The association between degenerative hip joint pathology and size of the gluteus maximus and tensor fascia lata muscles.

The aim of this study was to obtain, using Magnetic Resonance Imaging (MRI), muscle volume measurements for the gluteus maximus (upper: UGM and lower: LGM portions) and tensor fascia lata (TFL) muscles in both healthy subjects (n=12) and those with unilateral osteoarthritis (OA) of the hip (mild: n=6, and advanced: n=6). While control group subjects were symmetrical between sides for the muscles measured, subjects with hip joint pathology showed asymmetry in GM muscle volume dependent on stage of pathology. The LGM demonstrated atrophy around the affected hip in subjects with advanced pathology (p<0.05), however asymmetry of the UGM (p<0.01) could be attributed largely to hypertrophy on the unaffected side, based on between group comparisons of muscle volume. TFL showed no significant asymmetry, or difference compared to the normal control group. This study highlights the functional separation of UGM and LGM, and the similarities of the UGM and TFL, both superficial abductors appearing to maintain their size around the affected hip. Further research is required to determine the specific changes occurring in the deeper abductor muscles. This information may assist in the development of more targeted and effective exercise programmes in the management of OA of the hip.