Clinical and Biomechanical Evaluation of an Adaptive Polyarticulated Myoelectric Hand Prosthesis: A Case Report

Introduction: Adaptive polyarticulated myoelectric hands aim to improve grasp versatility and intuitiveness of use; however, objective clinical and biomechanical evidence supporting their functional impact remains limited. Case presentation: A 75-year-old right-hand-dominant male with a long-standing transradial traumatic amputation and over 30 years of experience with a myoelectric tridigital prosthesis underwent experimental evaluation of an adaptive polyarticulated myoelectric hand (Adam’s Hand®). Methods: Assessment included patient-reported outcome measures (Orthotics and Prosthetics User Survey—Upper Extremity Functional Status (OPUS-UEFS), Trinity Amputation and Prosthesis Experience Scales–Revised (TAPES-R), Disabilities of the Arm, Shoulder and Hand questionnaire (DASH), Short Form Health Survey 36 (SF-36)), standardized performance-based functional tests (Minnesota Manual Dexterity Test (MMDT), Box and Block Test (BBT), Southampton Hand Assessment Procedure (SHAP)), and laboratory-based biomechanical evaluation using optoelectronic motion capture and surface electromyography during Pointing, Hand-to-Mouth, and Grasping tasks. The adaptive prosthesis was tested after rapid artificial intelligence-based calibration, without structured training. Results: Patient-reported outcomes reflected high satisfaction and adaptation to the habitual prosthesis. Performance-based tests favored the habitual device in speed and dexterity, whereas the adaptive hand enabled additional grasp patterns. Biomechanically, the adaptive hand was smoother and faster during reaching, but less stable during grasping. Compensatory trunk and shoulder movements occurred with both devices, with a trend toward less compensation during reaching with the adaptive hand. Conclusions: This case highlights a task-dependent biomechanical profile of an adaptive polyarticulated myoelectric hand under first-use conditions. Rapid calibration may support immediate use for reaching, while optimal grasp control appears to require structured training.