Abstract
Introduction
In contrast to knee arthroplasty, there is no national register on high tibial osteotomy (HTO) in Sweden. The knowledge of the outcome of HTO as a treatment alternative for knee osteoarthritis (OA) is insufficient. The rate of revision to knee arthroplasty after HTO at 10 years has been reported to vary between 8 and 49%. The aim of the study was to evaluate the outcome of HTO performed in Sweden 1998–2007, expressed by rate of revision to knee arthroplasty.
Patienter och Material: 3 196 HTO (69% men) 30 years or older operated on for knee OA in Sweden 1998–2007 were identified through the in- and out-patient care registers from the Swedish National Board of Health and Welfare. Side, left/right, that was operated, diagnosis and indication for surgery were verified through surgical records. Conversions of HTO to knee arthroplasty before 2010 were identified through the Swedish Knee Arthroplasty Register (SKAR). In about 10% of the cases it was unknown what side the HTO had been performed on and thus if the arthroplasty had been on the same knee. In these cases we assumed a worst case scenario of all having been on the same side as the HTO. A 10-year survival analysis was performed using revision to an arthroplasty as the end point.
Result
The mean age was 52 years (range 30- 80) with 97% of the patients younger than 65 years. The cumulative revision rate (CRR) at 10 year was 29.4% (95% CI 27.2–32.9) after adjusting for age and gender. The risk of revision increased by increasing age and the risk of revision after adjusting for age was significantly higher in women than men RR 1.30 (95% CI 1.11–4.54). Most of the HTO's were performed by open wedge osteotomy using external fixation. The risk of revision was higher for closed wedge osteotomies when comparing the closed and open wedge methods RR1.29 (95% CI 1.08–1.55).
Conclusion
70% of the high tibial osteotomies performed in Sweden 1998–2007 had not been converted to a knee replacement, using the 10 year cumulative revision rate. If it is considering beneficial to have no implant in the knee, high tibial osteotomy may be considered as an alternative to TKA in the younger and physically active patients.
