Clinical outcomes of total knee arthroplasty for valgus knees caused by hip diseases: Coxitis knees and long leg arthropathies

Purpose

Coxitis knees and long leg arthropathies are similar pathological conditions; however, their clinical outcomes after total knee arthroplasty (TKA) have rarely been reported. The present study aimed to investigate clinical outcomes after TKA for these knee conditions, namely valgus knees caused by hip disease.

Methods

This retrospective cohort study included 19 TKAs performed on valgus knees caused by hip osteoarthritis (OA). Two years post-operatively, clinical outcomes, including range of motion and 2011 Knee Society Score (2011KSS), were assessed and were compared with pre-operative values. Pre-operative knee phenotypes, including lateral distal femoral angle and medial proximal tibial angle, were assessed, and their associations with clinical outcomes were investigated.

Results

All subscales of the 2011KSS improved significantly post-operatively (P ​< ​0.05). There was also a significant improvement in extension post-operatively (P ​< ​0.05). The mean femorotibial angle improved post-operatively from 157.7° to 175.2°(P ​< ​0.05). There were five coxitis knee patients who had knee OA on the ipsilateral side of the hip, and five long leg arthropathy patients who had knee OA on the contralateral side of the hip.

Conclusions

Satisfactory clinical outcomes were observed after TKA for valgus knees caused by hip OA, such as coxitis knees and long leg arthropathies.