To compare the early to mid-term outcomes and functional results of neutral alignment versus mild residual valgus following primary total knee arthroplasty (TKA) in patients with valgus knee deformity.

A retrospective analysis was conducted on 55 patients with valgus knees (57 knees) who met the inclusion criteria between January 2015 and August 2020. The follow-up duration were 2.8 to 8.5 years. Based on the hip-knee-ankle angle (HKA) measured on the first postoperative weight-bearing lower-limb X-ray, patients were divided into two groups: the neutral group (–3°≤HKA≤3°, n=33) and the mild valgus group (3°<HKA≤6°, n=24). The groups were compared using the American Knee Society score (KSS), the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), and the forgotten joint score-12 (FJS-12) were compared between the two groups using paired t tests or Wilcoxon signed-rank test. No case needs prosthetic knee revision during the follow-up period.

At the final follow-up, the neutral group demonstrated significantly better clinical and functional outcomes compared to the mild valgus group, including higher KSS knee scores (t=2.043, P<0.05), knee function scores (Z=-2.766, P<0.05), lower WOMAC scores (t=-3.327, P<0.05), and higher FJS-12 scores (t=2.485, P<0.05). Additionally, among preoperative valgus patients, those with a valgus angle of 9° to 15° achieved significantly higher KSS knee function scores compared to those with angles of 3° to 9°or >15° (H=6.189, P<0.05).

In patients with valgus-type OA undergoing TKA, adjusting the HKA alignment to a neutral position (±3°) significantly improves clinical and functional outcomes compared to mild residual valgus and enhances patient satisfaction. There may be an optimal range of postoperative alignment for different degrees of valgus, within which patients experience the most significant symptom relief and functional recovery. This finding provides valuable insights for optimizing personalized treatment strategies.