Two-year results of a multi-centre, randomized controlled trial comparing a second-generation uncemented trabecular metal-backed versus cemented polyethylene glenoid component in total shoulder arthroplasty

Aims To report early (two-year) postoperative findings from a randomized controlled trial (RCT) investigating disease-specific quality of life (QOL), clinical, patient-reported, and radiological outcomes in patients undergoing a total shoulder arthroplasty (TSA) with a second-generation uncemented trabecular metal (TM) glenoid versus a cemented polyethylene glenoid (POLY) component. Methods Five fellowship-trained surgeons from three centres participated. Patients aged between 18 and 79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Patients were randomized intraoperatively to either a TM or POLY glenoid component. Study intervals were: baseline, six weeks, six-, 12-, and 24 months postoperatively. The primary outcome was the Western Ontario Osteoarthritis Shoulder QOL score. Radiological images were reviewed for metal debris. Mixed effects repeated measures analysis of variance for within and between group comparisons were performed. Results A total of 93 patients were randomized (46 TM; 47 POLY). No significant or clinically important differences were found with patient-reported outcomes at 24-month follow-up. Regarding the glenoid components, there were no complications or revision surgeries in either group. Grade 1 metal debris was observed in three (6.5%) patients with TM glenoids at 24 months but outcomes were not negatively impacted. Conclusion Early results from this RCT showed no differences in disease-specific QOL, radiographs, complication rates, or shoulder function between uncemented second-generation TM and cemented POLY glenoids at 24 months postoperatively. Revision surgeries and reoperations were reported in both groups, but none attributed to glenoid implant failure. At 24 months postoperatively, Grade 1 metal debris was found in 6.5% of patients with a TM glenoid but did not negatively influence patient-reported outcomes. Longer-term follow-up is needed and is underway. Cite this article: Bone Jt Open 2021;2(9):728–736. </jats:sec

Glenoid Component Position Does Not Affect Short-Term Clinical and Radiologic Outcomes in Total Shoulder Arthroplasty

Background: Malpositioning of the glenoid component in total shoulder arthroplasty (TSA) remains the primary source of loosening. The purpose of this study is firstly, to quantify postoperative glenoid component position in patients having a TSA and secondly, to explore whether glenoid component radiolucency is associated with glenoid position, clinical outcomes and patient-reported measures in the short-term (two year) follow-up period. Methods: This study was a sub-study of a larger clinical trial that included patients who underwent a TSA and who were randomized into two different glenoid types with a minimum two-year follow-up period. Post-operative radiographic assessments (six weeks and two years) were used to measure glenoid component position (version, inclination, offset) and humeral head centering anterior–posterior (AP) and superior–inferior (SI), and to assess glenoid component radiolucent scoring (modified Lazarus). Pre-operative X-rays were used to measure glenoid version, inclination and Walch classification. Patient-reported measures (PROMs) included the EQ-5D health slider and the Western Ontario Osteoarthritis (WOOS) and American Shoulder and Elbow Surgeons (ASES) score and were captured at baseline and two years postoperative. Clinical outcomes including range of motion and complications were also documented. Statistical analysis included t-tests and regression modeling. Results: Ninety-one patients with an average age of 69.9 ± 6.2 years were included in this study. Glenoid component position improved significantly in version (−19.4 ± 8.6° to −17.7 ± 8.5°; p < 0.045) and inclination (11.5 ± 7.1° to 5.9 ± 6.3°; p < 0.00001) from preoperative to six weeks postoperative. Glenoid component offset in SI and humeral head centering in AP remained unchanged throughout the follow-up. Radiolucency (Lazarus classification) was recorded in 21 cases (17.3%) with a Lazarus score of 1 (15 cases) and 2 (6 cases). The EQ-5D health slider, WOOS and ASES, and ROM confirmed continuous improvements from the preoperative scores to the two-year follow-up (p < 0.05). Regression models showed no correlation between glenoid component radiolucency at two years and the postoperative week six glenoid component position; however, female gender was a significant variable. Conclusion: Glenoid component changes from its original native glenoid were observed following TSA. Glenoid inclination was improved more than version from baseline, and the humeral head remained well-centered in AP and SI at two years. Radiolucency of the glenoid at two years is not negatively associated with PROMs or component position; however, female gender was identified as a significant predictor and warrants further investigation. Complications are not associated with glenoid position or radiolucency, but longer-term follow-up is required.Medicine, Faculty ofNon UBCOrthopaedic Surgery, Department ofReviewedFacult