500 Section - Analysis of Biomechanical Changes in Unilateral transfemoral Amputees during Obstacle crossing with New-developed prosthetic Knee made in Korea

Objectives : The aim of this study was to evaluate the usability and stability of a newly developed mechanical polycentric knee prosthesis in Korea by comparing its biomechanical characteristics with those of a conventional knee prosthesis (CKP) during obstacle-crossing in unilateral transfemoral amputees.

Design: Five unilateral transfemoral amputees participated in this study. Each participant performed obstacle-crossing trials while wearing a CKP and the newly developed prosthesis (FIRST K1). Wooden obstacles (10 cm height/thickness, 1 m width) were crossed leading with the intact limb. Spatiotemporal, kinematic, kinetic, and ground reaction force (GRF) data were collected using a 3D motion analysis system (Motion Analysis®).

Results:

With the FIRST K1, the vertical toe-to-obstacle distance and the horizontal heel-to-obstacle distance significantly increased (p< .05), indicating increased clearance. In kinematic parameters, the maximal hip and knee flexion angles of the amputated limb increased significantly (p< .05). Conversely, maximal knee flexion and ankle dorsiflexion angles of the intact limb decreased (p< .05), suggesting reduced compensatory movement. Trunk ipsilateral rotation, anterior pelvic tilt, and ipsilateral pelvic drop and rotation also increased significantly (p< .05). GRF analysis showed no significant change in impact loading of the amputated limb, whereas impact load of the intact limb increased (p< .05).

 

Conclusion: The newly developed mechanical polycentric knee prosthesis (FIRST K1) increased swing-phase knee flexion and improved foot-obstacle clearance, supporting safer and more stable obstacle-crossing. These findings suggest that the FIRST K1 may enhance mobility and stability for transfemoral amputees and contribute to improved daily activity and quality of life. Further research with larger samples and long-term follow-up is needed to evaluate prolonged use and investigate associated muscle activation patterns.