Abstract
Coxitis knee is a condition defined as osteoarthritis of the knee due to ipsilateral or contralateral hip disorder. Although adduction contracture of the hip and leg length discrepancy have been regarded as the main causes, little is known of the influence of bilateral involvement of the hip joint. The aim of this paper is to report our experience of total knee arthroplasty (TKA) in treatment of coxitis knees and to discuss the pathomechanism and therapeutic strategy for this condition. Four coxitis knees with valgus deformity were treated by TKA or revision TKA. Two knees had adduction contractures of the ipsilateral hip and were treated with total hip arthroplasty (THA) followed by TKA. In the other two knees, a functional leg length discrepancy (a seemingly long leg) caused by Trendelenburg gait was implicated as the main cause. This was due to contralateral THA loosening, and they were treated by TKA or revision TKA followed by contralateral revision THAs. Constrained revision TKA implant was necessary in one knee. Coxitis knee should be treated with careful analysis of the pathomechanism of the knee deformity and the whole lower limb function.