Assessment of Dynamic Stability During Walking in Below-knee Amputation

Purpose: Dynamic stability reduces in patients with unilateral amputation; so, it is important to recognize changes in balance during walking. This study aimed to investigate the dynamic stability of unilateral below-knee amputation during walking. Methods: The present study was a quasi-experimental study, in which 10 patients with knee amputation and 10 healthy young people participated. The variables of the present study included spatiotemporal variables, center of mass (COM) variables in anteroposterior, and mediolateral directions, as well as stability margin variables in anteroposterior and mediolateral directions. The COM and marginal stability variables were extracted through Visual 3D software. The data were analyzed by independent and dependent t-tests, using SPSS V. 22 at a significance level of 0.05. Results: The mean difference between COM and the COP in the amputation group in the frontal plane on both sound and prosthetic sides was significantly higher than those in the healthy group (P=0.01). The difference in COM and COP in the toe-off phase of the amputation group in the sagittal plane on the prosthetic side was significantly less than that in the healthy group (P<0.01). Conclusion: The amputees suffer from poor dynamic stability during walking; so, they increase the positive margin of stability in the frontal plane and decrease the negative margin of stability in the sagittal plane. These patients decreased the excursion of COM in the sagittal and frontal plane, thereby using different gait patterns. However, the threats of falling in these patients are more than that of the healthy ones. Therefore, it is recommended to improve the dynamic stability of these patients in the frontal plane.