Failed anterior shoulder stabilization

J Shoulder Elbow Surg (2011) 20, 1340-1350

www.elsevier.com/locate/ymse

REVIEW ARTICLES

Failed anterior shoulder stabilization Craig S. Mauro, MDa,*, James E. Voos, MDb, Sommer Hammoud, MDc, David W. Altchek, MDc a

Burke and Bradley Orthopedics, University of Pittsburgh Medical Center, Pittsburgh, PA, USA Orthopaedic and Sports Medicine Clinic of Kansas City, Leawood, KS, USA c Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY, USA b

Rates of recurrent instability Historically, arthroscopic transglenoid suture and bioabsorbable tack fixation techniques had higher rates of recurrent instability than open techniques, with a meta-analysis demonstrating a recurrence rate of 18% with bioabsorbable tacks, 23% with transglenoid sutures, and 10% with open surgery.25 Other studies have demonstrated even higher rates of recurrence with the use of arthroscopic tacks or transglenoid sutures.32,35,65,70 The difference in recurrence between open and arthroscopic techniques may be narrowing with current suture anchor techniques, with recent studies reporting recurrent instability rates of 4% to 18% after arthroscopic anterior shoulder stabilization11,13,16,23,36,71 and 0% to 7% after open anterior stabilization.13,23 Recurrent instability, which can be atraumatic or result from a traumatic event, is typically classified as a subsequent dislocation, subluxation event, or persistent apprehension.10,37 Further, Walch and Mole72 noted that instability may also manifest as chronic pain (at least 6 months’ duration) in abduction and external rotation, without a defined history of dislocation or subluxation. Similarly, Boileau et al12 recently described the unstable painful shoulder (UPS) as an unrecognized anteroinferior instability (without any apparent history of instability, but

Investigational Review Board approval was not required for this review article. *Reprint requests: Craig S. Mauro, MD, University of Pittsburgh Medical Center, UPMC St. Margaret, Burke and Bradley Orthopedics, 200 Delafield Rd, Ste 4010, Pittsburgh, PA 15215, USA. E-mail address: [email protected] (C.S. Mauro).

with anatomic lesions indicative of instability) that causes shoulder pain in the young athlete. Several recent studies have prospectively quantified the rate of recurrent instability after anterior shoulder stabilization using modern suture anchor techniques:
Voos et al71 found an 18% recurrent instability rate after arthroscopic anterior shoulder stabilization of 83 consecutive patients; specifically, a subsequent dislocation occurred in 10% and a subluxation event or apprehension in 8%.
Carreira et al16 noted a recurrence rate of 10% in a series of 72 patients treated arthroscopically and monitored for a minimum of 2 years: 6% experienced a recurrent dislocation and 4% experienced subluxation events.
Kim et al36 evaluated 167 patients between 2 and 6 years after arthroscopic anterior stabilization and found a recurrent instability rate of 4%, with 1% sustaining a dislocation, 1% subluxations, and 2% apprehension. Two recent studies compared open and arthroscopic anterior shoulder stabilizations in a prospective, randomized fashion. Fabbriciani et al23 randomized 60 patients with isolated Bankart lesions to arthroscopic or open anterior stabilization and noted no dislocations at 2 years postoperatively in either group. However, they excluded an additional 44 patients because of findings at the arthroscopic examination such as capsular elongation and labral tearing extending to the inferior glenoid. Bottoni et al13 found no recurrent dislocations at a minimum of 2 years postoperatively in 61 patients from a military population who were randomized to open or arthroscopic stabilization after at least 6 months of supervised rehabilitation had failed. The overall failure rates were

1058-2746/$ - see front matter Ó 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. doi:10.1016/j.jse.2011.05.003

Failed anterior shoulder stabilization

1341

6.9% in the open group and 3.1% in the arthroscopic group, with the failures consisting of persistent shoulder pain without instability, subjective instability without further trauma, and a traumatic posterior shoulder injury from an assault. Why the failure rates in these prospective, randomized studies are lower than those in the other studies discussed is unclear, but smaller study size, overall patient population, and intraoperative patient selection criteria may have contributed.

Risk factors for recurrent instability Several risk factors have been implicated in the rate of recurrent instability after operative stabilization. These risk factors for recurrent instability have been elucidated from prospective evaluations of anterior shoulder stabilizations and from studies looking specifically at risk factors for failure. The risk factors that have been identified most commonly are younger patient age, capsular stretching, ligamentous laxity, number of anchors used, and contact athletics.* Bone loss on the glenoid or humeral side (Fig. 1) has also been identified as a risk factor and will be discussed further in the ‘‘Etiology of failure’’ section.3,11,14,15,33,71 Boileau et al11 sought to identify risk factors for recurrent shoulder instability after arthroscopic Bankart repair. Of the 91 patients who were monitored for a minimum of 2 years, 15% had recurrent instability in the form of a dislocation or a subluxation event, and an additional 10% had a persistent positive apprehension test. Several factors were associated with recurrent instability. Glenoid bone loss involving more than 25% of the glenoid surface, without a true bony Bankart fragment, was significantly associated with failure. A bony Bankart, however, was not associated with an increased rate of failure. A large Hill-Sachs lesion, a stretched inferior glenohumeral ligament, and anterior hyperlaxity were also significantly related to failure. Patients with 3 or fewer anchors also had higher rates of recurrent instability. Their multivariate analysis showed that the presence of a stretched inferior glenohumeral ligament, anterior hyperlaxity, or a glenoid compression fracture involving more than 25% of the glenoid surface led to a 75% recurrence rate. Similarly, Voos et al71 found that patients aged younger than 25 years, with ligamentous laxity and a large (>250 mm3) Hill-Sachs lesion, were at the greatest risk of recurrence.71 However, they found no difference in the number of suture anchors used between those who did and did not suffer a recurrence. Although some biomechanical studies have demonstrated increasing construct strength with more sutures,28,50 suggesting the number sutures used may be more important than the number of anchors used, no clinical studies ) 3, 9, 11, 14, 15, 32, 61, 71.

Figure 1 Axillary radiograph demonstrates humeral (dashed arrow) and glenoid (solid arrow) bone loss after a failed arthroscopic anterior stabilization.

have specifically correlated failure rates with the number of sutures. Porcellini et al56 recently investigated the predisposing factors for recurrent shoulder dislocation after arthroscopic treatment. They monitored 385 patients who were treated with arthroscopic anterior stabilization for anterior unidirectional instability and noted an overall redislocation rate of 8.1%. The recurrence rate was 13.3% in patients aged 22 years and younger and 6.3% in patients older than 22. They also noted a higher rate of redislocation in men (10.1% vs 2.8%) and in patients where an interval of more than 6 months had passed between the first dislocation and surgery (11.9% vs 4.8%). Imhoff et al32 found that the failure rate with arthroscopic anterior stabilization increased with lower patient age and a higher number of previous dislocations. They noted, however, that the failure rate was not influenced by the presence of a superior labrum anteroposterior tear or a rotator cuff tear. Balg and Boileau3 created a 10-point preoperative instability severity index score (ISIS) that can be used to identify risk factors for recurrent instability. They prospectively evaluated 131 patients who underwent arthroscopic anterior stabilization and identified 6 risk factors for recurrent instability: age younger than 20 years at the time of surgery, competitive participation in sports, contact sport, or those involving forced overhead activity, shoulder hyperlaxity, Hill-Sachs lesion visible on a plain anteroposterior (AP) radiograph with the arm in external rotation, or loss of the sclerotic inferior glenoid contour on a plain AP radiograph. When the ISIS was applied retrospectively to this cohort of patients, patients with a score exceeding 6 points had recurrence risk of 70%. These findings led them to recommend that patients with a score of 6 points or less are potentially good candidates for arthroscopic anterior stabilization. However, they recommend that patients with more than 6 points should undergo open surgery (ie, Latarjet procedure)

1342 because of the unacceptable recurrence risk of 70% with arthroscopic stabilization. Exposure to trauma is a risk factor for recurrent anterior shoulder instability and failed shoulder stabilization procedures. This finding is especially evident in the contact athlete.19,53,59 A study of the National Collegiate Athletic Association injury database found the sports with the highest rates of shoulder instability are men’s football, wrestling, and hockey.51 Reported failure rates of stabilization procedures in contact athletes are higher than in the general population.19,59,67 Two other recent studies suggested a trend toward collision sports as a risk factor for recurrent instability after arthroscopic stabilization17,71 Cho et al19 found a recurrence rate of 28.6% in collision athletes compared with 6.7% in noncollision athletes who underwent arthroscopic stabilization for shoulder instability. The high rates have brought some to suggest open stabilization is more appropriate in the contact athlete. Rhee et al59 compared arthroscopic and open anterior stabilization in 46 collision athletes and found a recurrence of 25% in the arthroscopic group vs 12.5% in the open group. Mazzocca et al,44 however, reported only an 11% recurrence rate in contact athletes treated arthroscopically, and Larrain et al40 reported a 7.5% recurrence rate in a series of rugby players selected for arthroscopic treatment. Pagnani and Dome53 reported the results of open stabilization in 58 American football players, with only 3% suffering recurrent subluxation at an average follow-up of 37 months.

Etiology of failure The etiology of failure in this context is identified through a thorough history and physical examination, further imaging, and most often in the published reports of anterior stabilization failure, inspection when the revision arthroscopic or open surgical intervention takes place. Recurrent instability may result from a new episode of major trauma after the initial repair or may occur without significant force. The etiology generally involves a soft tissue or bone issue, or both, and the most commonly cited contributors to the failure are diagnostic and technical errors, capsular or labral insufficiency (stretching, laxity, or tearing), and glenoid or humeral bone loss, or both.y In some cases, the etiology of failure of anterior shoulder stabilization is new, major trauma that disrupts an unhealed repair or causes a new rupture through the capsule, labrum, or glenoid bone (Fig. 2). These bony Bankart lesions may occur at the level of anchors used during the initial stabilization.4,20,26 Cho el al20 found that 88.5% of patients undergoing revision arthroscopy had sustained a re-tear of the repaired Bankart lesion, while

y

11, 14, 15, 19, 21, 49, 61, 64, 67.

C.S. Mauro et al.

Figure 2 Arthroscopic image shows a re-torn anterior capsulolabral complex (solid arrow) after a failed arthroscopic anterior stabilization. The dashed arrow indicates the remaining suture material. G, Glenoid; HH, humeral head.

11.5% had a re-tear size larger than that encountered during the index procedure. Tauber et al67 found at revision surgery that 17% of patients had a typical Bankart lesion with good capsule quality. Technical errors are one of the major causes of recurrent instability after primary anterior shoulder stabilization. An incorrect diagnosis before the index procedure may lead to the failure if posterior instability, multidirectional instability, or a humeral avulsion of the glenohumeral ligaments is neglected because it was not identified preoperatively or intraoperatively. Nonanatomic repair of capsulolabral tissue is frequently cited as a technical error discovered at the time of revision anterior shoulder stabilization.19,21,36,49,64 In the revision setting, Kim et al36 identified that a possible initial cause of failure was that labral tissue fixation was proximal or medial to the glenoid margin. Neri et al49 also reported improper placement of suture anchors at the time of revision stabilization. They emphasized that not recreating the anterior bumper or not reducing the anteroinferior capsular volume during the initial procedure may predispose the repair to failure. Sisto et al64 identified the importance of the anteroinferior capsular volume reduction, noting at the time of open revision Bankart repair that an anchor had not been placed inferior to the 4-o’clock position for a right shoulder or the 8-o’clock position for the left shoulder in 87% of patients. The general consensus is that bone loss on the humeral or glenoid side may contribute to failure after anterior shoulder stabilization. Tauber et al67 found a defect of the anterior bony glenoid rim in 56% in a series of patients undergoing revision anterior stabilization, whereas glenoid insufficiency was present in 89% of patients with failed anterior stabilization in a series by Burkhart and DeBeer.15

Failed anterior shoulder stabilization

1343

Humeral head defects have been observed in up to 100% of patients with recurrent dislocation at the time of arthroscopy.18,68 Recent reports have also shown high rates of Hill-Sachs lesions in first-time shoulder subluxations. Owens et al51 found 93% of military cadets had Hill-Sachs lesions on magnetic resonance imaging (MRI) when they presented with anterior shoulder subluxation.

The glenoid The glenoid is normally pear shaped, with a larger diameter below the midglenoid notch than above it.15 A significant glenoid bone defect has been defined by Burkhart and De Beer15 as one in which the arthroscopic appearance of the glenoid is that of an ‘‘inverted pear.’’ Bone loss can occur by 2 methods: acute fracture (ie, bony Bankart) and bony erosion or attrition (ie, inverted pear glenoid) that occurs with recurrent instability events.15,47,66 In either situation, the loss of glenoid articulating surface results in decreased articular conformity and surface area for articulation of the humeral head.14,33,74 Burkhart and DeBeer15 analyzed the relationship between glenohumeral bone loss and recurrent instability in 194 consecutive arthroscopic Bankart repairs. They noted an 11% recurrence rate, with 7% experiencing a dislocation and 4% experiencing subluxations. Of these patients with recurrent instability after the arthroscopic stabilization, 67% had significant bone defects (engaging Hill-Sachs or inverted-pear Bankart lesions). A comparison of 21 shoulders with significant bone defects with 173 without significant bone defects found 67% and 4% recurrence rates, respectively. The authors further analyzed the 101 contact athletes within their cohort: the recurrence rate was 6.5% in contact athletes without significant bone defects and 89% in those with significant bone defects. Radiographic evidence of glenoid bone loss may be apparent on standard AP and axillary radiographs; however, the probability of detecting any deficiencies is higher with the West Point view and the Bernageau view.8,22,31,60 Further, the Bernageau view has been used for calculating anterior glenoid bone loss.31 MRI is routinely used to assess articular cartilage and soft tissue (Fig. 3), and may also be used for quantification of a glenoid bone defect.29 Other authors, however, argue that MRI may underestimate the amount of glenoid bone loss and that 3-dimensional (3-D) computed tomography (CT) scans provide the most quantitative information for calculation of bone loss (Fig. 4).57,66 When bone loss is suspected, the use of a CT scan has been strongly suggested by several authors.55,57,69 Several methods for quantifying glenoid bone loss on CT scan have been described.57 Glenoid deficiency can be determined by placing a best-fit circle at the inferior portion of the glenoid and measuring the defect as a percentage of the total glenoid surface.30,66 Alternatively, in the PICO method (named for the philosopher Pico della Mirandola),

Figure 3 Axial magnetic resonance image demonstrates a torn and medially retracted anterior labrum with associated glenoid bone and cartilage (arrow).

Figure 4 A 3-dimensional computed tomography scan shows anterior, inferior glenoid bone loss (arrow).

a best-fit circle is drawn on the inferior portion of the contralateral, uninjured glenoid. The surface area (A) is digitally calculated, and this circle is then superimposed onto the injured glenoid. The surface area of defect (D) is measured, and the percentage of glenoid bone loss is calculated as (D/A)  100.7 Arthroscopic assessment of glenoid bone loss is ultimately the best means of evaluation. Lo et al42 described the use of the glenoid bare spot as an arthroscopic reference to measure the percentage of anterior-to-posterior bone loss. The measurements are made with the arthroscope in the anterosuperior portal. A calibrated probe is inserted via the posterior portal, and the distances from the anterior and posterior margins of the glenoid to the bare spot are measured. The percentage of bone loss is calculated as the difference between the two divided by twice the difference of the posterior rim to the bare spot. Several authors have assessed the critical amount of bone loss that results in an increased risk of instability27,33,42:
One study created osteotomies at a 45 inclination to the anterior glenoid in cadaveric specimens. Instability

1344

C.S. Mauro et al.

of the glenohumeral joint increased significantly at defects exceeding 21% (average, 6.8 mm) of the glenoid width.33
Another study reported that more than a 30% loss of the anterior-to-posterior width of the glenoid resulted in instability.27
In a 2-part study of the inverted pear glenoid in clinical subjects and cadavers, Lo et al42 concluded that bone loss of at least 25% to 27% of the width (average, 7.5 mm) of the inferior glenoid resulted in increased instability.42
Yamamoto et al76 recently demonstrated that a shoulder with 6-mm glenoid defect, which was equivalent to 25% of the glenoid width or 19% of the glenoid length or 26% of the glenoid surface area, remained unstable even after Bankart repair.

The humeral head Hill-Sachs lesions occur as the posterior and lateral portion of the humeral head impacts against the anterior glenoid rim during an instability episode. Burkhart and Danaceau14 first postulated that the resultant shortened rotational arc length of the humeral head on the glenoid as a result of Hill-Sachs lesions is an often under-treated risk factor for recurrent shoulder instability. A large lesion results in engagement of the defect with the glenoid, producing a sensation of subluxation or dislocation for the patient. They emphasized the importance of a dynamic arthroscopic assessment of the articular arc to fully understand the clinical pathology and to direct treatment. This engaging Hill-Sachs lesion is oriented such that it engages the anterior glenoid with the shoulder in abduction and external rotation. Standard radiographs often reveal evidence of HillSachs lesions, but special views may be required to better quantify the amount of bone loss. Of the standard shoulder series, the axillary view and the AP view with the arm in internal rotation provide the best visualization of the posterolateral humeral head.18,22,62 The Stryker notch view provides the best radiographic visualization of humeral head defects and should be obtained when evaluating any patient with recurrent instability.62 Similar to evaluation of the glenoid, 3-D CT scans provide the most accurate means of quantifying bone loss at the humeral head, and MRI allows for assessment of articular cartilage involvement. Arthroscopic evaluation at the time of surgery provides direct visualization and dynamic assessment of the size of the lesion (Fig. 5). The concept of the ‘‘glenoid track,’’ as proposed by Yamamoto et al,74,75 is based on the zone of contact between the glenoid and humeral head at various degrees of shoulder abduction. Their cadaveric study showed that a Hill-Sachs lesion is at risk of engagement and dislocation if it extends medially over the medial margin of the glenoid track, and they concluded that the location of the lesion is more

Figure 5 Arthroscopic image from the posterior portal shows humeral head bone loss (dashed arrow) with near engagement of the humeral head with the anterior edge of the glenoid (solid arrow).

important than the length or depth. This concept is based on earlier work by Burkhart and De Beer,15 who described the engaging Hill-Sachs lesions at the time of arthroscopy as a risk factor for failure of arthroscopic Bankart repairs. Voos et al71 reported that large (>250 mm3) Hill-Sachs lesions were a risk factor for recurrent dislocation after arthroscopic Bankart repair. Sekiya et al63 reported that humeral head defects as small as 12.5% have biomechanical consequences on shoulder stability. Kaar et al34 reported that glenohumeral stability decreases with a 5/8 radius defect in the humeral head with the arm in external rotation and abduction.

Treatment options and outcomes The surgeon treating a patient with recurrent instability after a failed anterior stabilization must understand the cause of the failure and consider the risk factors and the etiology of failure, including the status of the bone and capsule, to prevent further recurrence. Several authors have incorporated information about the soft tissues and bone of the shoulder into algorithms for the treatment of recurrent instability. However, there is little literature to guide the use of nonoperative treatment in this patient population. Marquardt et al43 compared the outcomes of 24 patients who failed anterior stabilization and were treated nonoperatively or with revision stabilization. Compared with the nonoperatively treated patients, they found that Rowe scores were significantly improved in those who underwent revision stabilization. All outcomes scores decreased in patients who required subsequent revisions, however. The major advantages of arthroscopic repair for instability are the ability to accurately identify and manage the specific pathoanatomy, less iatrogenic damage to normal tissues (especially the subscapularis muscle), lower postoperative pain, and improved cosmesis. However, the bone

Failed anterior shoulder stabilization loss from the anteroinferior glenoid, the humeral head, or a combination of both can present a significant challenge in revision stabilization surgery. Each must be quantified clinically, radiographically, and at the time of revision surgery to assure optimal shoulder stability and function. Several algorithms have been proposed to guide treatment for recurrent shoulder instability with varying degrees of glenoid bone loss.18,55 The consensus among most authors is that bone loss of the anteroinferior glenoid of more than 20% to 30% necessitates reconstruction using a bone block such as a Bristow-Latarjet (Fig. 6), iliac crest bone graft, or structural allograft.z The choice of arthroscopic, open softtissue repair, or reconstruction for glenoid bone loss of less than 25% is based on surgeon preference, patient activity demands, quality of remaining tissue, and previous surgical technique employed at the index procedure.1,18,52,53,55,69 Various techniques have been described to address humeral head bone loss, including remplissage, disimpaction, bone grafting, Bristow-Latarjet, humeral head allograft, humeral osteotomy, and prosthetic reconstruction.15,18,34,58,63,74 Chen et al18 published an algorithm based on a review of the literature to guide treatment of Hill-Sachs defects. Defects of less than 20% can be treated with standard shoulder stabilization, 20% to 30% may require tendon transfer or disimpaction with bone graft, 30% to 45% should be considered for bone graft or humeral osteotomy, and exceeding 45% requires prosthetic reconstruction. Sekiya et al63 reported that humeral head defects of 37.5% or greater may benefit from osteoarticular allograft to restore stability. Several authors have noted significant capsular laxity at the time of revision stabilization, and according to Rowe et al,61 the capsule is always overstretched in shoulder instability and that capsular redundancy must be addressed at surgery.41,67,77 Neer and Foster48 recommended a capsular shift and rotator interval closure to reduce capsular volume and thus prevent recurrent instability episodes. Creighton et al21 also indicated the need for rotator interval closure in 15 of 18 patients with failed traumatic instability repairs. They further reduced capsular volume by placing capsular plication sutures in the inferior and posteroinferior capsular tissue. Kim et al36 elected to close the rotator interval after Bankart repair if the patient had a grade I or II sulcus sign preoperatively or if there was significant capsular laxity after arthroscopic Bankart repair. Outcomes of revision procedures depend on the definition of failure (dislocation vs subluxation vs apprehension), outcome scores used, and patients selected for evaluation. Table I reports outcomes of recent studies evaluating revision anterior stabilization (Bankart repair with or without capsular shift). Studies of nonanatomic repairs or bone graft reconstructions were not included in this review. Open revision of failed open surgery has a reported failure rate of 8% to 26%.61,77 One of the first reports on

z

2, 3, 11, 14, 15, 18, 33, 42, 55, 69, 73.

1345

Figure 6 Anterior-posterior radiograph shows a shoulder after a Latarjet procedure (black arrow). A Hill-Sachs lesion is identified by the white arrow.

this topic was by Rowe et al61 in 1984. The revision stabilization involved separating the subscapularis muscle from the anterior capsule, incising the capsule just lateral to the glenoid, repairing the Bankart lesion through drill holes, and advancing and repairing the capsule to the anterior glenoid. They found good or excellent results in 92% using a scoring system designed to assess stability, function, and motion. Zabinski et al77 evaluated 43 patients who underwent revision open shoulder stabilization with a Bankart repair or capsular shift, or both, depending if a Bankart lesion or capsular laxity were present. The 23 patients with unidirectional anterior instability had a 17% recurrent dislocation rate after the revision. These patients ultimately had a 78% good or excellent outcome. They contrasted these patients with other patients in the series who had multidirectional instability, who had a 62% failure rate and a 43% good or excellent outcome. Two studies have evaluated outcomes of open revisions after a failed open or arthroscopic anterior stabilization41,45: Levine et al41 monitored 50 patients who underwent revision open anterior stabilization with capsular shift with or without a Bankart repair. At an average follow-up of 4.7 years, outcomes were good or excellent in 78%. They also noted that all 100% of the patients whose index procedure failed because of significant trauma had excellent results after revision surgery. However, only 67% patients without a new trauma after the index procedure achieved excellent or good results after revision surgery. Meehan and Petersen45 treated 25 patients with an open Bankart or capsular shift, or both, after a failed arthroscopic or open anterior shoulder stabilization and analyzed the prognostic association of patient demographics and pathologic variables on outcome scores. Factors that contributed to a negative outcome were glenohumeral arthritis, age older than 30 years, 2 or more previous instability procedures, a bony Bankart lesion, the diagnosis of multidirectional instability, and surgery involving the nondominant arm.

1346

C.S. Mauro et al.

Table I

Studies of revision anterior stabilization

Study

Year

(first author) 61

Rowe Zabinski77 Levine41 Meehan45 Sisto64 Cho20 Millar46 Boileau10 Kim37 Neri49 Creighton21 Patel54 Barnes5 Krueger38 Bartl6 Franceschi24

1984 1999 2000 2005 2007 2009 2008 2009 2002 2007 2007 2008 2009 2011 2011 2008

Level of evidence

(N)

Shoulders

IV IV IV IV IV IV III IV IV IV IV IV IV III IV IV

32 23 50 25 30 26 10 19 23 11 18 40 17 20 56 10

Failed primary surgery Open Open Open or arthroscopic Open or arthroscopic Arthroscopic Arthroscopic Open Open Open or arthroscopic Open or arthroscopic Open or arthroscopic Open or arthroscopic Open or arthroscopic Open or arthroscopic Open or arthroscopic Arthroscopic

Revision surgery Open Open Open Open Open Open Arthroscopic Arthroscopic Arthroscopic Arthroscopic Arthroscopic Arthroscopic Arthroscopic Arthroscopic Arthroscopic Arthroscopic

Follow-up

Recurrent instability, %

(years)

D

S

A

4.0 6.4 4.7 5.0 3.8 3.5 3.1 3.6 3.0 2.9 2.5 3.0 3.2 2.1 3.1 5.7

4 17 22 16 0 12 20 0 4 18 6 10 6 0 7 10

4 9 4 NR 0 NR NR 5 9 9 11 NR 0 NR 4 NR

NR 26) NR 21) 0 NR 10) 11 9 0 NR NR 18 10 0 NR

A, positive apprehension sign; D, dislocation; NR, not reported; S, subluxation. ) These studies did not distinguish whether the patients with a positive apprehension sign. were part of or in addition to the group of patients with dislocation or apprehension.

There have also been 2 recent reports evaluating open revisions of failed arthroscopic Bankart repairs.20,64 Sisto64 observed 30 patients and noted no recurrences of instability and a negative apprehension test in all patients. He found an improvement in the University of California, Los Angeles (UCLA) score from 17 to 30, with all patients noting a good or excellent outcome. The mean loss of external rotation was 8 , and 87% returned to their previous sports activity level. Cho et al20 monitored 26 shoulders in 25 patients who underwent open Bankart repair as revision surgery after a failed arthroscopic Bankart procedure. They had a recurrent dislocation rate of 11.5%, and in each of these patients, an engaging Hill-Sachs lesion and hyperlaxity had been noted on the initial revision surgery and then they sustained a trauma. At final follow-up, good or excellent results were noted in 88.5% of patients and 84.7% return to nearly preinjury activity levels. Two recent articles evaluated arthroscopic revision of failed open surgery10,46: Millar and Murrell46 compared 10 patients who underwent arthroscopic anterior stabilization after failure of a previous open reconstruction for anterior instability with 15 patients, matched for age and sex, who had a primary arthroscopic stabilization. Patients in both groups had similar outcomes in pain, function, and UCLA and Rowe shoulder scores, but the recurrent dislocation rate was 7% in the primary stabilization group and 20% in the revision group. Boileau et al10 performed a retrospective review of 19 patients who underwent an arthroscopic Bankart repair after a failed open stabilization. Of these, 85% had a good or excellent result by the Walch-Duplay score and 67% by

the Rowe score, 47% returned to sports at the same level, and 100% returned to their previous occupation. Several other articles have evaluated the outcomes of patients who underwent revision arthroscopic stabilization after a failed arthroscopic or open procedure5,6,21,37,38,49,54: Kim et al37 found all recurrent dislocations and subluxations were the result of reinjury during contact sports. Neri et al49 noted a mean Rowe score of 74 and a mean UCLA score of 29.6, both with good/excellent results in 72.7%. Creighton et al21 noted improvement in the American Shoulder and Elbow Surgeons score from 50 preoperatively to 76 postoperatively and good and excellent results in 72% of patients. Patel et al54 found a 10% redislocation rate, whereas Barnes et al5 reported 76% had a good or excellent rating using the Rowe scale. Bartl et al6 used a 5:30 portal to perform their arthroscopic revision reconstruction. They had an 11% recurrent instability rate. Krueger et al38 compared the outcomes of 20 patients who underwent revision arthroscopic anterior stabilization with 20 patients who had a primary arthroscopic anterior stabilization. No recurrent dislocations occurred in either group, but patients who underwent revision shoulder stabilization had lower subjective outcome scores than patients who underwent primary arthroscopic stabilization. One report evaluated patients who were treated with revision arthroscopic Bankart repair when recurrent anterior instability developed after an index arthroscopic Bankart repair.24 Franceschi et al24 monitored 10 patients for a minimum of 4 years and noted significant improvement in the UCLA score to a mean of 31.7. All returned to their previous sports levels.

Failed anterior shoulder stabilization

Figure 7

1347

Our treatment algorithm for revision anterior stabilization.

New concept

Treatment algorithm

As illustrated, there remains significant controversy over the multiple possible causes of failure of arthroscopic capsulolabral repair to restore stability to the anteriorly unstable shoulder. Lafosse et al39 and Ahmad et al1 have suggested that modern arthroscopic repair, with its emphasis on anchor placement at the articular edge, fails to restore the true anatomic footprint of the anterior capsulolabral complex. Both have described double-row, footprint-fixation techniques that incorporate suture anchors on the glenoid neck and on the glenoid rim to repair the capsulolabral complex to a broader bony surface. Ahmad et al1 found in a cadaveric study that the double-row repair re-establishes the native insertional footprint on the anterior inferior glenoid better than a single-row repair. They suggested that patients with severe capsulolabral injury or shoulders that require significant mobilization of the capsulolabral complex, such as anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesions, may be the most appropriate for this technique. This technique may also be considered in the other high-risk populations already described: younger patients, contact athletes, patients with mild bone loss on the glenoid or humerus, and patients with previous failed anterior stabilization. Further clinical evaluation of this emerging technique is warranted, as this improved restoration of the native capsulolabral anatomy may decrease the rate of failed anterior shoulder stabilization, especially in high-risk patients.

Our treatment algorithm for management of the failed anterior stabilization includes some of the features of the ISIS score (Fig. 7).3 The factors that we consider when determining whether to recommend revision arthroscopic stabilization, open stabilization, or open stabilization with glenoid or humeral head augmentation are patient age, sports played, number of previous dislocations, overall shoulder laxity, glenoid and humeral head bone loss, and tissue quality. We generally recommend open stabilization in the revision setting for patients who are younger than 20 years old, participate in contact athletics, or have hyperlaxity or poor tissue quality, which may be identified on diagnostic arthroscopy. If these patients present with less than 20% glenoid bone loss, we perform an open double-row capsulolabral repair, as described above. If the glenoid bone loss is between 20% and 30%, we perform an open stabilization. We perform a double-row capsulolabral repair, with incorporation of the bone fragment of the glenoid fragment if available, or a Latarjet in patients with larger defects or multiple risk factors for recurrence. With any glenoid defect exceeding 30%, we perform a Latarjet. In the setting of a Hill-Sachs defect of less than 20%, we proceed with our standard algorithm, as described above. With Hill-Sachs lesions of 20% to 30%, we consider remplissage tendon transfer or bone grafting in an open

1348 fashion, depending on the dynamic arthroscopic evaluation. Lesions exceeding 30% require consideration for osteochondral allograft transplantation.

Conclusions In the patient with a failed anterior shoulder stabilization, the treating surgeon must attempt to identify the cause of failure before embarking on revision stabilization. Confounding factors, such as bone loss, patient age, sport played, ligamentous laxity, capsule attenuation, and previous surgical approach used are critical to address. The revision setting necessitates close attention to surgical approach and consideration of both tradition and emerging arthroscopic and open techniques. Multiple studies have demonstrated successful treatment with revision anterior stabilization but have reported recurrent instability to be 10% to 27% after arthroscopic revision and 0% to 26% after open revision.

Disclaimer The authors, their immediate families, and any research foundations with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.

References 1. Ahmad CS, Galano GJ, Vorys GC, Covey AS, Gardner TR, Levine WN. Evaluation of glenoid capsulolabral complex insertional anatomy and restoration with single- and double-row capsulolabral repairs. J Shoulder Elbow Surg 2009;18:948-54. doi:10.1016/j.jse. 2009.03.022 2. Auffarth A, Schauer J, Matis N, Kofler B, Hitzl W, Resch H. The J-bone graft for anatomical glenoid reconstruction in recurrent posttraumatic anterior shoulder dislocation. Am J Sports Med 2008; 36:638-47. doi:10.1177/0363546507309672 3. Balg F, Boileau P. The instability severity index score. A simple pre-operative score to select patients for arthroscopic or open shoulder stabilisation. J Bone Joint Surg Br 2007;89:1470-7. doi:10.1302/0301620X.89B11.18962 4. Banerjee S, Weiser L, Connell D, Wallace AL. Glenoid rim fracture in contact athletes with absorbable suture anchor reconstruction. Arthroscopy 2009;25:560-2. doi:10.1016/j.arthro.2008.10.027 5. Barnes CJ, Getelman MH, Snyder SJ. Results of arthroscopic revision anterior shoulder reconstruction. Am J Sports Med 2009;37:715-9. doi:10.1177/0363546508328411 6. Bartl C, Schumann K, Paul J, Vogt S, Imhoff AB. Arthroscopic capsulolabral revision repair for recurrent anterior shoulder instability. Am J Sports Med 2011;39:511-8. doi:10.1177/0363546510388909 7. Baudi P, Righi P, Bolognesi D, Rivetta S, Rossi Urtoler E, Guicciardi N, et al. How to identify and calculate glenoid bone deficit. Chir Organi Mov 2005;90:145-52.

C.S. Mauro et al. 8. Bernageau J, Patte D, Debeyre J, Ferrane J. [Value of the glenoid profile in recurrent luxations of the shoulder]. Rev Chir Orthop Reparatrice Appar Mot 1976;62:142-7. 9. Bigliani LU, Newton PM, Steinmann SP, Connor PM, McLlveen SJ. Glenoid rim lesions associated with recurrent anterior dislocation of the shoulder. Am J Sports Med 1998;26:41-5. 10. Boileau P, Richou J, Lisai A, Chuinard C, Bicknell RT. The role of arthroscopy in revision of failed open anterior stabilization of the shoulder. Arthroscopy 2009;25:1075-84. doi:10.1016/j.arthro.2009.04.073 11. Boileau P, Villalba M, Hery JY, Balg F, Ahrens P, Neyton L. Risk factors for recurrence of shoulder instability after arthroscopic Bankart repair. J Bone Joint Surg Am 2006;88:1755-63. doi:10.2106/JBJS.E. 00817 12. Boileau P, Zumstein M, Balg F, Penington S, Bicknell RT. The unstable painful shoulder (UPS) as a cause of pain from unrecognized anteroinferior instability in the young athlete. J Shoulder Elbow Surg 2011;20:98-106. doi:10.1016/j.jse.2010.05.020 13. Bottoni CR, Smith EL, Berkowitz MJ, Towle RB, Moore JH. Arthroscopic versus open shoulder stabilization for recurrent anterior instability: a prospective randomized clinical trial. Am J Sports Med 2006;34:1730-7. doi:10.1177/0363546506288239 14. Burkhart SS, Danaceau SM. Articular arc length mismatch as a cause of failed Bankart repair. Arthroscopy 2000;16:740-4. doi:10.1053/jars. 2000.7794 15. Burkhart SS, De Beer JF. Traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repairs: significance of the inverted-pear glenoid and the humeral engaging HillSachs lesion. Arthroscopy 2000;16:677-94. 16. Carreira DS, Mazzocca AD, Oryhon J, Brown FM, Hayden JK, Romeo AA. A prospective outcome evaluation of arthroscopic Bankart repairs: minimum 2-year follow-up. Am J Sports Med 2006;34:771-7. doi:10.1177/0363546505283259 17. Castagna A, Markopoulos N, Conti M, Delle Rose G, Papadakou E, Garofalo R. Arthroscopic Bankart suture-anchor repair: radiological and clinical outcome at minimum 10 years of follow-up. Am J Sports Med 2010;38:2012-6. doi:10.1177/0363546510372614 18. Chen AL, Hunt SA, Hawkins RJ, Zuckerman JD. Management of bone loss associated with recurrent anterior glenohumeral instability. Am J Sports Med 2005;33:912-25. doi:10.1177/0363546505277074 19. Cho NS, Hwang JC, Rhee YG. Arthroscopic stabilization in anterior shoulder instability: collision athletes versus noncollision athletes. Arthroscopy 2006;22:947-53. doi:10.1016/j.arthro.2006.05.015 20. Cho NS, Yi JW, Lee BG, Rhee YG. Revision open Bankart surgery after arthroscopic repair for traumatic anterior shoulder instability. Am J Sports Med 2009;37:2158-64. doi:10.1177/0363546509339015 21. Creighton RA, Romeo AA, Brown FM Jr, Hayden JK, Verma NN. Revision arthroscopic shoulder instability repair. Arthroscopy 2007; 23:703-9. doi:10.1016/j.arthro.2007.01.021 22. Edwards TB, Boulahia A, Walch G. Radiographic analysis of bone defects in chronic anterior shoulder instability. Arthroscopy 2003;19: 732-9. doi:10.1016/S0749-8063(03)00684-4 23. Fabbriciani C, Milano G, Demontis A, Fadda S, Ziranu F, Mulas PD. Arthroscopic versus open treatment of Bankart lesion of the shoulder: a prospective randomized study. Arthroscopy 2004;20:456-62. doi:10. 1016/j.arthro.2004.03.001 24. Franceschi F, Longo UG, Ruzzini L, Rizzello G, Maffulli N, Denaro V. Arthroscopic salvage of failed arthroscopic Bankart repair: a prospective study with a minimum follow-up of 4 years. Am J Sports Med 2008;36:1330-6. doi:10.1177/0363546508314403 25. Freedman KB, Smith AP, Romeo AA, Cole BJ, Bach BR Jr. Open Bankart repair versus arthroscopic repair with transglenoid sutures or bioabsorbable tacks for recurrent anterior instability of the shoulder: a meta-analysis. Am J Sports Med 2004;32:1520-7. doi:10.1177/ 0363546504265188 26. Fritsch BA, Arciero RA, Taylor DC. Glenoid rim fracture after anchor repair: a report of 4 cases. Am J Sports Med 2010;38:1682-6. doi:10. 1177/0363546510364239

Failed anterior shoulder stabilization 27. Greis PE, Scuderi MG, Mohr A, Bachus KN, Burks RT. Glenohumeral articular contact areas and pressures following labral and osseous injury to the anteroinferior quadrant of the glenoid. J Shoulder Elbow Surg 2002;11:442-51. 28. Hoover SA, Weinhold P, Creighton RA, Spang JT. A biomechanical comparison and three single and two double loaded anchors for Bankart repair. Paper presented at: AAOS Annual Meeting, San Diego, CA, February 18, 2011. 29. Huijsmans PE, Haen PS, Kidd M, Dhert WJ, van der Hulst VP, Willems WJ. Quantification of a glenoid defect with three-dimensional computed tomography and magnetic resonance imaging: a cadaveric study. J Shoulder Elbow Surg 2007;16:803-9. doi:10.1016/j.jse.2007. 02.115 30. Huysmans PE, Haen PS, Kidd M, Dhert WJ, Willems JW. The shape of the inferior part of the glenoid: a cadaveric study. J Shoulder Elbow Surg 2006;15:759-63. doi:10.1016/j.jse.2005.09.001 31. Ikemoto RY, Nascimento LGP, Bueno RS, Strose E, Almeida LH, Murachovsky J. The technique to calculate glenoid bone loss with the Bernageau profile view: is it possible? Tech Shoulder Elbow Surg 2010;11:37-40. doi:10.1097/BTE.0b013e3181d47a2c 32. Imhoff AB, Ansah P, Tischer T, Reiter C, Bartl C, Hench M, et al. Arthroscopic repair of anterior-inferior glenohumeral instability using a portal at the 5:30-o’clock position: analysis of the effects of age, fixation method, and concomitant shoulder injury on surgical outcomes. Am J Sports Med 2010;38:1795-803. doi:10.1177/ 0363546510370199 33. Itoi E, Lee SB, Berglund LJ, Berge LL, An KN. The effect of a glenoid defect on anteroinferior stability of the shoulder after Bankart repair: a cadaveric study. J Bone Joint Surg Am 2000;82:35-46. 34. Kaar SG, Fening SD, Jones MH, Colbrunn RW, Miniaci A. Effect of humeral head defect size on glenohumeral stability: a cadaveric study of simulated Hill-Sachs defects. Am J Sports Med 2010;38:594-9. doi: 10.1177/0363546509350295 35. Kartus C, Kartus J, Matis N, Forstner R, Resch H. Long-term independent evaluation after arthroscopic extra-articular Bankart repair with absorbable tacks. A clinical and radiographic study with a seven to ten-year follow-up. J Bone Joint Surg Am 2007;89:1442-8. doi:10. 2106/JBJS.F.00363 36. Kim SH, Ha KI, Cho YB, Ryu BD, Oh I. Arthroscopic anterior stabilization of the shoulder: two to six-year follow-up. J Bone Joint Surg Am 2003;85:1511-8. 37. Kim SH, Ha KI, Kim YM. Arthroscopic revision Bankart repair: a prospective outcome study. Arthroscopy 2002;18:469-82. doi:10. 1053/jars.2002.32230 38. Krueger D, Kraus N, Pauly S, Chen J, Scheibel M. Subjective and objective outcome after revision arthroscopic stabilization for recurrent anterior instability versus initial shoulder stabilization. Am J Sports Med 2011;39:71-7. doi:10.1177/0363546510379336 39. Lafosse L, Baier GP, Jost B. Footprint fixation for arthroscopic reconstruction in anterior shoulder instability: the Cassiopeia doublerow technique. Arthroscopy 2006;22:231.e1-6. doi:10.1016/j.arthro. 2005.11.008 40. Larrain MV, Montenegro HJ, Mauas DM, Collazo CC, Pavon F. Arthroscopic management of traumatic anterior shoulder instability in collision athletes: analysis of 204 cases with a 4- to 9-year follow-up and results with the suture anchor technique. Arthroscopy 2006;22: 1283-9. doi:10.1016/j.arthro.2006.07.052 41. Levine WN, Arroyo JS, Pollock RG, Flatow EL, Bigliani LU. Open revision stabilization surgery for recurrent anterior glenohumeral instability. Am J Sports Med 2000;28:156-60. 42. Lo IK, Parten PM, Burkhart SS. The inverted pear glenoid: an indicator of significant glenoid bone loss. Arthroscopy 2004;20:169-74. doi:10.1016/j.arthro.2003.11.036 43. Marquardt B, Garmann S, Schulte T, Witt KA, Steinbeck J, Potzl W. Outcome after failed traumatic anterior shoulder instability repair with and without surgical revision. J Shoulder Elbow Surg 2007;16:742-7. doi:10.1016/j.jse.2007.02.132

1349 44. Mazzocca AD, Brown FM Jr, Carreira DS, Hayden J, Romeo AA. Arthroscopic anterior shoulder stabilization of collision and contact athletes. Am J Sports Med 2005;33:52-60. doi:10.1177/ 0363546504268037 45. Meehan RE, Petersen SA. Results and factors affecting outcome of revision surgery for shoulder instability. J Shoulder Elbow Surg 2005; 14:31-7. doi:10.1016/j.jse.2004.05.005 46. Millar NL, Murrell GA. The effectiveness of arthroscopic stabilisation for failed open shoulder instability surgery. J Bone Joint Surg Br 2008; 90:745-50. doi:10.1302/0301-620X.90B6.20018 47. Mologne TS, Provencher MT, Menzel KA, Vachon TA, Dewing CB. Arthroscopic stabilization in patients with an inverted pear glenoid: results in patients with bone loss of the anterior glenoid. Am J Sports Med 2007;35:1276-83. doi:10.1177/0363546507300262 48. Neer CS 2nd, Foster CR. Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder. A preliminary report. J Bone Joint Surg Am 1980;62:897-908. 49. Neri BR, Tuckman DV, Bravman JT, Yim D, Sahajpal DT, Rokito AS. Arthroscopic revision of Bankart repair. J Shoulder Elbow Surg 2007; 16:419-24. doi:10.1016/j.jse.2006.05.016 50. Nho SJ, Frank RM, Van Thiel GS, Wang FC, Wang VM, Provencher MT, et al. A biomechanical analysis of anterior Bankart repair using suture anchors. Am J Sports Med 2010;38:1405-12. doi: 10.1177/0363546509359069 51. Owens CB, Nelson BJ, Duffey ML, Mountcastle SB, Taylor DC, Cameron KL, et al. Pathoanatomy of first-time, traumatic, anterior glenohumeral subluxation events. J Bone Joint Surg Am 2010;92: 1605-11. doi:10.2106/JBJS.I.00851 52. Pagnani MJ. Open capsular repair without bone block for recurrent anterior shoulder instability in patients with and without bony defects of the glenoid and/or humeral head. Am J Sports Med 2008;36:1805-12. doi:10.1177/0363546508316284 53. Pagnani MJ, Dome DC. Surgical treatment of traumatic anterior shoulder instability in American football players. J Bone Joint Surg Am 2002;84:711-5. 54. Patel RV, Apostle K, Leith JM, Regan WD. Revision arthroscopic capsulolabral reconstruction for recurrent instability of the shoulder. J Bone Joint Surg Br 2008;90:1462-7. doi:10.1302/0301-620X.90B11. 21072 55. Piasecki DP, Verma NN, Romeo AA, Levine WN, Bach BR Jr, Provencher MT. Glenoid bone deficiency in recurrent anterior shoulder instability: diagnosis and management. J Am Acad Orthop Surg 2009;17:482-93. 56. Porcellini G, Campi F, Pegreffi F, Castagna A, Paladini P. Predisposing factors for recurrent shoulder dislocation after arthroscopic treatment. J Bone Joint Surg Am 2009;91:2537-42. doi:10.2106/JBJS.H.01126 57. Provencher MT, Bhatia S, Ghodadra NS, Grumet RC, Bach BR Jr, Dewing CB, et al. Recurrent shoulder instability: current concepts for evaluation and management of glenoid bone loss. J Bone Joint Surg Am 2010;92(suppl 2):133-51. doi:10.2106/JBJS.J.00906 58. Purchase RJ, Wolf EM, Hobgood ER, Pollock ME, Smalley CC. Hill-Sachs ‘‘remplissage’’: an arthroscopic solution for the engaging Hill-Sachs lesion. Arthroscopy 2008;24:723-6. doi:10.1016/j.arthro. 2008.03.015 59. Rhee YG, Ha JH, Cho NS. Anterior shoulder stabilization in collision athletes: arthroscopic versus open Bankart repair. Am J Sports Med 2006;34:979-85. doi:10.1177/0363546505283267 60. Rokous JR, Feagin JA, Abbott HG. Modified axillary roentgenogram. A useful adjunct in the diagnosis of recurrent instability of the shoulder. Clin Orthop Relat Res 1972;82:84-6. 61. Rowe CR, Zarins B, Ciullo JV. Recurrent anterior dislocation of the shoulder after surgical repair. Apparent causes of failure and treatment. J Bone Joint Surg Am 1984;66:159-68. 62. Rozing PM, de Bakker HM, Obermann WR. Radiographic views in recurrent anterior shoulder dislocation. Comparison of six methods for identification of typical lesions. Acta Orthop Scand 1986;57:328-30.

1350 63. Sekiya JK, Wickwire AC, Stehle JH, Debski RE. Hill-Sachs defects and repair using osteoarticular allograft transplantation: biomechanical analysis using a joint compression model. Am J Sports Med 2009;37: 2459-66. doi:10.1177/0363546509341576 64. Sisto DJ. Revision of failed arthroscopic Bankart repairs. Am J Sports Med 2007;35:537-41. doi:10.1177/0363546506296520 65. Speer KP, Warren RF, Pagnani M, Warner JJ. An arthroscopic technique for anterior stabilization of the shoulder with a bioabsorbable tack. J Bone Joint Surg Am 1996;78:1801-7. 66. Sugaya H, Moriishi J, Dohi M, Kon Y, Tsuchiya A. Glenoid rim morphology in recurrent anterior glenohumeral instability. J Bone Joint Surg Am 2003;85:878-84. 67. Tauber M, Resch H, Forstner R, Raffl M, Schauer J. Reasons for failure after surgical repair of anterior shoulder instability. J Shoulder Elbow Surg 2004;13:279-85. doi:10.1016/S1058274604000254 68. Taylor DC, Arciero RA. Pathologic changes associated with shoulder dislocations. Arthroscopic and physical examination findings in first-time, traumatic anterior dislocations. Am J Sports Med 1997;25: 306-11. 69. Tonino PM, Gerber C, Itoi E, Porcellini G, Sonnabend D, Walch G. Complex shoulder disorders: evaluation and treatment. J Am Acad Orthop Surg 2009;17:125-36. 70. van Oostveen DP, Schild FJ, van Haeff MJ, Saris DB. Suture anchors are superior to transglenoid sutures in arthroscopic shoulder stabilization. Arthroscopy 2006;22:1290-7. doi:10.1016/j.arthro.2006.07.006

C.S. Mauro et al. 71. Voos JE, Livermore RW, Feeley BT, Altchek DW, Williams RJ, Warren RF, et al. Prospective evaluation of arthroscopic Bankart repairs for anterior instability. Am J Sports Med 2010;38:302-7. doi: 10.1177/0363546509348049 72. Walch G, Mole D. Instabilite et luxations de l’epaule (articulation gleno-humerale). Encycl Med Chir 1991;A10:1-14. 73. Wellmann M, Petersen W, Zantop T, Herbort M, Kobbe P, Raschke MJ, et al. Open shoulder repair of osseous glenoid defects: biomechanical effectiveness of the Latarjet procedure versus a contoured structural bone graft. Am J Sports Med 2009;37:87-94. doi:10. 1177/0363546508326714 74. Yamamoto N, Itoi E, Abe H, Kikuchi K, Seki N, Minagawa H, et al. Effect of an anterior glenoid defect on anterior shoulder stability: a cadaveric study. Am J Sports Med 2009;37:949-54. doi:10.1177/ 0363546508330139 75. Yamamoto N, Itoi E, Abe H, Minagawa H, Seki N, Shimada Y, et al. Contact between the glenoid and the humeral head in abduction, external rotation, and horizontal extension: a new concept of glenoid track. J Shoulder Elbow Surg 2007;16:649-56. doi:10.1016/j.jse.2006. 12.012 76. Yamamoto N, Muraki T, Sperling JW, Steinmann SP, Cofield RH, Itoi E, et al. Stabilizing mechanism in bone-grafting of a large glenoid defect. J Bone Joint Surg Am 2010;92:2059-66. doi:10.2106/JBJS.I.00261 77. Zabinski SJ, Callaway GH, Cohen S, Warren RF. Revision shoulder stabilization: 2- to 10-year results. J Shoulder Elbow Surg 1999;8:58-65.