High tibial osteotomy (HTO) is a joint preserving treatment of unicompartmental osteoarthritis in the knee. In cases with insufficient or deteriorating clinical results patients may undergo a total knee arthroplasty (TKA). The influence of prior HTO on TKA survival is debated.
We conducted a population-based registry study comparing 1044 primary TKAs in patients with prior HTO to 63,763 de novo TKAs inserted from 1997 to 2015. Implant survival was estimated by Kaplan-Meier analysis with revision of any kind as endpoint. Patient and surgery characteristics, including choice of implant design, were compared and their influence on TKA survival was estimated by Cox regression. Finally, indications of revision were compared between the groups.
TKA following HTO had an inferior survival with a 10-year estimated survival of 91% compared to 94% for de novo TKA, corresponding to a crude hazard ratio (HR) of 1.73 (P < .001). However, after adjustment for differences in gender and age this risk diminished (HR 1.19, P = .09). The choice of implant constraint was similar between the groups and in both groups posterior stabilized TKA was associated with inferior survival with an adjusted HR of 1.46 (P = .03) in post-HTO TKA when compared to cruciate-retaining TKA.
TKA following HTO had a crude inferior survival when compared to TKA without prior surgery of any kind. The inferior survival was explainable by patient characteristics, defined by male gender and lower age, rather than the prior HTO. However, when the prior HTO resulted in the use of posterior stabilized TKA the survival decreased.