Asymmetry of the Center of Pressure During Gait After Amputation of Lower Limbs

Retrospective, non-randomized, observational, single-center longitudinal study at the University Rehabilitation Hospital of Grau du Roi CHU of Nîmes, France. From January 2012 to Janvier 2023 patients hospitalized for lower limb amputation, were extracted from the computer database of the motion analysis laboratory (2 baropodometric platforms, Zebris, Germany). All patients with lower limb amputations, unilateral or bilateral, walking with or without technical aids, were included regardless of the level (trans-femoral or trans-tibial). Only patients hospitalized in the locomotor rehabilitation department were included in the study. Patients who were not autonomous for walking and required a third person (human assistance) were not included. Finally, deceased patients were also excluded from the study population. Prior to data collection, all participants received a note of non-objection. The study was reported on the Health Data Hub, and data collection and analysis were performed according to the MR004 reference methodologies.

Walking amputee patients hospitalized in the locomotor rehabilitation department benefited from a systematic gait assessment before discharge from hospital after rehabilitation and validation of the prosthesis. During the gait analysis, on baropodometric platforms, the software provides a number of parameters: spatiotemporal, pressure distribution, vertical component of the ground reaction force and trajectory of the center of pressure. All patients were recorded over a distance of ten meters including the two meters of acceleration and deceleration according to the validity of the TM-10 for a duration of two minutes.

The parameters from the CoP trajectory are calculated from the coordinates calculated in the platform reference frame. A processing of these data will be specially developed within the service. Three key parameters of the COP have been retained: Lateral symmetry (LS; the left/right offset of the intersection point, where the "zero position" is equivalent to perfect symmetry), lateral variability (LV; the standard deviation of the intersection point in the lateral direction, where "zero" equals constant steps in terms of width between the legs), and anteroposterior variability (APV; the standard deviation of the intersection point in the anteroposterior direction, where "zero" equals constant strides while walking on the treadmill). These parameters, which allow for the assessment of continuous COP trajectories with multiple strides, reflect the overall movements of individuals throughout the gait cycle.