Factors Affecting Changes in Ankle Symptoms Following Total Knee Arthroplasty for Varus Knee Osteoarthritis.

Background

We aimed to investigate the impact of pre- and postoperative radiological parameters on ankle symptoms after total knee arthroplasty (TKA) in patients who have genu varum deformity.

Methods

This study comprised 56 patients (85 cases) who had TKA between January 4, 2023, and May 31, 2024, and who completed 12-month follow-up. Radiologic parameters included the mechanical tibio-femoral angle, talar tilt angle (TA), hindfoot alignment view angle (HAVA), frontal tibial ground angle, varus talar tilt angle (varTA), and valgus talar tilt angle (valTA). The Foot Function Index (FFI) was assessed. All parameters were measured before and 12 months after surgery.

Results

After TKA, the absolute values of HAVA, TA, varTA, and valTA significantly decreased. The preoperative FFI scores were significantly higher in patients who had greater preoperative TA and varTA. There were 15 cases (17.6%) in which patients reported the development or worsening of ankle symptoms. Patients whose ankle symptoms worsened after TKA had a significantly higher prevalence of concomitant ankle osteoarthritis. In the multivariate analysis, postoperative HAVA (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.2 to 2.3) and TA (OR = 1.8; 95% CI = 1.3 to 2.7) were independent risk factors for worsening ankle symptoms.

Conclusion

Preoperative TA and varTA levels were increased in patients who had preoperative ankle pain. Postoperative ankle pain was associated with concomitant ankle osteoarthritis and increased postoperative TA and HAVA, whereas in ankles without preoperative osteoarthritis, postoperative coronal alignment parameters were not significantly related to short-term (12-month) changes in ankle symptoms. Thorough radiographic evaluation of the ankle joint is recommended for patients who have pre- and postoperative ankle pain following TKA.