Long term outcomes of residual valgus alignment after total knee arthroplasty for valgus knee deformity: a minimum 10-year follow up.

Abstract

This study aimed to evaluate the impact of postoperative hip-knee-ankle (HKA) angle on clinical outcomes and survivorship in total knee arthroplasty (TKA) patients with valgus knee. We retrospectively reviewed TKAs performed for valgus knee deformity between January 2005 and February 2015. Patients were categorized into two groups based on postoperative HKA angle: neutrally aligned (0° ± 3°) and residual valgus groups (>3°). Preoperative and postoperative clinical outcomes, including the Western Ontario and McMaster University Osteoarthritis (WOMAC) Index and Knee Society Scores (KSSs), as well as radiographic parameters such as HKA angle and lateral distal femoral angle (LDFA), were compared between the groups. Survivorship analysis was also conducted. A total of 73 knees (64 patients) were included, with a mean follow-up period of 140.1 ± 14.4 months. Of these, 55 and 18 knees were classified as neutrally aligned and residual valgus group, respectively. The preoperative HKA angle and LDFA were significantly different between the two groups. Postoperative LDFA (88.6° ± 1.8° vs. 86.7° ± 1.7°, P < 0.001) differed significantly. However, long-term WOMAC Index and KSSs were comparable. The cumulative survival rates were 96.4 % in the neutrally aligned group and 100 % in the residual valgus group, with no significant difference (P = 0.322). The residual valgus group exhibited more severe preoperative femoral valgus. Primary cause of postoperative residual valgus was residual femoral valgus. Residual valgus alignment was not related to inferior long-term clinical outcomes and survival rates compared to neutrally aligned TKA for preoperative valgus deformity.