The effect of patient, provider and surgical factors on survivorship of high tibial osteotomy to total knee arthroplasty: a population-based study

The aim of this study was to identify the survivorship of high tibial osteotomy (HTO) to total knee arthroplasty (TKA) on a population level, and identify the patient, provider and surgical factors that influenced eventual TKA. Administrative records from physician billings and hospital admissions were used to identify all adults in Ontario, Canada, who underwent an HTO from 1994 to 2010. The primary outcome was time to TKA, which was estimated using Kaplan-Meier (KM) survival analysis. A Cox proportional hazards model examined the risk associated with patient factors (age, sex, income and co-morbidity score), provider factors (hospital status, surgeon volume and surgeon year in practice) and surgical factors (concurrent ligament reconstruction or bone grafting; and previous chondral or meniscal surgery). A total of 2671 patients who underwent HTO met inclusion. The median age was 46 years (interquartile range 39-53 years), and 62 % were male. The KM survivorship of HTO to TKA at 10 years was 0.67 +/- 0.01. Older age [HR 1.05 (95 % CI 1.04, 1.06), p < 0.001; 5 % increased risk for each year over age 46], female sex [HR 1.35 (95 % CI 1.17, 1.55), p < 0.001], higher comorbidity score [HR 1.58 (95 % CI 1.12, 2.22), p = 0.009] and a prior history of arthroscopy/meniscectomy [HR 1.24 (95 % CI 1.08, 1.43), p = 0.002] increased the risk of eventual TKA. However, HTO with concurrent ligament reconstruction was associated with lower [HR 0.62 (95 % CI 0.43, 0.88), p = 0.008] risk of eventual TKA. In this population, two-thirds of patients were able to avoid a TKA for 10 years after HTO. Specific factors such as older age, female sex, higher comorbidity and prior meniscectomy lowered survival rates. An understanding of patient risk factors for conversion to TKA may help guide surgeons in their selection of patients who will benefit most from HTO. Retrospective cohort study, III.