Anatomic total shoulder arthroplasty for B2 glenoids treated with asymmetric reaming has equivalent survivorship and patient outcomes compared with type A glenoids at a mean 9-year follow-up.

BACKGROUND: Walch B2 glenoids can present a challenge to shoulder arthroplasty surgeons. Short-term studies have demonstrated that corrective reaming to 10° of retroversion in anatomic total shoulder arthroplasty (aTSA) can result in good outcomes; however, there is little data reporting the long-term outcomes in this cohort. B2 glenoids treated with high-side reaming present a theoretical risk of early glenoid component failure as one may ream into the subchondral bone. This study aimed to demonstrate that (1) B2 glenoids treated with corrective reaming have durable results and (2) offer similar results to Walch A1/2 in long-term follow-up. METHODS: Patients who underwent aTSA by a single surgeon (E.L.F.) were identified from a shoulder arthroplasty registry. Inclusion criteria included Walch A1, A2, or B2 glenoid; a diagnosis of primary shoulder osteoarthritis; and a minimum radiographic and clinical follow-up of 5 years. Forty-three patients with B2 glenoids were compared to a cohort of 42 patients with A1 or A2 glenoids. Preoperative computed tomography (CT) and radiographs were used to assess deformity, glenoid version, and posterior subluxation of the humeral head. Postoperatively, patients were assessed with radiographs and patient-reported outcome measures including American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, Simple Shoulder Test (SST) score, and visual analog scale (VAS). RESULTS: Eighty-five shoulders (82 patients, 42 B2 and 43 A1/A2 glenoids) with an average follow-up of 9.4 years were included. In the B2 cohort, the average retroversion was 21.1° and posterior subluxation was 69.4% compared with 10.6° (P < .001) and 57.5% (P < .001), respectively, in the A1 or A2 cohort. The cohort demographics were similar except for male sex (B2 69.8% vs. A1 or A2 37.2%, P = .008). There was no difference between the cohorts in their improvement in ASES (P = .807), SST (P = .586), and VAS (P = .930) scores. There was no difference in lateral humeral offset (P = .889) or acromial humeral interval (P = .468) between initial postoperative and final follow-up visits. Survivorship for B2 glenoids was 97.6%, 94.1%, and 73.3% at 5, 10, and 15 years, respectively, compared with 97.6%, 91.9%, and 83.5% in type A glenoids. The revision rate was similar between the 2 groups (P = .432). Lazarus score (P = .682) and rates of humeral radiolucency (P = .366) and humeral osteolysis (P = .194) were similar between the 2 cohorts at final follow-up. CONCLUSION: Asymmetric reaming of patients with B2 glenoids is a reliable method of glenoid preparation with excellent mid- to long-term clinical results, patient-reported outcomes, and low revision rates similar to their A1 and A2 counterparts.

Total shoulder arthroplasty in patients with a B2 glenoid addressed with corrective reaming: mean 8-year follow-up.

BACKGROUND: The management of Walch B2 glenoid deformities in primary glenohumeral osteoarthritis is frequently debated. Previous literature has shown that the treatment of B2 glenoids with high-side reaming and anatomic total shoulder arthroplasty (aTSA) perform well in the short-term but is associated with an increased glenoid component failure rate in severe deformities. Therefore, many have explored alternative options, including augmented anatomic glenoid components and reverse shoulder arthroplasty. Our goal in this study is to provide mid-term radiographic and clinical outcomes after high-side reaming and aTSA for B2 glenoids. METHODS: Patients were followed both clinically and radiographically. Preoperative computed tomography scans were used for retrospective analysis of deformity. Both preoperative and postoperative visual analog scale pain, American Shoulder and Elbow Surgeons score, and Simple Shoulder Test scores were collected. Radiographs were analyzed preoperatively and postoperatively for humeral head decentering relative to the glenoid vault, immediate glenoid seating, and final glenoid peg radiolucency. RESULTS: Of the original cohort of 59 patients (6 now deceased) reported at a mean radiographic follow-up of 3.4 years, 34 shoulders in 33 patients with B2 glenoids (mean retroversion 18.9°, range 4°-32°) were available for follow-up at a mean of 8.6 years (range 5.5-11.2) after high-side glenoid reaming with aTSA. Three (5.1%) of the original 59 shoulder were revised. At final follow-up, 3 of 30 (10.0%) shoulders had radiographic glenoid component failure, but were unrevised. Glenoid component failure was associated with worse initial glenoid component seating (mean Lazarus score 1.2 vs. 2.0, P = .002). Glenoid failure was also associated with increased posterior humeral head subluxation at 2-4 year follow-up (mean 5.6% vs. 12.6%, P = .045) and at final follow-up (mean 7.0% vs. 21%, P = .002). There was no association between glenoid component failure and preoperative retroversion, inclination, or humeral head subluxation (all P > .05). Glenoid component failure was associated with worse American Shoulder and Elbow Surgeons (88 vs. 73) and visual analog scale pain (0.8 vs. 2.1) scores (both P = .03). CONCLUSIONS: At a mean of 8.6 years, 88% of shoulders available for follow-up had well-fixed glenoid components. Glenoid component failure was associated with poor initial glenoid component seating, with failed components having an average of 25% of the glenoid component not seated. Preoperative deformity such as glenoid retroversion, inclination, or humeral head subluxation did not predict glenoid component failure. This study supports that initial glenoid component seating and recurrence of posterior humeral head subluxation may be the most important factors for mid-term glenoid component survival in aTSA in patients with B2 glenoids.