Hip abductor muscle activity as subjects with hip prostheses walk with different methods of using a cane

Abstract

Background and Purpose. Using a cane held contralateral to a prosthetic hip is presumed to be an effective way to reduce the demands on the hip abductor (HA) muscles and, therefore, the forces on the implant. In this study, surface electromyographic (EMG) activity was measured from the HA muscles to test this notion. Subjects. Twenty-four active subjects (9 female, 15 male) with unilateral prosthetic hips were tested. The subjects, aged 40 to 86 years (X̄=63.3, SD=10.7), were not regular cane users. Methods. Surface EMG activity and cane force were analyzed while the subjects walked with the cane held (1) contralateral to the prosthesis (CL-CANE), (2) ipsilateral to the prosthesis (IL-CANE), and (3) contralateral to the prosthesis with instructions for the subject to push with a 'near-maximal effort' (CL-CANE+). Results. Only the following conditions showed a change in HA muscle EMG activity as compared with not using a cane: CL-CANE=-31.1%, CL- CANE+=-42.3 %. Conclusion and Discussion. Holding the cane contralateral to the prosthetic hip appears to be an effective method of reducing demands on the HA muscles.