Higher conversion rate to knee arthroplasty in female patients following medial open‐wedge high tibial osteotomy

Purpose Most studies about medial open‐wedge high tibial osteotomy (HTO) reported outcomes without focusing on gender differences. Therefore, the study compared the long‐term survival rate and postoperative subjective knee function after HTO in female versus male patients with symptomatic medial compartment knee osteoarthritis. Methods The data of three cohorts with long‐term outcomes were analysed (n = 245; 32% females; age: 49 ± 7 years; Kellgren Lawrence Grade I 6.1%, II 32.7%, III 42.4%; IV 18.8%). The minimum follow‐up was at least 6 years or an earlier conversion to total knee arthroplasty (TKA). The gender‐specific survival rate after HTO was calculated after 5 and 10 years and compared using Kaplan–Meier analysis and the logrank test. Baseline characteristics and subjective knee function (International Knee Documentation Committee [IKDC]/Lysholm) were analysed between both genders. Results Forty of 78 (51.3%) women and 41 of 167 men (24.5%) underwent TKA. HTO survival in females was significantly lower (p = 0.0010). The 5‐ and 10‐year survival rates were 85.9% and 62.6% for females and 93.4% and 77.7% for males. In females and males, from preoperative to the last follow‐up, the IKDC (43 ± 15 to 58 ± 17; 47 ± 14 to 67 ± 18) and the Lysholm (42 ± 18 to 72 ± 18; 55 ± 22 to 77 ± 23) improved significantly (all p