Bruce S. Miller, MD, MS; Asheesh Bedi, MD; and Jack W. Weick, MD
The glenohumeral joint is a ball and socket joint with motion attainable across multiple degrees of freedom. The design of the joint allows for a variety of complex movements that are put on demonstration in athletes. However, this degree of motion comes at the expense of increased risk of instability, particularly in collision athletes. Disruption of any one of the multiple stabilizers in the shoulder places the joint at risk for dislocation. Glenohumeral instability is a common injury in young athletes. A review of collegiate athletes found shoulder instability reported at a rate of 0.12 per 1000 athlete exposures.1
Collision sports are typically among the most injury-prone sports in all anatomic locations.2 High-speed contact with other players or the playing surface places the glenohumeral joint at risk in these athletes. Sports such as football, wrestling, hockey, and rugby are associated with increased risk of shoulder instability.1,3 In a 5-year study of US high school students, the largest number of shoulder dislocations occurred in collision sports, highlighting that this issue is not exclusive to elite level athletes, but rather affects athletes playing collision sports at all levels.4 Furthermore, athletes in collision sports are at increased risk of recurrent instability events with reported recurrent instability rates ranging from 39% to 94%.5–8
Glenohumeral instability frequently results in significant lost time in sport. Special considerations must be taken into account for collision athletes given the nature of their sport and the risk of recurrence in this population. This chapter focuses on return to play after glenohumeral instability in the collision athlete. After a brief discussion on the injury mechanism and pattern in these athletes, we discuss strategies for injury prevention, nonoperative management and return to play, operative management and return to play, postoperative rehabilitation for the collision athlete, risks after returning to play, and recurrence.
HISTORY OF TREATMENT
Prior to 1923, anterior shoulder dislocations were largely attributed to excessive shoulder capsular laxity and weakness of the surrounding musculature. If surgical intervention was addressed, the main focus was capsular plication techniques. In 1923, Bankart described the “essential lesion” of recurrent glenohumeral instability.9 After Bankart’s description, focus gradually shifted away from capsular plication to surgical management of the labrum and glenoid. In the 1980s and 1990s, arthroscopic management of recurrent glenohumeral instability gained traction. As techniques improved in the late 1990s to early 2000s, arthroscopic outcomes were comparable to open surgical interventions with the benefit of decreased surgical morbidity.10–12
Overall, little attention was paid specifically to collision athletes or athletes in general and return to play after glenohumeral instability events until the last 10 to 15 years. However, focus on treatment has shifted from nonoperative intervention with aggressive, prolonged rehabilitation to operative intervention, though tailored to the patient’s sports scheduled when possible. Studies more recently have shown some success in return to play after glenohumeral instability events, and this will be discussed in more detail later in the chapter.
|ACTION||ANATOMY OF INJURY|
|Tackle or check with shoulder||SLAP tear, Bankart|
|Direct impact with ground||Bony Bankart, SLAP tear|
|Diving with arms extended||Bankart, SLAP tear, rotator cuff tear|
|Axial load to outstretched arm (eg, blocking lineman)||Posterior labral tear|
|Fall with flexed arm in ball carrier||Posterior labral tear|
Abbreviation: SLAP, superior labrum anterior-to-posterior.
Traumatic anterior shoulder dislocation can result in bone and/or soft-tissue injury. Bankart lesions represent an avulsion of the inferior glenohumeral ligament-labrum complex from the anterior glenoid rim. Incidence of Bankart lesions after anterior instability events has been shown to be greater than 90%.13,14 Anterior shoulder dislocation may also lead to anterior-inferior glenoid bone loss, referred to as a “bony Bankart” lesion. This bone loss can be an acute fracture from a single trauma or attritional bone loss as a sequela of chronic recurrent events. When significant bone loss occurs, the patient is at risk of recurrent instability with little force. The traditional cutoff of bony Bankart bone loss for which there is concern for recurrent instability is approximately 25% of the glenoid. However, in collision athletes, bone loss as low as 10% to 20% may be a risk for recurrence given the high energy the joint will face in collisions.15,16 Anterior shoulder instability events can result in other associated injuries in conjunction with Bankart lesions including anterior periosteal sleeve avulsions, humeral avulsion of the glenohumeral ligament, glenolabral articular disruption, superior labrum anterior-to-posterior tears, and multidirectional instability/capsular insufficiency.
Hill-Sachs deformities of the posterolateral humeral head are often found with anterior shoulder instability. Incidence of Hill-Sachs deformities has been described as high as 67% to 93% in these patients.14,17 When a Hill-Sachs lesion is identified, it is possible to determine whether it is “engaging” or not engaging. An engaging Hill-Sachs lesion occurs if the medial margin of the lesion extends inside the glenoid tract. This has surgical implications that will be discussed in more detail later in the chapter. The incidence of engaging Hill-Sachs lesions has been reported to be 7% of all Hill-Sachs defects.18
In the collision athlete, the injury can be due to a direct tackle or check with the shoulder, direct impact with the ground against the shoulder, diving with arms extended, an axial load to an outstretched and flexed armed such as in an offensive lineman, or in a flexed fall pattern in a ball carrier.19 A tackler typically holds his or her arms in an abducted, externally rotated position and faces a posteriorly directed force on the glenohumeral joint. Direct impact with the ground occurs with the athlete falling onto the lateral aspect of the shoulder with the arm most often held in internal rotation. This force is often compounded by an opposing player falling directly on the athlete, providing additional stresses to the glenohumeral joint. Diving with an extended arm (such as when diving for the goal line in football or rugby) results in a posterior force to the glenohumeral joint, but with the arm forward flexed. Offensive linemen can suffer posterior shoulder injuries as they face large axial loads against an outstretched, forward-flexed arm. Flexed-fall injuries in a ball carrier can also result in more posteriorly focused shoulder injuries. Table 27-1 illustrates the typical mechanisms of shoulder instability in collision athletes and common injury patterns resulting from these actions.
Initial evaluation after a shoulder dislocation event begins with a thorough history and physical. In the collision athlete, careful determination of the timing, previous instability, and recurrence are important. The athlete may or may not describe a specific episode or, alternatively, may describe recurrent looseness, laxity, or feelings of instability. He or she may also endorse apprehension with overhead activities. Additionally, whether the athlete is in-season and the athlete’s overall goals and level of competition play a crucial role in treatment selection and overall return to play.
Acute presentations of shoulder dislocations should be reduced as soon as possible. After reduction, careful neurovascular exam, with special attention to axillary nerve function, should be performed. Once the acute trauma situation is resolved, or in a patient presenting with feelings of instability without a traumatic dislocation, a thorough physical exam is recommended. Active and passive range of motion (ROM) should be evaluated and compared to the contralateral extremity. Strength testing of the upper extremity including the rotator cuff, deltoid, biceps, triceps, and brachialis is performed in addition to complete sensory exam. When a patient endorses feelings of instability, anterior apprehension testing and relocation test should be performed. Both of these tests have very high reported specificities (96% anterior apprehension, 92% relocation) and relatively high sensitivities (72% anterior apprehension, 81% relocation).20 Load-and-shift testing should also be performed to assess the amount of translation of the humeral head on the glenoid. For patients with concern for posterior instability, for example in an offensive or defensive lineman, a posterior apprehension test can be performed. This test also has a very high reported specificity (92%), though sensitivity is lower (42%).21 The jerk test and posterior load-and-shift can also be performed.
Imaging evaluation starts with x-rays of the shoulder, which should include anteroposterior, Grashey, scapular-Y, and axillary (or West Point) views to ensure concentric glenohumeral reduction and to evaluate for any obvious fracture or bone loss. A computed tomography scan should be considered for recurrent dislocators or if there is concern for bone loss. In collision athletes in particular it is important to evaluate the extent of any glenoid bone loss because this can change operative management. Magnetic resonance imaging (MRI) and Magnetic resonance arthrogram (MRA) can be useful to evaluate soft-tissue pathology. MRI and MRA also allow for visualization of osseous anatomy of the glenohumeral joint and any underlying bony edema from acute trauma.
High-level collision athletes often require surgery to minimize the risk of recurrence and return the athlete to his or her prior level of competition. However, there are clinical situations in which nonoperative management can be used in the collision athlete. In-season athletes can use nonoperative treatments to return to play quickly, complete the season, and delay operative stabilization until the off season. Additionally, nonoperative management may be used for lower-demand athletes who do not desire surgery that suffered nontraumatic instability and have no significant glenoid bone loss. Significant bone loss in the form of more than 25% of the glenoid, recurrent dislocators, and engaging Hill-Sachs lesions should be a general contraindication for return to play in season with nonoperative management.
Nonoperative management has been shown to allow for a high rate of return to play in-season; however, this comes at a cost of risk for recurrent instability events. Dickens et al prospectively studied nonoperative treatment for anterior traumatic shoulder instability events in collegiate athletes. They found that 73% of athletes were able to return to sport after a median of 5 days. However, only 27% of these athletes were able to complete the season without a recurrent instability event.5 This study did not distinguish outcomes between collision and noncollision athletes. Buss et al evaluated return to play in season after an anterior instability event management nonoperatively. They found 90% of the 30 athletes studied were able to return to play after a median of 10 days. Thirty-seven percent of these athletes suffered recurrent instability at some point during the season on return to play.22 Again, this study did not substratify the results based on collision vs noncollision athletes. In collision athletes, the decision to delay operative intervention should be made carefully and only after a thorough discussion with the patient about the risk of recurrent dislocation.
After reduction of a glenohumeral dislocation, the shoulder is immobilized in a sling. Whether to place the shoulder in internal or external rotation has been debated; however, MRI studies have shown placement of the arm in external rotation decreases the displacement of the labrum.23 Conflicting data exist as to whether this clinically makes a difference in terms of the risk of repeat instability events; however, compliance is typically higher when the patient is immobilized in internal rotation.24,25 Duration of immobilization is controversial. Historically, the shoulder was immobilized for long durations, up to 3 to 6 weeks. However, collision athletes treated with immobilization for 4 weeks followed by therapy were found to have recurrence rates up to 90%.26 More recently, early mobilization and therapy have been promoted for in-season athletes to return to play during the season.5,22 These studies showed high return-to-play rates (73% to 90%) within 5 to 10 days. However, as discussed earlier, risk of recurrence is high (27% to 37% later in the same season). Additionally, frequently collision athletes require surgical stabilization in the off season.
Accelerated physical therapy programs can be used to return the athlete to play during the same season as the instability event if desired. The goal of this is to minimize pain and restore motion and strength to near the preinstability event level. In the first 5 to 7 days after the injury, gentle ROM and cryotherapy are initiated to improve patient comfort. After this, strengthening is initiated for dynamic shoulder stabilizers. Sports-specific drills are initiated once the shoulder strength is near that of the contralateral extremity and return to play (with or without a brace) is considered at this time.27
Shoulder bracing to limit shoulder abduction, extension, and external rotation may be used once the athlete has returned to play when managed nonoperatively (Figure 27-1). These braces are designed to stabilize the shoulder in a vulnerable position for anterior instability. Athletes may endorse a subjective feeling of improvement in shoulder stability; however, there are few data to show improvement in rates of instability events.5,22 Despite the overall limited data, these braces are frequently used for collision athletes given the risk of the shoulder being placed in a vulnerable position with high-energy forces to the joint. These braces may also provide improvement or a decrease in pain in the shoulder when collision events occur. Multiple commercial braces currently exist (Sully Shoulder Stabilizer, SAWA Shoulder Orthosis). The key for the braces is controlled ROM and prevention of placement of the shoulder in a compromising position. Higher-constraining braces should be considered in athletes expecting direct collisions or frequent compromising positioning of the shoulder (eg, offensive lineman, linebackers, rugby).