High hip center arthroplasty in the treatment of severe hip dysplasia: Are knee and ankle compromised?

ABSTRACT

BACKGROUND: There is limited information about the effect of hip center location on gait parameters of knee and ankle. This study aimed to compare anatomical vs. high hip center arthroplasty according to gait parameters of knee and ankle and investigate whether the high hip center has any adverse effect on these joints or not. METHODS: 20 patients who underwent unilateral total hip arthroplasty (Group 1; 10 patients with anatomical reconstruction, Group 2; 10 patients with high hip center) due to Crowe type III-IV developmental dysplasia of the hip and completed 2 years of follow-up were included. The patients were examined by 3-D gait analysis. FINDINGS: The maximum extension of the knee on the operated side was lower in Group 2 (p = 0.044). Longitudinal knee joint force was higher in Group 2 on both operated (p = 0.041) and non-operated sides (p = 0.031). Lateral knee joint force was also higher in Group 2 (p = 0.023). No significant difference was detected in ankle parameters. INTERPRETATION: Unilateral high hip center has been shown to restrict the dynamic knee range of motion on the operated side and increase the knee load on both sides, thus putting the knees at risk for osteoarthritis. LEVEL OF EVIDENCE Level III, Retrospective comparative study.