Total knee arthroplasty following high tibial osteotomy - a radiological evaluation

Abstract

The purpose of this study was to evaluate the results of total knee arthroplasty (TKA) following a closed wedge high tibial osteotomy (HTO). A total of 16 TKAs were performed in 16 pacients who had previously undergone a closed wedge (HTO) as a treatement for knee osteoarthritis. The radiographic results were evaluated with respect to the femurotibial angle (FTA), joint line height (JLH), tibial bone resection and Insall-Salvati ratio. The FTA improved in average, from 6.5 degree of varus preoperatively at 5.7 degree of valgus postoperatively. The JLH averaged 14.34 mm preop and 13.81 mm at the last follow-up. The amount of tibial bone resection averaged 5.98 mm, face to 7.5 mm for knees without HTO. The Insall-Salvati ratio was 1.127 preop and 1.172 postop. A meticulous surgical technique may lead to satisfactory results in TKA after HTO, considering the correction of the deformity, the re-estabilish of JLH and the amount of the tibial bone resection.

Keywords: knee arthroplasty; radiological evaluation; tibial osteotomy.

Figure 1. The JLH was measured from the fibular head on AP X ray view. The postoperative JLH was raised from the preoperative JLH

Figure 2. The amount of bone resection at the tibial plateau in TKA was measured on AP X ray view. "c" was defined as the shortest vertical distance between the fibular head and the lateral tibial plateau be­fore TKA. "d" was defined as the shortest vertical distance between the fibular head and the tibial cut sur­face at the last follow-up. The amount of bone resection at the tibial plateau in TKA was calculated as "c-d"

Figure 3. The ISR on the lateral view of the X-ray.The preoperative ISR is the ratio of the length of the patellar tendon to the length of the patella.The ISR at the last follow-up is the ratio of the length of patellar tendon to the length of the patella. Preoperativ ISR and I SR at the last follow-up were compared