Effects of ankle arthrodesis on functioning of the knee and hip joints during walking at natural velocity

Background: Ankle arthrodesis is probably still the safest method of treating painful, lesioned ankle in patients with rheumatoid arthritis or osteoarthritis with significant symptoms that do not respond to conservative treatment. The aim of this study was to present the effects of the ankle arthrodesis on correct functioning of the knee and hip joints during walking at natural velocity.Materials and methods: The study was conducted in the Biokinetics Laboratory of the Academy of Physical Education in Kraków. Fourteen patients with ankle arthrodesis, aged from 34 to 66 years (mean: 54 years), were enrolled into the study and participated in the testing sessions. Angular changes of the knees and hips in three planes of movement during particular gait phases were evaluated by a three–dimensional motion analysis system: Vicon®. The results of locomotion analysis were compared to a control group that consisted of thirty healthy persons aged 40–60 years.Results: Significant differences in the movement of the knees and hips in the three planes of motion were observed between the two groups. In the frontal plane, knees moved symmetrically, but during all the gait phases, knees were in a significant valgus deformity. In the transversal plane, knees were in a significant external rotation during all gait phases. In the saggital plane, hips moved with limited extension. There was also a significant external rotation, outside the biomechanical normal range, of both hips in the transversal plane.Conclusions: The most significant deviations from the biomechanical normal range were found in the frontal and transversal planes for knees and in the saggital and transversal planes for hips.