Selective Use of Modern Cementless Total Knee Arthroplasty is Not Associated with Increased Risk of Revision in Patients Aged 65 or Greater: An Analysis from the American Joint Replacement Registry.

Abstract

Introduction Modern highly porous surfaces have increased confidence and use of cementless total knee arthroplasty (TKA) in the United States. As cementless TKA use increases, there remains a paucity of literature regarding associated risk of revision in patients aged 65 or older. Methods We analyzed American Joint Replacement Registry (AJRR) data from January 2012 to March 2020 identifying patients aged 65 and older undergoing primary TKA with linked cases to supplemental Centers for Medicare and Medicaid data. Patients with hybrid fixation, reverse hybrid fixation, missing component data, highly constrained implants, and stem extension/augmentation were excluded. We identified 442,745 cemented TKAs and 19,841 modern cementless TKAs with minimum 2-year follow-up. Cumulative Incident Function (CIF) curves and cause-specific Cox models evaluated the risk of all-cause revision and revision for mechanical loosening, adjusting for BMI, sex, age, cruciate retaining (CR) vs posterior stabilized (PS) femoral design, patellar resurfacing, and Charlson Comorbidity Index (CCI). Results Patients with cementless compared to cemented TKA were younger (mean age 71.9 vs 73.2, p <0.001), more likely to be male sex (48.8% vs 39.0%, p<0.001), more likely to have a CR femoral design (81.1% vs 45.7%, p<0.001), less likely to have patellar resurfacing (92.7% vs 95.0%, P<0.001), and had a lower CCI (mean 2.9 vs 3.1, p<0.001). Adjusted Hazard Ratios (HRs) showed no difference in associated risk for all-cause revision (HR 1.07, 95% CI 0.92-1.24, p=0.382) or revision for mechanical loosening (HR 1.38, 95% CI 0.9-2.12, p=0.14) for cementless vs cemented TKA. Conclusion Our results suggest that current selective use of cementless fixation for TKA in patients aged 65 and older in the United States is not associated with an increased risk of revision. While encouraging, further study is necessary to establish indications for use in this age group prior to broader adoption in this patient population.