Quantitative Measurements of Hip Abductor Muscle Strength After Total Hip Arthroplasty Using the Direct Lateral Approach: Recovery of the Abductor Strength in Total Hip Arthroplasty

Twelve osteoarthritic female patients with unilateral involvement underwent total hip arthroplasty (THA) using the direct lateral approach (DLA). After discharge, a home program of isometric muscle exercises on both sides of the hip was prescribed for 6 months. Clinical evaluation and measurement of the strength of hip abductor muscles were performed at 6 months, 1 and 2 years postoperatively. Statistically significant improvement in the Merle d' Aubigne hip score was obtained at 6 months postoperatively, but the recovery of hip abductor muscle strength was slightly delayed. The ratio of peak torque of abductor muscles in the operated hip to that in the non-operated hip was 68.6 ± 31.4% preoperatively and reached 77.8 ± 31.4% at 6 months, 91.5 ± 21.2% at 1 year, and 93.4 ± 20.8% at 2 years postoperatively. Our results indicate that the DLA does not have a deleterious effect on recovery of the abductor muscle strength.