Quadrilateral Linkage Orthopedic Distractor for Bone Alignment
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Solution Overview
Problem
Existing orthopedic distractors and compressors struggle to maintain optimal alignment and angular control of bone fragments during procedures, leading to complications such as malunion, delayed union, and nonunion.
Innovation Solution
A mechanism featuring linked quadrilateral linkages with a common point, allowing independent control of the relative distances and angles of bone fixation elements, is introduced. This mechanism includes a screw actuator that adjusts the distance and angle of the quadrilateral linkages, ensuring precise alignment and angular control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple pivoting handle mechanism is used for bone compression, then the device structure is simple, but the alignment precision is lost during compression due to arc movement
Solution Approach 1:
The patent implements a dynamic alignment maintenance mechanism where the distal ends of the arms are constrained to move along a straight line rather than following an arc. This is achieved through a guidance mechanism that allows the arms to pivot while maintaining collinear alignment of the bone fragments throughout the compression process, resolving the contradiction between simple structure and precision maintenance
Solution Approach 2:
The patent introduces an additional degree of freedom by allowing the arms to not only pivot about their proximal joints but also to translate along their longitudinal axes. This dimensional change enables the distal ends to maintain straight-line movement while the proximal ends pivot, preserving alignment precision without requiring an overly complex mechanism
2Ease of operation
If the distal ends of the arms follow an arc during compression, then the device can be operated simply by squeezing handles, but the bone alignment is lost after compression
Solution Approach 1:
The patent creates a dynamic system where the arms can pivot about proximal joints for ease of operation while simultaneously maintaining straight-line movement of distal ends through a guidance mechanism. This allows the surgeon to simply squeeze handles while the mechanism dynamically adjusts to preserve bone alignment throughout compression
Solution Approach 2:
The patent introduces an intermediary guidance mechanism between the pivoting arms and the bone fragments. This intermediary component constrains the distal ends of the arms to move along a straight line, mediating between the simple pivoting motion and the requirement for precise alignment maintenance during compression
3Device complexity
If a fixed-angle device is used for bone fixation, then the device structure is simple, but the adaptability to different angular deformities is limited
Solution Approach 1:
The patent implements adjustable angular relationships between the arms, allowing the device to adapt to different angular deformities. The arms can be positioned at various angles relative to each other and locked in place, providing versatility for correcting different types of bone fractures and deformities without requiring multiple fixed-angle devices
Solution Approach 2:
The patent creates a universal bone fixation device that can handle multiple types of fractures and angular deformities through its adjustable arm configuration. The same device structure can be adapted to different clinical scenarios by adjusting the angular relationship between arms, eliminating the need for multiple specialized fixed-angle devices
Data Source
AI summary
An orthopedic instrument, comprising a pair of pivotally-connected arms, extending beyond a pivot axis of a first pivot; a pair of feet mounted to ends of the pair of pivotally-connected arms; and a quadrilateral linkage configured to maintain parallelism between the pair of feet over a range of angles and to selectively alter a distance between the pair of feet.