Gait Assessment in the Transtibial Mercer Universal Prosthesis with “Neutral alignment”

Standardizing socket design and maintaining a default socket alignment in transtibial prostheses are innovations aiming to simplify fitting procedures and reduce prosthetic service costs—particularly in low-income countries. This study evaluated the Mercer Universal Prosthesis (MUP), which utilizes a standardized "neutral alignment" concept, in comparison to custom-made conventional prostheses (CVP). Twenty transtibial amputees (n=20) completed gait assessments using their existing CVP and immediately (< 1 hr) post-fitting with a new MUP. As a result, the MUP group reported a significant difference between prosthetic and intact limb both hip and knee kinematics (p<0.05) , but there was no change in the CVP group. When compared with MUP’s sound limb, post hoc analysis showed both hip flexion and hip range of motion (ROM) in the MUP’ prosthetic limb significantly increased by 5.70 and 7.30 (p=0.002 and p<0.001, respectively). Spatial and temporal gait parameters were comparable between the MUP and CVP groups, and gait symmetry showed no significant differences, indicating that prosthetic users maintained consistent gait mechanics across both devices. Notably, immediate acceptance of the MUP device by all participants highlights its feasibility and effectiveness in clinical practice.