To investigate the correlation between the degree of lower limb alignment correction (neutral alignment vs. residual valgus) and clinical outcomes after total knee arthroplasty (TKA) in patients with varying degrees of valgus knee deformity.

A retrospective study analyzed patients who underwent primary TKA at Affiliated Hospital of Nantong University from March 2019 to November 2022 due to unilateral knee valgus deformity. Patients with extra-articular deformities and those using restrictive prostheses were excluded. A total of 157 patients were enrolled. According to preoperative femorotibial angle (FTA) measured on Ximages, the patients were divided into three groups: mild valgus group (7°< FTA < 15°, n=80), moderate valgus group (15°≤FTA ≤ 30°, n=56), and severe valgus group (FTA > 30°, n=21). FTA, range of motion (ROM), Hospital for Special Surgery score (HSS), Western Ontario and McMaster University osteoarthritis index (WOMAC) and patient satisfaction were recorded and analyzed statistically. Data were analyzed using one-way analysis of variance, independent samples t test, and chi square or Fisher’s exact test.

The mean follow-up was (34.2±5.8) months. In the preoperative mild valgus group, patients with postoperative neutral alignment showed significantly higher satisfaction (χ²=10.02), HSS (F=3.78), and WOMAC (F=3.44) compared to those with postoperative valgus alignment (all P<0.05). In the preoperative moderate and severe valgus group, the patients with postoperative valgus alignment showed significantly higher satisfaction (χ²=8.97, 6.24, both P<0.05) and greater improvement of HSS (F=4.85, t=4.91, both P<0.05), WOMAC (F=3.53, t=6.54, both P<0.05), and SF-36 score (F=3.52, t=2.18, both P<0.05) than thepatients with postoperative neutral alignment. Deep vein thrombosis occurred in one case in moderate group, artificial prosthesis aseptic loosening occurred in two cases in severe group. No infection, anchylosis or recurrent dislocation of knee-cap occurred during follow-up.

For mild valgus before operation, correction to neutral alignment achieved better outcomes than leaving residual valgus. For preoperative moderate and severe valgus, retaining residual valgus postoperatively ensured satisfactory clinical outcomes too.