Total knee arthroplasty (TKA) after high tibial osteotomy (HTO) is a technically demanding procedure, and concerns have been raised that previous HTO might compromise the outcome of TKA. The aims of the study were to assess the survivorship of TKA after HTO and to determine whether the survivorship is similar to that of primary TKA without previous HTO.
Using the Finnish Arthroplasty Register and the National Hospital Discharge Register, we extracted the data of 1,036 patients [mean age 64.3 years; followup 6.7 years (0-22)] who had undergone TKA after a previous HTO between 1987 and 2008. From this cohort, we calculated the Kaplan-Meier survivorship and compared the survivorship of these cases to that of 4,143 age- and gender-matched patients who had undergone primary TKAs without previous HTO.
In the TKA after HTO group, we found Kaplan-Meier survivorship to be 95.3% at 5 years, 91.8% at 10 years, and 88.4% at 15 years. Those survivorship values were lower than those of patients who had TKA without previous HTO (97.2, 94.5, and 90.6%, respectively) (hazard ratio 1.40; 95% confidence interval 1.09-1.81; p = 0.010).
Previous studies have described technical difficulties during the TKA procedure after HTO, but they have found no adverse effects on the outcome. Our study supports previous research, and despite the slightly higher revision rate, TKA after HTO provides satisfactory results when compared to routine primary TKAs.