TY - JOUR AU - Hasan, Shaho AU - Kaptein, Bart L AU - Marang-van de Mheen, Perla J AU - van Hamersveld, Koen T AU - Nelissen, Rob G H H AU - Toksvig-Larsen, Sören PY - 2022/01/24 Y2 - 2024/03/29 TI - Late stabilization after initial migration in patients undergoing cemented total knee arthroplasty: a 5-year followup of 2 randomized controlled trials using radiostereometric analysis JF - Acta Orthopaedica JA - ActaO VL - 93 IS - SE - Randomized clinical trial DO - 10.2340/17453674.2022.1381 UR - https://actaorthop.org/actao/article/view/1381 SP - 271-276 AB - <p><strong>Background and purpose:</strong> In total knee arthroplasty (TKA), metal-backed (MBT) and all-polyethylene (APT) designs have shown comparable implant migration up to 2 years postoperatively using radiostereometric analysis (RSA). However, studies comparing mid-term migration of both designs are lacking. Furthermore, continuously migrating TKAs up to 2 years may continue to migrate or stabilize thereafter. Therefore, we compared 5-year migration of MBT and APT using either cruciate-stabilizing (CS) or posteriorstabilizing (PS) designs and specifically assessed migration profiles of continuously migrating TKAs beyond 2 years.</p><p><strong>Patients and methods:</strong> The present study includes results from 2 randomized trials comparing migration of cemented MBT with APT of either CS (CS study, n = 59) or PS (PS study, n = 56) design. 2 surgeons performed all surgeries. We used a linear mixed model for the analyses.</p><p><strong>Results:</strong> The overall migration between MBT and APT TKAs was similar for either the CS or PS design over a 5-year period. In both studies combined, 9 implants showed continuous migration in the second postoperative year, of which 1 (APT-CS) was revised for instability, 4 (2 MBT-CS, MBT-PS, APT-PS) stabilized, and 4 (2 MBT-CS, APT-CS, MBT-PS) lacked 5-year data.</p><p><strong>Interpretation:</strong> Overall migration was similar between MBT and APT TKAs up to 5 years, for both the CS and PS design. 4 initially migrating TKAs stabilized between 2- and 5-year follow-up, stressing the need for longer-term followup to determine whether second-year continuous migration correctly predicts loosening.</p> ER -