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Multidirectional Instability in the Female Athlete
Author's Accepted Manuscript
Multidirectional Instability in the Female Athlete Elizabeth A. Cody MD, Sabrina M. Strickland MD
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To appear in: Oper Tech Sports Med
Cite this article as: Elizabeth A. Cody MD, Sabrina M. Strickland MD, Multidirectional Instability in the Female Athlete, Oper Tech Sports Med , http://dx.doi.org/10.1053/j.otsm.2014.02.003 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1 Multidirectional Instability in the Female Athlete
Elizabeth A. Cody, MD* Sabrina M. Strickland, MD*
*Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY 10021 Associate Professor Orthopaedic Surgery, Hospital for Special Surgery Corresponding Author: Sabrina M. Strickland, MD Hospital for Special Surgery 535 East 70th Street New York, NY 10021 Phone: 212-606-1725 Fax: 646-797-8715 Email: [email protected]
Conflict of Interest Statement: No conflict
Keywords: multidirectional instability, shoulder instability, female athlete, capsular shift
2 Abstract: Multidirectional instability of the shoulder (MDI) is the least common form of shoulder instability. Female athletes tend to favor sports that both reward and demand flexibilitysuch as gymnastics, ice skating, diving, yoga, and cheerleading and therefore MDI may become more symptomatic. It is characterized by a global laxity of the joint capsule which leads to symptomatic inferior instability in addition to anterior and/or posterior instability. Patients with MDI are atypical in that they will often have no history of trauma and may present with only vague complaints. They tend to have a loose, patulous inferior capsule in addition to altered glenohumeral and scapulothoracic mechanics, which contribute to instability. Female athletes may be particularly susceptible to MDI due to an increased predisposition to joint hyperlaxity. In addition, female athletes tend to favor sports that both reward and demand flexibility such as gymnastics, ice skating, diving, yoga, and cheerleading, which may cause MDI to become more symptomatic. The goals of treatment include pain relief, functional rehabilitation, and return to sport. Most patients will respond well to a rehabilitation protocol involving strengthening of the rotator cuff, scapular stabilization exercises, and proprioceptive training exercises. For patients who fail to respond to conservative treatment, open or arthroscopic capsular shift may be performed, with technique tailored to the patient’s individual pathology. Postoperative rehabilitation aims to restore range of motion, flexibility, and strength while protecting the integrity of the surgical repair. With close adherence to a well-designed rehabilitation protocol, patients may achieve predictably good outcomes, with a low recurrence rate of instability and a high rate of return to sports. Patients should be advised that surgery may decrease their range of motion, and that they may not be able to return to the same level of athletic competition.
3 Introduction: The shoulder is the most mobile joint in the body. However, this attribute also renders it particularly susceptible to pathologic instability, especially in athletes who routinely place undue stress on the shoulder. The unstable shoulder in the athlete can be a difficult entity to treat given the multiple etiologies and pathologies involved. This difficulty is most pronounced in the case of multidirectional shoulder instability (MDI). In contrast to straightforward anterior or posterior instability, MDI is characterized by a global laxity of the joint capsule, causing instability in more than one direction. It is most commonly defined as symptomatic laxity of the shoulder with the ability to dislocate or sublux the shoulder inferiorly as well as in at least one other direction.1 In 1980, Neer first identified MDI as a unique entity warranting individual evaluation and treatment.2 Patients with MDI comprise less than 10% of patients with shoulder instability.3,4 Among studies of patients with MDI, roughly half are women and a majority have no history of trauma.5-9 In some series, about half of the patients also have findings of generalized ligamentous laxity.8,10 However, generalized ligamentous laxity does not necessarily correlate with shoulder laxity.10 And while shoulder hyperlaxity may predispose to MDI, the lax shoulder must also be symptomatic in order to qualify a diagnosis of MDI. Perhaps as a result of the more chronic nature of multidirectional instability, Largacha et al. found that patients with multidirectional instability were more likely to have deficits in range of motion and strength than patients with traumatic anterior instability. In addition, women had more deficits in physical function and comfort than men with the same diagnosis.11 These findings highlight the importance of careful attention to history, examination, and the patient’s treatment goals. This chapter will review relevant anatomy and biomechanics, aspects of history
4 and physical examination, imaging studies, and conservative and surgical treatment options for the female athlete with MDI. Anatomy and Biomechanics: The static stabilizers of the shoulder include the capsule, glenohumeral ligaments, and the labrum; the dynamic stabilizers consist of the rotator cuff, deltoid, and long head of the biceps. While deficiencies in any of these structures can contribute to instability, capsular and labral deficiencies are viewed as the essential lesions in MDI. In the absence of trauma, repeated minor injuries (microtrauma) or repetitive athletic use can stretch out the capsule and its surrounding ligamentous structures, leading to acquired joint hyperlaxity and predisposing to instability. As the shoulder is ranged through internal rotation, external rotation, adduction, and abduction, different segments of the capsuloligamentous system tighten and loosen to prevent excessive translation of the humeral head.12 When the shoulder is abducted to 90° and externally rotated, the inferior glenohumeral ligament complex (IGHLC) is the primary restraint against anterior translation. It consists of anterior and posterior bands with a hammock-like pouch in between, which enables the two bands to reciprocally tighten as the humeral head rotates.13 As the arm is adducted from 90°, the middle glenohumeral ligament becomes the main restraint against anterior translation. As the arm returns back to a position of adduction, the superior glenohumeral ligament adds additional stabilization against anterior translation.14 Posterior translation is mainly prevented by the posterior band of the IGHLC and the anterior-superior region of the capsule (the rotator interval capsule) when the shoulder is in 90° of abduction. The rotator interval capsule is also important in resisting inferior translation, together with the superior glenohumeral ligament, when the shoulder is held in adduction. The role played by the rotator interval capsule has been studied by Harryman et al., who showed that incision of
5 the rotator interval capsule increases inferior translation on the sulcus test by 100%.15 When the arm is abducted to 45°, the capsuloligamentous structures are the most lax and the shoulder is most susceptible to superior-inferior translation. At this point, the anterior band of the IGHLC becomes the main restraint against inferior translation. As the arm moves to 90°, the posterior band of the IGHLC becomes the main restraint against inferior translation.16 Patients with MDI typically have anatomic findings of a large, patulous inferior capsular pouch and an attenuated rotator interval capsule.17 These static stabilizers maintain stability at extremes of glenohumeral motion; at mid-range positions, the dynamic stabilizers of the biceps tendon and the rotator cuff maintain stability by compressing the humeral head into the glenoid concavity. This concavity-compression effect is required to keep the humeral head opposed against the relatively small, shallow glenoid fossa.18 In patients with MDI, who are most often symptomatic in the mid-range positions, it is therefore important to address the dynamic stabilizers in addition to the capsuloligamentous structures. Negative intra-articular pressure provides an additional means to support glenohumeral opposition. Its effect is most pronounced in the relaxed arm, in the absence of the active compressive forces of the rotator cuff. After a disruption in the capsule, restoration of this negative pressure may be impossible, removing one extra restraint against instability. Loss of the shoulder’s proprioceptive feedback mechanism can further add to instability. Barden et al. found that patients with MDI showed significantly greater errors than control subjects in a series of proprioception-based upper limb repositioning tasks.19 Consequently, in the setting of impaired proprioception, patients with MDI may be predisposed to excessive humeral translation due to loss of reflexive muscular protection.16
6 Loss of normal scapulothoracic motion is another important contributor to glenohumeral instability. As the shoulder is ranged, the scapula should move conjointly to keep the glenoid appropriately positioned under the humeral head. If there is decreased scapulothoracic movement, glenohumeral mechanics are altered, and the humeral head is more likely to translate on the glenoid as the shoulder approaches extremes of range of motion. Relative to asymptomatic controls, patients with MDI have been shown to have a significant decrease in scapular rotation, leading to an increase in humeral internal rotation as the shoulder is abducted.20 In addition, if the scapular stabilizers are weak, the scapula will droop laterally under the weight of the arm, predisposing to inferior translation of the humeral head.21 These findings highlight the importance of scapular stabilization exercises during rehabilitation. History and Physical Examination: The diagnosis of MDI is largely based on history and physical examination. Reported symptoms can be vague and vary widely, but often include shoulder fatigue or aching, pain at night, feelings of joint looseness or slipping, and transient neurologic—usually sensory— symptoms. In patients reporting neurologic symptoms, cervical radiculopathy and thoracic outlet syndrome must be ruled out.17,22 A history of trauma should be recorded, although many patients will report none. Repeated microtrauma and athletic overuse are often sufficient to cause symptomatic laxity. Commonly implicated sports include swimming (especially butterfly or backstroke), gymnastics, and overhead throwing sports. In patients who report recurrent subluxations or dislocations, the clinician should clarify the frequency, causative mechanism, and ease of reduction. Recurrent subluxations are more common than locked dislocations, and in the event of dislocations, patients with MDI usually relocate easily. They typically will not report a trip to the emergency
7 room for re-location. Additionally, some patients even have the ability to voluntarily dislocate. While some of these patients have psychiatric comorbidity associated with poor treatment outcomes, these cases are rare.14 Characteristically, patients with MDI experience symptoms during normal daily activities in the midrange of glenohumeral motion. Symptoms elicited by certain activities can give clues to the direction of instability. Symptoms occurring with movements involving abduction, extension, and external rotation—such as overhead throwing—are suggestive of anterior instability. Symptoms occurring with movements involving forward flexion, adduction, and internal rotation—such as pushing open a door—suggest posterior instability.23 Of note, pain with these movements can also be attributable to impingement, which is often found together with MDI as a result of increased joint translation.22 Symptoms occurring with downward traction on the arm—as when carrying a heavy bag—suggest inferior instability.24 These patients will often complain of pain, weakness, or paresthesia due to traction on the brachial plexus.14 Among patients with MDI, anteroinferior instability is the most common presentation.4,25 On initial examination, gender, age, and build of the patient should be noted. A young, slender woman with less developed musculature is the typical patient with MDI. The shoulder may have a squared appearance due to inferior subluxation of the humeral head, which reveals the morphology of the acromion. Widening of previous scars is another common clinical finding in patients with MDI.14 While most patients with MDI will have hyperlaxity of that joint, all patients should be assessed for signs of generalized ligamentous laxity. The Beighton scale, assessed using five physical signs of joint hyperextensibility, may be used for diagnosis (Table 1, Figure 1).26 Among patients with MDI, generalized hyperlaxity has been reported in up to 75% in some
8 series.8 Some studies have reported higher prevalence of hyperlaxity among women,27 suggesting that women may be more susceptible to MDI. However, the available data does not necessarily support a causal relationship between generalized hyperlaxity and MDI.25 Interestingly, Caplan et al. found a statistically significant association between ligamentous laxity and traumatic shoulder instability, but not MDI.4 A family history of hereditary collagen disorders should also be elucidated, as patients with collagen disorders such as Ehlers-Danlos syndrome and Marfan syndrome are less likely to respond well to the soft-tissue instability repairs that are the mainstay of surgical treatment.17 When we have a high level of suspicion for a collagen disorder, patients are referred for genetic testing. Although this rarely changes the management of the condition, it is helpful to both the surgeon as well as patient in the decision making process. It is critical for the clinician to distinguish between asymptomatic laxity and symptomatic instability. Physical examination maneuvers that reproduce pain, dysesthesias, or apprehension are essential to the diagnosis of MDI. These maneuvers include the load and shift test, the apprehension and relocation tests, and the sulcus test. The unaffected shoulder should be examined first to help put the patient at ease.14 When the arm is carefully positioned and if apprehension is used to define a positive provocative test, then all of the above tests have been shown to have good interexaminer agreement and reliability.28 The sulcus test is used to assess for inferior instability. With the patient’s arm resting at the side, downward traction is applied, translating the humerus inferiorly on the glenoid and producing a soft tissue depression just below the acromion (Figure 2). The acromiohumeral distance is then measured: <1 cm corresponds to a grade of 1+, 1 to 2 cm corresponds to 2+, and greater than 2 cm corresponds to 3+.16,29,30 Regardless of the grade, the sulcus sign should only
9 be interpreted as a sign of instability if it reproduces symptoms.1 Inferior instability can also be tested by holding the arm in 90° of abduction and applying inferior force to the humeral head; inferior translation in this position suggests redundancy of the inferior capsule.16 The load and shift test are used to assess for anterior and posterior instability. The patient lies supine with her shoulder slightly over the edge of the table. The arm is held in 20° of abduction in the scapular plane as the examiner applies an axial load to compress the humeral head into the glenoid fossa. The examiner then attempts anterior and posterior translation of the humeral head. By the grading system reported by Silliman and Hawkins, movement of the humeral head up to the rim of the glenoid but no further qualifies as grade 1. If the humeral head is felt to move over the rim of the glenoid, but then spontaneously reduces once pressure is removed, it is grade 2. If the head remains dislocated once pressure is removed, it is grade 3.31 A variation of this test is performed with the patient sitting upright, with the arm at 70 to 80° of abduction in the scapular plane. The examiner stabilizes the acromion with one hand while manipulating the humeral head with the other.32 The apprehension and relocation tests are also used to assess for anterior instability. The patient again lies supine with the shoulder slightly over the edge of the table and the arm in 90° of abduction. The examiner then attempts external rotation of the arm. If the patient feels apprehension—a feeling of impending anterior instability—or other symptoms of instability are produced, the test is positive. At this point, the relocation test is performed by placing a posteriorly-directed force against the humeral head anteriorly. If this maneuver relieves the patient’s symptoms, allowing further external rotation, the test is positive. When performing the relocation test, relief of pain should be distinguished from relief of apprehension. Relief of
10 apprehension is more sensitive and specific for instability than relief of pain, which can also be found in patients with rotator cuff tendinitis.33 Imaging: MDI is a clinical diagnosis, and so imaging largely has an adjunctive role. It can help identify other shoulder pathology that may be contributing to symptoms and it can help in determining treatment plans. Radiographs, ultrasound, computed tomography, and magnetic resonance imaging (MRI) may all be used given the appropriate clinical indications. All patients should have radiographs taken as part of their initial evaluation. The instability series we use includes a true anteroposterior view of the glenoid, anteroposterior views of the shoulder in internal and external rotation, a West Point axillary view, and a Stryker notch view. Radiographs are useful for identifying bony lesions, such as a Hill-Sach’s or bony Bankart lesion. Glenohumeral alignment and humeral head and glenoid morphology can also be evaluated on radiographs. Degenerative changes, loose bodies, or periarticular calcifications will be apparent. MRI is ordered when clinically indicated to better evaluate the rotator cuff tendons and musculature, labrum, biceps tendon, and humeral head and glenoid. It has the advantage of multiplanar assessment without ionizing radiation or the need for contrast. For complete evaluation, axial, oblique sagittal, and oblique coronal series should be obtained. Magnetic resonance arthrography for assessment of width and depth of labral tears has good correlation with findings on arthroscopy,34 and so if indicated, may be useful for surgical planning. However, in patients with MDI, MRI is often normal and may only identify minor abnormalities that are not significant clinically.
11 Ultrasonography and computed tomography can also be useful modalities in certain cases. Ultrasonography can be used to detect rotator cuff tears. However, given its inability to assess the deeper structures of the shoulder, its utility is limited. Computed tomography with intra-articular contrast can be used to identify osseous lesions and assess labral and capsular integrity. This study is also not ideal as it is an invasive procedure and exposes the patient to ionizing radiation. Given the superior ability of MRI to identify the soft tissue lesions that characterize MDI, MRI is often a preferable test over ultrasonography and computed tomography. Conservative Treatment: Most patients with multidirectional shoulder instability can be managed successfully with conservative non-surgical treatment. This is especially the case for the adolescent female athlete with joint hypermobility, whose symptoms of instability may lessen with age.2,4,14,25,35-37 The nonoperative approach consists of patient education, activity modification, and physical rehabilitation. A physical therapy protocol for MDI should consist of progressive resistive exercises to strengthen the rotator cuff musculature, scapular stabilizers, and the deltoid (Figures 4-6).37 While the static stabilizers of the shoulder will remain unchanged, physical therapy can help improve muscle tone and proprioception in the shoulder musculature, thereby leading to an improvement in symptoms.22 While undergoing rehabilitation, patients should be counseled to avoid movements that produce symptoms. Pain should be minimized, if necessary with a brief trial of immobilization, a nonsteroidal anti-inflammatory drug, or a mild analgesic.14 Kronberg et al. showed that patients with generalized joint laxity and shoulder instability have a significant imbalance of shoulder muscular control compared to normal controls.38 Similarly, Nyiri et al. found that patients with MDI have significant alterations in shoulder
12 kinematics and muscle activation during active range of motion compared to controls.39 These findings suggest that patients with MDI may improve if muscular deficiencies are addressed. Supporting the role of conservative management of MDI, Burkhead et al. found that 88% of patients with MDI can have good or excellent results after treatment with a physical rehabilitation protocol. Of note, they also found that patients with a traumatic etiology for their instability were much less likely than patients with atraumatic instability to respond to physical therapy.37 Surgical Treatment: At our institution, patients who remain symptomatic after a minimum of three months of formal physical therapy are candidates for surgical treatment. Surgery for MDI most commonly involves arthroscopic capsular shift, although occasionally a surgeon may elect to perform an open procedure. These therapies enable treatment of the redundant capsule that is the hallmark of MDI. Surgical capsular shift has been shown to restore the normal kinematics of the shoulder, unlike physical therapy alone, which merely strengthens the muscles but does not affect the altered kinematics found in patients with MDI.39 These findings support pursuing surgery when patients remain symptomatic after conservative treatment. Figure 7 outlines our approach to surgical treatment of MDI. There are relatively few studies that report on outcomes from surgery for MDI specifically, as opposed to other forms of instability. Neer and Foster were the first authors to recognize MDI as a distinct entity from anterior and posterior instability, and to describe the inferior capsular shift procedure. They noted that patients with more than one direction of instability had inferior outcomes following procedures that only addressed anterior or posterior pathology. By tightening the anterior or posterior capsule alone, these procedures caused
13 worsening of instability in the non-addressed directions. In Neer and Foster’s series of 40 shoulders that underwent an inferior capsular shift, only one of 40 shoulders experienced recurrent instability. Half of the study patients were female.2 Bak et al. studied 25 patients (26 shoulders) with MDI who were treated with inferior capsular shift, 7 of whom were women. 92% of shoulders had excellent or good outcomes, with the remaining 8% (2 patients) experiencing recurrent instability. Overall, 84% of patients returned to their sport. Among the 21 patients involved in overhead sports, 16 (76%) patients returned to their previous sport but only 12 (57%) reached their preinjury level.40 In a study of 40 athletes (43 shoulders) with MDI, 16 of whom were women, Baker et al. evaluated outcomes from arthroscopic stabilization performed by one surgeon. At a minimum 2 years of follow-up, 93% of patients had good or excellent outcomes on a subjective stability scale. 91% of patients had full or satisfactory range of motion, 98% had normal or slightly decreased strength, and 86% were able to return to their sport. All patients were able to return to their normal daily activities. 9% were deemed failures due to either their ASES score (70) or continued symptomatic instability.5 Jacobson et al. conducted a meta-analysis comparing arthroscopic capsular plication with open inferior capsular shift in patients with MDI and found comparable results in regard to recurrent instability, return to sport, loss of external rotation, and overall complications.9 Among patients from all included studies, there were equal numbers of male and female patients (106 and 111). The overall procedure failure rate, defined as recurrent instability, was 12% in the open capsular shift group and 20% in the arthroscopic capsular plication group. In the arthroscopic group, patients with a history of prior surgery and patients with workers’ compensation claims accounted for over half of the cases of recurrent instability.5,40,41 80% of patients treated with
14 open surgery were able to return to their preoperative level of sport, compared to 86% of patients in the arthroscopic group, a difference which did not achieve statistic significance.9 More outcomes research still needs to be done to clarify the benefits of open versus arthroscopic surgery. At our institution, there is a trend toward the open capsular shift for true MDI patients. However, many of us still utilize arthroscopic capsular plication with suture anchors depending on the history and the exam under anesthesia. For patients with a history of prior surgery or large bony defects, open capsular shift is still often indicated together with an additional bony procedure, either Bristow or Latarjet to treat a glenoid defect and Remplissage or bone graft for large humeral head defects. Surgical Technique: It is important to recognize the patient with MDI and note her directions of instability on examination, since treatment of only one direction may cause worsening of symptoms in the untreated directions. Surgery should aim to reduce excess capsular laxity in the appropriate dimensions while avoiding over-tightening of the capsule. This is often best determined at the time of surgery with the exam under anesthesia. Yeargan et al. found that patient satisfaction following surgery for multidirectional instability was significantly associated with greater forward elevation and external rotation.42 Patients with hyperlaxity should be counseled that surgery is likely to reduce their range of motion, which may affect their athletic performance.22 The open inferior capsular shift, first described by Neer and Foster in 1980,2 has been the gold standard surgical treatment for MDI. Via an anterior approach, posterior approach, or arthroscopy, different modifications of this procedure can be used to reduce inferior capsular laxity as well as tighten the anterior and/or posterior joint capsules, depending on the patient’s
15 individual pathology. Closure of the rotator interval capsule can be added to increase inferior stability in adduction and posterior stability in flexion.15 Thermal capsular shrinkage was another surgical treatment option, initially popular due to its ease and good early outcome reports. However, longer follow-up data revealed unacceptably high failure rates as well as occasional catastrophic loss of capsular tissue, presumably due to an inflammatory reaction within the capsule. Consequently, this procedure was abandoned and we do not recommend it for patients with MDI. Both open capsular shift and arthroscopic capsulorrhaphy have been shown to be effective for patients with MDI in terms of increasing stability, decreasing pain, and allowing return to sports. For patients undergoing arthroscopic capsulorrhaphy, recent reports have demonstrated improved stability both biomechanically as well as clinically with the use of suture anchors.43 Current techniques in arthroscopic surgery allow circumferential capsular tightening which may prove more successful than open techniques with the advantage of lower morbidity. Our preferred surgical technique is performed with the patient under general anesthesia in the lateral position (Figure 8). The patient is positioned on a beanbag with an inflatable bolster one hand width inferior to their axilla on the downside. The use of a traction device (such as a Spider, Smith and Nephew, TN) allows for incremental adjustment with a bump placed in the surgical side axilla to help with distraction and visualization of the inferior glenoid (Figure 9). One may be aided by an assistant (especially for anterior labral repair) pulling posteriorly during suture passing. Prior to incision, all bony landmarks should be identified and marked (Figure 10). The posterior portal is established first, just inferior and lateral to the posterolateral tip of the acromion. An anterosuperior portal is placed just lateral and proximal to the coracoid under
16 direct arthroscopic visualization just anterior to the biceps tendon. A diagnostic arthroscopy is then performed with careful attention to the labrum circumferentially, capsular quality, and location and extent of chondral injury. The anterior cannula is then exchanged for a 7 mm threaded cannula and the camera is placed anteriorly as a second 7 mm cannula is placed posteriorly over a switching stick. Then a spinal needle is used to localize the percutaneous position and a small stab incision is made. A suture anchor is placed percutaneously at the 6 o’clock position (this is true for both anterior only and anterior/posterior repairs) (Figure 11). A 90 degree suture lasso (Arthrex, Naples, FL) or similar suture passing device is then placed percutaneously through the posterior stab incision used for the anchor placement and the capsule is incised to allow adequate shortening of the inferior glenohumeral ligaments. If needed, a “jump bite” (e.g. a suture passer passed through capsule, then out, and then back in to pass the suture through the labrum) can be taken to further reduce capsular volume. We find the use of a screw-in plastic cannula over a cannulated metal trochar (Arthrocare, Sunnyvale, CA) placed over a switching stick extremely useful as the capsule in these patients can be elastic and difficult to pass cannulas through. The looped suture as well as a limb from the suture anchor is then brought out of the posterior portal and shuttled and then tagged. This procedure is repeated as necessary up the edge of the posterior glenoid until the capsular volume has been adequately decreased. Inferiorly, use of standard suture anchors or all-suture suture anchors with curved drill guides allows easier access to the correct position on the glenoid. Some surgeons choose to tie posteriorly as they go, but we find doing so makes the anterior repair more difficult, so we leave them untied until we have addressed the anterior side. Use of the lateral Wilmington portal is often helpful for repair of the superior labrum, which can also be done percutaneously without a cannula.
17 Attention is then re-directed towards the anterior capsulorrhaphy. The camera is once again placed posteriorly, and a stab incision placed anterolaterally, inferior to the anterior cannula, is utilized to place the anterior inferior anchor. We prefer non-absorbable anchors such as PEEK or all-suture suture anchors, although bio-absorbable or bio-composite anchors may be used as well. The suture passer is then passed percutaneously and utilized to “take a bite” or pass through the capsule (Figure 12) so as to allow adequate shortening of the capsule and anterior glenohumeral ligaments, reducing capsular laxity, drive-through sign, and overall capsular volume. Similar to the posterior technique, the suture loop as well as one limb of the suture from the suture anchor is brought out the anterior superior cannula and shuttled—this suture will be used as the post. The other suture from the anchor is brought out anteriorly and tied, careful to keep the knot on the capsular side (Figure 13). Additional anchors are placed anteriorly as necessary and sometimes we utilize knotless or push loc (Arthrex, Naples, FL) anchors as we move superiorly. Rehabilitation: The success of surgery depends on tailoring of the procedure to the patient’s symptoms and treatment goals, as well as on strict adherence to the postoperative rehabilitation protocol.14 As recurrent instability tends to manifest early in the post-operative period, such a protocol involves careful, slow progression of range of motion after 3 to 6 weeks of immobilization. Patients should not expect to return to full participation in sports until at least 6 months postoperatively. The emphasis in the first 3 weeks after surgery is on protecting the surgical repair with sling immobilization. The arm is positioned in approximately ten degrees of internal rotation with an abduction pillow or brace. Pain, inflammation, and swelling should be appropriately
18 controlled with analgesics and icing. We recommend an ice water circulation system which is marketed by several companies. Gentle range of motion exercises should include active assisted elevation in the scapular plane to a maximum of 90 degrees, external rotation to 20 to 30 degrees, and gentle deltoid isometrics. From weeks 3 to 6, range of motion is gradually increased. For patients with arthroscopic repairs, elevation may be progressed to 120 degrees and external rotation to 45 degrees. For patients with open repairs, elevation may be progressed further to 145 degrees and external rotation to 60 degrees. External and internal rotation isometrics may be begun at this point, in addition to scapular stabilization and rotator cuff strengthening exercises. During this period, at the discretion of the clinician, immobilization may be discontinued. On average, we discontinue use of the sling at 4 weeks unless we are worried about patient compliance. From weeks 6 to 12, rehabilitation aims to restore full shoulder range of motion, strength, and endurance. Isotonic and stabilization exercises focusing on the rotator cuff and periscapular musculature are increased. Humeral head rhythmic stabilization exercises and other proprioceptive neuromuscular facilitation (PNF) drills are begun to improve shoulder proprioception. PNF exercises are used to re-educate the shoulder musculature. They involve repetitive patterned movements that work to increase flexibility, strength, muscular coordination, and proprioceptive feedback. Throughout the rehabilitation protocol, it is important to protect the surgical repair by avoiding excessive stretch of the anterior capsule and over-aggressive range of motion. Conclusions: MDI in the female athlete is a multifactorial problem that requires a thorough history and physical examination and carefully tailored treatment. Most patients will respond well to
19 conservative treatment with a rehabilitation protocol involving progressive strengthening of the shoulder musculature. For patients with continued pain and disability after conservative therapy, the capsular shift procedure (open or athroscopic) has proved successful in improving stability and allowing return to sports. Careful post-operative rehabilitation is critical to the success of surgery. Patients may expect to return to full participation in their sport at a minimum of 6 months post-operatively, although not necessarily at the same level of competition as previously.
20 Tables & Figures Table 1: Beighton scale for diagnosis of congenital joint hyperlaxity
Figure 1: Elbow hyperextension indicative of hyperlaxity.
Figure 2: Demonstration of the sulcus sign. Note that regardless of degree of depression, the test is only positive if it reproduces the patient’s symptoms.
Figure 3: Coronal MRI image demonstrating a patulous inferior capsule (arrow) in a patient with MDI.
Figures 4 and 5: Scapular stabilization exercises.
Figure 6: Humeral head rhythmic stabilization exercises.
Figure 7: Approach to surgical treatment of MDI.
Figure 8: The patient is positioned in the lateral decubitus position for arthroscopic capsular repair.
Figure 9: Use of a traction device such as that shown here and a bump under the axilla can help with distraction and visualization of the inferior glenoid.
21 Figure 10: The shoulder marked with landmarks and entry points for the portals to be used.
Figure 11: Drilling adjacent to the labrum for suture anchor placement.
Figure 12: Utilizing a suture passer to grab tissue and labrum.
Figure 13: Arthroscopic image after tying down multiple sutures.
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13. O'Brien SJ, Neves MC, Arnoczky SP, et al: The anatomy and histology of the inferior glenohumeral ligament complex of the shoulder. Am J Sports Med 18:449-56, 1990.
14. Beasley L, Faryniarz DA, Hannafin JA: Multidirectional instability of the shoulder in the female athlete. Clin Sports Med 19:331-49, 2000.
15. Harryman DT,2nd, Sidles JA, Harris SL, et al: The role of the rotator interval capsule in passive motion and stability of the shoulder. J Bone Joint Surg Am 74:53-66, 1992.
16. Warner JJ, Deng XH, Warren RF, et al: Static capsuloligamentous restraints to superiorinferior translation of the glenohumeral joint. Am J Sports Med 20:675-85, 1992.
24 17. Schenk TJ, Brems JJ: Multidirectional instability of the shoulder: pathophysiology, diagnosis, and management. J Am Acad Orthop Surg 6:65-72, 1998.
18. Lippitt S, Matsen F: Mechanisms of glenohumeral joint stability. Clin Orthop Relat Res 20-8, 1993.
19. Barden JM, Balyk R, Raso VJ, et al: Dynamic upper limb proprioception in multidirectional shoulder instability. Clin Orthop Relat Res 181-9, 2004.
20. Ogston JB, Ludewig PM: Differences in 3-dimensional shoulder kinematics between persons with multidirectional instability and asymptomatic controls. Am J Sports Med 35:1361-70, 2007.
21. Mallon WJ, Speer KP: Multidirectional instability: current concepts. J Shoulder Elbow Surg 4:54-64, 1995.
22. Johnson SM, Robinson CM: Shoulder Instability in Patients with Joint Hyperlaxity. J Bone Joint Surg 92:1545-57, 2010.
23. Carson EW, Warren RF. Multidirectional instability: diagnosis and management. In: Craig EV, editor. Clinical Orthopaedics. Philadelphia: Lippincott Williams and Wilkins; 1999. p.20312.
24. Cordasco FA: Understanding multidirectional instability of the shoulder. J Athl Train 35:278-85, 2000.
25. Brown GA, Tan JL, Kirkley A: The lax shoulder in females. Issues, answers, but many more questions. Clin Orthop Relat Res 110-22, 2000.
25 26. Beighton P, Horan F: Orthopaedic aspects of the Ehlers-Danlos syndrome. J Bone Joint Surg Br 51:444-53, 1969.
27. Seckin U, Tur BS, Yilmaz O, et al: The prevalence of joint hypermobility among high school students. Rheumatol Int 25:260-3, 2005.
28. Tzannes A, Paxinos A, Callanan M, et al: An assessment of the interexaminer reliability of tests for shoulder instability. J Shoulder Elbow Surg 13:18-23, 2004.
29. Norris TR: Diagnostic techniques for shoulder instability. Instr Course Lect 34:239-57, 1985.
30. Bahk M, Keyurapan E, Tasaki A, et al: Laxity testing of the shoulder: a review. Am J Sports Med 35:131-44, 2007.
31. Silliman JF, Hawkins RJ: Classification and physical diagnosis of instability of the shoulder. Clin Orthop Relat Res 7-19, 1993.
32. Speer KP: Anatomy and pathomechanics of shoulder instability. Clin Sports Med 14:751-60, 1995.
33. Speer KP, Hannafin JA, Altchek DW, et al: An evaluation of the shoulder relocation test. Am J Sports Med 22:177-83, 1994.
34. Jana M, Srivastava DN, Sharma R, et al: Magnetic resonance arthrography for assessing severity of glenohumeral labroligamentous lesions. J Orthop Surg 20:230-5, 2012.
35. Dines DM, Levinson M: The conservative management of the unstable shoulder including rehabilitation. Clin Sports Med 14:797-816, 1995.
26 36. Mahaffey BL, Smith PA: Shoulder instability in young athletes. Am Fam Physician 59:277382, 1999.
37. Burkhead WZ,Jr, Rockwood CA,Jr: Treatment of instability of the shoulder with an exercise program. J Bone Joint Surg Am 74:890-6, 1992.
38. Kronberg M, Brostrom LA, Nemeth G: Differences in shoulder muscle activity between patients with generalized joint laxity and normal controls. Clin Orthop Relat Res 181-92, 1991.
39. Nyiri P, Illyés Á, Kiss R, et al: Intermediate biomechanical analysis of the effect of physiotherapy only compared with capsular shift and physiotherapy in multidirectional shoulder instability. J Shoulder Elbow Surg 19:802-13, 2010.
40. Bak K, Spring BJ, Henderson JP: Inferior capsular shift procedure in athletes with multidirectional instability based on isolated capsular and ligamentous redundancy. Am J Sports Med 28:466-71, 2000.
41. Treacy SH, Savoie FH,3rd, Field LD: Arthroscopic treatment of multidirectional instability. J Shoulder Elbow Surg 8:345-50, 1999.
42. Yeargan SA, Briggs KK, Horan MP, et al: Determinants of patient satisfaction following surgery for multidirectional instability. Orthopedics 31:647, 2008.
43. Tjoumakaris FP, Bradley JP: The rationale for an arthroscopic approach to shoulder stabilization. Arthroscopy 27:1422-33, 2011.
Table
Characteristic
Scoring*
Passive dorsiflexion of the little finger beyond 90°
1 point for each hand
Passive apposition of the thumb to the ipsilateral forearm
1 point for each hand
Active elbow hyperextension beyond 10°
1 point for each elbow
Active knee hyperextension beyond 10°
1 point for each knee
Forward flexion of the trunk with knees fully extended so that
1 point
palms lie flat on the floor *A score of 4 points or greater is diagnostic of hyperlaxity.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Multidirectional Instability in the Female Athlete Elizabeth A. Cody MD, Sabrina M. Strickland MD
PII: DOI: Reference:
www.elsevier.com/locate/enganabound S1060-1872(14)00004-5 http://dx.doi.org/10.1053/j.otsm.2014.02.003 YOTSM50429
To appear in: Oper Tech Sports Med
Cite this article as: Elizabeth A. Cody MD, Sabrina M. Strickland MD, Multidirectional Instability in the Female Athlete, Oper Tech Sports Med , http://dx.doi.org/10.1053/j.otsm.2014.02.003 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1 Multidirectional Instability in the Female Athlete
Elizabeth A. Cody, MD* Sabrina M. Strickland, MD*
*Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY 10021 Associate Professor Orthopaedic Surgery, Hospital for Special Surgery Corresponding Author: Sabrina M. Strickland, MD Hospital for Special Surgery 535 East 70th Street New York, NY 10021 Phone: 212-606-1725 Fax: 646-797-8715 Email: [email protected]
Conflict of Interest Statement: No conflict
Keywords: multidirectional instability, shoulder instability, female athlete, capsular shift
2 Abstract: Multidirectional instability of the shoulder (MDI) is the least common form of shoulder instability. Female athletes tend to favor sports that both reward and demand flexibilitysuch as gymnastics, ice skating, diving, yoga, and cheerleading and therefore MDI may become more symptomatic. It is characterized by a global laxity of the joint capsule which leads to symptomatic inferior instability in addition to anterior and/or posterior instability. Patients with MDI are atypical in that they will often have no history of trauma and may present with only vague complaints. They tend to have a loose, patulous inferior capsule in addition to altered glenohumeral and scapulothoracic mechanics, which contribute to instability. Female athletes may be particularly susceptible to MDI due to an increased predisposition to joint hyperlaxity. In addition, female athletes tend to favor sports that both reward and demand flexibility such as gymnastics, ice skating, diving, yoga, and cheerleading, which may cause MDI to become more symptomatic. The goals of treatment include pain relief, functional rehabilitation, and return to sport. Most patients will respond well to a rehabilitation protocol involving strengthening of the rotator cuff, scapular stabilization exercises, and proprioceptive training exercises. For patients who fail to respond to conservative treatment, open or arthroscopic capsular shift may be performed, with technique tailored to the patient’s individual pathology. Postoperative rehabilitation aims to restore range of motion, flexibility, and strength while protecting the integrity of the surgical repair. With close adherence to a well-designed rehabilitation protocol, patients may achieve predictably good outcomes, with a low recurrence rate of instability and a high rate of return to sports. Patients should be advised that surgery may decrease their range of motion, and that they may not be able to return to the same level of athletic competition.
3 Introduction: The shoulder is the most mobile joint in the body. However, this attribute also renders it particularly susceptible to pathologic instability, especially in athletes who routinely place undue stress on the shoulder. The unstable shoulder in the athlete can be a difficult entity to treat given the multiple etiologies and pathologies involved. This difficulty is most pronounced in the case of multidirectional shoulder instability (MDI). In contrast to straightforward anterior or posterior instability, MDI is characterized by a global laxity of the joint capsule, causing instability in more than one direction. It is most commonly defined as symptomatic laxity of the shoulder with the ability to dislocate or sublux the shoulder inferiorly as well as in at least one other direction.1 In 1980, Neer first identified MDI as a unique entity warranting individual evaluation and treatment.2 Patients with MDI comprise less than 10% of patients with shoulder instability.3,4 Among studies of patients with MDI, roughly half are women and a majority have no history of trauma.5-9 In some series, about half of the patients also have findings of generalized ligamentous laxity.8,10 However, generalized ligamentous laxity does not necessarily correlate with shoulder laxity.10 And while shoulder hyperlaxity may predispose to MDI, the lax shoulder must also be symptomatic in order to qualify a diagnosis of MDI. Perhaps as a result of the more chronic nature of multidirectional instability, Largacha et al. found that patients with multidirectional instability were more likely to have deficits in range of motion and strength than patients with traumatic anterior instability. In addition, women had more deficits in physical function and comfort than men with the same diagnosis.11 These findings highlight the importance of careful attention to history, examination, and the patient’s treatment goals. This chapter will review relevant anatomy and biomechanics, aspects of history
4 and physical examination, imaging studies, and conservative and surgical treatment options for the female athlete with MDI. Anatomy and Biomechanics: The static stabilizers of the shoulder include the capsule, glenohumeral ligaments, and the labrum; the dynamic stabilizers consist of the rotator cuff, deltoid, and long head of the biceps. While deficiencies in any of these structures can contribute to instability, capsular and labral deficiencies are viewed as the essential lesions in MDI. In the absence of trauma, repeated minor injuries (microtrauma) or repetitive athletic use can stretch out the capsule and its surrounding ligamentous structures, leading to acquired joint hyperlaxity and predisposing to instability. As the shoulder is ranged through internal rotation, external rotation, adduction, and abduction, different segments of the capsuloligamentous system tighten and loosen to prevent excessive translation of the humeral head.12 When the shoulder is abducted to 90° and externally rotated, the inferior glenohumeral ligament complex (IGHLC) is the primary restraint against anterior translation. It consists of anterior and posterior bands with a hammock-like pouch in between, which enables the two bands to reciprocally tighten as the humeral head rotates.13 As the arm is adducted from 90°, the middle glenohumeral ligament becomes the main restraint against anterior translation. As the arm returns back to a position of adduction, the superior glenohumeral ligament adds additional stabilization against anterior translation.14 Posterior translation is mainly prevented by the posterior band of the IGHLC and the anterior-superior region of the capsule (the rotator interval capsule) when the shoulder is in 90° of abduction. The rotator interval capsule is also important in resisting inferior translation, together with the superior glenohumeral ligament, when the shoulder is held in adduction. The role played by the rotator interval capsule has been studied by Harryman et al., who showed that incision of
5 the rotator interval capsule increases inferior translation on the sulcus test by 100%.15 When the arm is abducted to 45°, the capsuloligamentous structures are the most lax and the shoulder is most susceptible to superior-inferior translation. At this point, the anterior band of the IGHLC becomes the main restraint against inferior translation. As the arm moves to 90°, the posterior band of the IGHLC becomes the main restraint against inferior translation.16 Patients with MDI typically have anatomic findings of a large, patulous inferior capsular pouch and an attenuated rotator interval capsule.17 These static stabilizers maintain stability at extremes of glenohumeral motion; at mid-range positions, the dynamic stabilizers of the biceps tendon and the rotator cuff maintain stability by compressing the humeral head into the glenoid concavity. This concavity-compression effect is required to keep the humeral head opposed against the relatively small, shallow glenoid fossa.18 In patients with MDI, who are most often symptomatic in the mid-range positions, it is therefore important to address the dynamic stabilizers in addition to the capsuloligamentous structures. Negative intra-articular pressure provides an additional means to support glenohumeral opposition. Its effect is most pronounced in the relaxed arm, in the absence of the active compressive forces of the rotator cuff. After a disruption in the capsule, restoration of this negative pressure may be impossible, removing one extra restraint against instability. Loss of the shoulder’s proprioceptive feedback mechanism can further add to instability. Barden et al. found that patients with MDI showed significantly greater errors than control subjects in a series of proprioception-based upper limb repositioning tasks.19 Consequently, in the setting of impaired proprioception, patients with MDI may be predisposed to excessive humeral translation due to loss of reflexive muscular protection.16
6 Loss of normal scapulothoracic motion is another important contributor to glenohumeral instability. As the shoulder is ranged, the scapula should move conjointly to keep the glenoid appropriately positioned under the humeral head. If there is decreased scapulothoracic movement, glenohumeral mechanics are altered, and the humeral head is more likely to translate on the glenoid as the shoulder approaches extremes of range of motion. Relative to asymptomatic controls, patients with MDI have been shown to have a significant decrease in scapular rotation, leading to an increase in humeral internal rotation as the shoulder is abducted.20 In addition, if the scapular stabilizers are weak, the scapula will droop laterally under the weight of the arm, predisposing to inferior translation of the humeral head.21 These findings highlight the importance of scapular stabilization exercises during rehabilitation. History and Physical Examination: The diagnosis of MDI is largely based on history and physical examination. Reported symptoms can be vague and vary widely, but often include shoulder fatigue or aching, pain at night, feelings of joint looseness or slipping, and transient neurologic—usually sensory— symptoms. In patients reporting neurologic symptoms, cervical radiculopathy and thoracic outlet syndrome must be ruled out.17,22 A history of trauma should be recorded, although many patients will report none. Repeated microtrauma and athletic overuse are often sufficient to cause symptomatic laxity. Commonly implicated sports include swimming (especially butterfly or backstroke), gymnastics, and overhead throwing sports. In patients who report recurrent subluxations or dislocations, the clinician should clarify the frequency, causative mechanism, and ease of reduction. Recurrent subluxations are more common than locked dislocations, and in the event of dislocations, patients with MDI usually relocate easily. They typically will not report a trip to the emergency
7 room for re-location. Additionally, some patients even have the ability to voluntarily dislocate. While some of these patients have psychiatric comorbidity associated with poor treatment outcomes, these cases are rare.14 Characteristically, patients with MDI experience symptoms during normal daily activities in the midrange of glenohumeral motion. Symptoms elicited by certain activities can give clues to the direction of instability. Symptoms occurring with movements involving abduction, extension, and external rotation—such as overhead throwing—are suggestive of anterior instability. Symptoms occurring with movements involving forward flexion, adduction, and internal rotation—such as pushing open a door—suggest posterior instability.23 Of note, pain with these movements can also be attributable to impingement, which is often found together with MDI as a result of increased joint translation.22 Symptoms occurring with downward traction on the arm—as when carrying a heavy bag—suggest inferior instability.24 These patients will often complain of pain, weakness, or paresthesia due to traction on the brachial plexus.14 Among patients with MDI, anteroinferior instability is the most common presentation.4,25 On initial examination, gender, age, and build of the patient should be noted. A young, slender woman with less developed musculature is the typical patient with MDI. The shoulder may have a squared appearance due to inferior subluxation of the humeral head, which reveals the morphology of the acromion. Widening of previous scars is another common clinical finding in patients with MDI.14 While most patients with MDI will have hyperlaxity of that joint, all patients should be assessed for signs of generalized ligamentous laxity. The Beighton scale, assessed using five physical signs of joint hyperextensibility, may be used for diagnosis (Table 1, Figure 1).26 Among patients with MDI, generalized hyperlaxity has been reported in up to 75% in some
8 series.8 Some studies have reported higher prevalence of hyperlaxity among women,27 suggesting that women may be more susceptible to MDI. However, the available data does not necessarily support a causal relationship between generalized hyperlaxity and MDI.25 Interestingly, Caplan et al. found a statistically significant association between ligamentous laxity and traumatic shoulder instability, but not MDI.4 A family history of hereditary collagen disorders should also be elucidated, as patients with collagen disorders such as Ehlers-Danlos syndrome and Marfan syndrome are less likely to respond well to the soft-tissue instability repairs that are the mainstay of surgical treatment.17 When we have a high level of suspicion for a collagen disorder, patients are referred for genetic testing. Although this rarely changes the management of the condition, it is helpful to both the surgeon as well as patient in the decision making process. It is critical for the clinician to distinguish between asymptomatic laxity and symptomatic instability. Physical examination maneuvers that reproduce pain, dysesthesias, or apprehension are essential to the diagnosis of MDI. These maneuvers include the load and shift test, the apprehension and relocation tests, and the sulcus test. The unaffected shoulder should be examined first to help put the patient at ease.14 When the arm is carefully positioned and if apprehension is used to define a positive provocative test, then all of the above tests have been shown to have good interexaminer agreement and reliability.28 The sulcus test is used to assess for inferior instability. With the patient’s arm resting at the side, downward traction is applied, translating the humerus inferiorly on the glenoid and producing a soft tissue depression just below the acromion (Figure 2). The acromiohumeral distance is then measured: <1 cm corresponds to a grade of 1+, 1 to 2 cm corresponds to 2+, and greater than 2 cm corresponds to 3+.16,29,30 Regardless of the grade, the sulcus sign should only
9 be interpreted as a sign of instability if it reproduces symptoms.1 Inferior instability can also be tested by holding the arm in 90° of abduction and applying inferior force to the humeral head; inferior translation in this position suggests redundancy of the inferior capsule.16 The load and shift test are used to assess for anterior and posterior instability. The patient lies supine with her shoulder slightly over the edge of the table. The arm is held in 20° of abduction in the scapular plane as the examiner applies an axial load to compress the humeral head into the glenoid fossa. The examiner then attempts anterior and posterior translation of the humeral head. By the grading system reported by Silliman and Hawkins, movement of the humeral head up to the rim of the glenoid but no further qualifies as grade 1. If the humeral head is felt to move over the rim of the glenoid, but then spontaneously reduces once pressure is removed, it is grade 2. If the head remains dislocated once pressure is removed, it is grade 3.31 A variation of this test is performed with the patient sitting upright, with the arm at 70 to 80° of abduction in the scapular plane. The examiner stabilizes the acromion with one hand while manipulating the humeral head with the other.32 The apprehension and relocation tests are also used to assess for anterior instability. The patient again lies supine with the shoulder slightly over the edge of the table and the arm in 90° of abduction. The examiner then attempts external rotation of the arm. If the patient feels apprehension—a feeling of impending anterior instability—or other symptoms of instability are produced, the test is positive. At this point, the relocation test is performed by placing a posteriorly-directed force against the humeral head anteriorly. If this maneuver relieves the patient’s symptoms, allowing further external rotation, the test is positive. When performing the relocation test, relief of pain should be distinguished from relief of apprehension. Relief of
10 apprehension is more sensitive and specific for instability than relief of pain, which can also be found in patients with rotator cuff tendinitis.33 Imaging: MDI is a clinical diagnosis, and so imaging largely has an adjunctive role. It can help identify other shoulder pathology that may be contributing to symptoms and it can help in determining treatment plans. Radiographs, ultrasound, computed tomography, and magnetic resonance imaging (MRI) may all be used given the appropriate clinical indications. All patients should have radiographs taken as part of their initial evaluation. The instability series we use includes a true anteroposterior view of the glenoid, anteroposterior views of the shoulder in internal and external rotation, a West Point axillary view, and a Stryker notch view. Radiographs are useful for identifying bony lesions, such as a Hill-Sach’s or bony Bankart lesion. Glenohumeral alignment and humeral head and glenoid morphology can also be evaluated on radiographs. Degenerative changes, loose bodies, or periarticular calcifications will be apparent. MRI is ordered when clinically indicated to better evaluate the rotator cuff tendons and musculature, labrum, biceps tendon, and humeral head and glenoid. It has the advantage of multiplanar assessment without ionizing radiation or the need for contrast. For complete evaluation, axial, oblique sagittal, and oblique coronal series should be obtained. Magnetic resonance arthrography for assessment of width and depth of labral tears has good correlation with findings on arthroscopy,34 and so if indicated, may be useful for surgical planning. However, in patients with MDI, MRI is often normal and may only identify minor abnormalities that are not significant clinically.
11 Ultrasonography and computed tomography can also be useful modalities in certain cases. Ultrasonography can be used to detect rotator cuff tears. However, given its inability to assess the deeper structures of the shoulder, its utility is limited. Computed tomography with intra-articular contrast can be used to identify osseous lesions and assess labral and capsular integrity. This study is also not ideal as it is an invasive procedure and exposes the patient to ionizing radiation. Given the superior ability of MRI to identify the soft tissue lesions that characterize MDI, MRI is often a preferable test over ultrasonography and computed tomography. Conservative Treatment: Most patients with multidirectional shoulder instability can be managed successfully with conservative non-surgical treatment. This is especially the case for the adolescent female athlete with joint hypermobility, whose symptoms of instability may lessen with age.2,4,14,25,35-37 The nonoperative approach consists of patient education, activity modification, and physical rehabilitation. A physical therapy protocol for MDI should consist of progressive resistive exercises to strengthen the rotator cuff musculature, scapular stabilizers, and the deltoid (Figures 4-6).37 While the static stabilizers of the shoulder will remain unchanged, physical therapy can help improve muscle tone and proprioception in the shoulder musculature, thereby leading to an improvement in symptoms.22 While undergoing rehabilitation, patients should be counseled to avoid movements that produce symptoms. Pain should be minimized, if necessary with a brief trial of immobilization, a nonsteroidal anti-inflammatory drug, or a mild analgesic.14 Kronberg et al. showed that patients with generalized joint laxity and shoulder instability have a significant imbalance of shoulder muscular control compared to normal controls.38 Similarly, Nyiri et al. found that patients with MDI have significant alterations in shoulder
12 kinematics and muscle activation during active range of motion compared to controls.39 These findings suggest that patients with MDI may improve if muscular deficiencies are addressed. Supporting the role of conservative management of MDI, Burkhead et al. found that 88% of patients with MDI can have good or excellent results after treatment with a physical rehabilitation protocol. Of note, they also found that patients with a traumatic etiology for their instability were much less likely than patients with atraumatic instability to respond to physical therapy.37 Surgical Treatment: At our institution, patients who remain symptomatic after a minimum of three months of formal physical therapy are candidates for surgical treatment. Surgery for MDI most commonly involves arthroscopic capsular shift, although occasionally a surgeon may elect to perform an open procedure. These therapies enable treatment of the redundant capsule that is the hallmark of MDI. Surgical capsular shift has been shown to restore the normal kinematics of the shoulder, unlike physical therapy alone, which merely strengthens the muscles but does not affect the altered kinematics found in patients with MDI.39 These findings support pursuing surgery when patients remain symptomatic after conservative treatment. Figure 7 outlines our approach to surgical treatment of MDI. There are relatively few studies that report on outcomes from surgery for MDI specifically, as opposed to other forms of instability. Neer and Foster were the first authors to recognize MDI as a distinct entity from anterior and posterior instability, and to describe the inferior capsular shift procedure. They noted that patients with more than one direction of instability had inferior outcomes following procedures that only addressed anterior or posterior pathology. By tightening the anterior or posterior capsule alone, these procedures caused
13 worsening of instability in the non-addressed directions. In Neer and Foster’s series of 40 shoulders that underwent an inferior capsular shift, only one of 40 shoulders experienced recurrent instability. Half of the study patients were female.2 Bak et al. studied 25 patients (26 shoulders) with MDI who were treated with inferior capsular shift, 7 of whom were women. 92% of shoulders had excellent or good outcomes, with the remaining 8% (2 patients) experiencing recurrent instability. Overall, 84% of patients returned to their sport. Among the 21 patients involved in overhead sports, 16 (76%) patients returned to their previous sport but only 12 (57%) reached their preinjury level.40 In a study of 40 athletes (43 shoulders) with MDI, 16 of whom were women, Baker et al. evaluated outcomes from arthroscopic stabilization performed by one surgeon. At a minimum 2 years of follow-up, 93% of patients had good or excellent outcomes on a subjective stability scale. 91% of patients had full or satisfactory range of motion, 98% had normal or slightly decreased strength, and 86% were able to return to their sport. All patients were able to return to their normal daily activities. 9% were deemed failures due to either their ASES score (70) or continued symptomatic instability.5 Jacobson et al. conducted a meta-analysis comparing arthroscopic capsular plication with open inferior capsular shift in patients with MDI and found comparable results in regard to recurrent instability, return to sport, loss of external rotation, and overall complications.9 Among patients from all included studies, there were equal numbers of male and female patients (106 and 111). The overall procedure failure rate, defined as recurrent instability, was 12% in the open capsular shift group and 20% in the arthroscopic capsular plication group. In the arthroscopic group, patients with a history of prior surgery and patients with workers’ compensation claims accounted for over half of the cases of recurrent instability.5,40,41 80% of patients treated with
14 open surgery were able to return to their preoperative level of sport, compared to 86% of patients in the arthroscopic group, a difference which did not achieve statistic significance.9 More outcomes research still needs to be done to clarify the benefits of open versus arthroscopic surgery. At our institution, there is a trend toward the open capsular shift for true MDI patients. However, many of us still utilize arthroscopic capsular plication with suture anchors depending on the history and the exam under anesthesia. For patients with a history of prior surgery or large bony defects, open capsular shift is still often indicated together with an additional bony procedure, either Bristow or Latarjet to treat a glenoid defect and Remplissage or bone graft for large humeral head defects. Surgical Technique: It is important to recognize the patient with MDI and note her directions of instability on examination, since treatment of only one direction may cause worsening of symptoms in the untreated directions. Surgery should aim to reduce excess capsular laxity in the appropriate dimensions while avoiding over-tightening of the capsule. This is often best determined at the time of surgery with the exam under anesthesia. Yeargan et al. found that patient satisfaction following surgery for multidirectional instability was significantly associated with greater forward elevation and external rotation.42 Patients with hyperlaxity should be counseled that surgery is likely to reduce their range of motion, which may affect their athletic performance.22 The open inferior capsular shift, first described by Neer and Foster in 1980,2 has been the gold standard surgical treatment for MDI. Via an anterior approach, posterior approach, or arthroscopy, different modifications of this procedure can be used to reduce inferior capsular laxity as well as tighten the anterior and/or posterior joint capsules, depending on the patient’s
15 individual pathology. Closure of the rotator interval capsule can be added to increase inferior stability in adduction and posterior stability in flexion.15 Thermal capsular shrinkage was another surgical treatment option, initially popular due to its ease and good early outcome reports. However, longer follow-up data revealed unacceptably high failure rates as well as occasional catastrophic loss of capsular tissue, presumably due to an inflammatory reaction within the capsule. Consequently, this procedure was abandoned and we do not recommend it for patients with MDI. Both open capsular shift and arthroscopic capsulorrhaphy have been shown to be effective for patients with MDI in terms of increasing stability, decreasing pain, and allowing return to sports. For patients undergoing arthroscopic capsulorrhaphy, recent reports have demonstrated improved stability both biomechanically as well as clinically with the use of suture anchors.43 Current techniques in arthroscopic surgery allow circumferential capsular tightening which may prove more successful than open techniques with the advantage of lower morbidity. Our preferred surgical technique is performed with the patient under general anesthesia in the lateral position (Figure 8). The patient is positioned on a beanbag with an inflatable bolster one hand width inferior to their axilla on the downside. The use of a traction device (such as a Spider, Smith and Nephew, TN) allows for incremental adjustment with a bump placed in the surgical side axilla to help with distraction and visualization of the inferior glenoid (Figure 9). One may be aided by an assistant (especially for anterior labral repair) pulling posteriorly during suture passing. Prior to incision, all bony landmarks should be identified and marked (Figure 10). The posterior portal is established first, just inferior and lateral to the posterolateral tip of the acromion. An anterosuperior portal is placed just lateral and proximal to the coracoid under
16 direct arthroscopic visualization just anterior to the biceps tendon. A diagnostic arthroscopy is then performed with careful attention to the labrum circumferentially, capsular quality, and location and extent of chondral injury. The anterior cannula is then exchanged for a 7 mm threaded cannula and the camera is placed anteriorly as a second 7 mm cannula is placed posteriorly over a switching stick. Then a spinal needle is used to localize the percutaneous position and a small stab incision is made. A suture anchor is placed percutaneously at the 6 o’clock position (this is true for both anterior only and anterior/posterior repairs) (Figure 11). A 90 degree suture lasso (Arthrex, Naples, FL) or similar suture passing device is then placed percutaneously through the posterior stab incision used for the anchor placement and the capsule is incised to allow adequate shortening of the inferior glenohumeral ligaments. If needed, a “jump bite” (e.g. a suture passer passed through capsule, then out, and then back in to pass the suture through the labrum) can be taken to further reduce capsular volume. We find the use of a screw-in plastic cannula over a cannulated metal trochar (Arthrocare, Sunnyvale, CA) placed over a switching stick extremely useful as the capsule in these patients can be elastic and difficult to pass cannulas through. The looped suture as well as a limb from the suture anchor is then brought out of the posterior portal and shuttled and then tagged. This procedure is repeated as necessary up the edge of the posterior glenoid until the capsular volume has been adequately decreased. Inferiorly, use of standard suture anchors or all-suture suture anchors with curved drill guides allows easier access to the correct position on the glenoid. Some surgeons choose to tie posteriorly as they go, but we find doing so makes the anterior repair more difficult, so we leave them untied until we have addressed the anterior side. Use of the lateral Wilmington portal is often helpful for repair of the superior labrum, which can also be done percutaneously without a cannula.
17 Attention is then re-directed towards the anterior capsulorrhaphy. The camera is once again placed posteriorly, and a stab incision placed anterolaterally, inferior to the anterior cannula, is utilized to place the anterior inferior anchor. We prefer non-absorbable anchors such as PEEK or all-suture suture anchors, although bio-absorbable or bio-composite anchors may be used as well. The suture passer is then passed percutaneously and utilized to “take a bite” or pass through the capsule (Figure 12) so as to allow adequate shortening of the capsule and anterior glenohumeral ligaments, reducing capsular laxity, drive-through sign, and overall capsular volume. Similar to the posterior technique, the suture loop as well as one limb of the suture from the suture anchor is brought out the anterior superior cannula and shuttled—this suture will be used as the post. The other suture from the anchor is brought out anteriorly and tied, careful to keep the knot on the capsular side (Figure 13). Additional anchors are placed anteriorly as necessary and sometimes we utilize knotless or push loc (Arthrex, Naples, FL) anchors as we move superiorly. Rehabilitation: The success of surgery depends on tailoring of the procedure to the patient’s symptoms and treatment goals, as well as on strict adherence to the postoperative rehabilitation protocol.14 As recurrent instability tends to manifest early in the post-operative period, such a protocol involves careful, slow progression of range of motion after 3 to 6 weeks of immobilization. Patients should not expect to return to full participation in sports until at least 6 months postoperatively. The emphasis in the first 3 weeks after surgery is on protecting the surgical repair with sling immobilization. The arm is positioned in approximately ten degrees of internal rotation with an abduction pillow or brace. Pain, inflammation, and swelling should be appropriately
18 controlled with analgesics and icing. We recommend an ice water circulation system which is marketed by several companies. Gentle range of motion exercises should include active assisted elevation in the scapular plane to a maximum of 90 degrees, external rotation to 20 to 30 degrees, and gentle deltoid isometrics. From weeks 3 to 6, range of motion is gradually increased. For patients with arthroscopic repairs, elevation may be progressed to 120 degrees and external rotation to 45 degrees. For patients with open repairs, elevation may be progressed further to 145 degrees and external rotation to 60 degrees. External and internal rotation isometrics may be begun at this point, in addition to scapular stabilization and rotator cuff strengthening exercises. During this period, at the discretion of the clinician, immobilization may be discontinued. On average, we discontinue use of the sling at 4 weeks unless we are worried about patient compliance. From weeks 6 to 12, rehabilitation aims to restore full shoulder range of motion, strength, and endurance. Isotonic and stabilization exercises focusing on the rotator cuff and periscapular musculature are increased. Humeral head rhythmic stabilization exercises and other proprioceptive neuromuscular facilitation (PNF) drills are begun to improve shoulder proprioception. PNF exercises are used to re-educate the shoulder musculature. They involve repetitive patterned movements that work to increase flexibility, strength, muscular coordination, and proprioceptive feedback. Throughout the rehabilitation protocol, it is important to protect the surgical repair by avoiding excessive stretch of the anterior capsule and over-aggressive range of motion. Conclusions: MDI in the female athlete is a multifactorial problem that requires a thorough history and physical examination and carefully tailored treatment. Most patients will respond well to
19 conservative treatment with a rehabilitation protocol involving progressive strengthening of the shoulder musculature. For patients with continued pain and disability after conservative therapy, the capsular shift procedure (open or athroscopic) has proved successful in improving stability and allowing return to sports. Careful post-operative rehabilitation is critical to the success of surgery. Patients may expect to return to full participation in their sport at a minimum of 6 months post-operatively, although not necessarily at the same level of competition as previously.
20 Tables & Figures Table 1: Beighton scale for diagnosis of congenital joint hyperlaxity
Figure 1: Elbow hyperextension indicative of hyperlaxity.
Figure 2: Demonstration of the sulcus sign. Note that regardless of degree of depression, the test is only positive if it reproduces the patient’s symptoms.
Figure 3: Coronal MRI image demonstrating a patulous inferior capsule (arrow) in a patient with MDI.
Figures 4 and 5: Scapular stabilization exercises.
Figure 6: Humeral head rhythmic stabilization exercises.
Figure 7: Approach to surgical treatment of MDI.
Figure 8: The patient is positioned in the lateral decubitus position for arthroscopic capsular repair.
Figure 9: Use of a traction device such as that shown here and a bump under the axilla can help with distraction and visualization of the inferior glenoid.
21 Figure 10: The shoulder marked with landmarks and entry points for the portals to be used.
Figure 11: Drilling adjacent to the labrum for suture anchor placement.
Figure 12: Utilizing a suture passer to grab tissue and labrum.
Figure 13: Arthroscopic image after tying down multiple sutures.
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Table
Characteristic
Scoring*
Passive dorsiflexion of the little finger beyond 90°
1 point for each hand
Passive apposition of the thumb to the ipsilateral forearm
1 point for each hand
Active elbow hyperextension beyond 10°
1 point for each elbow
Active knee hyperextension beyond 10°
1 point for each knee
Forward flexion of the trunk with knees fully extended so that
1 point
palms lie flat on the floor *A score of 4 points or greater is diagnostic of hyperlaxity.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9