500 Section - Comparison of the Effectiveness of Conventional prosthetic ankle and Microprocessor-Controlled Prostheses in Patients with Unilateral Transtibial Amputation

Objectives : The RoFT® microprocessor-controlled prosthetic ankle (MPA-2), the first MPA developed in South Korea, was designed to compensate for the loss of ankle plantar flexor function in transtibial amputees. This study aimed to compare the clinical performance of MPA-2 with a conventional prosthetic ankle (CPA) and an internationally used MPA (Meridium®, MPA-1). We evaluated whether MPA-2 provides biomechanical, functional, and patient-perceived benefits by assessing gait characteristics, metabolic energy expenditure, and user satisfaction in individuals with unilateral transtibial amputation.

Design: A multicenter randomized crossover controlled trial was conducted with 18 unilateral transtibial amputees at three hospitals. Participants used CPA, MPA-1, and MPA-2 in randomized order, each for a 2-week accommodation period with a 2-week CPA washout between MPAs. Assessments included three-dimensional gait analysis (spatiotemporal, kinematic, kinetic, and ground reaction forces), cardiopulmonary exercise testing (CPET), and the Korean version of the Prosthesis Evaluation Questionnaire (K-PEQ). Gait tests were performed at self-selected walking speed on a 10 m walkway, and CPET evaluated metabolic cost during treadmill walking.

Results: MPA-2 improved ankle kinematics and power generation, showing greater ankle range of motion, increased dorsiflexion in late stance, and markedly higher peak positive ankle power compared with CPA and MPA-1. Propulsion-related ground reaction forces were also higher with MPA-2, suggesting reduced compensatory hip effort. On the intact limb, peak vertical GRF was lower with MPA-2 than with CPA, indicating reduced joint loading. However, MPA-2 showed increased braking forces, likely related to its heavier weight. CPET parameters showed no significant differences. In the K-PEQ, MPA-2 scored better than CPA in clothing compatibility and sweat accumulation but was inferior in noise-related items.

Conclusion: MPA-2 promoted a more physiologic gait pattern with improved ankle mobility, propulsion, and reduced intact-limb loading. Despite increased braking forces, MPA-2 demonstrated meaningful functional and patient-reported advantages, supporting its clinical utility and further development.