Abstract
Aim
This controlled study uses gait analysis to evaluate patients' pre- and post-ankle arthroplasty, post-ankle arthrodesis and compares the results with a healthy control group to assess whether these theoretical benefits are borne out in clinical practice.
Method
Five patient groups (arthrodesis, arthroses, arthroplasty after 6 and 12 months and control) each consisting of 12 patients were analysed in our gait laboratory and the following parameters obtained at two different walking speeds: velocity, cadence, step length, stride length, the timing of toe off and the duration of stance phase. In addition, the ground reaction force during the whole gait cycle was recorded, as well as the range of movement of the knee and of the foot in relation to the tibia in walking and functional tests.
Results
Subjects who had undergone arthrodesis were able to go faster with a longer step length on the affected side than their counterparts with an ankle prosthesis. However, this gain seemed to be at the expense of a symmetrical gait pattern and increased knee movement. Ankle prostheses also produced a stance phase and ground reaction force that was closer to the control group in duration and timing and also a more symmetrical timing of toe off.
Discussion
Overall, our data supports the clinical observation that the gait pattern after total ankle replacement is more symmetrical with a less pronounced limp than in ankle arthrodesis. It is hoped that this will lead to decreased strain on neighbouring joints; however, the long term benefit of this is not yet established. It is not yet clear whether the long term implant survivorship of total ankle replacement is of sufficient duration to justify this unproven benefit.
