Upper limb loadings of gait with crutches.

Long-term crutch users and patients with arthritis are particularly susceptible to upper limb joint degeneration during aided gait. The function of the walking aid for stability, support, and restraint/propulsion must be optimized with the upper limb loadings caused by the aids. Post-operative total hip replacement (THR) patients, tibial fracture, and paraplegic subjects using sticks and elbow crutches were analyzed in this study. Elbow and shoulder joint centers and aid orientations were monitored simultaneously in three dimensions and combined with aid forces to determine upper limb moment loadings. Three loading effects were observed: tendency for the aids to cause 1) the elbow to flex and shoulder to extend, 2) the elbow and shoulder to extend, and 3) the shoulder to abduct. Moment values of up to 0.10 Nm per body weight (BW) causing the shoulder to extend were measured, i.e., of similar magnitude to the moments at the hip in unaided gait. A modification of the elbow crutch, designed to improve medial-lateral stability, was unsuccessful in use due to wrist instability. This reinforced the requirement that crutch designs integrate the aid's function in gait with the ability of the upper limb joints to balance the applied loads.