Adjustable Prosthesis Locking Mechanism for Arthrodesis-Arthroplasty Conversion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing arthrodesis prostheses are limited in adjustability and cannot easily convert between arthrodesis and arthroplasty modes, requiring full replacement for changes in joint functionality and lacking tools for precise adjustment.

Innovation Solution

A prosthesis design featuring locking and lockable members with conical holes and threads, allowing for adjustable and secure attachment to bones, enabling conversion between arthrodesis and arthroplasty modes without full replacement, and facilitating precise positioning using a screw tool.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a prosthesis is designed for arthrodesis only, then the joint is firmly fused, but the prosthesis cannot be converted to arthroplasty mode and requires full replacement for flexibility restoration

Engineering Contradiction:

Improveconversion between arthrodesis and arthroplasty modesVSAvoidprosthesis structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The prosthesis incorporates a dynamic locking mechanism that can transition between locked (arthrodesis) and unlocked (arthroplasty) states. The lockable member can be selectively engaged or disengaged from the locking member, allowing the joint to switch between fixed and mobile configurations without replacing the entire prosthesis.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The prosthesis is designed with multi-functional components that serve dual purposes. The same prosthesis structure can function as either an arthrodesis device or an arthroplasty device depending on the engagement state of the locking mechanism, eliminating the need for separate prostheses for different functional requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If adjustment of prosthesis members is performed using special tools, then precise positioning is achieved, but the adjustment process becomes complex and time-consuming

Engineering Contradiction:

Improvepositioning precision of prosthesis membersVSAvoidadjustment process

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The locking mechanism is designed to be self-aligning and self-locking. The lockable member automatically engages with the locking member when pushed against the bone, eliminating the need for special adjustment tools. The conical holes guide the members into proper alignment, and the threaded connection provides automatic locking upon engagement.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If the entire prosthesis is replaced to restore joint flexibility, then full functionality is restored, but surgical time and incision size increase

Engineering Contradiction:

Improvejoint flexibilityVSAvoidsurgical time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The prosthesis is divided into separable components with independent locking and lockable members. This segmentation allows selective engagement or disengagement of the locking mechanism without removing the entire prosthesis, enabling quick conversion between arthrodesis and arthroplasty modes during surgery.

Inventive Principle:

Principle #1Segmentation

4Stability of the object's composition

If previous prosthesis members are discarded after arthrodesis, then the joint remains fused, but the opportunity to restore flexibility is lost

Engineering Contradiction:

Improvejoint fusion stabilityVSAvoidfuture flexibility restoration

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The locking mechanism is designed to be reversible, allowing the lockable member to be disengaged from the locking member if needed. This enables the prosthesis to transition from a permanently fixed state back to a mobile state, recovering the flexibility function without discarding the prosthesis components.

Inventive Principle:

Principle #34Discarding and recovering

Data Source

PatentEP3092979B1prosthesis

Publication Date: 2019.03.27 SWEMAC INNOVATION

Figure 1
Figure 2~4
Figure 5~6

AI summary

A prosthesis for primary arthrodesis can be used for arthroplasty and a prosthesis for arthroplasty comprises members for arthrodesis. The prosthesis (1c) for primary arthrodesis comprises a locking member (33c) with an attachment portion (16c) which is insertable into a hole (8c) in a first attachment member (4c) of the prosthesis for location of the locking member therein, and a lockable member (34c). The lockable member (34c) comprises an attachment portion (16c) which is insertable into a hole (9c) in the second attachment member (5c) for location of the lockable member therein. The lockable member (34c) is configured for adjustable setting thereof relative to the locking member (33c) and for fixation thereof, in set position, to the locking member.