Risk and Timing of Total Knee Arthroplasty After High Tibial Osteotomy: A Cohort Study With 10-Year Follow-Up.

Abstract

High tibial osteotomy (HTO) is a joint-preserving procedure used to relieve pain and delay, or even eliminate, the need for total knee arthroplasty (TKA). The aim of this study was to quantify the incidence of TKA after HTO and identify risk factors associated with conversion. Patients undergoing HTO at a single academic center from 1996 to 2015 were identified using a validated deidentified synthetic data platform from real patient data, ensuring a minimum of 10 years of follow-up. Patients aged 18 years with procedural codes for HTO were included. The primary outcome was TKA incidence; the secondary outcome was time to TKA. A modified Poisson regression evaluated associations between TKA, age, and BMI among individuals with complete BMI data. A total of 207 patients (mean age, 41.3 ± 11.2 years; 62.8% male) were identified. Mean follow-up was 17.8 ± 4.8 years. Overall, 20 patients (9.9%) underwent TKA. Those converting to TKA were significantly older at HTO (45.3 ± 6.1 vs. 40.9 ± 11.6 years; P = 0.009) and had higher BMI (35.7 ± 6.4 vs. 29.4 ± 5.2; P = 0.01). TKA incidence increased over time: 5.9% at 10 years, 10.8% at 15 years, and 22.0% at 20 years. Higher BMI was independently associated with increased TKA risk (RR = 1.13; 95% CI, 1.04 to 1.23; P = 0.004). In this cohort with minimum 10-year follow-up, HTO demonstrated approximately a 90% knee survivorship at a mean of 17.8 years. Age and BMI at the time of HTO were associated with increased risk of TKA conversion and should be considered during patient counseling and selection.