Saddle-Shaped Prosthesis for Multi-Axis Joint Osteotomy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current surgical techniques for treating arthritic multi-axis joints, such as the first carpo-metacarpal joint, do not effectively achieve a combination of early reestablishment of range of motion, reduction of pain, recovery of strength, and stabilization of the joint, and lack accurate means for performing wedge osteotomy and prosthetic devices that emulate its results.
Innovation Solution
A cutting guide system and pre-formed plates with fasteners for performing osteotomy, along with prosthetic devices that emulate the post-osteotomy geometry of the joint, are provided to stabilize and restore the joint's functionality, including a prosthesis with a saddle-shaped articular surface that harmonizes with the trapezium's surface and a powered diamond tip burr for precise osteophyte removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a prosthetic device is used to substitute the 1CMC joint, then range of motion is improved, but pain reduction and joint stabilization are insufficient
Solution Approach 1:
The prosthesis is divided into separate components: a proximal articulation portion, a distal articulation portion, and a strut portion. This segmentation allows each component to be optimized for its specific function - the proximal and distal portions provide articulation surfaces for range of motion while the strut provides structural stabilization.
Solution Approach 2:
The prosthesis utilizes composite construction with a metal stem portion and polymer articulation surfaces. This composite approach combines the strength and stability of metal with the wear-resistant properties of polymer, achieving both joint stabilization and durable range of motion.
2Reliability
If wedge osteotomy is performed to restore joint stability, then pain is reduced, but accurate means for performing the osteotomy are unavailable
Solution Approach 1:
A cutting guide is introduced as an intermediary tool during the osteotomy procedure. The cutting guide is positioned on the metacarpal bone and provides precise mechanical guidance for the osteotome, enabling accurate wedge resection while the prosthesis emulates the post-osteotomy geometry to restore stability.
Solution Approach 2:
The cutting guide is installed on the metacarpal bone before performing the osteotomy. This preliminary positioning action establishes the exact cutting path and orientation needed to achieve the desired wedge geometry, ensuring precision before the actual bone cutting occurs.
3Reliability
If the trapezium is removed and tendon graft is used, then joint stability is improved, but range of motion and strength recovery are limited
Solution Approach 1:
The prosthesis is designed to copy the anatomical geometry of the native 1CMC joint, including the saddle-shaped articular surfaces. By replicating the natural joint architecture rather than using simple tendon grafts, the prosthesis restores both stability and the complex range of motion required for thumb function.
Solution Approach 2:
The prosthesis incorporates a saddle-shaped articular surface with specific curvature in both the dorsal-palmar and radial-ulnar planes. This curved geometry replicates the natural articulation between the first metacarpal and trapezium, enabling multi-axis rotation and comprehensive range of motion while providing stable load transmission.
Data Source
Figure 1A~1B
Figure 2~3B
Figure 4A~4B
AI summary
A system, devices and methods for performing an osteotomy on a bone of a multi-axis joint are provided. A cutting guide system is provided for performing one or more cuts to the bone, using the articular surfaces of the articulating bones as a reference. If desired, a prosthesis can be used to emulate the osteotomy and substitute for a damaged articular surface of a bone of a multiaxis joint.