Ankle joint fusion -- determination of optimal position by gait analysis.

The influence of the position of the ankle joint on the gait pattern was examined in 12 patients. All had stable unilateral tibio-talar arthrodesis for posttraumatic osteoarthrosis. Six were fused in 8 to 12 degrees of plantar flexion, six in neutral or calcaneus position. A total of 48 steps with and without shoes was analyzed and compared statistically with 24 steps on the normal side. After arthrodesis in equinus position, lower leg and knee take up an unfavourable position before heel-off, with the result that the center of gravity is elevated more than normal. This is particularly the case barefoot but is also observed when shoes are worn. On the basis of gait evaluation, ankle joint arthrodesis should be performed in the neutral position for both men and women.