Partial Resurfacing for Humeral Head Defects Associated With Recurrent Shoulder Instability

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1 Partial Resurfacing for Humeral Head Defects Associated With Recurrent Shoulder Instability MATTHEW C. BESSETTE, MD; NICHOLAS C. FRISCH, MD; PRADEEP KODALI, MD; MORGAN H. JONES, MD; ANTHONY MINIACI, MD, FRCSC abstract Recurrent traumatic shoulder instability is a complex clinical entity that commonly affects young, active patients. Humeral head defects are frequently associated with this condition, but specific treatment to stabilize the shoulder is rarely needed. Management options for defects of the humeral head that do necessitate treatment carry various risks and disadvantages, including the need for bone or soft tissue healing, complications related to hardware, and loss of motion. Partial prosthetic resurfacing has been reported as a treatment option. The current study retrospectively reviewed a cohort of patients with recurrent or locked anterior and posterior instability who underwent partial prosthetic humeral head resurfacing for significant Hill-Sachs and reverse Hill-Sachs lesions. At an average of 36.4 months after the index procedure, 16 patients were contacted by mail and telephone. Of the study group, 13 patients underwent partial resurfacing for anterior instability and 3 patients underwent partial resurfacing for posterior instability. No patient had a repeat dislocation. In addition, 77% of patients in the anterior instability cohort and all of the patients in the posterior instability cohort returned to their full preinjury activity level. For the anterior instability cohort, significant improvements from preoperatively to final follow-up occurred for mean Musculoskeletal Review of System score (4.54, P<.0001) and Short Form-12 physical component score (9.52, P=.002). For the combined cohort, the Penn Shoulder Score improved by 36.4 points (P=.059). This study showed the effectiveness of partial humeral head resurfacing for preventing redislocation for patients with significant Hill-Sachs and reverse Hill-Sachs lesions. [Orthopedics. 2017; 40(6):e996-e1003.] Traumatic anterior shoulder instability is a common musculoskeletal injury, especially in young, active men. There has been an increase in the surgical treatment of associated capsulolabral injuries, with a trend favoring arthroscopic management over open management. 1 In addition to injuries of the anteroinferior capsulolabral complex (Bankart lesions), osteochondral injuries to the adjacent anteroinferior glenoid (bony Bankart lesions) 2 and posterior humeral head injuries (Hill-Sachs lesions) are created at the time of dislocation, most commonly in combination. 3,4 Hill-Sachs lesions have been described in 47% to 80% of primary anterior dislocations and among up to 100% of patients with recurrent instability. 5 The size of these bony injuries has been shown to correlate with the number of recurrent dislocations. 6 The size and location of reverse Hill-Sachs lesions created during posterior dislocations also can determine whether they will engage the The authors are from the Department of Orthopaedic Surgery (MCB, MHJ, AM), Cleveland Clinic Foundation, Cleveland, Ohio; Presence Medical Group (NCF), Chicago, Illinois; and Hillcroft Medical Clinic (PK), Houston, Texas. Drs Bessette, Frisch, Kodali, and Jones have no relevant financial relationships to disclose. Dr Miniaci is a paid consultant for Arthrosurface, receives royalties from Arthrosurface and Zimmer, and holds patents with Arthrosurface and Zimmer. Correspondence should be addressed to: Matthew C. Bessette, MD, Department of Orthopaedic Surgery, Cleveland Clinic Foundation, 5555 Transportation Blvd, Cleveland, OH (mcbessette@gmail.com). Received: February 14, 2017; Accepted: September 5, doi: / e996 COPYRIGHT SLACK INCORPORATED

2 glenoid and create a risk factor for recurrent instability. 7 Burkhart and De Beer 8 defined an engaging Hill-Sachs lesion as a humeral defect that contacts the anterior rim of the glenoid at 90 abduction and various degrees of external rotation. Increased attention has been paid to glenoid bone loss in the management of recurrent dislocations, with an increase in the number of coracoid transfer procedures performed annually. 1 Humeral head defects are less commonly addressed. Options for engaging Hill-Sachs and reverse Hill-Sachs lesions range from benign neglect to remplissage, transhumeral impaction grafting, rotational osteotomy, osteochondral allograft transplantation, shoulder arthroplasty, and lesser tuberosity transfer. 3 Treatment is controversial because no procedure has shown superiority and all are associated with various risks and strengths. Several reports have described partial resurfacing of the humeral head defect with a Hemi- CAP implant (Arthrosurface, Franklin, Massachusetts) to restore more native intra-articular anatomy without compromising shoulder range of motion, specifically in the setting of instability This study is the first to evaluate a cohort of patients with large Hill-Sachs and reverse Hill-Sachs lesions whose treatment included filling of humeral head defects with HemiCAP implants. Indications include defects that affect more than 20% to 25% of the articular surface and locked posterior dislocations. The study hypothesis was that treatment, including the use of this implant, would successfully prevent recurrent instability and improve patient-reported outcomes. Figure 1: Intraoperative photograph (a) and 2-year postoperative true anteroposterior (b), anteroposterior (c), and axillary lateral (d) radiographs of a HemiCAP (Arthrosurface, Franklin, Massachusetts) partial resurfacing implant for a Hill-Sachs lesion in a patient with anterior shoulder instability. MATERIALS AND METHODS This retrospective cohort study used prospectively collected preoperative data and was approved by the institutional review board at the study institution. The study included patients of any age who underwent partial humeral head resurfacing with a HemiCAP implant for the treatment of Hill Sachs or reverse Hill-Sachs lesions at the study institution after more than 1 dislocation or subluxation event or a locked dislocation. No limitations were placed on concomitant procedures. A surgical outcomes database was searched to identify all patients who underwent shoulder hemiarthroplasty, Bankart repair, or capsulorrhaphy with 2 attending surgeons, as noted by current procedural terminology code 23470, 23455, or Electronic medical records were then reviewed to identify patients who underwent partial humeral head resurfacing for Hill-Sachs or reverse Hill-Sachs lesions. Information about the index procedure and subsequent clinical follow-up was recorded. Patients who had follow-up of less than 2 years were excluded. Prospective preoperative data were collected at the time of surgery and included the 12-Item Short Form Health Survey (SF-12) physical component scores, Review of Musculoskeletal System scores, and in some cases, the Penn Shoulder Score. The SF-12 physical component scores measure the patient s overall health and physical limitations with a score of 0 to 100, with 100 indicating the highest level of health. The Review of Musculoskeletal System score uses a scale of 0 to 10 to indicate limitations that patients experience because of their extremities, with 0 indicating no limitation. 12 The Penn Shoulder Score is a validated shoulder-specific questionnaire that includes subscales for function, pain, and satisfaction. It is recorded on a scale of 0 to 100, with 100 indicating the best result possible. 13 Partial resurfacing of the humeral head was used to treat both Hill-Sachs (Figure 1) and reverse Hill-Sachs (Figure 2) le- NOVEMBER/DECEMBER 2017 e997

3 Figure 2: Intraoperative photographs showing reaming of a reverse Hill-Sachs lesion (a) and placement of a HemiCAP (Arthrosurface, Franklin, Massachusetts) partial resurfacing implant (b) for a patient with posterior shoulder instability. Postoperative anteroposterior (c) and axillary lateral (d) radiographs showing hardware placement. Figure 3: An axial magnetic resonance image was used to estimate the size of the Hill-Sachs lesion. The perimeter of the articular surface was estimated with lines connecting points along the articular surface with stock image software (Syngo; Siemens Medical Solutions USA, Inc, Malvern, Pennsylvania). In this case, the total articular surface measured 91 mm. The 27 mm that measured the medial to lateral extent of the Hill-Sachs lesion (in this case, the lateral aspect extended to the rotator cuff footprint) was divided by the total diameter to obtain a percentage of bone loss: (27 mm/91 mm) 100=29.7%. sions that were believed to be at risk for engaging the glenoid rim. Surgical indications for resurfacing of defects were lesions that encompassed more than 25% of the native humeral head diameter, or more than 20% when there were combined lesions of the humeral head and glenoid. 14 The outer diameter of the articular surface was measured manually by determining the distance between multiple points on the articular surface on axial magnetic resonance imaging (MRI) or computed tomography (CT) sequences (Figure 3). The size of the defect was compared with the estimated diameter of the native, uninjured articular cartilage at the largest level of the defect. This technique also is used for the treatment of unsuccessful previous labral repairs and for patients with instability at less than 45 elevation. The glenoid track was not evaluated or used for this study. 15 For posterior dislocations, indications included locked or recurrent dislocations and defects that were believed to be engaging and unstable on internal rotation on preoperative clinical examination. Complete resurfacing, or hemiarthroplasty, is not typically considered unless the patient is older than 50 years and more than 50% of the humeral head is compromised. Use of the implant rather than alternative procedures was discussed with each patient, and a shared decision was made after the risks and benefits of each were described. Prosthetic resurfacing was specifically used in favor of allograft to avoid the need to wait for matched donor availability and to avoid the complications of nonunion or graft collapse. For the anterior instability cohort, glenoid bone loss was treated with a coracoid transfer as opposed to labral repair when the defect encompassed more than 20% of the glenoid width. Bone loss was assessed on preoperative 2-dimensional sagittal MRI or CT imaging by measuring the distances between the anterior and posterior glenoid margins and the bare spot. All surgical procedures were completed by the senior author (A.M.) and a partner; they were not involved in data collection or analysis. The surgical technique was described previously. 11 A deltopectoral approach was used, followed by subscapularis tenotomy for intra-articular access. Prosthetic resurfacing was performed after capsular release was completed as needed to access the humeral head lesion. The smallest circumferential implant that could fully cover the defect was used in each case. After implantation, capsulolabral and glenoid repair or augmentation was completed as needed. Further procedures e998 COPYRIGHT SLACK INCORPORATED

4 were completed based on preoperative assessment of bone loss and intraoperative assessment of capsulolabral injury. The subscapularis was repaired with sutures. The subscapularis repair was protected for 3 months postoperatively to avoid active resisted internal rotation. Because of the tertiary nature of the attending surgeons practice, serial clinical follow-up for many patients was difficult, and patients were frequently discharged from practice after 6 months. Patients who were eligible for inclusion were mailed a letter that included outcome questionnaires. Patients were then contacted via telephone and asked a series of questions about stability, stiffness, and revision surgery (Table 1), and they were asked to return their patientreported outcome measures. The primary outcome of this study was recurrent instability, as determined by telephone interview and chart review. Complications, including infection and reoperation, were recorded from patient charts and survey responses. Preoperative and final follow-up SF-12 physical component scores, Review of Musculoskeletal System scores, and Penn Shoulder Scores were compared with a Wilcoxon signed-rank test, with P<.05 indicating statistical significance. Subgroup analysis was conducted to identify patients with anterior and posterior instability. Excel (Microsoft, Redmond, Washington) and XLSTAT (Addinsoft, New York, New York) software was used for statistical analysis. RESULTS A total of 21 patients who met the inclusion and exclusion criteria were identified. Despite repeated attempts via mail and telephone, 5 patients could not be contacted. Of the remaining 16 patients, 13 underwent partial resurfacing for Hill-Sachs lesions and 3 underwent resurfacing for reverse Hill-Sachs lesions (Figure 4). Implant diameter ranged from 25 to 40 mm. The cohort with anterior instability included 3 female patients, and the remainder of the patients in the anterior and posterior cohorts were male. Mean age at the time of the surgery was 32.3 years (range, years) for the anterior instability cohort, with average follow-up of 36.9 months (range, months). Of the 13 patients, 8 (62%) had undergone previous arthroscopic treatment for instability, and 6 of 8 procedures were performed outside of the study Table 1 Telephone Questionnaire at Final Follow-up Have you dislocated your shoulder since surgery? Do you ever have a sensation of instability or does your shoulder feel as if it slips out of place? Do you worry about putting your arm in certain positions because it might slip out? Do you feel you have full range of motion of your shoulder? Do you feel that your shoulder is at all stiff? If you have had a dislocation or problems with instability, what were the circumstances that led to the recurrent dislocation or instability? Have you had any further treatment or evaluation of your shoulder? If yes, have you had any additional surgery on your shoulder? Are you back to the normal activities you had before your injury? Figure 4: Patients available for follow-up and associated procedures in addition to partial humeral head resurfacing. institution. Of the 13 patients, 2 had acute instability, defined as the initial instability event within 3 months of presentation. No previous treatment directly addressed any humeral head defect. All patients underwent preoperative MRI or CT to better define bony and soft tissue injuries. In addition to partial humeral head resurfacing, patients underwent concurrent rotator cuff repair (1 NOVEMBER/DECEMBER 2017 e999

5 Table 2 Demographic Data and Answers to Telephone Questionnaire Characteristic Anterior Instability Posterior Instability Patients, No Age, average (range), y 32.2 (17-49) 51.3 (29-72) Male patients, No Follow-up, average (range), mo 36.9 (25-56) 34.3 (25-53) Previous surgery, No. 8 (62%) 0 HemiCAP a with labral repair or capsular 7 (53.8%) 1 (33%) shift, No. HemiCAP with Latarjet, No. 5 (38.5%) 0 Postoperative dislocation, No. 0 0 Complication requiring reoperation, No. 2 (15%) 0 Full subjective range of motion, No. 11 (85%) 3 (100%) Return to full activity, No. 10 (77%) 3 (100%) Sensation of instability, No. 5 (38%) 0 a Arthrosurface, Franklin, Massachusetts. Table 3 Patient-Reported Outcome Scores Outcome Measure Anterior Instability Posterior Instability 12-Item Short Form Health Survey physical component score Preoperative Postoperative Change P Review of Musculoskeletal System score Preoperative Postoperative Change P < patient, 7.7%), Bankart repair or capsular shift (7 patients, 53.8%), or Latarjet coracoid transfer (5 patients, 38.5%). The Latarjet procedure was performed for patients with greater than 20% glenoid bone loss as determined by preoperative imaging. When significant bone loss was not present, capsulolabral repair was performed. Mean age at surgery was 51.3 years (range, years) for the posterior instability group, with average follow-up of 34.3 months (range, months). No patient had undergone previous surgery to address posterior instability. All patients had the initial injury within 3 months of presentation. Two had a locked posterior dislocation when evaluated by the attending surgeon, and the other had repeated instability events. One patient underwent labral repair at the time of humeral head resurfacing, 1 did not have posterior labral pathology on direct visualization, and 1 did not have an assessment of the posterior labrum noted in the operative report. No patient in either the anterior or posterior instability cohort reported recurrent dislocation of the operative shoulder at final follow-up. Of the 5 patients who were unable to be contacted after the index procedure, no patient s chart showed subsequent dislocation (range of follow-up, 6-18 months). Of the 13 patients with anterior instability, 8 (62%) reported no sensation of instability, regardless of arm position, and the remaining 5 (38%) reported a mild sensation of instability with the arm fully extended or with overhead activities. Of these 13 patients, 11 had regained full range of motion and 2 reported mild restrictions. In 1 case, loss of range of motion was attributed to stiffness, and the other was caused by a sensation of instability. In addition, 10 patients (77%) reported full return to activities compared with preinjury activity levels, including waterskiing, squash, snowboarding, college-level ice hockey, rugby, and rock climbing. For the posterior instability cohort, all 3 patients reported no sensation of instability despite arm positioning. In addition, all 3 had full return to shoulder range of motion and returned to preinjury activity levels (Table 2). All 16 patients had both pre- and postoperative Review of Musculoskeletal System scores available for analysis. For the anterior instability group, 1 patient did not have preoperative SF-12 physical component scores available, but SF-12 physical component scores were available for all other patients. For the anterior instability cohort, mean Review of Musculoskeletal System score improved from 7.69 preoperatively to 3.15 postoperatively (P=.003). For patients with posterior instability, mean Review of Musculoskeletal System score improved from 5.33 to 0.66 (P=.37). The SF-12 physical component scores improved from 39.9 to 49.4 (P=.01) for the anterior instability group and from 32.7 to 51.0 (P=.18) for the posterior instability group (Table 3). Changes in Penn Shoul- e1000 COPYRIGHT SLACK INCORPORATED

6 Table 4 Patient-Reported Outcome Scores No. of Patients Average Score Penn Shoulder Score Anterior Instability Posterior Instability Preoperative Postoperative Difference P Function Pain Satisfaction Total der Scores were calculated only for patients who had pre- and postoperative data available for comparison. The number of patients with available scores from each cohort is noted in Table 4. Anterior and posterior cohorts were combined because of low numbers. The total Penn Shoulder Score improved an average of 36.4 points (P=.059). Two patients who were treated for anterior instability reported complications that required reoperation. One patient lost 30 of forward flexion after a delay in the initiation of postoperative therapy and underwent manipulation under anesthesia and arthroscopic lysis of adhesions 3 months after the index procedure. The second patient had a seizure 1 month after the index procedure that resulted in rupture of the subscapularis tendon repair but no dislocation. Of the patients who had posterior instability, 1 had ipsilateral clavicle fracture 5 months after the index resurfacing and underwent open plating. The chart of 1 patient who could not be contacted and thus was excluded from the study noted that the patient underwent irrigation and debridement with retention of the prosthesis for infection. This patient had undergone 1 surgical procedure before partial resurfacing. DISCUSSION Recurrent glenohumeral instability is a difficult clinical entity, with evolving treatment options. This study found no postoperative instability events despite a high proportion of patients who had undergone previous unsuccessful surgery. This finding shows the efficacy of partial humeral head resurfacing for preventing recurrent instability events while treating clinically significant humeral head defects and shows that, with short-term followup, this procedure is a viable treatment modality. Injuries and deficiencies of the capsulolabral complex, glenoid, and humeral head can contribute to instability in varying proportions. Arthroscopic capsulolabral repair is the most common treatment modality for shoulder instability, 1 although the rate of recurrent instability was 18% in a meta-analysis by Lenters et al. 16 In the current study, 62% of patients with anterior instability had undergone previous unsuccessful arthroscopic stabilization. Balg and Boileau 17 proposed the use of the instability severity index score to help surgeons to identify patients who are at high risk for recurrent instability after arthroscopic Bankart repair. In addition to patient-specific traits, including age, participation in contact or noncontact sports, and hyperlaxity, bone loss in the glenoid or humeral head increases the risk of failure. Although Hill-Sachs lesions have been observed among most patients with initial or recurrent dislocations, 5,18 few cases require treatment to establish a stable shoulder. Lesions involving less than 20% of the humeral head typically do not lead to instability, whereas those involving more than 40% of the humeral head significantly increase the likelihood of recurrent instability. 6,19 In cadaveric models, defects of 25% to 31% of the humeral head diameter lead to instability in abduction and external rotation. 20,21 The position and the orientation of the lesion also alter the risk of recurrence, with engaging lesions more likely to contribute to further instability. 8 The senior author (A.M.) uses 20% to 25% involvement of the articular surface diameter on axial MRI or CT imaging as an indication that treatment of the defect is necessary, depending on the level of glenoid bone loss. Resurfacing is preferred to restore the articular geometry without compromising range of motion or introducing risks associated with bony or allograft healing. Various surgical treatment options for humeral head lesions are available. Remplissage, or tenodesis of the rotator cuff tendons into the bony defect, can be used to render the defect extra-articular; however, this can restrict rotation of the shoulder. 22,23 Humeroplasty involves disimpaction of the defect through a cortical window, which can be technically challenging and is more suitable for smaller lesions. 24 Proximal humeral rotational osteotomy can change an engaging lesion to a nonengaging lesion, although it is associated with complications with hardware and bone healing as well as stiffness. 25 Osteochondral allograft transplantation can restore a congruent articular surface, but it is limited by graft availability as well as NOVEMBER/DECEMBER 2017 e1001

7 the risks of disease transmission, failure or delay of graft healing, and hardware complications. 26,27 Reverse Hill-Sachs lesions also can be treated with lesser tuberosity transfers, which can limit the strength and motion of internal rotation. 28 Although arthroplasty remains a viable salvage option in older, lower-demand populations, it is not a durable solution for young, active patients. Previous reports documented successful treatment of several patients with partial resurfacing of humeral head defects with HemiCAP implants. 9,10 The current study demonstrates the efficacy of this technique for preventing recurrent dislocations for both anterior and posterior instability in a larger cohort while maintaining satisfactory range of motion and activity levels. The anterior instability cohort showed significant improvement of SF-12 physical component scores and Review of Musculoskeletal System scores after surgery. The same improvement was not seen for the posterior instability cohort or for the total Penn Shoulder Score, although this was likely the result of the small sample size because the difference in scores is large enough to be clinically relevant. Although little statistical knowledge is gained from this cohort, the fact that these patients did not have further instability events is important. The study cohort included a heterogeneous patient population treated with various combinations of procedures. Humeral defects that require surgical treatment are rare and often are seen in the setting of coexisting glenoid and capsulolabral deficiency. Although it would be ideal to study the effect of partial resurfacing in isolation with a more homogeneous population, it would be difficult to report on a significant number of patients without compromising adequate treatment of all risk factors for recurrent instability. The limited numbers of patients included in this study made useful multivariate analysis impossible. Although the primary outcome was recurrent instability, more complete capture of patient-reported outcome scores would provide a more accurate description of patient perceptions and function after surgery. A 38% rate of patients reporting a sense of apprehension in certain positions is high and could be considered a failure for those patients, even though no subsequent dislocations occurred. One concern about the use of a prosthetic implant in a young, active population is implant survival. Previous studies of the HemiCAP implant used for osteonecrosis and osteoarthritis showed durable radiographic results. 29,30 Without a polyethylene glenoid component, there is also a lower risk of component loosening or generation of wear debris, a much greater concern for total shoulder arthroplasty. 31 Ideally, radiographic follow-up would be available to evaluate the implants in situ. 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