Assessment of the impact of prosthetic foot support flexibility on gait in a patient after lower limb amputation at thigh level

Abstract

Objective. The article presents the results of experimental studies, the main objective of which was to determine how the degree of flexibility of the lower limb prosthesis support system impacts the pattern of secondarily learned gait in a patient after amputation. Material and methods. The study was carried out on a patient (35-year-old man) after lower limb amputation at the level of 1/3 of the proximal femur, who followed a previously planned walking path. Inclusion criteria: gender F and M, amputation at 1/3 of the proximal femur, age below 40, traumatic amputation, average level of activity, use of a prosthesis for at least one year. Exclusion criteria: age over 40, amputations below 1/3 of the proximal femur, amputations for vascular reasons, activity level below average, use of a prosthesis for under one year. During the study, the patient was equipped with three support systems corresponding to three degrees of flexibility of the prosthetic foot (soft, medium, hard). Biomechanical data during gait was collected using FlexinFit by Sensor Medica for assessing the pressure between the foot and the inside of the shoe. Results. In the entire gait cycle, the support phase on the healthy limb was the longest. The hard support system generates the greatest asymmetry of the transferred loads between the limbs. In this support variant, the difference in load between the healthy limb and the amputated limb was 1,330 kg/m2, which represented an asymmetry of 21%. In terms of load distribution, the best support was medium support – medium support flexibility, for which the difference in load between the healthy limb and the amputated limb was 770 kg/m2, which was an asymmetry of 12%. Conclusions. When designing a prosthesis for people after lower limb amputation, it is crucial to correctly adjust its features to the individual needs of each patient (adjusting prosthesis kinematics, adjusting support system stiffness), so that gait is possibly closest to normal with low energy demand.