Impact of patellofemoral osteoarthritis on long-term outcome of high tibial osteotomy and effects of ventralization of tibial tubercle

Background. Medial compartment osteoarthritis (OA) of the knee frequently accompanies patellofemoral osteoarthritis (PF-OA). No consensus has been reached whether it is better to include treatment for the PF joint at the time of high tibial osteotomy (HTO), or if treatment of the PF joint is unnecessary. The purpose of this comparative retrospective study on medial compartment OA of the knee accompanying PF-OA was to examine the effects of PF-OA on the long-term outcome of HTO and to evaluate the significance of ventralization of the tibial tubercle when combined with HTO. Methods. We studied the impact of PF-OA on the long-term outcome of HTO and the effects of ventralization of the tibial tubercle, which was performed in conjunction with HTO for medial and PF compartment OA more than 10 years previously. The 42 subjects included 14 men (15 knees) and 26 women (27 knees). Their mean age at the time of surgery was 60.7 years, and the follow-up period was 10-15 years (average 12 years). Ventralization of the tibial tubercle was performed on 18 knees. Results. A significant relation was observed between improvement of the clinical knee score and preoperative radiological PF-OA stage in the HTO patients (P < 0.05). Radiologically, no correlation was observed between the shift in radiological PF-OA stage and the presence or absence of ventralization of the tibial tubercle. Among the preoperative radiological moderate and severe PF-OA cases, no significant relation was found between the presence or absence of ventralization of the tibial tubercle performed with HTO and improvement of the knee joint function score. Conclusion. In cases of severe PF-OA in which HTO was performed, ventralization of the tibial tubercle as combined surgery did not prove effective at the long-term follow-up.