Pre-assembled External Fixation with One-Way Locking
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Solution Overview
Problem
Current external fixation systems are cumbersome to assemble and require significant time, often necessitating pre-assembly on a back table, and lack a one-way motion lock to maintain limb length during stabilization, which can be technically demanding and require additional assistance.
Innovation Solution
A pre-assembled external fixation system with a one-way locking mechanism that allows for provisional locking and adjustment, enabling secure stabilization of fractures or joints without the need for extensive assembly, utilizing polyaxial joints and a removable tab to convert between unlocked and locked configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional external fixation systems are assembled on the back table, then the frame can be pre-configured, but significant time is spent assembling clamp bodies and adjusting components
Solution Approach 1:
The clamp bodies are pre-assembled with rods and locking mechanisms in a controlled manufacturing environment before sterilization and packaging. This preliminary assembly eliminates time-consuming intraoperative assembly steps while maintaining sterility through sealed packaging until use.
Solution Approach 2:
Multiple components (clamp bodies, rods, locking mechanisms) are merged into a single pre-assembled unit that functions as an integrated system. This merging eliminates the need to assemble separate components during surgery, directly reducing assembly time while maintaining ease of use through unified design.
2Adaptability or versatility
If sliding rods and moving clamps are used for adjustment, then the frame can be customized, but the application and tightening becomes cumbersome
Solution Approach 1:
Traditional sliding rods and moving clamps requiring manual manipulation are replaced with a locking mechanism that uses a simple cam or lever action. This substitution maintains adjustability while dramatically simplifying the tightening operation to a single motion, reducing technical demand and assistant requirements.
Solution Approach 2:
The locking mechanism is designed to be self-locking, where the act of tightening automatically secures the position without requiring additional steps or assistance. The mechanism serves itself by maintaining the locked state through its own structural design, eliminating the need for continuous manual adjustment or multiple personnel.
3Manufacturing precision
If the limb is stretched against muscle tension to restore proper length, then fracture reduction is achieved, but the surgeon must hold significant tension while assistants tighten clamps
Solution Approach 1:
The manual tension-holding technique is replaced with a ratchet or one-way locking mechanism that mechanically maintains the stretched position. This substitution allows the surgeon to achieve precise fracture reduction without continuously holding tension, as the mechanism automatically maintains the reduced position during clamp tightening.
Solution Approach 2:
A mechanical intermediary device (ratchet mechanism) is introduced between the surgeon's tension application and the final locked position. This intermediary automatically maintains the tension force and converts it into a stable locked state, eliminating the need for the surgeon to continuously exert force while assistants perform tightening operations.
4Reliability
If multiple assistants are used to hold tension and tighten clamps, then proper fixation is achieved, but the procedure requires more personnel and increases complexity
Solution Approach 1:
The fixation system is designed to be self-sufficient, with built-in mechanisms that automatically maintain tension and lock positions without requiring multiple assistants. The self-service design maintains fixation reliability through automatic locking features while reducing procedural complexity by eliminating the coordination of multiple personnel.
Solution Approach 2:
The human element of tension-holding is extracted from the procedure through mechanical devices that automatically perform this function. By removing the need for assistants to manually hold tension, the system reduces procedural complexity while maintaining or improving reliability through consistent mechanical locking.
Data Source
AI summary
External fixation systems, and methods for immobilizing joints or fractured bones. An external fixation system may include one or more clamp assemblies connected to one or more rod assemblies at polyaxial joints. Each rod assembly may be length adjustable, and may include a one-way locking mechanism to provisionally lock the length of the rod assembly, and additional locking mechanisms to permanently lock the length of the rod assembly. The system may be deployed pre-assembled as a unit to immobilize a joint or fracture. Another external fixation system further includes a spanning member extending transverse to the rod assemblies. Two or more external fixation systems may be deployed in a stacked configuration on one set of bone pins to immobilize two joints and/or fractures. The systems may be provided in kits including guiding instrumentation, bone pins and pin clamping assemblies for connecting the bone pins to the external fixation systems.