BACKGROUND: Fixation of the glenoid component in anatomic total shoulder arthroplasty (aTSA) is critical for implant longevity. The aim of this study was to compare long-term implant survival and clinical outcomes between keeled and pegged glenoid components of the Eclipse™ stemless aTSA, and to evaluate the influence of humeral head material on revision rates and functional outcomes. METHODS: A retrospective, bicentric analysis was conducted on 90 patients who underwent aTSA between 2011 and 2016. Patients were classified into three groups based on the specific glenoid and humeral components received: Group 1 had keeled cemented all-polyethylene glenoid components with cobalt-chromium humeral heads (n = 38); Group 2, pegged cemented all-polyethylene glenoid components with cobalt-chromium humeral heads (n = 14); and Group 3 received pegged cemented all-polyethylene glenoid components with titanium-coated humeral heads (n = 38). Propensity score matching was performed between Groups 1 and 3 with adjustments made for age, sex, and glenoid morphology. The primary outcome was implant survival at five years. Secondary outcomes included the Constant score and glenohumeral distance (GHD) evaluated at baseline and the 5-year follow-up with additional analysis of postoperative changes in GHD. Revisions were documented throughout the follow-up period. Implant survival was evaluated using Kaplan-Meier estimates with log-rank tests. Multivariable Cox proportional hazards regression was then performed to adjust for potential confounders with sensitivity analyses conducted to assess the robustness of the findings. RESULTS: Baseline patient characteristics of age, sex, and glenoid morphology were similar among the three groups. Median implant survival of 102 months for Group 1 was significantly longer compared to 66 and 73 months for Groups 2 and 3, respectively (P < 0.0001). The median 5-year Constant score was significantly higher in Group 1 (80.0) compared to Groups 2 (37.5) and 3 (32.5) (P < 0.001). Baseline and 5-year GHDs and the difference over time were similar across patient groups (P ≥ 0.203). Revision rates were significantly lower for Group 1 (13%) over Groups 2 and 3 (53%) (P < 0.001). CONCLUSION: For our aTSA cohort, keeled glenoid components with cobalt-chromium humeral heads demonstrate the best implant survival and clinical outcomes. For the pegged components the type of humeral head material used had no influence on implant survival and clinical outcome. The mechanisms behind glenoid component failure remain to be clarified. LEVEL OF EVIDENCE: Level III; Retrospective Cohort Comparison, Treatment Study.
Kraus et al. (Fri,) studied this question.