The shoulder is the most mobile, but also the least stable joint in the body. Stability is obtained by static and dynamic factors. Static restraints such as glenoid version, humeral version, glenoid labrum, glenohumeral ligaments, and glenohumeral joint capsule provide static stability. Dynamic stability is provided by the rotator cuff, deltoid and biceps muscles through a concavity-compression effect on the humeral head within the glenoid socket.1
Glenohumeral instability is the inability to maintain the humeral head centered in the glenoid fossa. Instability can arise from either a single traumatic episode or may have an atraumatic etiology. Patients with traumatic etiology generally have unidirectional anterior instability with a labral detachment (Bankart lesion), and are frequently successfully treated with surgery when the instability is recurrent; hence the acronym TUBS has been used for these patients (Fig. 1).2 On the contrary, atraumatic instability patients often have multidirectional and bilateral hyperlaxity, an intact labrum, and are often treated with a rehabilitation program. If surgery is needed, it must shift the inferior capsule and close the rotator interval; hence the acronym AMBRII has been used in these patients.2
The anatomic causes of recurrent instability can be multifactorial including lesions such as labrum detachments, humeral head impression fractures, glenoid rim fractures, redundancy of the capsule, rotator interval lesions, and tearing or avulsion of the glenohumeral ligaments. Recurrent instability is a common consequence of traumatic dislocation in adolescents. However, in the skeletally immature, shoulder trauma more commonly results in a proximal humeral physeal or metaphyseal fracture3,4 than a dislocation. In a large series of patients with glenohumeral instability, the proportion of skeletally immature patients ranges from 1% to 5%.5–10
Consequently, there is limited number of studies investigating shoulder instability solely in the pediatric age group. Anterior instability is by far the most common traumatic dislocation seen in adolescent athletes; however, posterior subluxation/dislocation and multidirectional instability are seen frequently, particularly in gymnasts, swimmers, and some throwers. The aim of this review article is to delineate the management of various types of shoulder instability in the pediatric age group.
TRAUMATIC ANTERIOR SHOULDER DISLOCATION
Traumatic anterior shoulder dislocations represent more than 90% of shoulder dislocations and are commonly seen in adolescents participating in contact or collision sports.11 The patient with a traumatic anterior dislocation presents with pain, limited motion, and deformity. The humeral head may be palpated anteriorly or in the axilla and the arm is typically held in a slightly abducted, externally rotated position. Careful examination, particularly of the axillary nerve for deltoid area sensibility and motor function in addition to brachial, and radial pulses, is essential to rule out neurovascular injury. Anteroposterior and axillary lateral views of the glenohumeral joint show the dislocation and identify associated fractures or Hill-Sachs lesions. Gentle reduction of an anterior dislocation is performed by one of several techniques including traction-countertraction, prone positioning (Stimson maneuver), or abduction maneuvers. In a prolonged dislocation, sedation may be necessary. Post-reduction radiographs are appropriate. After a brief period of immobilization, a rehabilitation program focused on shoulder girdle strengthening and avoiding the apprehension position is initiated.
Recently, there has been increased interest in the position of arm immobilization. The traditional method of positioning is to immobilize the arm in a sling and swathe in adduction and internal rotation. Magnetic resonance imaging,12 arthroscopic observations,13 a cadaveric study,14 and a randomized-controlled clinical trial15 suggest that immobilization in external rotation after shoulder dislocation reduces the risk of recurrence.
Age seems to be the most important factor with respect to the recurrence of anterior unidirectional instability. Rowe8,9 reported 100% recurrence in children less than 10 years old and 94% recurrence in patients from 11 to 20 years old. Marans et al7 reported 100% recurrence, Postacchini et al16 reported 86% recurrence, and Deitch et al17 reported 75% recurrence in adolescent patients. Other investigators have reported similar results, although none of these studies have isolated the pediatric group as the primary focus of their reports.18–20
Traditional treatment for traumatic anterior shoulder dislocation in the civilian population is nonoperative, including a brief period of rest followed by return to activities when the shoulder is asymptomatic. Owing to the high recurrence rate after single traumatic anterior dislocation in adolescents and young adults, several prospective randomized studies have compared nonoperative treatment of patients with first-time, traumatic shoulder dislocation with immediate arthroscopic (Fig. 2) or open Bankart repair. Bottoni et al21 reported 11% recurrent instability in patients who had an arthroscopic Bankart repair with a bioabsorbable tack versus 75% recurrent instability in the nonoperatively treated patients. Kirkley et al22 not only reported 19% recurrent dislocation in the surgical group versus 60% in the nonoperative group, but also showed significant difference in the disease-specific quality of life between the surgically and nonoperatively treated groups. Jakobsen et al23 in a randomized study comparing open repair to nonoperative treatment with a minimum follow-up of 2 years showed 3% recurrence in the open repair group versus 56% recurrence in the nonoperative treatment group. The patients were evaluated after 10 years with the use of Oxford self-assessment score. Satisfactory results were obtained for 72% of the patients in the operative treatment group versus 25% in the nonoperative group because of recurrence, instability, pain, or stiffness. Furthermore, bone loss may begin with the initial instability event and worsens with repetitive subluxations.24 This is especially a risk in athletes because of repetitive trauma (contact/collision sports) and positioning their arms in the provocative position (overhead sports) in addition to being young.
The indications for operative treatment of the acute dislocation in the adolescent athlete are still controversial. Magnetic resonance scans or magnetic resonance arthrograms are obtained to visualize the labrum, capsule, and the ligaments in cases in which surgical repair of a primary dislocation is considered. Surgical repair can be done with open or arthroscopic repair techniques. The 3.5% rate of recurrent instability after open Bankart repair serves as the standard with which all other techniques are compared.25 Several systematic review and meta-analysis studies comparing arthroscopic versus open anterior shoulder stabilization revealed that arthroscopic repairs were originally associated with a significantly higher risk of recurrent instability and reoperation.26,27 With newer anchors and capsulorraphy techniques, the results of randomized controlled trials of arthroscopic versus open anterior repair have showed that open and arthroscopic surgery results are comparable in terms of recurrent instability with more loss of motion in the open treatment group.28,29 In addition, open shoulder stabilization may lead to atrophy or fatty infiltration and hence postoperative dysfunction of the subscapularis muscle.30,31
One of the retrospective series reporting strictly on adolescent patients reported a 31% redislocation rate after surgical stabilization. However, as most of their patients were operated elsewhere, it was impossible to analyze this patient group with regard to open versus arthroscopic techniques.17 Another retrospective series strictly on adolescents treated with arthroscopic Bankart repair showed a 13.3% recurrent instability.32 Mazzocca et al11 used arthroscopic anterior shoulder stabilization in collision and contact athletes younger than 20 years and found an 11% recurrence of dislocations. These redislocation rates are higher than the redislocation rates after arthroscopic Bankart repair in the adult population. This may be explained by activity level modification and better compliance in adults compared with the eagerness of the young athletes to return to unrestricted sports activity despite the risk of possible redislocation.32
POSTERIOR SHOULDER DISLOCATION
Traumatic posterior instability is unusual, occurring in 2% to 5% of those with shoulder instability.33 With posterior dislocation, the coracoid process may be prominent anteriorly and the arm is often held in internal rotation and adduction. Posterior dislocations can be missed radiographically because of inadequate lateral images. Nonsurgical treatment is successful in 65% to 80% of patients with recurrent posterior subluxation.34,35 The aim is to strengthen the posteror deltoid, external rotators, and periscapular muscles to compensate for the damaged or deficient static stabilizers. Open or arthroscopic surgical approaches addressing posterior capsulolabral injury and redundancy such as posterior Bankart repair or capsular shift with rotator interval closure36–38 have been used in patients who failed a conservative approach.
Most cases of posterior dislocation in young patients are associated with multidirectional instability. Although there are limited data strictly for children and adolescents, the incidence of multidirectional instability is estimated to be approximately 10% because of increased ligamentous laxity associated with youth.39 Atraumatic instability can be seen in the pediatric athlete without a clear history of trauma and may occur with throwing, hitting, swimming, or overhead serving. There may be an absence of pain with these episodes of subluxation and spontaneous reduction. Clinical examination often reveals signs of generalized ligamentous laxity including hyperextensibility of the elbows, knees, and metacarpophalangeal joints.40 Shoulder examination will reveal signs of multidirectional instability including a sulcus sign that causes apprehension and excessive translation with anterior and posterior drawer tests, and the ability to subluxate the humeral head to the glenoid rim or sometimes past the glenoid rim with the load and shift test. A vigorous and lengthy (up to 6 mo) rehabilitation program stressing shoulder girdle and periscapular strengthening is successful in most patients.21 For patients who fail nonoperative management, an open or arthroscopic capsular shift reconstruction is considered.41 Classically, capsulorraphy and rotator interval closure have been performed via open inferior capsular shift.41 More recently, arthroscopic techniques have been developed.42,43 Arthroscopic thermal capsulorraphy was popular briefly; however, it has been recently abandoned because of high failure rates.44,45
Voluntary (habitual) subluxation is diagnosed when a child develops and then uses the ability to subluxate one or both shoulders in one or more directions. This can be the result of abnormal or poorly synchronized muscle activity.46 Huber and Gerber47 reported long-term follow-up of 25 children with voluntary subluxation, and found that skillful neglect with no restriction of activity was better than any form of surgical treatment. In their operated group, instability recurred, pain was more common, and subjective satisfaction was less. Physical therapy focusing on muscle training and feedback has been reported as successful in up to 82% of the patients.46
Traumatic anterior shoulder instability is the most common form of shoulder instability with high recurrence rates in certain subsets of patients. On the basis of the emerging literature, we now currently offer arthroscopic stabilization surgery for the active adolescent patients with first-time traumatic anterior shoulder dislocation. In addition, arthroscopic stabilization surgery is offered to young adult athletes with first-time acute traumatic anterior shoulder dislocation if they are participating in contact or collusion sports or are currently serving in the military. We continue to manage the first-time traumatic anterior shoulder dislocation in the civilian population nonoperatively.
1. Lee SB, An KN. Dynamic glenohumeral stability provided by three heads of the deltoid muscle. Clin Orthop Relat Res. 2002;400:40–47.
2. Thomas SC, Matsen FA III. An approach to the repair of avulsion of the glenohumeral ligaments in the management of traumatic anterior glenohumeral instability. J Bone Joint Surg Am. 1989;71:506–513.
3. Dameron TB, Reibel DB. Fractures involving the proximal humeral epiphyseal plate. J Bone Joint Surg. 1969;51:289–297.
4. Gregg-Smith SJ, White SH. Fracture dislocation of the proximal humeral epiphysis. Injury. 1992;23:199–200.
5. Asher MA. Dislocations of the upper extremity in children. Orthop Clin North Am. 1976;7:583–591.
6. Hovelius L. Anterior dislocation of the shoulder in teenagers and young adults. J Bone Joint Surg. 1987;69A:393–399.
7. Marans HJ, Angel KR, Schemitsch EH. The fate of traumatic anterior dislocation of the shoulder in children. J Bone Joint Surg. 1992;74A:1242–1244.
8. Rowe CR. Anterior dislocation of the shoulder: prognosis and treatment. Surg Clin North Am. 1963;43:1609–1614.
9. Rowe CR. Prognosis in dislocation of the shoulder. J Bone Joint Surg. 1956;38A:957–77.
10. Wagner KT, Lyne ED. Adolescent traumatic dislocations of the shoulder with open epiphysis. J Pediatr Orthop. 1983;3:61–62.
11. Mazzocca AD, Brown FM, Carreira DS, et al. Arthroscopic anterior shoulder stabilization of collision and contact athletes. Am J Sports Med. 2005;33:52–60.
12. Itoi E, Sashi R, Minagawa H, et al. Position of immobilization after dislocation of the glenohumeral joint. A study with use of magnetic resonance imaging. J Bone Joint Surg Am. 2001;83:661–667.
13. Hart WJ, Kelly CP. Arthroscopic observation of capsulolabral reduction after shoulder dislocation. J Shoulder Elbow Surg. 2005;14:134–137.
14. Miller BS, Sonnabend DH, Hatrick C, et al. Should acute anterior dislocations of the shoulder be immobilized in external rotation? A cadaveric study. J Shoulder Elbow Surg. 2004;13:589–592.
15. Itoi E, Hatakeyama Y, Sato T, et al. Immobilization in external rotation after shoulder dislocation reduces the risk of recurrence. A randomized controlled trial. J Bone Joint Surg Am. 2007;89:2124–2131.
16. Postacchini F, Gumina S, Cinotti G. Anterior shoulder dislocation in adolescents. J Shoulder Elbow Surg. 2000;9:470–474.
17. Deitch J, Mehlman CT, Foad SL, et al. Traumatic anterior shoulder dislocation in adolescents. Am J Sports Med. 2003;31:758–763.
18. Hovelius L, Lind B, Thorling J. Primary dislocation of the shoulder. Factors affecting two year prognosis. Clin Orthop. 1983;176:181–185.
19. Hovelius L, Thorling J, Fredin H. Recurrent anterior dislocation of the shoulder: results after the Bankart and Putti-Platt operations. J Bone Joint Surg Am. 1987;69:393–399.
20. Ireland ML, Hutchinson MR. Upper extremity injuries in young athletes. Clin Sports Med. 1995;14:533–569.
21. Bottoni CR, Wilckens JH, DeBerardino TM, et al. A prospective, randomized evaluation of arthroscopic stabilization versus nonoperative treatment in patients with acute, traumatic, first-time shoulder dislocations. Am J Sports Med. 2002;30:576–580.
22. Kirkley A, Werstine R, Ratjek A, et al. Prospective randomized clinical trial comparing the effectiveness of immediate arthroscopic stabilization versus immobilization and rehabilitation in first traumatic anterior dislocations of the shoulder: long-term evaluation. Arthroscopy. 2005;21:55–63.
23. Jakobsen BW, Johannsen HV, Suder P, et al. Primary repair versus conservative treatment of first-time traumatic anterior dislocation of the shoulder: a randomized study with 10-year follow-up. Arthroscopy. 2007;23:118–123.
24. Habermeyer P, Gleyze P, Rickert M. Evolution of lesions of the labrum-ligament complex in posttraumatic anterior shoulder instability
: a prospective study. J Shoulder Elbow Surg. 1999;8:66–74.
25. Rowe CR, Patel D, Southmayd WW. The Bankart procedure: a long-term end-result study. J Bone Joint Surg Am. 1978;60:1–16.
26. Lenters TR, Franta AK, Wolf FM, et al. Arthroscopic compared with open repairs for recurrent anterior shoulder instability
. A systematic review and meta-analysis of the literature. J Bone Joint Surg Am. 2007;89:244–254.
27. Freedman KB, Smith AP, Romeo AA, et al. Open Bankart repair versus arthroscopic repair with transglenoid sutures or bioabsorbable tacks for recurrent anterior instability of the shoulder: a meta-analysis. Am J Sports Med. 2004;32:1520–1527.
28. Bottoni CR, Smith EL, Berkowitz MJ, et al. Arthroscopic versus open shoulder stabilization for recurrent anterior instability after arthroscopic Bankart repair. Am J Sports Med. 2006;34:1730–1737.
29. Fabbriciani C, Milano G, Demontis A, et al. Arthroscopic versus open treatment of Bankart lesion of the shoulder: a prospective randomized study. Arthroscopy. 2004;20:456–462.
30. Sachs RA, Williams B, Stone ML, et al. Open Bankart repair: correlation of results with postoperative subscapularis function. Am J Sports Med. 2005;33:1458–1462.
31. Scheibel M, Tsynman A, Magosch P, et al. Postoperative subscapularis muscle insufficiency after primary and revision open shoulder stabilization. Am J Sports Med. 2006;34:1586–1593.
32. Jones KJ, Wiesel B, Ganley TJ, et al. Functional outcomes of early arthroscopic Bankart repair in adolescents aged 11 to 18 years. J Pediatr Orthop. 2007;27:209–213.
33. Arciero RA, Mazzocca AD. Traumatic posterior shoulder subluxation with labral injury: suture anchor technique. Tech Shoulder Elbow Surg. 2004;5:13–24.
34. Burkhead WZ Jr, Rockwood CA Jr. Treatment of instability of the shoulder with an exercise program. J Bone Joint Surg Am. 1992;74:890–896.
35. Hurley JA, Anderson TE, Dear W, et al. Posterior shoulder instability
: surgical versus conservative results with evaluation of glenoid version. Am J Sports Med. 1992;20:396–400.
36. Williams RJ III, Strickland S, Cohen M, et al. Arthroscopic repair for traumatic posterior shoulder instability
. Am J Sports Med. 2003;31:203–209.
37. Kim SH, Ha KI, Park JH, et al. Arthroscopic posterior labral repair and capsular shift for traumatic unidirectional recurrent posterior subluxation of the shoulder. J Bone Joint Surg Am. 2003;85:1479–1487.
38. Wolf EM, Eakin CL. Arthroscopic capsular plication for posterior shoulder instability
. Arthroscopy. 1998;14:153–163.
39. Good CR, MacGillivray JD. Traumatic shoulder dislocation in the adolescent athlete: advances in surgical treatment. Curr Opin Pediatr. 2005;17:25–29.
40. Carter C, Sweetnam R. Recurrent dislocation of the patella and the shoulder: their association with familial joint laxity. J Bone Joint Surg. 1960;42B:721–727.
41. Neer CS, Foster DR. Inferior capsular shift for involuntary inferior and multidirectional instability
of the shoulder. J Bone Joint Surg. 1980;62A:897–908.
42. Caprise PA Jr, Sekiya JK. Open and Arthroscopic treatment of multidirectional instability
of the shoulder. Arthroscopy. 2006;22:1126–1131.
43. Gartsman GM, Roddey TS, Hammerman SM. Arthroscopic treatment of multidirectional glenohumeral instability: 2- to 5-year follow-up. Arthroscopy. 2001;17:236–243.
44. D'Alessandro DF, Bradley JP, Fleischli JE, et al. Prospective evaluation of thermal capsulorrhaphy for shoulder instability
: indications and results, two- to five-year follow-up. Am J Sports Med. 2004;32:21–33.
45. Miniaci A, Codsi MJ. Thermal capsulorrhaphy for the treatment of shoulder instability
. Am J Sports Med. 2006;34:1356–1363.
46. Takwale VJ, Calvert P, Rattue H. Involuntary positional instability of the shoulder in adolescents and young adults. Is there any benefit from treatment? J Bone Joint Surg Br. 2000;82-B:719–723.
47. Huber H, Gerber C. Voluntary subluxation of the shoulder in children. A long-term follow-up study of 36 shoulders. J Bone Joint Surg Br. 1994;76-B:118–122.