In Asian women undergoing total knee arthroplasty, lower leg morphology in those with rheumatoid arthritis differed from those with osteoarthritis

Objectives: This retrospective, single-center study aimed to compare leg morphology between patients with rheumatoid arthritis (RA) and those with osteoarthritis (OA) undergoing total knee arthroplasty (TKA). Methods: We enrolled 70 RA and 327 OA female patients undergoing TKA. Hip-knee-ankle angle (HKA), femorotibial angle (FTA), valgus correction angle (VCA), and femoral/tibial bowing were measured using full-length radiographs. Femoral bowing of more than 3° or tibial bowing more than 2°, either laterally or medially, was considered substantial. Distribution of these results and the incidence of substantial bowing in RA and OA were compared. Results: HKA, FTA, and VCA were significantly smaller in RA than those in OA. Femoral bowing was significantly smaller in RA (mean angle: 0.04° ± 3.1°) than that in OA (mean angle: 2.1° ± 3.6°) (p