Introduction: High tibial osteotomy is an established procedure for the mid-term treatment of unicompartmental osteoarthritis of the knee, especially in young patients. Nevertheless, its performance at the proximal end of the tibia, close to the site of insertion of the extensor mechanism of the knee, might produce anatomic alterations of the latter, which, in turn, could influence the final result.
Aim: The purpose of the present retrospective study is the radiologic evaluation of the anatomic changes of the extensor mechanism of the knee, caused by high tibial valgus osteotomy (closed-wedge step osteotomy, with internal fixation).
Material – Method: For this purpose we studied the X-rays of 44 kness (pre-op, p-op and 1 year p-op) that had undergone the above procedure. The assessed variables were the horizontal and vertical shift of tibial tubercle as well as the position of the patella (patellar vertical height, Linclau, Caton).
Results: We didn’t find any statistically significant difference of the postoperative position of the patella with respect to the preoperative one (p=0.88), whereas there was definite proximal and anterior shift of the tibial tubercle in a statistically significant degree (p<
0.01) with respect to the preoperative situation.
Conclusions: The certain type of high tibial osteotomy seems to impart an unloading effect on the patellofemoral joint (due to the anterior shift of the tibial tubercle). On the contrary, the vertical shift of the tibial tubercle seems to have no effect to the postoperative position of the patella.