Does Wearable Crutch Walking Excessively Load the Hip Joint?

Abstract

PURPOSE: As an alternative to using traditional axillary crutches for non-weightbearing, the use of a wearable crutch has been associated with better functional outcomes. However, hip and back pain have been reported as side effects. This may be due to the reduced ability of the lower extremity to attenuate ground reaction forces. The primary objective was to compare compressive forces at the hip between wearable crutch walking, normal walking and axillary crutch walking. It was hypothesized that hip forces would be higher with wearable crutch walking compared with normal walking and axillary crutch walking. METHODS: Three-dimensional kinematics and ground reaction forces were measured in 12 healthy subjects (11 men, 1 woman, age 36±10 yr) during normal gait, axillary crutch ambulation and wearable crutch walking (iWalk 2.0). Hip and trunk range of motion, as well as peak vGRF and peak hip and low back compressive force during the stance phase, were compared for the three conditions using repeated-measures ANOVA. RESULTS: Gait speed while wearing the wearable crutch was reduced 44% compared to normal gait and 33% compared to crutch ambulation (P < 0.001). Frontal and sagittal plane hip range of motion were both significantly reduced during both crutch conditions compared to normal gait (P<0.001). Trunk range of motion in both planes was greatest during wearable crutch walking compared to both normal gait and crutch ambulation (P<0.001). Peak vGRF while wearing the hands-free crutch was 12% lower than normal gait (P<0.001) and 30% lower than crutch ambulation (P<0.001). Peak compressive hip force during wearable crutch walking was 11% lower than during normal walking (P = 0.026) and 30% lower than during axillary crutch walking (P<0.001). Low back compressive force during wearable crutch walking was 18% higher than during normal walking (P=0.03) but not different than during axillary crutch walking (1.4 % difference P>0.05) CONCLUSIONS: Despite a reduction in the shock-absorbing ability of the lower extremity, vGRF and compressive hip forces were not increased during wearable crutch walking. Although low back compressive force did increase with this device, it did not exceed the forces during axillary crutch walking. Therefore, the wearable crutch seems to be safe for patients who are required to be non-weightbearing.