Objective: The aim of this study was to test the hypothesis that hip muscle function (strength and endurance) improves after total hip arthroplasty and is important for minimizing limping gait.
Design: Fifty-two patients who underwent total hip arthroplasty were assessed before and 6 mos after receiving a unilateral total hip endoprosthesis (Adaptiva stem with a Harris-Galante acetabular component). Severity of limping was assessed using a 4-point ordinal scale. Pain was assessed using a standardized ordinal scale. Eccentric, concentric, and isometric muscle strength and endurance of the hip extensors, flexors, adductors, and abductors were measured using a dynamometer.
Results: Postoperative limping severity and pain were significantly lower and postoperative muscle strength and endurance were significantly higher than the preoperative values (P < 0.05). The association between impaired muscle strength and endurance and limping severity was stronger postoperatively than preoperatively. This association was stronger for the hip extensor and flexor muscles than for the hip adductor and abductor muscles. Pain level was not associated with postoperative limping severity.
Conclusions: Hip extensor and flexor muscle strength and endurance seem to be relevant for minimizing postoperative limping in patients after total hip arthroplasty. Rehabilitation programs should include exercises aimed at improving hip extensor and flexor strength and endurance to improve gait function.