Total knee arthroplasty in valgus knees achieves comparable outcomes to varus knees: a propensity score matched multicenter study.

Abstract

Total knee arthroplasty (TKA) in valgus deformity remains technically challenging due to capsulo-ligamentous imbalances. This multicenter propensity score-matched study aimed to compare functional and radiographic outcomes of TKA for valgus knees versus a matched control group of varus knees, and identify independent prognostic factors. In this retrospective multicenter cohort study with propensity score matching (Monastir and Mahdia University Hospitals, between 2015 and 2022), we included 120 patients (132 knees) who underwent TKA for osteoarthritis with valgus deformity. A control group of 120 patients (132 knees) operated for varus deformity was constituted using propensity score matching (age, sex, BMI, preoperative IKS score, year of surgery). The primary outcome was the 2011 IKS score at a mean follow-up of 5.2 ± 2.5 years. Kaplan-Meier survival curves were generated. Multivariate logistic regression identified prognostic factors. After matching, both groups were comparable for all demographic variables. The global IKS score improved from 91.3 ± 14.2 to 166.5 ± 15.8 in the valgus group, with no significant difference compared to the varus group (167.2 ± 14.9; p = 0.68). Five-year implant survival was 98.5% (95% CI [96.2-99.4]) in the valgus group versus 99.2% (95% CI [97.1-99.8]) in the varus group (p = 0.54). Multivariate analysis identified three independent factors associated with excellent functional outcome: absence of postoperative laxity (OR = 4.3; 95% CI [2.1-8.9]; p < 0.001), rehabilitation duration within three months (OR = 3.4; 95% CI [1.7-6.9]; p = 0.002), and patellar resurfacing (OR = 2.2; 95% CI [1.2-4.3]; p = 0.02). After propensity score matching, TKA for valgus deformity achieves functional outcomes and 5-year survival comparable to TKA for varus deformity. The quality of ligamentous balancing and early intensive rehabilitation are the major determinants of success. (Retrospective comparative study with propensity score matching).