Total knee arthroplasty following closed wedge high tibial osteotomy

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 13 patients who had previously undergone a closed wedge HTO. The clinical results were reviewed using the Hospital for Special Surgery (HSS) score. The radiographic results were evaluated with respect to the femorotibial angle (FTA), joint line height (JLH) and tibial bone resection. The average HSS score before TKA was 63.6, which improved to 92.8 at the last follow-up. The FTA averaged varus 0.9 preoperatively and valgus 5.7 at the last follow-up. The JLH averaged 13.9 mm preoperatively and 15.6 mm at the last follow-up. The amount of tibial bone resection averaged 4.8 mm. A meticulous surgical technique can produce satisfactory results in TKA after HTO, considering the correction of the deformity, JLH and the amount of the tibial bone resection.

Fig. 1

The JLH was measured from the fibular head on the anteroposterior view of the X-ray. The anatomical position of the lateral joint line was re-established with minimal resection of the lateral tibial bone and enough thickness of polyethylene insert usage. The postoperative JLH (b) was raised from the preoperative JLH (a)

Fig. 2

The amount of bone resection at the tibial plateau in TKA was measured radiographically on the anteroposterior view of the X-ray. “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”

Fig. 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 and is denoted by LT/LP. The ISR at the last follow-up is the ratio of the length of patellar tendon to the length of the patella and is denoted by LT’/LP’. Preoperative ISR and ISR at the last follow-up were compared (correlation analysis)

Fig. 4

a The preoperative roentgenograms of the left knee of a 63-year-old woman with a prior history of HTO 18 years earlier showed joint space narrowing and a varus deformity. JLH was 14.5 mm and ISR was 0.95. b This patient underwent TKA under navigation control. The X-rays taken at the last follow-up show good alignment and a restoration of the JLH. The JLH was 15.2 mm and ISR was 0.91. The amount of tibial bone resection was 3.0 mm