Ten-year clinical outcomes of modular unlinked bicompartmental knee arthroplasty using an onlay-type patellofemoral arthroplasty.

BACKGROUND: Long-term clinical data on bicompartmental knee arthroplasty (BiKA) using a third-generation onlay-type patellofemoral arthroplasty (PFA) remain limited. This study aimed to evaluate the 10-year clinical outcomes of modular unlinked BiKA combining an onlay PFA with medial unicompartmental knee arthroplasty (UKA) in patients with bicompartmental knee osteoarthritis (OA).

METHODS: Seventy-two patients (73 knees; mean age, 68.9 years) who underwent BiKA between 2011 and 2013 at a single institution were retrospectively reviewed. Clinical outcomes were assessed using knee range of motion (ROM), the 2011 Knee Society Score (KSS), and the Japanese Knee Osteoarthritis Measure (JKOM). Radiographic findings and postoperative complications were also evaluated.

RESULTS: At 10 years, 52 of 73 knees (71.2%) remained in follow-up. Mean postoperative ROM was 134.5°, mean 2011 KSS was 115.8 points, and mean JKOM score improved from 37.5 to 20.7 points. Among 21 knees lost before 10 years, final available outcomes also remained favorable. Most discontinuations occurred between 5 and 10 years postoperatively. No radiographic evidence of implant loosening or subsidence was identified in any of the 73 knees during follow-up. Complications requiring reoperation occurred in four knees. No knee required conversion to total knee arthroplasty.

CONCLUSIONS: Modular unlinked BiKA using an onlay PFA demonstrated meaningful clinical outcomes at a minimum of 10 years in a carefully selected patient cohort. These findings support the use of this procedure as a treatment option for appropriately selected patients with bicompartmental knee OA, although interpretation should be made with caution due to loss to follow-up and limited generalizability.