Dynamic hip stability,strength and pain before and after hip abductor strengthening exercises for patients with dysplastic hips

PURPOSE: We compared the dynamic instability of dysplastic hips using a triaxial accelerometer before and after abductor muscle strengthening exercises to determine if such exercises could achieve improvements in hip pain and associated symptoms.

METHODS: We evaluated 17 hips in 17 female patients with a mean age of 37 years who presented with hip joint symptoms and acetabular dysplasia. At the initial diagnosis, we used a triaxial accelerometer to measure dynamic instability of the hip during walking. Patients were taught how and instructed to perform abductor muscle strengthening exercises for 3 months. After this time, we re-measured. we compared these values before and after exercise.

RESULTS: The average abductor muscle strength improved from 104.4± 35.4 N to 124.3 ± 35.9 N after exercise, an improvement of approximately 16%. The overall magnitude of acceleration significantly decreased from 2.40 ± 0.34 m/s $^{2}$ at pre-exercise to 1.82 ± 0.28 m/s $^{2}$ at post-exercise (p < 0.0001). The VAS also significantly improved (p=0.0005). In all cases, hip joint symptoms were significantly improved by the performance of the studied abductor muscle strengthening exercises.

CONCLUSIONS: Using a triaxial accelerometer, we have shown that instability of the hip during walking can be improved by abductor muscle strengthening exercises.