Monoplanar Hinged External Fixator for Dynamic Joint Distraction
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Solution Overview
Problem
Existing solutions for fixing and distracting joints, particularly the proximal interphalangeal joint, are bulky, imprecise, and do not allow for natural flexion and extension, posing challenges in achieving controlled distraction and preservation of joint motion during healing.
Innovation Solution
A monoplanar fixator/distractor device with an adjustable dynamic distraction mechanism, comprising bone engagement modules with pins and clamps, and a rod assembly that forms a constrained pivot axis, allowing for controlled distraction and fixation of joints while permitting natural motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing fixator solutions are used for joint fixation and distraction, then joint stabilization is achieved, but the device becomes bulky and imprecise with respect to distraction control
Solution Approach 1:
The fixator device is divided into separate functional modules: bone engagement modules with pins and clamps, a rod assembly with constrained pivot axis, and an adjustable dynamic distraction mechanism. This segmentation allows each component to be optimized independently, reducing overall device bulk while maintaining precision control capabilities.
Solution Approach 2:
The distraction mechanism is designed to be dynamically adjustable, allowing precise control of distraction distance through movable clamps on the rod assembly. This dynamic adjustment capability enables precise distraction control without requiring oversized fixed structures.
2Ease of operation
If existing fixator solutions are used for joint fixation, then bone stabilization is achieved, but natural flexion and extension motion is restricted
Solution Approach 1:
The constrained pivot axis acts as an intermediary element that mediates between the stabilization requirement and motion preservation need. It allows rotation around a fixed axis (providing stabilization) while permitting natural flexion and extension motion (providing ease of operation).
Solution Approach 2:
The device transitions from a static fixed structure to a dynamic system where the rod assembly can rotate around the constrained pivot axis. This dynamic capability allows the joint to maintain stabilization while performing natural motion during healing.
3Manufacturing precision
If existing fixator solutions are used for joint distraction, then bone alignment is achieved, but patient tolerance is reduced due to device bulk
Solution Approach 1:
By segmenting the device into compact modular components (pins, clamps, constrained pivot axis, distraction mechanism), the overall device bulk is reduced while maintaining alignment precision capabilities in each module.
Solution Approach 2:
The device allows adjustment of distraction parameters through the dynamic mechanism, enabling precise bone alignment while the reduced bulk design improves patient comfort and tolerance during the healing process.
Data Source
AI summary
An adjustable dynamic distraction mechanism connects proximal and distal components of a fixator system to enable adjustment of the distraction between proximal and distal bones of a joint and fixation thereof. The device is dynamic in that once fixation of distraction is set, the distal portion of the anatomy may be permitted to move essentially freely to flex and extend by rotation at the natural axis of the joint.