Injuries, Uncategorized

Shoulder Instability in Adolescent Athletes – Matthew D. Milewski, MD and Carl W. Nissen, MD

Introduction

Shoulder instability in young patients is a well-recognized spectrum of pathology from common traumatic anterior dislocations to recurrent multidirectional instability.  In young adolescent or pediatric patients with open proximal humeral physes, shoulder instability was once thought to be far less common than physeal injury but may be more common than once believed. 1 2  Both traumatic and non-traumatic shoulder instability in young patients have been found to have a high rate of recurrence and appropriate treatment is paramount to reducing the risk of recurrence and facilitating young patients return to sports and other physical activities.

Epidemiology

Shoulder instability is fairly common with a rate of 11.2 per 100,000 3 with younger, athletic males to be most frequently affected.  Occurring in all ages, the peak age is seen in 18-25 year olds. Wagner and Lyne found that 4.7% of the shoulder dislocations in their study occurred in children with open physes. 4 The classic study by Rowe in 1956 reviewing 500 shoulder dislocations found that 20% of these dislocations occurred in patients between the ages of 10 and 20 years of age but only 8 patients who were less than 10 years of age had dislocations. 1 More recent studies have estimated that up to 40% of shoulder instability events may occur in patients younger than 22 years of age. 2, 5 More striking is the high rate of recurrence in young active patients often quoted to be as high as 70-100% in these patients. 1, 4, 6 Rowe found the rate of recurrence in patients less than 10 years of age to be 100%, and 94% if between 10 and 20 years of age while Wagner found an 80% rate of recurrence in 9 patients with open proximal humeral physes.

When compared to traumatic instability, the incidence and prevalence of multidirectional instability is difficult to estimate.  Emery and Mullaji examined 150 asymptomatic shoulders in patients between the ages of 13 and 18 and found 57% of boys and 48% of girls had signs of shoulder instability. 7 While the incidence of multidirectional instability appears to be less than the incidence of traumatic anterior shoulder instability, multidirectional instability is seen more commonly in some specific groups such as overhead athletes especially swimmers and gymnasts. 8  9

Anatomy

The anatomy of the glenohumeral joint has been studied for many years with the understanding of the joint and ligamentous structures being significantly improved with the advent of shoulder arthroscopy. The capsuloligamentous complex includes both anterior and posterior glenohumeral ligaments each functioning to stabilize the joint with the arm working in different positions.  Stability is further enhanced by the presence of the cartilaginous labrum along the glenoid rim.  While still present in ligamentously lax individuals, as arthroscopy has identified, this group often has a pristine, smooth articular cartilage, with an ‘endless pool’ appearance of the labrum (Fig. 1), and often a thin almost translucent shoulder capsules.

Shoulder stability and function relies greatly on the muscles about the shoulder girdle.  The rotator cuff and deltoid muscles are focused upon and trained specifically to improve sports performance.  It is often forgotten, however, that these muscles also perform important function as shoulder stabilizers.  The rotator cuff works perhaps primarily to center the humeral head within the glenoid and allow the larger muscles to function efficiently.  Also often forgotten are the scapular muscles, which more than any other structure involved with the shoulder girdle, provide the foundation for shoulder function and stability. .  Our evaluation and care of shoulders begins and often can end with the scapular stabilizers.

History

There is such a wide spectrum of pathology with shoulder instability in younger patients and therefore the history and physical exam is paramount in understanding a particular young patient’s pathology and prognosis. In the initial evaluation of the adolescent patient with shoulder instability, it is important to understand whether there was an underlying joint laxity present prior to the first instability event or whether the instability issue followed a traumatic event. These younger patients may only describe intense shoulder pain, a “dead arm” feeling, or occasionally paresthesias in the distal upper extremity associated with subluxation or dislocation events.

Anterior shoulder instability comprises 90-95% of shoulder instability and a good history can provide essential clues to the primary direction of instability.  Pain in the abducted and externally rotated position is usually indicative of anterior shoulder instability.  Pain with internal rotation and pushing forward such as during a bench press maneuver may be indicative of posterior shoulder instability.

The symptoms of recurrent shoulder instability in the young patient are even more vague with atraumatic instability often occurring during activities of daily living.  However, atraumatic instability can also occur during sporting events particularly during noncontact sports such as overhead serving in racquet sports, during certain swimming strokes, or during weightlifting activities.  These patients describe occasional pain or mechanical symptoms such as “popping” in the shoulder.

Physical Exam

Evaluation of a young skeletally immature patient with suspected shoulder instability includes a standard trauma series of radiographs. The possibility of a proximal humeral physeal fracture is high and must be determined before shoulder instability management is undertaken.  After excluding such a fracture, the physical exam for the younger patient with shoulder instability starts with an exam of the cervical spine and scapulae. While cervical spine issues are less common in adolescent patients, scapular winging is not uncommon and needs to be identified when present. Our exam then evaluates range-of-motion and gross motor strength of each muscle about the shoulder girdle.  Additionally, all young patients with suspected glenohumeral instability should be evaluated for generalized hyperlaxity.  The Beighton-Horan scale for joint hyperlaxity combines increased laxity at various joints including the hand, elbow, knee and trunk.  (Table 1)  A score equal or greater than 4 on a 9 point scale is considered diagnostic for hyperlaxity.

Though possible to be done in many ways, should be done in a manner to separate the different aspects of the shoulder including the scapulothoracic joint and the glenohumeral joint.  We often will examine these patients in both the supine and seated position to help separate the site of pain and pathology.  While seated the scapulothoracic joint is obviously more easily visualized than while supine and we believe it is better evaluated with regards to motion and strength in this position.  Posterior pain when testing the seated patient is important to note especially in overhead athletes as this suggests either posterior instability or posterior labral pathology.  A seated examination is then followed by a supine exam.  In this position the stabilization of the scapula against the exam table allows the glenohumeral joint to be isolated as best as possible.  As a part of the exam, several provocative maneuvers to test shoulder instability are utilized.  These include the anterior apprehension test, Jobe relocation test, anterior and posterior load-and-shift tests, Kim’s posterior jerk test, hyperabduction test and the sulcus sign. 10 The anterior and posterior load-and-shift tests are generally done with the patient supine to stabilize the scapula.

Aside from the standard radiographs mentioned above, further evaluation is often needed.  In the case of posterior instability and when a concern of glenoid fractures exists we often will obtain a CT scan with glenoid 3-D reconstruction.  More commonly, however, further imaging includes a MRI.  The MRI can help establish not only the presence of labral and ligamentous injuries but also often their extent.  Imaging of the shoulder in patients with suspected multidirectional instability can be challenging to interpret as the “tell tale” signs of instability that often accompany acute traumatic shoulder instability such as labral, capsular or ligamentous tears are usually present.   Several imaging findings can be helpful in evaluating the patient with suspected multidirectional instability, although it is especially important in these patients to put the imaging findings in the appropriate clinical context with their history and physical exam findings.   It is our practice, except in the acute setting, to add an intra-articular injection of contrast to increase the chance of seeing a labral tear if it is present.

Treatment and Outcomes

Conservative treatment of adolescent anterior shoulder instability

Conservative treatment may include an initial period of sling or shoulder immobilizer use followed by activity modification and physical therapy for range of motion and strengthening.   Return to play is allowed once painless full range of motion and normal, protective strength is achieved.  Shoulder harness bracing is often utilized for young football players, or other contact athletes such as hockey and lacrosse players, who seek to return play during the same season in which the instability has begun though the utility and effectiveness of bracing is not clear.  The option to return to play with an unstable shoulder requires a full understanding by the young athlete and their family.  The main concern associated with conservative management of traumatic first-time anterior shoulder instability is the risk of recurrent instability.  This risk is significant and most reports document this risk to be 60% or greater. 1 4 6 11 12 13  Of interest, while most adolescent patients with shoulder instability do fall into this group at high risk, there does seem to be a group of very young athletes – perhaps under age 12 – where conservative management is not abysmal and may be an appropriate decision. 13

As opposed to unidirectional instability, care of multi-directional instability and the patient with Atraumatic, Multidirectional, Bilateral, Recurrent, Instability (AMBRI) is even more commonly conservative.  Burkhead and Rockwood described conservative management in this group as good or excellent for 80%. 14 Takwale et al. described 90% good results with specialized physical therapy for “involuntary positional instability”. 15.

Operative treatment of adolescent anterior shoulder instability

Operative intervention is advocated for recurrent instability after traumatic anterior shoulder dislocations in young patients and for some in high-risk sports after a first-time shoulder instability event. A few studies have specifically examined the results of surgical stabilization for traumatic anterior shoulder instability in pediatric and adolescent patients.16 4 6 17 13 16 18

Newer studies have examined arthroscopic treatment of traumatic shoulder instability in pediatric and adolescent populations.  Mazzocca et al. examined a late adolescent population between 14 and 20 years of age that were contact and collision athletes and treated with arthroscopic anterior shoulder stabilization with a low recurrence rate of 11%. 16 Jones et al. reported on 32 anterior arthroscopic Bankart repairs in 30 patients.  The average age of the patients was 15 and there was a 15.6% rate of recurrence after surgery.

Overall, arthroscopic stabilization for traumatic anterior shoulder instability appears to be an effective treatment in younger populations with recurrence rates that approach the rates seen in collegiate age populations.  Primary surgical treatment after first-time traumatic anterior shoulder instability may be appropriate in adolescent patients given the risk of recurrence in these younger populations.

Operative treatment of multidirectional instability is also appropriate in young patients that have failed conservative treatment though the algorithm for these athletes is not as well worked out or defined.  While we certainly agree that these individuals require more intensive pre-operative discussions and explanations as well as more structured post-operative management, we do not believe that this group should be viewed differently than other shoulder instability patients. Traditional operative treatment of multidirectional instability of the shoulder involved open inferior capsular shift as described by Neer and Foster. 19 More recently several authors have shown excellent results in MDI patients though few have reported specifically on adolescents.  Though these authors demonstrated good pain relief, authors were cautious in the ability to return adolescent athletes to competitive levels after open procedures. 20 21 As the treatment of traumatic shoulder instability has gravitated towards arthroscopic techniques, so has the operative treatment of multidirectional instability.  Advantages to arthroscopic treatment include the ability to address anterior, inferior and particularly posterior pathology at the same time and close the rotator interval if deemed necessary. 22. 23 24 25 In more recent arthroscopic studies, recurrence rates are reported to be between 2 and 12% and subjective outcome scores report satisfactory results after 88-97% of procedures.  Again, however, few of these studies have focused on the adolescent athlete.

One of the specific improvements in surgical technique that has occurred with the change to arthroscopic techniques is the ability to address the rotator cuff interval.  While the closure of the rotator interval remains a controversial portion of arthroscopic management of glenohumeral instability, the addition of a closure in selected patients is important and can improve outcomes.  Harryman et al. initially showed in vitro imbrication to the rotator interval capsule resisted inferior and posterior translation. 26 Others have shown that rotator interval closure may not affect posterior stability but can affect anterior stability. 27 As mentioned, however, not all unstable shoulders – traumatic or atraumatic – should have the rotator cuff interval closed routinely as that closure may restrict external rotation.

Rehabilitation

Rehabilitation after arthroscopic anterior stabilization for anterior shoulder instability or pan-capsular capsulorrhaphy for multidirectional instability generally begins with a period of immobilization.  During this time maintaining finger, wrist and elbow motion is imperative.  Isometric peri-scapular muscle activation along with range of motion activities begins with physical therapy and at home exercise programs including pendulum exercises, table slides and wall pulleys.  Isometric shoulder exercises are begun in weeks 2-4 and advanced to isotonic exercises in weeks 4-8. Stationary bike and elliptical use without use of the arms are allowed prior to sling discontinuation with running after the sling has been discontinued. At 3 months and once full range-of-motion as well as near normal strength has been achieved, we initiate sport-specific training.  Isokinetic strength testing of shoulder internal and external rotators, along with endurance and power testing of the upper extremity is done prior to return to sport, which is generally at the four-month post-operative point.  Return-to-sports is predicated by achieving rehabilitative milestones as above as well as the specific sport that is being played.  Non-contact, non-overhead sports are possible often by the four-month mark.  Contact sports are generally not allowed before six month post-operatively.  Overhead sports also are allowed at the six-month mark though we will normally initiate a tossing or interval-throwing program at four months.

Rehabilitation after pan-capsular procedures for multidirectional instability may be progressed more slowly given the extent of instability, amount of capsular shift needed, and often-poor quality of soft tissue in these cases.

Conclusions

Instability of the shoulder is a common issue faced by sports medicine providers caring for adolescent patients.  A thorough history and physical exam along with relevant imaging allows a complete diagnosis and can guide initial treatment.  Given the high risk of recurrent instability adolescent patients who seek to return to competitive contact sports, in our opinion, should consider arthroscopic stabilization after a first-time instability event.  Multidirectional instability should be treated initially with conservative rehabilitation. Arthroscopic techniques may now approach the results found from traditional open capsular shift procedures.  Future studies should be designed to examine the outcomes in solely adolescent populations after both conservative and operative treatment of shoulder instability.

  1. Rowe CR. Prognosis in dislocations of the shoulder. Journal of Bone and Joint Surgery 1956;38-A(5):957-977.
  2. Cleeman E, Flatow E. Shoulder dislocations in the young patient. Orthopaedic Clinics in North America 2000;31(2):217-229.
  3. Simonet WT, Cofield RH. Prognosis in anterior shoulder dislocation. American Journal of Sports Medicine 1984;12(1):19-24.
  4. Wagner K, Lyne ED. Adolescent traumatic dislocations of the shoulder with open epiphysis. Journal of Pediatric Orthopaedics 1983;3(1):61-62.
  5. Hovelius L, Augustini B, Fredin H, et al. Primary anterior dislocation of the shoulder in young patients – a ten-year prospective study. JBJS (A) 1996;78:1677-1684.
  6. Marans HJ, Angel KR, Schemitsch EH, et al. The fate of traumatic anterior shoulder dislocation in children. Journal of Bone and Joint Surgery 1992;74(8):1242-1244.
  7. Emery RJ, Mullaji AB. Glenohumeral joint instabilityin normal adolescents. Incidence and significance. Journal of Bone and Joint Surgery – British 1991;73(3):406-408.
  8. Baker CL, Brooks AA. Arthroscopy of the elbow. Clinics in Sports Medicine 1996;15(2):261-281.
  9. Meeusen R, Borms J. Gymnastics injuries. Sports Med 1992;13(5):337-356.
  10. Gaskill TR, Taylor DC, Millett PJ. Management of multidirectional instability of the shoulder. Journal of the American Academy of Orthopaedic Surgeons 2011;19(12):758-767.
  11. Hovelius L. Anterior dislocation of the shoulder in teen-agers and young adults. Five year prognosis. Journal of Bone and Joint Surgery 1987;69A(3):393-399.
  12. Deitch J, Mehlman CT, Foad SL, et al. Traumatic Anterior Shoulder Dislocation in Adolescents. Am J Sports Med 2003;31(5):758-763.
  13. Postacchini F, Gumina S, Cinotti G. Anterior shoulder dislocation in adolescents. Journal of shoulder and elbow surgery / American Shoulder and Elbow Surgeons [et al] 2000;9(6):470-474.
  14. Burkhead WZ, Rockwood CA. Treatment of instability of the shoulder with an exercise program. Journal of Bone and Joint Surgery 1992;74A(6):890-902.
  15. Takwale VJ, Calvert P, Rattue H. Involuntary positional instability of the shoulder in adoelscents and young adults. Is there any benefit from treatment? Journal of Bone and Joint Surgery – British 2000;82(5):719-723.
  16. Mazzocca AD, Brown FJ, Carreira DS, et al. Arthroscopic anterior shoulder stabilization of collision and contact athletes. American Journal of Sports Medicine 2005;33(1):52-60.
  17. Deitch J, Mehlman CT, Foad SL, et al. Traumatic Anterior Shoulder Dislocation in Adolescents. The American Journal of Sports Medicine 2003;31(5):758-763.
  18. Jones KJ, Wiesel B, Ganley TJ, et al. Vol 272007.
  19. Neer CSI, Foster CR. Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder. A preliminary report. Journal of Bone and Joint Surgery 1980;62A(6):897-908.
  20. Jacobson E, Forssblad M, Weidenhielm L, et al. Knee Arthroscopy with the Use of Local Anesthesia—An Increased Risk for Repeat Arthroscopy?: A Prospective, Randomized Study with a Six-Month Follow-up. The American Journal of Sports Medicine 2002;30(1):61-65.
  21. Altchek DW, Warren RF, Skyhar MJ, et al. T-plasty modification of the bankart procedure for multidirectional instability of the anterior and inferior types. Journal of Bone and Joint Surgery 1991;73A(1):105-112.
  22. Kim SH, Ha KI, Yoo JC, et al. Vol 202004.
  23. Gartsman GM, Roddey TS, Hammerman SM. Arthroscopic treatment of anterior-inferior glenohumeral instability. Two to five-year follow-up. Journal of Bone and Joint Surgery American Volume 2001;83-A(4):991-1003.
  24. Kim SH, Park JC, Park JS, et al. Vol 322004.
  25. Baker CL, Mascarenhas R, Kline AJ, et al. Arthroscopic Treatment of Multidirectional Shoulder Instability in Athletes. The American Journal of Sports Medicine 2009;37(9):1712-1720.
  26. Harryman D, Sidles J, Harris L, et al. The role of the rotator interval capsule in passive motion and stability of the shoulder. JBJS 1992;74-A:54-66.
  27. Mologne TS, Zhao K, Hongo M, et al. The Addition of Rotator Interval Closure After Arthroscopic Repair of Either Anterior or Posterior Shoulder Instability. The American Journal of Sports Medicine 2008;36(6):1123-1131.

Table 1

Place hands flat on floor without bending knees 1 point
Hyperextend knees 1 point each
Hyperextend elbows 1 point each
Bend thumb backwards to touch forearm 1 point each
Touch little finger beyond 90 degrees 1 point each
Total points (9 points maximum)
   

Beighton-Horan laxity score.  A score of greater than 4 suggests hyperlaxity.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s