Management of Recurrent Anterior Shoulder Instability

The Problem

Recurrent shoulder instability is a difficult problem arising from a destabilizing injury to the static and dynamic anterior restraints of the glenohumeral joint. The most common lesion found in anterior instability is an avulsion of the anteroinferior capsulolabral structures from the glenoid rim (Bankart lesion). Recurrent shoulder dislocation events may also result in acute fractures and/or attritional glenoid bone deficiency with subsequent loss of the static restraints of the glenohumeral joint. This attritional glenoid bone loss is increasingly being recognized as a cause of recurrent shoulder instability in addition to failed shoulder stabilization surgery. The workup and treatment of patients with recurrent shoulder instability requires careful attention to the bony and soft tissue contributors to glenohumeral stability.

Clinical Presentation

Traumatic anterior shoulder instability classically results from a fall or collision with the arm in an externally rotated and abducted position. This may result in the classic Bankart lesion in which the anteroinferior capsulolabral complex detaches from the glenoid, thereby disrupting the primary static stabilizer of the glenohumeral joint in the externally rotated and abducted position. Other pathologies that may also contribute to anterior instability include capsular laxity, rotator interval laxity, a humeral avulsion of the glenohumeral ligament (HAGL), and glenoid bone deficiency either from acute fracture or bony erosion from recurrent instability events. The prevalence of glenoid bone loss has been found in up to 22% of patients after the initial dislocation event, between 0 and 90% of patients with recurrent instability, and up to 89% of patients with recurrent instability after failed stabilization.

A complete and thorough history should be obtained when evaluating complaints of recurrent shoulder instability. Key questions addressed when obtaining the patient history include: age at time of first instability event, the position of the arm at the time of dislocation, chronicity and number of dislocations, traumatic or atraumatic etiology, presence and location of pain, presence of mechanical symptoms, and sports or recreational pursuits. Additional history to obtain as part of the preoperative evaluation should include previous surgical interventions including failed stabilization procedures, and patient expectations of treatment.

Key aspects of patient history that raise suspicion for glenoid bone loss in the setting of recurrent instability include:

• High-energy mechanism at time of dislocation, particularly axial loading of the glenoid

• Arm abducted (>70 degrees) and extended (>30 degrees) at time of dislocation

• Instability at midranges of motion (20-60 degrees of abduction)

• Progressive ease of subluxation and/or subsequent dislocation with lower energy mechanisms

• Prolonged history of recurrent instability (often > 6 months)

Diagnostic Workup

Physical Exam

A comprehensive physical examination of the affected shoulder and comparison to the contralateral shoulder will confirm the diagnosis of instability and also assess for other concomitant shoulder pathology, such as rotator cuff tears, superior labral anterior-posterior (SLAP) lesions and cartilage injury.

Physical examination of the shoulder should include:

• Visual inspection for deformity, rotator cuff atrophy, or scapular dyskinesia

• Active and passive range of motion (ROM) and rotator cuff strength testing

• Neurovascular exam (including assessment for axillary nerve injury)

• Provocative labral signs (O’Brien’s test)

• Direction and magnitude of shoulder instability including special exam maneuvers such as apprehension test, relocation test, load and shift testing, sulcus sign, Gagey hyperabduction sign

To assess for glenoid bone loss, the shoulder apprehension test should be performed at varying degrees of abduction and external rotation. Positive findings for glenoid bone loss are a positive apprehension test in midranges of abduction (30-90 degrees) and lesser amounts of external rotation. Other physical exam findings indicative of glenoid bone loss include anterior translation of the humeral head over the glenoid rim with load and shift testing.

Imaging Findings

Imaging is a critical aspect of pre-operative planning and assessment for glenoid deficiency. Standard plain films including glenohumeral anteroposterior (AP) (Grashey), scapular Y, and axillary lateral views should be obtained as part of the initial evaluation of instability. In addition to standard plain film views, specialized glenoid views may aid detection of anterior glenoid fractures or erosion with higher yield. These include a West Point view (tangential view of the anteroinferior aspect of the glenoid) and apical oblique (Garth) view, which is often easier to obtain than a West Point view in the setting of acute dislocation.

In order to evaluate for possible Hill-Sachs lesions, both a Stryker notch view (arm forward flexed 100 degrees; x-ray centered over the coracoid at 10 degree cephalad) and AP view with internal humeral rotation should be obtained.

A computed tomography (CT) scan and/or a CT arthrogram should be obtained if glenoid bone loss is suspected based on plain films and in patients with a history of recurrent instability. CT scans with 3-dimensional (3D) reconstructions are the gold standard for quantifying glenoid bone loss as it allows for digital subtraction of the humeral head to provide an en face sagittal oblique view of the glenoid surface (Figure 1). Glenoid bone loss is quantified as the percentage of bone missing from a best-fit circle superimposed on the inferior two-thirds of the glenoid rim on sagittal oblique images. CT arthrogram can be useful as it also allows evaluation of the degree of capsulolabral injury and rotatory cuff integrity.

Figure 1.

Glenoid bone loss can also be estimated at time of arthroscopy. The glenoid bare area marks the center of a circle superimposed over the inferior two-thirds of the glenoid. A calibrated probe can be used to estimate the distance from the bare area to the anterior edge of osseous lesion (A) and from bare area to posterior glenoid rim (B). Percent bone loss is calculated as (B-A)/(2*B) X 100%. The bare area method is most accurate for Bankart lesions that are parallel to the long axis of the glenoid. Despite its limitations, arthroscopic evaluation of glenoid bone loss should be part of the decision-making process prior to undertaking stabilization procedures.

Non–Operative Management

Non–surgical management may be appropriate for patients with <15% glenoid bone loss who have:

• low activity demands (non-overhead athletes)

• sedentary lifestyle

• advanced age

• significant comorbidities and high surgical risk

• history of voluntary dislocations

Non–surgical management consists of a period of immobilization followed by progressive ROM exercises, from passive to active-assist to active.

A specialized physical therapy program should entail strengthening of the rotator cuff, deltoid, and periscapular stabilizers. Pre-injury activity and the amount of bone loss are the major factors influencing the decision between non-operative and operative management.

Indications for Surgery

Factors influencing surgical decision-making in patients with recurrent instability include prior procedures performed (if any), the degree of glenoid deficiency present, patient expectations, and target post-operative activity level. Young active patients (age < 30 years) are encouraged to undergo surgical intervention as progressive glenoid erosion worsens instability and decreases options for future glenoid reconstruction. Patients with acute glenoid fractures are also encouraged to undergo surgical fixation of the bony fragment, as delayed surgery may impact fragment healing and lead to bony attrition. Surgical intervention is most commonly indicated when non-operative management fails to provide a stable arc of motion during functional activities.

A treatment algorithm is shown based on degree of glenoid bone loss:

Bone Loss <15%: Open or arthroscopic capsulolabral repair; open or arthroscopic bony avulsion repair

The majority of patients presenting with recurrent anterior instability have a low degree of glenoid bone loss (<15%). Excellent clinical results have been demonstrated with both open and arthroscopic capsulolabral repairs. Bone fragments may be anatomically incorporated into the repair to enhance success of the stabilization procedure.

Bone Loss of 15-25%: Open or arthroscopic capsulolabral repair; open or arthroscopic bony Bankart repair; open bony reconstruction of the glenoid rim

Bony restoration becomes increasingly important to stability as the percentage of glenoid deficiency increases. Anatomic incorporation of bone fragments into the repair should be performed whenever possible. Good to excellent results have been reported when bone is restored to the anterior glenoid rim, while poor outcomes are more likely when a bony fragment is not available for repair, which may occur in situations of attritional loss. Although the gold standard for recurrent instability has been open capsulolabral repair, arthroscopic repair has been shown to be effective. High demand shoulders, such as those in contact athletes, may benefit from open bony reconstruction when 25% bone loss is present.

Bone Loss >25-30%: Open repair of the glenoid rim; Latarjet procedure; structural bone graft

In cases of bone loss greater than 25-30%, open bony augmentation of the glenoid is required to re-establish shoulder stability. For acute fracture, open anatomic reduction and fixation of bone fragments along with repair of capsulolabral tissues is recommended. Commonly, the glenoid is found to be deficient without an available fracture fragment as a consequence of attritional bone loss. In order to reconstruct to the glenoid in cases of attritional bone loss, open bone augmentation is performed: options include the Latarjet procedure, Bristow procedure, or structural bone graft. Structural bone graft choices include iliac crest autograft or allograft, where the curve of the inner table of the iliac crest is selected to match the curvature of the glenoid, with the concave inner table of the graft facing laterally.

Surgical Technique

Arthroscopic capsulolabral repair

Anesthesia

Interscalene block followed by general anesthesia

Positioning

Patient is placed in lateral decubitus position with longitudinal traction of 5-7 pounds

Diagnostic arthroscopy

Posterior portal is placed 2 cm inferior to the posterolateral edge of the acromion (Figure 2)

Figure 2.

30 degree scope is inserted

Anterosuperior portal is created using outside-in technique proximal in the rotator interval, just anterior to the biceps, and a 7 mm cannula is placed.

A diagnostic arthroscopy is performed to identify the Bankart lesion and assess for concomitant pathology

Labral preparation

With visualization from the anterosuperior portal, a tissue liberator is used to mobilize the anteroinferior capsulolabral complex until subscapularis muscle fibers are visible.

Use a burr or bone rasp to roughen the anterior glenoid surface and create punctate glenoid bleeding

Posterolateral (7 o'clock) portal creation

Using outside-in technique with an 18-gauge spinal needle, a posterolateral portal is created approximately 4 cm lateral to the posterolateral corner of the acromion and in line with the posterior border of the clavicle (Figure 3). Spinal needle trajectory is near perpendicular to the floor, generally aimed at the coracoid, hugging the humeral head.

Figure 3.

An 8.25mm cannula is inserted at this position his portal is useful for taking an inferior capsulolabral tissue bite and for suture shuttling

Anteroinferior (5 o'clock) portal creation

Using outside-in technique with an 18-gauge spinal needle, an anteroinferior portal is created percutaneously, passing through the subscapularis tendon.

The arthroscopic drill guide is inserted into this portal site allowing for anchor drilling and placement

Labral repair

After placement of the initial anchor, a Spectrum (ConMed Linvatec) is used through the posterolateral portal to grasp the inferior capsule inferior to the anchor, avoiding the axillary nerve and bringing the labrum back to the glenoid, thereby enhancing plication of the inferior capsular pouch (Figure 4)

Figure 4.

Sutures are then shuttled using a simple hoop suture configuration as this allows tensioning and bumper re-creation at the inferior glenoid

Sutures are secured with a sliding knot followed by alternating half-hitches with attention to place the knot away from the articular surface

Additional anchors are placed along the anterior glenoid 3-5 mm apart with capsulolabral bites taken with the Spectrum, now inserted through the anterosuperior cannula, grasping tissue inferior to the anchor to facilitate the inferior capsular shift.

Sutures are shuttled and tied with a sliding knot

Typically a minimum of 3 suture anchors are placed between the 3- and 6 o’clock positions for an anteroinferior labral tear

Latarjet Procedure

Setup

Patient is placed into beach chair position with all bony prominence well padded. Operative extremity is prepped and draped in sterile fashion. The arm is placed on a padded Mayo stand.

Surgical Exposure

Vertical skin incision is made over deltopectoral interval extending from the tip of the coracoid 4-5 cm towards the axillary fold. Deltopectoral interval is identified and cephalic vein taken laterally. With the arm in abduction and external rotation, a Hohmann retractor is placed over the coracoid process to improve exposure.

Incise the coracoacromial ligament (CAL) 1 cm lateral from its coracoid attachment with the arm in external rotation and release the underlying coracohumeral ligament. This can be used to repair the capsule at the end of the case.

With the arm adducted and internally rotated, release the pectoralis minor from the coracoid. Remove any soft tissue from the under-surface of the coracoid using a periosteal elevator.

A 90-degree oscillating saw or curved ½” osteotome can be used to harvest a 22-25 mm coracoid fragment. The osteotomy is performed perpendicular to the coracoid process. The osteotomy can be completed with an osteotome. (Figure 5)

Figure 5.

With the arm abducted and externally rotated, grasp the coracoid fragment and release remaining coracohumeral ligament attachments, and then return the arm to neutral position. Clear remaining soft tissue off the inferior surface of the coracoid using a scalpel. Decorticate the inferior surface using an oscillating saw to create a broad flat cancellous bed. This will be approximated against the glenoid. Care is taken not to pull the coracoid to minimize any injury potential of the musculocutaneous nerve.

Place an osteotome beneath the coracoid and use a 3.2 mm drill to create two drill holes in the central axis of the coracoid approximately 1cm apart.

With the arm adducted and externally rotated, the upper lateral border of the conjoint tendon is released using Mayo scissors for about 5 cm. Push the coracoid beneath the pectoralis major to expose the subscapularis.

Glenoid Exposure

Place arm in adducted and externally rotated position. The subscapularis tendon is split using Mayo scissors in line with the muscle fibers. The split is performed at about midpoint of the subscapularis tendon. With the capsule visualized, a swab is placed into the subscapularis fossa to improve exposure, and a Hohmann retractor is placed over the sponge.

Using a Bennett retractor on the inferior subscapularis, extend the lateral aspect of the split to the lesser tuberosity to visualize the joint line, but avoid the biceps tendon. Make a 1-2 cm vertical incision in the capsule. Place a retractor (Fukuda or Trillat) into the glenohumeral joint.

To further improve exposure, place a 4 mm Steinman pin as high as possible into the superior scapular neck. Place a retractor as medial as possible on the scapular neck, and a small Hohmann is placed inferiorly between the capsule and subscapularis.

Glenoid Preparation & Fixation

Use a knife to dissect off the anterior-inferior labrum and periosteum. An elevator can be used to elevate this flap from the glenoid. Decorticate the anterior inferior glenoid to create a flat surface using a high-speed burr.

Place the coracoid graft against the glenoid and ensure it is flush with the glenoid surface.

Temporarily fix the coracoid with a 1.6 mm K-wire and then drill in a lag fashion for 3.5 mm fully threaded cortical screws. Inspect the final position and use a high-speed burr to remove any lateral overhang. (Figure 6)

Figure 6.

Place the arm in adduction and full external rotation. Two #1 absorbable braided sutures are used to repair the capsule that had been dissected off the glenoid to the stump of the CAL.

Remove all retractors. The surgical wound is irrigated. The subscapularis split is repaired with a #1 vicryl suture lateral to the graft. The wound is closed in layers.

Post-operative Care

Sling for 3-4 weeks for comfort. Passive shoulder ROM begins on post-operative day 1 with pendulum exercises and scapular strengthening.

Activities of daily living are permitted after 2 weeks. Return to sports at approximately 4 months.

Glenoid Reconstruction With Iliac Crest Bone Graft

Patient is placed on a beach chair at about 45-degree position. The beach chair bolsters along the iliac crest are positioned to provide support for the patient but not to impede access to the iliac crest for graft harvest. The shoulder and iliac crest are prepped and draped. We prefer to harvest the contralateral iliac crest.

A deltopectoral incision is made, and the interval is sharply dissected. The sub-deltoid plane is released, and a self-retaining shoulder retractor is inserted. The subscapularis is split longitudinally.

The capsule is exposed and dissected sub-periosteally as medial as possible. This can then be tagged with a #2 non-absorbable suture. Remaining labral tissue should be preserved for later repair. However, if there is significant attritional glenoid bone loss without repairable labral tissue, then a high-speed burr can be used to abrade the scapular neck and flatten the surface to accept the bone graft.

Iliac crest bone graft (ICBG) is harvested via a longitudinal incision over the iliac crest well posterior to the anterior-superior iliac spine to avoid risk of injury to the lateral femoral cutaneous nerve. Electrocautery is used to develop a periosteal sleeve off the top of the iliac crest. A Cobb elevator is used to strip the inner table and outer table. Cobra retractors are placed to improve exposure. A saw and osteotome are used to complete a tri-cortical graft harvest. The wound is irrigated and hemostasis obtained with thrombin-soaked Gelfoam. Wound is closed in layers and dressed.

Prepare the ICBG on the back table to match the concavity of the native glenoid. The ICBG inner table is concave and will become the glenoid surface.

The graft is then provisionally fixed to the glenoid with two 1.6 mm Kirschner wires, taking care not to block planned screw placement. The graft can then be fixed to the glenoid with 3.5 mm fully threaded cortical screws using lag technique. The screws start on the outer cortex of the ICBG.

Prior to final tightening of the screws, a loop of non-absorbable suture is placed around the shaft of the screw to provide secure fixation of the capsule after screw tightening. (Figure 7)

Figure 7.

Labrum and capsule are repaired, and wound is closed in layers.

Post-operative care

Sling for 3-4 weeks for comfort. Passive shoulder ROM begins on post-operative day 1 with pendulum exercises and scapular strengthening.

Activities of daily living are permitted after 2 weeks. Return to sports at approximately 4 months.

Pearls and Pitfalls of Technique

Pearls

Obtain a pre-operative CT with 3D reconstructions to understand the size, location, and geometry of glenoid bone loss.

Pre-operatively evaluate and address other pathology including HAGL lesion and Hill-Sachs lesion.

Perform an examination under anesthesia to assess the amount of translation and decide the amount of capsular plication to perform.

The axillary nerve is closest at the 6 o’clock position on the glenoid.

Pitfalls

Failure to evaluate and address the degree of glenoid bone loss and perform glenoid reconstruction when indicated.

Failure to adequately mobilize the anteroinferior capsulolabral complex to at least the 6 o’clock position during arthroscopic repair.

Failure to place enough fixation points on the glenoid during arthroscopic repair.

Aggressive retraction during open procedures can lead to nerve injury.

Potential Complications

The overall rate of recurrence from arthroscopic stabilization is 4-10%. The most common reasons for failure include not addressing capsular laxity and improper anchor positioning. Over-tightening of the soft tissues can result in stiffness, particularly loss of external rotation. Neurovascular injuries including axillary nerve injury are rare but do occur. Failure to comply with a structured post-operative rehabilitation program may result in rupture of the repair. Furthermore, arthrosis of the glenohumeral joint may develop with both operative and non-operative management and is highest after non-anatomic repairs.

Post operative Rehabilitation

Arthroscopic stabilization

Patients are typically made non-weight bearing in an abduction sling for 4-6 weeks post-operatively. Physical therapy is initiated at 7-10 days with passive and active-assisted ROM. Weeks 6-12 include active ROM exercises and a scapular stabilization program. Gradual strengthening is begun at around 8-12 weeks. Sport-specific exercises are initiated at 4 months, and a return to full activity is typically possible at 5-6 months.

Latarjet

Sling for 3-4 weeks for comfort. Passive shoulder ROM begins on post-operative day 1 with pendulum exercises and scapular strengthening.

Activities of daily living are permitted after 2 weeks. Return to sports at approximately 4 months.

ICBG Reconstruction

Sling for 3-4 weeks for comfort. Passive shoulder ROM begins on post-operative day 1 with pendulum exercises and scapular strengthening.

Activities of daily living are permitted after 2 weeks. Return to sports at approximately 4 months.

Outcomes/Evidence in the Literature

Provencher, MT, Bhatia, S, Ghodadra, NS, Grumet, RC, Bach, BR, Dewing, CB. “Recurrent shoulder instability: current concepts for evaluation and management of glenoid bone loss”. J Bone Joint Surg Am. vol. 92 Suppl 2. 2010. pp. 133-51. (Review article outlining diagnosis and management of recurrent shoulder instability with a focus on evaluation of glenoid bone loss and surgical management options.)

Provencher, MT, Ghodadra, N, Romeo, AA. “Arthroscopic management of anterior instability: pearls, pitfalls, and lessons learned”. Orthop Clin North Am. vol. 41. 2010. pp. 325-37. (Review article focusing specifically on the pearls and pitfalls that are important to recognize in the pre-operative workup, intra-operative evaluation, and arthroscopic surgery to optimize surgical outcomes for anterior instability.)

Harris, JD, Gupta, AK, Mall, NA, Abrams, GD, McCormick, FM, Cole, BJ. “Long-term outcomes after Bankart shoulder stabilization”. Arthroscopy. vol. 29. 2013. pp. 920-33. (Systematic review of clinical outcomes studies after open or arthroscopic Bankart repair with minimum 5 years follow-up. No significant difference was found in the rate of recurrent instability, clinical outcome scores, or rate of return to sport. No significant difference was shown in the incidence of post-operative osteoarthritis with open versus arthroscopic suture anchor repair.)

Lenters, TR, Franta, AK, Wolf, FM, Leopold, SS, Matsen, FA. “Arthroscopic compared with open repairs for recurrent anterior shoulder instability. A systematic review and meta-analysis of the literature”. J Bone Joint Surg Am. vol. 89. 2007. pp. 244-54. (Meta-analysis of clinical outcomes after open or arthroscopic Bankart repair showing significantly higher rates of recurrent instability, recurrent dislocation, and re-operation in arthroscopic versus open repairs.)

Kang, RW, Frank, RM, Nho, SJ, Ghodadra, NS, Verma, NN, Romeo, AA. “Complications associated with anterior shoulder instability repair”. Arthroscopy. vol. 25. 2009. pp. 909-20. (Review article that describes the complications associated with open and arthroscopic anterior instability repair and provides recommendations on techniques to identify and avoid common complications.)

Cole, BJ, L’Insalata, J, Irrgang, J, Warner, JJ. “Comparison of arthroscopic and open anterior shoulder stabilization. A two to six-year follow-up study”. J Bone Joint Surg Am. vol. 82-A. 2000. pp. 1108-1114. (A Series of 63 consecutive patients with recurrent traumatic anterior shoulder instability treated with either arthroscopic Bankart repair or open capsular shift. Both techniques yielded comparable results with no significant difference in prevalence of failure.)

Creighton, RA, Romeo, AA, Brown, FM, Hayden, JK, Verma, NN. “Revision arthroscopic shoulder instability repair”. Arthroscopy. vol. 23. 2007. pp. 703-709. (A Series of 18 patients who underwent revision arthroscopic labral fixation for failed instability repairs. Thirteen of eighteen had satisfactory results, and there was clinically significant improvement in pain score, simple shoulder test score, and American Shoulder and Elbow Surgeon (ASES) score.)

Rhee, YG, Ha, JH, Cho, NS. “Anterior shoulder stabilization in collision athletes: arthroscopic versus open Bankart repair”. Am J Sports Med. vol. 34. 2006. pp. 979-985. (Comparison of arthroscopic versus open Bankart repair in collision athletes showing improvement in visual analogue scale (VAS), Rowe, and Constant scores in both groups. There were higher rates of recurrent instability (25%) after arthroscopic repair versus open repair (12.5%).)

Warner, JJ, Gill, TJ, O’Hollerhan, J D, Pathare, N, Millett, PJ. “Anatomical glenoid reconstruction for recurrent anterior glenohumeral instability with glenoid deficiency using an autogenous tricortical iliac crest bone graft”. Am J Sports Med. vol. 34. 2006. pp. 205-212. (A Series of 11 patients using tricortical iliac crest autograft to reconstruct large glenoid bone defects of recurrent anterior instability. At mean 33-month follow-up, there were no recurrent episodes of instability.)

Piasecki, DP, Verma, NN, Romeo, AA, Levine, WN, Bach, BR, Provencher, MT. “Glenoid bone deficiency in recurrent anterior shoulder instability: diagnosis and management”. J Am Acad Orthop Surg. vol. 17. 2009. pp. 482-493. (Review article describing the diagnosis and management of glenoid bone deficiency in recurrent anterior shoulder instability.)

Summary

Recurrent instability of the glenohumeral joint is most commonly associated with a Bankart lesion. However, traumatic shoulder dislocation can be associated with glenoid rim fracture or attritional glenoid bone loss. Optimal management of recurrent shoulder instability includes assessment of anterior glenoid deficiency with a thorough history, physical examination, and imaging studies. Patients with less than 15% of anterior glenoid bone loss do well with arthroscopic capsulolabral repair. Patients with 15-25% glenoid deficiency must be evaluated on an individual basis with possible arthroscopic repair with incorporation of the osseous lesion. Patients with over 25% glenoid deficiency typically require open reconstruction of the anterior glenoid rim with either the coracoid process (Latarjet procedure) or structural bone graft.

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