Preoperative knee stiffness and total knee arthroplasty outcomes.

A retrospective case-control study was conducted to evaluate 1-year total knee arthroplasty (TKA) outcomes among preoperative stiff knees, range of motion (ROM) 80° or less, compared with nonstiff preoperative knees, ROM 100° or greater. A total of 134 stiff knee cases were compared with a matched cohort of 134 non-stiff knee controls. Knee Society Score and Oxford Knee Score change scores from baseline to 1 year were similar between the groups. Stiff knees experienced a significantly greater mean improvement in ROM from baseline to 1 year (30.8° ± 18.8°) as compared with nonstiff knees (1.1° ± 12.8°) (P < .0001). Although ultimate ROM of a TKA can be restricted secondary to preoperative stiffness, improvements in outcomes and ROM are not affected. We conclude that progression of stiffness should not in and of itself lead to earlier intervention of TKA in most cases.