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.