Osteotomy Guide for Preserving Joint Axis of Rotation
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Solution Overview
Problem
Existing osteotomy techniques disrupt the biomechanics of bones adjacent joints, altering the instantaneous axis of rotation and tendon pull directions, leading to non-anatomic joint function.
Innovation Solution
A surgical guide and method that includes a cutter guide for making parallel cuts transverse to the bone axis, a reduction mechanism to align bone portions along a predefined path, and fixation mechanisms to maintain anatomical relationships, preserving joint mechanics and promoting healing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If freehand cutting of the bone is performed followed by sliding one bone fragment relative to the other, then the bone can be repositioned, but the instantaneous axis of rotation changes and tendon pull direction changes resulting in non-anatomic joint function
Solution Approach 1:
The guide is attached to the bone before cutting, establishing the correct orientation and position for the osteotomy cut. This preliminary positioning ensures that when the bone is later repositioned, it returns to its original anatomic alignment, preserving the instantaneous axis of rotation and tendon pull directions.
Solution Approach 2:
The guide acts as an intermediary device between the cutting tool and the bone, and later between the repositioning mechanism and the bone fragments. It provides reference surfaces and alignment features that ensure the bone portions are repositioned along the correct path to maintain original joint mechanics.
2Reliability
If a guide with reduction mechanism is used to move bone portions along a predefined path, then joint mechanics are preserved, but the device complexity increases
Solution Approach 1:
The guide is divided into separate components: a base portion that attaches to the bone, a cutter guide portion for guiding the osteotomy cut, and a reduction mechanism portion for repositioning the bone fragments. This segmentation allows each component to perform its specific function while keeping the overall device manageable and sterilizable.
Solution Approach 2:
The guide utilizes the third dimension by extending perpendicular to the bone surface with reference surfaces that engage anatomical landmarks. This vertical dimension provides stable positioning and orientation control, enabling precise control of bone repositioning in three-dimensional space while maintaining a relatively simple overall structure.
Data Source
AI summary
A guide and method useful in cutting and rejoining bones is presented. The guide is particularly useful in performing an osteotomy of a long bone adjacent a joint such as a hand or foot.