Assessment of hip abductors by MRI after total hip arthroplasty and effect of fatty atrophy on functional outcome

Abstract

Objectives
The aim of this study was to evaluate how fatty atrophy (FA) of the hip abductors in operated and non-operated hips affected the functional outcome following arthroplasty.
Methods
Forty-four hips of 22 patients (8 males and 14 females; mean age: 60?±?14.4 (range: 24–84)) who matched the inclusion criteria and willing to participate in the study were retrospectively evaluated. The mean follow-up was 13.8?±?2.3 (range: 10–18) months Magnetic resonance imaging (MRI) and Harris Hip Score (HHS) were used to evaluate muscle degeneration and functional outcome after unilateral THA through a posterolateral approach. The FA grade was evaluated using Goutallier grading system. Non-operated hips of subjects were used as the control. Age, duration after the operation, gluteal muscle FA, and the relationships with HHS were evaluated.
Results
FA was more evident in the operated hip (p??0.05), whereas there was a positive correlation with the contra-lateral hip (p?Conclusion
Following THA, there was marked FA in the operated hip compared to that in the contralateral hip. In these cases, degree of FA in the replaced hip did not correlate with patients' age. Fatty atrophy of the gluteus minimus precedes that of gluteus medius. FA of the contralateral gluteus minimus and patient age are strongly correlated with lower HHS. Level of evidence: Level IV, diagnostic study.
Level of evidence
Level IV, diagnostic study.
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