Prosthetic Socket with Direction-Dependent Surface Design

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Solution Overview

Problem

The existing methods for fitting patients with amputations, particularly geriatric patients, with prosthetic sockets are complex, time-consuming, and require extensive adaptation, leading to prolonged periods of restricted mobility and activity, especially in cases of diabetes-induced amputations where volume fluctuations and limited mobility are concerns.

Innovation Solution

A prosthetic socket with a curved, open cross-section and clamping means that allows radial displacement of shell ends for easy adaptation to the amputation stump, enabling quick fitting and removal, along with a direction-dependent surface design for the liner and shell to enhance stability and comfort, and adjustable connection means for various amputation levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a classic plaster molding process is used to produce a prosthetic socket, then a high degree of stability and activity can be provided for the prosthesis user, but the individual adaptation is extremely complex and time-consuming, requiring nine to twelve months between operation and completion

Engineering Contradiction:
Improvestability and activityVSAvoidtime from operation to prosthesis completion
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The prosthetic socket is divided into a modular system consisting of a universal socket base and separate adaptive components (shells, liners, clamping mechanisms) that can be independently adjusted and combined. This segmentation allows rapid adaptation without requiring complete custom molding, reducing the time from operation to prosthesis completion while maintaining stability through the modular design that can be individually optimized for each patient's needs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention employs adjustable parameters including variable shell positions, adjustable clamping forces, and interchangeable liners that can be modified to accommodate changing stump dimensions. This parametric adaptability allows the universal socket to be customized for individual patients without requiring time-consuming custom molding, enabling rapid deployment while maintaining the stability needed for active use.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a prosthesis socket is individually adapted to the amputation stump through multiple fittings, then a high degree of stability is achieved, but the process requires a trained orthopedic technician and takes nine to twelve months

Engineering Contradiction:
ImprovestabilityVSAvoidcomplexity of adaptation process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The prosthetic system incorporates self-adjusting features including automatic clamping mechanisms and adaptive liners that can be easily modified by patients or caregivers without requiring specialized technical knowledge. The modular design with standardized interfaces allows for simple assembly and adjustment, enabling the system to be adapted to individual stump characteristics without the need for trained orthopedic technicians while maintaining stability through the inherent adaptability of the components.

Inventive Principle:
Principle #25Self-service

3Loss of time

If a prosthesis socket is designed for rapid fitting, then the period of restricted mobility is reduced, but the adaptation to volume fluctuations and individual stump contours becomes more difficult

Engineering Contradiction:
Improveperiod of restricted mobilityVSAvoidadaptation to volume fluctuations
Core Design Contradiction:
Loss of timeVSAdaptability or versatility

Solution Approach 1:

The prosthetic socket incorporates dynamic elements including adjustable clamping mechanisms that can be tightened or loosened to accommodate volume fluctuations, and flexible liners that adapt to changing stump contours. The modular shell system allows for rapid reconfiguration as the stump heals and changes size, enabling the prosthesis to be quickly fitted initially and then easily adjusted over time without requiring remolding, thus maintaining adaptability while reducing the initial period of restricted mobility.

Inventive Principle:
Principle #15Dynamics

4Weight of moving object

If the shell is made from dimensionally stable plastic to reduce weight, then the prosthesis is lighter and more comfortable, but the areas of different elasticity required for stability and comfort must be carefully engineered

Engineering Contradiction:
Improveprosthesis weightVSAvoidmanufacturing complexity of variable elasticity areas
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The prosthetic shell is designed with local variations in thickness and material properties, creating zones of different stiffness tailored to specific anatomical regions. Thinner, more flexible areas are positioned where comfort is prioritized, while thicker, stiffer regions provide structural support and stability. This localized differentiation of material properties allows the lightweight plastic construction to simultaneously achieve both comfort and stability without requiring complex manufacturing processes, as the variations can be incorporated through standard molding techniques.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3100704B1Prosthesis shaft and system comprising a prosthesis shaft and a prosthetic device
Publication Date: 2017.11.29 OTTO BOCK HEALTHCARE GMBH
  • EP3100704B1 patent drawingFigure 1
  • EP3100704B1 patent drawingFigure 2
  • EP3100704B1 patent drawingFigure 3~4

AI summary

Prosthetic socket for receiving an amputation stump of an extremity with connecting means for a distal prosthetic device (2), wherein the prosthetic socket (1) has at least one shell (10; 11, 12) which has a curved, open cross-section and whose shell ends overlap each other at least partially in the applied state and at least one clamping means (14, 15) is arranged on the shell (10; 11, 12) which is effective in the circumferential direction and clamps the shell ends to each other and the shell (10; 11, 12) is made of a dimensionally stable plastic with areas of different elasticity, characterized in that the inside (111, 121) of the shell (11, 12) has a direction-dependent surface design which provides higher resistance against an insertion direction of the amputation stump than in the insertion direction.