Triangular Profile Bone Broach for Minimally Invasive Cavity Preparation
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Solution Overview
Problem
Current bone preparation methods for artificial joint prostheses, such as hip replacements, require large incisions due to the limitations of existing broaches and milling systems, leading to longer recovery times and increased psychological and financial strain on patients.
Innovation Solution
A broaching system that uses a guided broach with a triangular profile and a conical portion, allowing for the creation of a triangular cavity in the bone through a smaller incision by mounting a broach on a shaft with cutting teeth at an acute angle, reducing the size of the incision needed for calcar preparation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional broaches or rasps are used for bone preparation, then the surgeon can guide the instrument manually, but the instrument is deflected by harder sections of bone and cannot create a precise triangular cavity
Solution Approach 1:
The patent introduces a guide needle as an intermediary element that is inserted into the bone first to establish a precise trajectory. The broach then follows this pre-established path, eliminating deflection issues while maintaining ease of operation. The guide needle acts as a mediator between the surgeon's intent and the broaching action, ensuring the instrument stays on the correct path even when encountering harder bone sections.
2Manufacturing precision
If milling systems are used for bone preparation, then precise bone preparation can be achieved, but a large incision is required to accommodate the milling assembly
Solution Approach 1:
The patent divides the bone preparation process into separate sequential steps: first inserting a guide needle through a small incision, then removing the needle and inserting a broach that follows the same trajectory. This segmentation allows each instrument to be simpler and smaller than a complete milling system, eliminating the need for large incisions while maintaining precision through the guide-broach coordination.
Solution Approach 2:
The patent extracts the guiding function from the broach itself and separates it into a distinct guide needle component. By taking out the trajectory-establishment function from the bone-removal function, the system allows the broach to be simpler and smaller, accommodating a smaller incision while the guide needle ensures precision is not compromised.
3Manufacturing precision
If a guide needle is inserted into the bone to establish a precise trajectory, then the broach can follow the correct path, but the guide needle may be deflected by harder sections of bone
Solution Approach 1:
The patent applies preliminary action by having the guide needle establish the trajectory first, creating a prepared path through the bone before the actual broaching occurs. This preliminary trajectory establishment allows the surgeon to verify correct positioning before committing to the bone removal process, ensuring both accuracy and reliability.
Solution Approach 2:
The patent replaces the complex mechanical interaction of a self-guiding broach with a simpler two-component system: a passive guide needle that establishes geometry and an active broach that follows it. This substitution reduces the mechanical complexity and potential for deflection by separating the guidance and cutting functions into distinct, optimized components.
Data Source
AI summary
A device for creating a cavity in a bone, said cavity having a cross-section which has a generally triangular profile having a first side generally parallel with an axis of the bone and a second side forming an acute angle with the first side, and contiguous with a pre-existing conical cavity, includes a shaft having a longitudinal axis and including a proximal portion and a distal portion, wherein the proximal portion has a larger cross section perpendicular to the longitudinal axis than the corresponding cross section of the distal portion, and a broach non-rotationally supported by the shaft and having a first cutting side supported at the acute angle relative to the longitudinal axis of the shaft, wherein the distal portion of the shaft is formed to include witness marks which when registered with an indicator after advancing the shaft facilitate selection of an appropriately sized prosthesis component.