Static and dynamic postural balance after successful mobile-bearing total ankle arthroplasty.

Abstract

To investigate static and dynamic postural balance after successful total ankle arthroplasty by using dynamic posturography. A controlled trial study. A national university orthopedic and rehabilitation hospital. Patients (n=30, 21 men, 9 women; mean age, 58y) and age- and sex-matched healthy controls (n=30). Thirty patients who underwent unilateral total ankle arthroplasty with a cementless mobile-bearing ankle prosthesis and 30 age- and sex-matched healthy control subjects were included. Using computerized dynamic posturography, sensory (sensory organization test [SOT]), and motor (limit of stability [LOS], rhythmic weight shift [RWS], and weight bearing) impairment assessments were performed at an average of 15 months after total ankle arthroplasty. In the SOT, results of the SOT-2 test reflecting mainly proprioception showed no significant difference between patients and controls, but patients demonstrated significantly lower scores for SOT-4, -5, and -6 as a measure of dynamic postural balance and required more hip movement to maintain balance. In the motor-control tests, patients showed significantly lower measures in indices of LOS test except the mean reaction time and the forward/backward directional control and on-axis velocity of the RWS test. Weight bearing was observed asymmetrically in patients. Patients had a higher degree of dynamic postural imbalance and relied less on ankle strategy to maintain balance than controls. Also, patients showed the deficit of motor control ability as compared with age- and sex-matched healthy controls.