How does the level of lower limb amputation affect spatiotemporal gait asymmetry and cautious gait criteria to inform tailored rehabilitation interventions? A retrospective study analyzing gait patterns in individuals with unilateral lower limb amputations. 49 amputees (22 (45 %) transtibial, 27 (55 %) transfemoral) compared to 30 healthy controls, evaluated between January 2018 and June 2023. INTERVENTION PARTICIPANTS: performed a spontaneous walking speed test on a pressure mat (Zebris® FDM 2 & 3 System, 100 Hz, v 1.18.44, GmbH, Isny, Germany) after completing rehabilitation. Gait symmetry and cautious gait were assessed using spatio-temporal parameters, center of pressure (CoP) displacement, and foot segment forces. Increased asymmetry was observed in stance phase duration, step length, stance duration, and walking speed (95 % CI 0.398-0.658) depending on the level of amputation. Transfemoral amputees showed significant increases in step width (95 % CI 0.201-0.512), double support phase (95 % CI 0.000-0.150), and medio-lateral CoP displacement (95 % CI 0.039-0.326). The increased asymmetry in spatio-temporal parameters suggests different compensation strategies between transfemoral and transtibial levels. These differences highlight the importance of the rehabilitation paradigm in managing asymmetry and its underlying compensations during locomotor activities. The level of amputation significantly impacts gait asymmetry and cautious gait parameters. Transfemoral amputees exhibit more pronounced cautious gait characteristics, likely due to the need for greater stabilization. These findings underscore the importance of personalized rehabilitation to address specific compensations and gait abnormalities based on amputation level.

To test a novel instrumented knee brace intended for use as a rehabilitation system, based on inertial measurement units (IMU) to monitor home-based exercises, the device was compared to the gold standard of motion analysis. The purpose was to validate a new calibration method through functional tasks and assessed the value of adding magnetometers for motion analysis. Thirteen healthy young adults performed a 60-second gait test at a comfortable walking speed on a treadmill. Knee kinematics were captured simultaneously, using the instrumented knee brace and an optoelectronic camera system (OCS). The intraclass correlation coefficient (ICC) showed excellent reliability for the three axes of rotation with and without magnetometers, with values ranging between 0.900 and 0.972. Pearson’s r coefficient showed good to excellent correlation for the three axes, with the root mean square error (RMSE) under 3° with the IMUs and slightly higher with the magnetometers. The instrumented knee brace obtained certain clinical parameters, as did the OCS. The instrumented knee brace seems to be a valid tool to assess ambulatory knee kinematics, with an RMSE of <3°, which is sufficient for clinical interpretations. Indeed, this portable system can obtain certain clinical parameters just as well as the gold standard of motion analysis. However, the addition of magnetometers showed no significant advantage in terms of enhancing accuracy.

Human locomotion relies on a proximal–distal organization of joint mechanical work that adapts to task constraints, such as those imposed by inclined walking. In individuals with transtibial amputation, loss of the biological ankle disrupts this organization, leading to proximal alterations and inter-limb asymmetries. Active mechatronic prosthetic feet have been developed within a biomechanical biomimicry framework to restore distal positive mechanical work. This exploratory study quantified the effects of an active mechatronic prosthetic foot on joint mechanical work during inclined walking. Four individuals with transtibial amputation performed instrumented treadmill walking at −3°, 0°, and +3° using their habitual passive foot and a powered foot. Positive and negative mechanical work at the ankle, knee, and hip were computed using inverse dynamics and compared with a normative reference database (n = 20). The powered foot induced modest, task-dependent modifications, mainly at the ankle and knee. In downhill walking, it promoted a more symmetrical redistribution of negative mechanical work, particularly at the knee, suggesting a partial reduction in contralateral overload. In uphill walking, distal assistance increased prosthetic-side positive work, reflecting slope-dependent reallocation rather than normalization. Although a multivariate deviation score indicated reduced deviation under the powered condition, full convergence toward the asymptomatic organization was not achieved.