Shoulder Range of Motion Rehabilitation Robot Incorporating Scapulohumeral Rhythm for Frozen Shoulder

2025-04-14

AI Summary

Compensatory shoulder elevation during passive rehabilitation of adhesive capsulitis (frozen shoulder) compromises therapeutic efficacy. Method: This study proposes a 6-degree-of-freedom shoulder rehabilitation robot featuring a novel single-degree-of-freedom scapular press mechanism—the first to actively suppress scapular elevation and other compensatory motions in robotic rehabilitation. Integrating contralateral motion recording and playback control, we develop a biomechanics-informed scapulohumeral rhythm (SHR) coordination algorithm and a personalized two-phase operation paradigm. Results: Experimental evaluation demonstrates motion playback RMSE < 1°; under simulated frozen shoulder conditions, the system significantly delays onset of compensatory shrugging and improves adherence of affected-side abduction/flexion trajectories to normative SHR patterns. This work establishes a novel paradigm and key enabling technologies for precise, rhythm-aware passive rehabilitation of adhesive capsulitis.

Technology Category

• Intelligent Robots: Manipulation
• Planning, Routing, and Scheduling: Replanning and Plan Repair
• Cognitive Modeling & Cognitive Systems: Adaptive Behavior

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: Fairness-aware retrieval and ranking
• Search and Retrieval-Augmented AI: Personalized, context-aware and across-device search

Abstract

This paper presents a novel rehabilitation robot designed to address the challenges of passive range of motion (PROM) exercises for frozen shoulder patients by integrating advanced scapulohumeral rhythm stabilization. Frozen shoulder is characterized by limited glenohumeral motion and disrupted scapulohumeral rhythm, with therapist-assisted interventions being highly effective for restoring normal shoulder function. While existing robotic solutions replicate natural shoulder biomechanics, they lack the ability to stabilize compensatory movements, such as shoulder shrugging, which are critical for effective rehabilitation. Our proposed device features a 6 degrees of freedom (DoF) mechanism, including 5 DoF for shoulder motion and an innovative 1 DoF Joint press for scapular stabilization. The robot employs a personalized two-phase operation: recording normal shoulder movement patterns from the unaffected side and applying them to guide the affected side. Experimental results demonstrated the robot's ability to replicate recorded motion patterns with high precision, with root mean square error (RMSE) values consistently below 1 degree. In simulated frozen shoulder conditions, the robot effectively suppressed scapular elevation, delaying the onset of compensatory movements and guiding the affected shoulder to move more closely in alignment with normal shoulder motion, particularly during arm elevation movements such as abduction and flexion. These findings confirm the robot's potential as a rehabilitation tool capable of automating PROM exercises while correcting compensatory movements. The system provides a foundation for advanced, personalized rehabilitation for patients with frozen shoulders.

Problem

• Develops a robot for frozen shoulder rehabilitation with scapulohumeral rhythm stabilization
• Addresses compensatory movement issues in existing robotic rehabilitation solutions
• Personalizes therapy by replicating normal shoulder motion from the unaffected side

Innovation

• 6 DoF mechanism with scapular stabilization
• Personalized two-phase operation system
• Precise motion replication with low RMSE