Design of prosthetic components for skiing: a preliminary study

Introduction: Prostheses are fundamental for daily living and to allow participation in sport. However, current components may not optimize the skiers' center of mass (COM), resulting in poor control and balance. This may explain why transfemoral prosthesis users often choose to ski without prostheses.

Materials and Methods: Existing literature on skiing biomechanics, skiing with limb loss, and the available prosthetic componentry for skiing was examined. Normal biomechanics were ascertained for comparison with an able-bodied skier and 2 two-track skiers using transfemoral prostheses. Laser posture (LP), body segment parameters (BSPs), and pressure-sensitive insoles (PSIs) were compared to determine an appropriate method for calculating the COM in skiers while on the slopes. One able-bodied skier and two skiers with transfemoral amputation were filmed skiing through a set course. The participants wore markers to aid in joint location and help determine the skier's rotation. The footage was analyzed using video analysis software (Siliconcoach) to compare joint angles. The COM for each participant was compared by calculating BSPs.

Results: The results indicated that available prosthetic knee joints do not achieve comparable biomechanics to ablebodied skiers.

Conclusions: Current prosthetic knees designed to resist flexion for high activity resulted in two-track skiers having difficulty when flexing the knee during the inside of the turn. In addition, it was found that increasing the knee flexion resulted in posterior translation of the COM, which can lead to poor ski control.