Leaving Residual Varus Alignment After Total Knee Arthroplasty Does Not Improve Patient Outcomes

Abstract

Background Recent popularity of kinematic alignment and constitutional varus has caused some surgeons to leave varus limbs in residual varus after total knee arthroplasty (TKA). This study assessed whether if patients left in residual varus have improved outcomes compared with those fully corrected to neutral alignment. Methods A retrospective review of 361 consecutive primary TKAs was performed. Anatomic tibiofemoral alignment was measured and knees were categorized as neutral, varus, or valgus. Modern Knee Society scores and University of California Los Angeles Activity Level scores were collected at minimum 1-year follow-up. Results After exclusions for confounds and loss to follow-up, 262 knees were available for analysis, 67% (176) of which were preoperatively varus. Sixty-six percent of varus knees were corrected to neutral, 25.6% were left in residual varus, and 8.5% were corrected to valgus. Median Knee Society objective scores at latest follow-up were greater in knees corrected to neutral (97), followed by knees corrected to varus (95), and valgus (93; P = .025), but post hoc comparisons between pairs of medians were not significant. There was no difference between groups in any other outcome measure (P ≥ .245) or the amount of improvement from baseline (P ≥ .423). Sixty percent of native varus patients corrected to neutral, 64% of those corrected to varus, and 40% of those corrected to valgus reported that their knee felt normal (P = .193). Conclusion Findings fail to support the notion that leaving varus knees in residual varus will improve outcomes and pain. Caution is advised when leaving limbs in residual varus after TKA.