Internal impingement results from pinching of the rotator cuff between the posterosuperior labrum and the greater tuberosity. The pain usually occurs with repetitive maximal shoulder internal rotation and abduction, which leads to cumulative microtrauma and eventual articular-sided rotator cuff pathology.4 The patient will complain of pain with shoulder internal rotation and abduction. Neer’s and Hawkin’s tests are helpful in detecting internal impingement.
Shoulder girdle fatigue from lack of conditioning and overthrowing—or the tight posterior capsule often seen in throwing athletes—may also contribute to the disorder.4
Treatment. Proper management involves relative rest from overhead activities, and an individualized rehabilitation program that includes dynamic stretching/strengthening through the rotator cuff, posterior capsule, and scapular stabilizers. Injecting a corticosteroid-analgesic solution into the subacromial space may help you arrive at a diagnosis and also offers symptomatic relief.1,3 Consider bursectomy, arthroscopic acromioplasty, capsulotomy and/or debridement for recalcitrant cases.4,5
Shoulder labrum pathology
What you’ll see. Overhead-throwing athletes are at risk of labral tears. The externally rotated, abducted arm of a thrower causes posterior rotation of the biceps anchor, peeling the biceps from its superior labrum attachment,6 a superior labrum anterior and posterior (SLAP) tear, or a type II tear from anterior to posterior. SLAP tears may lead to shoulder catching and locking. The patient may complain of vague shoulder pain,7 which is worse in the late cocking phase. O’Brien’s test will be positive.
Magnetic resonance imaging (MRI) with arthrogram can reveal a labral tear. Consider ordering an MRI when the athlete’s pain is accompanied by mechanical symptoms, such as locking, catching, or instability, or if the shoulder signs and symptoms do not appear to be responding to appropriate physical therapy interventions after a period of time—usually 4 to 6 weeks.
Treatment. For small tears, conservative management includes relative rest and physical therapy.3 Depending on the tear morphology, consider arthroscopic labral debridement or repair if conservative measures fail. The literature offers mixed conclusions on the benefits of surgery, with varying rates of full return to play.8-10
Shoulder instability
What you’ll see. Instability in throwing athletes is multifactorial, and rarely due to an isolated shoulder structure injury.11 Patients will complain that their shoulder feels as if it is going to come out of its socket, even when they are not throwing. To help detect instability, look for the sulcus sign, and do a load and shift test and an apprehension-relocation test.
Two categories of injury. Instability injuries fall into 2 primary categories: TUBS (Traumatic, Unilateral, associated with Bankart lesion, treated with Surgery) and AMBRI (Atraumatic, Multidirectional, Bilateral, treated with Rehabilitation, Inferior capsular shift).
As its name makes clear, TUBS is associated with a Bankart lesion (an avulsion of the anteroinferior glenoid labrum to its attachment to the humerus). Shoulder x-rays, including outlet, axillary lateral, and anteroposterior views,3 may reveal a bony Bankart lesion. You may also see a Hill-Sachs lesion here, which is noted on the humeral posterolateral head as a depression in the bony cortex.
AMBRI is more common than TUBS in throwers. Athletes often gain a competitive edge by increasing external rotation. However, when overdone, this results in the excessive laxity seen in AMBRI. While rare, acute traumatic dislocation can occur in those with AMBRI-type instability.
Treatment. Scapular stabilization exercises, dynamic rotator cuff strengthening, relative rest, and a short course (7-10 days) of nonsteroidal anti-inflammatory drugs are the mainstays of shoulder instability treatment in the throwing athlete.1,3 A throwing program may be started when the athlete is asymptomatic and has rested. You may also need to prescribe a longer rest period of 4 to 6 weeks if the symptoms return after commencing activity. For recalcitrant cases, consider surgery (via open or arthroscopic approaches6) to treat the associated underlying pathology.
Glenohumeral internal rotation deficit
What you’ll see. Posterior capsular contracture, common in the throwing athlete’s shoulder, causes decreased internal rotation and posterior shift of the total arc of glenohumeral motion.3 The patient may complain of decreased ability to reach backwards or pain when attempting to do so.
The anterior aspect of the shoulder’s capsule also lengthens, allowing anterior capsular laxity that causes additional problems, including internal impingement, SLAP tears, articular-sided, partial-thickness rotator cuff tears, and posterosuperior rotator cuff impingement. The risk for this cascade of complications increases in patients with throwing-shoulder internal rotation deficits ≥25° compared with the nonthrowing side, and a total arc of motion <180°.12
Treatment. Stretching the tight posterior capsule using the sleeper stretch (FIGURE 2) or the cross-body stretch (FIGURE 3) has proven very successful, with 90% of athletes seeing their symptoms resolve within 2 weeks.13,14 If conservative treatment is ineffective, consider selective arthroscopic capsular release of the posterior inferior glenohumeral ligament.
FIGURE 2
The sleeper stretch
FIGURE 3
The cross-body stretch
