Abstract
How do we treat severe knee OA with bowing deformity of tibia after malunion. Correction osteotomy with TKA was usually performed. However, there were risks of severe several complications. This is a case report of the patient received TKA didn't accept the risks of correction osteotomy.
74 year-old- lady consulted our clinic with chief complains of left knee pain and disability of walking. Her left knee pain began 20 years ago without any episodes. Her walking ability getting worse gradually in these 5 months. However, she have been received conservative treatment. She suffered left tibia fracture and received ORIF at age 21. Her course of after the surgery was not satisfied with infection. Finally her tibia achieved union. However, her tibia demonstrated bowing and shortening with varus deformity.
Her knee joint also demonstrated varus deformity with ROM 95(ext. −20, flex. 115). There were pressure pain at the medial joint space, demonstrated varus-valgus instability. Roentgenograms showed severe OA with defect of medial tibial condyle (Fig.1) and malunion of the tibia with bowing deformity. Mechanical FTA angle was 151 degrees (Fig.2). Deformity angle of the malunion tibia was 25 degrees.
Severe knee OA with tibia deformity was indication of TKA with correction tibial osteotomy. We proposed TKA with correction tibial osteotomy for her. We also explain risks and benefits of the surgery for her. She didn't want osteotomy for risks of infection and non-union, she decided that she receive only TKA. We planned TKA with tibial extension stem and fix with tilting position in the tibia shaft using bone cement. TKA was performed the same as planning (Fig.3). Her leg alignment corrected good position with ROM 125 (ext. 0, flex. 125) at follow-up.
It was recommended that TKA for severe deformity without correction osteotomy is generally performed under 20 degrees of the correction angle. Our case was out of indication for this point of view. However, precise check of the pre-surgical roentgenograms could get solution of the difficult surgery. We are thinking of longevity of the implants because of unexpected stress, so we should need long follow–up of this case.
