Multi-viscosity Silicone Prosthetic Liner for Limb Adaptation
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Solution Overview
Problem
Conventional prosthetic liners fail to balance flexibility and fit, leading to discomfort and limited functionality for amputees, especially those engaging in active lifestyles, due to structural changes in the residual limb and inadequate accommodation of varying stresses.
Innovation Solution
A novel prosthetic liner with a closed-ended, air-tight tubular sleeve made of integral layers of different viscosity silicone elastomers, featuring two zones of Shore A durometer hardness and a lubricious coating, allowing for easy donning and doffing while reducing friction and pressure, and incorporating a flexible elongate arm to distribute weight and reduce negative pressure during gait.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional liners are made with uniform hardness, then manufacturing is simple, but they cannot accommodate structural changes in the residual limb over time
Solution Approach 1:
The liner incorporates multiple zones with different Shore A durometer hardness values within a single liner structure. Specifically, it includes a softer distal zone (20-40 Shore A) for comfort and adaptation to residual limb changes, and a harder proximal zone (40-60 Shore A) for structural support and suspension. This local differentiation allows the liner to adapt to structural changes in the residual limb while maintaining overall structural integrity.
2Reliability
If liners are made with higher resilience, then durability improves, but ease of donning and doffing deteriorates
Solution Approach 1:
The liner uses a gradient hardness design where the distal end (20-40 Shore A) is softer to facilitate easy donning and doffing by allowing the liner to stretch and conform to the residual limb, while the proximal end (40-60 Shore A) is harder to provide durability and structural support during active use.
3Strength
If liners are made with supplemental structural elements, then strength improves, but comfort and ease of use deteriorate
Solution Approach 1:
The liner is constructed as a composite structure integrating two different viscosity silicone elastomers into a single seamless liner. The first silicone elastomer forms the distal zone with lower viscosity for comfort, while the second silicone elastomer forms the proximal zone with higher viscosity for strength. This composite approach provides structural strength without the need for separate supplemental elements that would compromise comfort.
4Ease of manufacture
If liners are made with single-material construction, then manufacturing is simple, but they cannot provide both comfort and support simultaneously
Solution Approach 1:
The liner varies the viscosity parameter of the silicone elastomer throughout its length, with the distal zone having lower viscosity (softer) and the proximal zone having higher viscosity (harder). This parameter change within the same material family (silicone elastomer) allows the liner to provide both comfort and support simultaneously while maintaining a relatively simple single-material construction approach.
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 liner provides enhanced comfort, durability, and support, allowing amputees to engage in active lifestyles without compromising fit or comfort, while reducing friction and pressure on the residual limb, thus minimizing the risk of sores and improving functional abilities.
Implementation Method 1
being coated with a lubricious layer
Implementation Method 2
the silicone elastomer of said integral layer construction having two different zones of Shore A durometer hardness
Data Source
AI summary
A novel enhanced liner for prostheses provides for better for either off of the shelf or in customized form, to line a prosthetic used by amputees. Striking a balance between controlling the tear strength and imparting resiliency results in a user friendly product that can be easily donned, and doffed and worn without the drawbacks of the prior art. A unique coating allows the user to remove it like a tubular sock-member, and support comfort and convenience.