Gait analysis and functional outcomes following ankle arthrodesis for isolated ankle arthritis.

BACKGROUND: The functional outcomes following ankle arthrodesis are not known. The purpose of the present study was to compare the intermediate-term clinical results for a group of patients in whom an ankle arthrodesis had been performed with use of modern surgical techniques with the findings for a group of healthy gender and age-matched controls on the basis of validated outcome measures and gait analysis.
METHODS: Twenty-six patients who had undergone ankle arthrodesis for the treatment of isolated unilateral ankle arthritis were identified and retrospectively assessed clinically and radiographically. The mean age at the time of surgery was fifty-four years, and the mean interval between surgery and assessment was forty-four months. A gender and age-matched control group of twenty-seven individuals was recruited for comparison. All subjects were evaluated with gait analysis, the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale, the Musculoskeletal Outcomes Data Evaluation and Management Systems (MODEMS) questionnaire, and the Ankle Osteoarthritis Scale (AOS).
RESULTS: On preliminary review, twenty of the twenty-six patients were completely satisfied or satisfied with their surgical outcome. All patients but one stated that they would undergo the surgery again. Five patients stated that they did not notice a gait abnormality. Twelve patients wore orthotics, and all believed that the use of the orthotics improved their gait. When the functional outcome scores in the arthrodesis group were compared with those in the control group, specific scores assessing hindfoot pain and satisfaction were similar. However, scores focusing on ankle-hindfoot function and disability revealed significant differences. Gait analysis also identified significant differences between the two groups with regard to cadence and stride length. In addition, there was significantly decreased sagittal, coronal, and transverse range of motion of the hindfoot and midfoot during the stance and swing phases of gait in the arthrodesis group. Radiographic review demonstrated that four of the twenty-six patients had development of moderate to severe arthritis of the subtalar joint.
CONCLUSIONS: In the intermediate term following an arthrodesis for the treatment of end-stage ankle arthritis, pain is reliably relieved and there is good patient satisfaction. However, there are substantial differences between patients and the normal population with regard to hindfoot function and gait. On the basis of these results, patients should be counseled that an ankle fusion will help to relieve pain and to improve overall function; however, it is a salvage procedure that will cause persistent alterations in gait with a potential for deterioration due to the development of ipsilateral hindfoot arthritis.