Preoperative flexion contracture does not affect outcome in total knee arthroplasty: A case-control study of 2,634 TKAs.

BACKGROUND

One issue in total knee arthroplasty (TKA) is management of preoperative flexion contracture, which may be associated with poor functional outcome.

AIM: The aim of this study was to compare functional results in TKA with or without preoperative flexion contracture, treated according to a standardized algorithm of tissue release and bone cut.

PATIENTS AND METHOD: A single-center retrospective case-control study was performed on prospectively collected data for the period 1987-2016. Patients with >10̊ flexion contracture were assigned to the "contracture" group and associated to a selected control group at a ratio of 1:4. Clinical analysis used pre and post-operative International Knee Society (IKS) scores. The significance threshold was set at p<0.05.

RESULTS

Eight hundred and forty-nine cases and 3,304 controls were included, comprising a total of 2,838 male and 1,315 female participants. Mean preoperative extension deficit was 13̊±6̊ in the contracture group and 1̊±2̊ in controls. Preoperative IKS total and functional scores were significantly poorer in the contracture group (38±18 and 54±20) than in controls (52±16 and 59±19) (p<0.001). Postoperatively, the two groups did not significantly differ in IKS functional score (77±22 vs. 79±21, p=0.143). There were differences in IKS knee score (87±12 vs. 88±13, p=0.006) and maximal flexion (114̊±14̊ vs. 119̊±13̊, p<0.0001) that were statistically, but not clinically, significant.

DISCUSSION: A systematic standardized algorithm for surgical treatment of flexion contracture during primary total knee arthroplasty provided clinical outcomes similar to those of patients without preoperative flexion contracture.

LEVEL OF EVIDENCE: III; case-control study.