[Plastic surgery of the ligament for chronic lateral instability of the ankle].

Ten patients with chronic lateral instability of the ankle have been treated by operation using a homograft of preserved skin and scar tissue to reinforce the lateral ligament complex. The technique is simple and cheap. We have analysed the functional stability of the ankles after operation by E. M. G. and Cybex studies of the appropriate muscle groups when standing on an unstable platform and during normal gait. The passive tension of the ligaments is of greater value in stabilising the ankle than active contraction of the muscles. The peroneus brevis has an important action in opposing varus stress, and should be preserved rather than used for ligament substitution.