of motion is encouraged as the released capsule can scar and result in recurrent capsular contracture.

Once rehabilitation has progressed to full painless range of motion and normal strength and stability, a structured return to throw program ensues. These programs can be tailored to the athlete and type of surgery, but in general involve interval throwing drills starting at short distances (i.e. 45 feet on flat ground) and progressing to longer distances (i.e. 120 feet on flat ground). This is then followed by throwing off the mound as well as building up of strength and stamina.

Throwing programs should incorporate strengthening, stretching, warm up, and mechanics in addition to throwing. The athlete should be supervised with careful monitoring of symptoms, as well as mechanics. This close supervision is essential throughout the rehabilitation process with progression from one phase to the next based on the achievement of specific milestones.

Outcomes/Evidence in the Literature

Burkhart, SS, Morgan, CD, Kibler, WB. “The disabled throwing shoulder: spectrum of pathology Part I: pathoanatomy and biomechanics”. Arthroscopy. vol. 19. 2003. pp. 404-420.

Burkhart, SS, Morgan, CD, Kibler, WB. “The disabled throwing shoulder: spectrum of pathology. Part II: evaluation and treatment of SLAP lesions in throwers”. Arthroscopy. vol. 19. 2003. pp. 531-539.

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. vol. 19. 2003. pp. 641-661. Three part invited series in Arthroscopy which overviewed the disabled throwing shoulder and set forth the link between throwing mechanics and the injuries sustained by the overhead athlete. The series demonstrated the importance of a comprehensive rehabilitation program addressing shoulder stiffness and scapular dyskinesis for improving functional outcomes with and without surgery.)

Craig, EV. “The shoulder”. 2013. (Comprehensive text including detailed reviews of pathophysiology, current surgical techniques, and rehabilitation protocols.)

Iannotti, JP, Williams, GR, Miniaci, A, Zuckerman, JD. “Disorders of the shoulder: diagnosis & management”. 2014. (The treatment of shoulder injuries in the throwing athlete requires a full understanding of the pathomechanics and adaptive changes seen in this population. Often times surgical stabilization fails to return the patient to their pre-injury functional level.)

Kibler, WB, Kuhn, JE, Wilk, K. “The disabled throwing shoulder: spectrum of pathology-10-year update”. Arthroscopy. vol. 29. 2013. pp. 141-161.e126. (Update on the original Burkhart article referenced above from a meeting of invited participants. The article stresses the role and clinical evaluation of the kinetic chain, scapula, GIRD, and total range of motion deficits. The current treatment of SLAP and rotator cuff injuries in throwing athletes should include an exhaustive rehabilitation protocol with surgery being indicated only as a salvage maneuver.)

Knesek, M, Skendzel, JG, Dines, JS, Altchek, DW, Allen, AA, Bedi, A. “Diagnosis and management of superior labral anterior posterior tears in throwing athletes”. Am J Sports Med. vol. 41. 2013. pp. 444-460. (The throwing athlete with a disabled throwing shoulder with clinical and historical findings that correlate with MR arthrography should undergo extensive therapy and rehabilitation before undergoing repair of their SLAP lesion. Superior labrum anterior to posterior lesions are often found in combination with pathologic lesions of the rotator cuff and capsule. Non-operative rehabilitation is the mainstay of treatment as poor return to play results have been found in competitive overhead athletes after surgical repair of a SLAP II lesion.)

Lintner, DM. “Superior labrum anterior to posterior tears in throwing athletes”. Instr Course Lect.. vol. 62. 2013. pp. 491-500. (The cause of pain in the throwing athlete can be confusing as many positive findings may be found but must be correlated with history and physical exam. Functional outcomes after surgical repair of a SLAP lesion with or without repair of the rotator cuff is inferior to non-surgical treatment.)

Neri, BR, ElAttrache, NS, Owsley, KC, Mohr, K, Yocum, LA. “Outcome of type II superior labral anterior posterior repairs in elite overhead athletes: effect of concomitant partial-thickness rotator cuff tears”. Am J Sports Med. vol. 39. 2011. pp. 114-120. (In this series of throwing athletes presented who underwent repair of their type II SLAP lesion the rate of return to pre-injury level was 57 percent. The presence of a partial rotator cuff tear correlated with an inability to return to previous level of function.)

Reynolds, SB, Dugas, JR, Cain, EL, McMichael, CS, Andrews, JR. “Débridement of small partial-thickness rotator cuff tears in elite overhead throwers”. Clin Orthop Relat Res. vol. 466. 2008. pp. 614-621. (Partial rotator cuff tears are defined as less than 50 percent of tendon thickness. Debridement of these tears in elite overhead throwing athletes will allow most to return to competitive professional pitching; however, only approximately half are expected to return to their previous level of competition.)

Sayde, WM, Cohen, SB, Ciccotti, MG, Dodson, CC. “Return to play after Type II superior labral anterior-posterior lesion repairs in athletes: a systematic review”. Clin Orthop Relat Res. vol. 470. 2012. pp. 1595-1600. (Systematic review of 506 patients who underwent repair of their type II SLAP lesion, with 198 of these being overhead throwing athletes and 81 defined as baseball players. Overhead athletes were found to have a lower return to play rate with anchor fixation being found to be the most effective at returning patients to their prior functional status.)

Van Kleunen, JP, Tucker, SA, Field, LD, Savoie, FH. “Return to high-level throwing after combination infraspinatus repair, SLAP repair, and release of glenohumeral internal rotation deficit”. Am J Sports Med. vol. 40. 2012. pp. 2536-2541. (In patients undergoing repair of concomitant SLAP and rotator cuff injuries a dismal prognosis can be expected with only 35 percent returning to their pre-injury level of play.)

Summary

Management of shoulder injuries in throwing athletes can be challenging. Specific anatomic adaptations in the thrower that may be considered pathological in the general population may actually allow the thrower to perform at a high level. Treatment should start with shutting down the thrower, followed by a course of rehabilitation. Surgery is sometimes needed, but many studies show poor rates of return to throw. Regardless of treatment, a structured return to throw program is essential to recondition the athlete’s shoulder prior to return to competition.

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