The effects of a semi-rigid soled shoe compared to walking barefoot on knee adduction moment

On a background of literature suggesting that certain rigid soled shoes may increase the knee adduction moment during gait this study was performed to look at specific postoperative shoe - the Medishoe. This shoe is used on a daily basis in a district general hospital orthopaedic department for patients post-operatively to protect wounds and fixations.

Using force plates and an opto-electronic motion capture system with retroreflective markers the knee adduction moment was estimated in ten healthy subject both with and without the shoe during normal gait. The angle at which the ground reaction acted with respect to the ground in the coronal plane as well as the tibiofemoral angle were also calculated using the Qualsys software - both with and without the Medishoe.

Two-tailed paired t-tests using a 95% confidence interval showed that there was no significant difference between the two groups in the estimated knee adduction moment (p = 0.238), tibiofemoral angle (p = 0.4952) and the angle of the ground reaction force to the ground (p = 0.059).

There was no significant difference in the estimated knee adduction moment between the two groups, although there was a statistical trend to an alteration in the angle of the ground reaction force. Further work involving a greater number of subjects and a three dimensional model would further answer the question as to whether these or other post-operative shoes have a significant effect on the knee adduction moment.