Adaptable Socket System with Compressive Paddles for Prosthetic Motion Control
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Solution Overview
Problem
Conventional prosthetic sockets experience lost motion between the socket walls and underlying skeletal structures, leading to disassociation between body part movement and prosthetic movement, which can result in re-injury, poorer rehabilitation outcomes, and increased time for successful rehabilitation.
Innovation Solution
The Rapidly Adaptable Socket System (RAS) addresses this by using compressing devices with paddles that displace excess tissue to capture underlying skeletal structures, allowing for optimal tissue compression and adjustable fitting to minimize lost motion, with manual or automatic adjustments and integrated electronics for monitoring and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional sockets fully encapsulate the limb with compressive force, then the socket provides structural support and stability, but lost motion occurs between the socket walls and underlying skeletal structures
Solution Approach 1:
The socket is divided into multiple functional zones: a compressive zone with paddles for skeletal structure capture, a transition zone, and a distal zone. This segmentation allows different portions of the socket to perform different functions - the compressive zone minimizes lost motion through targeted skeletal capture while other zones provide overall support and comfort.
Solution Approach 2:
The socket applies compressive force locally at specific sites over underlying skeletal structures rather than uniformly across the entire limb. Paddles are positioned to contact specific bony prominences, creating localized compression points that capture skeletal motion while allowing other areas to remain less compressed for comfort and tissue health.
2Manufacturing precision
If conventional sockets are custom-fitted through multistage processes, then the socket achieves optimal fit and comfort, but the fitting process is time-consuming and expensive
Solution Approach 1:
The socket incorporates pre-positioned paddles and compression zones that are designed to automatically align with key skeletal structures during donning. This preliminary positioning eliminates the need for extensive manual shaping and multiple fitting stages, as the critical skeletal capture geometry is built into the socket structure from manufacturing.
Solution Approach 2:
The socket design allows the user's own limb anatomy to guide the positioning of paddles against skeletal structures during donning. The flexible material and paddle geometry enable automatic self-alignment with bony prominences, reducing dependence on skilled technicians for precise fitting while maintaining high fit accuracy.
3Ease of operation
If conventional sockets use flexible materials for comfort, then the socket adapts to limb shape, but the socket cannot effectively capture underlying skeletal structures
Solution Approach 1:
The socket uses flexible material overall for comfort and adaptability, but incorporates rigid or semi-rigid paddles at specific locations to contact and capture skeletal structures. This local quality differentiation allows the socket to be comfortable and conforming in most areas while maintaining firm, reliable contact with underlying bones at critical paddle sites.
Solution Approach 2:
The socket combines flexible materials (such as thermoplastic polymers or elastomers) with rigid paddle elements (possibly made from carbon fiber, metal, or stiff plastic). This composite construction allows the flexible portions to conform to the limb for comfort while the rigid paddles provide stable skeletal structure capture without deforming under load.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The RAS system reduces lost motion between the socket and skeletal structures, enhancing the association between body part and prosthetic movement, improving comfort, reducing re-injury risk, and streamlining the fitting process, thereby facilitating more efficient rehabilitation and user adaptation.
Implementation Method 1
The paddles are configured to interface with a skeletal structure of the target and compress soft tissue of the target against the bone
Data Source
AI summary
A method of engaging a limb with an interface using an external tool is described. The method includes the steps of: (i) removably attaching one or more actuators of the external tool to one or more paddles of the interface; (ii) operating the actuators to adjust a position of the paddles inward or outward relative to a longitudinal axis of the interface; and (iii) selecting a compression force for each of the paddles so as to compress target areas of soft tissue in the limb against skeletal structure to reduce motion of the skeletal structure towards an inner surface of the paddles.