Guided Reaming of Complex Bone Sockets Along Offset Trajectories
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Solution Overview
Problem
Existing reaming systems for prosthetic implants struggle to accurately and efficiently create spaces in bone for asymmetric or partially-symmetric sleeves, often removing healthy bone and requiring complex, multi-step setups.
Innovation Solution
A reaming system that allows a reamer to move along offset, angled, or variable trajectories relative to the stem, using guideposts and pivoting mechanisms to create complex shaped sockets for sleeves or cones, enabling single-step formation of asymmetric or partially-symmetric bone pockets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional reaming systems are used with symmetric sleeves, then the reaming process can be performed with simple axial insertion, but the system removes too much healthy bone and cannot accommodate asymmetric anatomies
Solution Approach 1:
The patent applies asymmetry by providing guideposts with non-circular cross-sections (e.g., rectangular, oval, or other asymmetric shapes) that correspond to the asymmetric shape of the sleeve. This asymmetric guidepost geometry enables the reamer to follow a controlled path that removes only the necessary bone while preserving healthy bone, thereby resolving the contradiction between manufacturing simplicity and bone conservation.
Solution Approach 2:
The patent employs dynamic movement of the reamer along the guidepost, allowing the reamer to move not only axially but also in lateral and rotational directions. This dynamic reaming path, guided by the asymmetric guidepost, enables precise control over bone removal, achieving both surgical simplicity and conservation of healthy bone.
2Loss of substance
If asymmetric sleeves are used to fit patient anatomy, then healthy bone is preserved, but the reaming process becomes difficult to execute freehand and requires complex trajectories
Solution Approach 1:
The guidepost serves as an intermediary element between the reamer and the bone. The asymmetric guidepost with its specific cross-sectional shape guides the reamer along the required complex trajectory, translating the difficulty of freehand asymmetric reaming into a simple guided operation. This intermediary structure enables easy execution while preserving healthy bone.
Solution Approach 2:
The patent changes the geometric parameters of the guidepost (cross-sectional shape, size, and orientation) to match the asymmetric anatomy and desired sleeve fit. By adjusting these parameters, the system enables simple guided reaming operations that accommodate various asymmetric anatomical configurations while preserving healthy bone.
3Manufacturing precision
If reaming rigs with multiple positions are used to create shaped spaces, then complex sleeve shapes can be achieved, but the system requires multiple reaming steps and complex setup
Solution Approach 1:
The patent extracts the guiding function from a complex multi-position reaming rig and concentrates it into a single asymmetric guidepost. This guidepost integrates multiple guiding functions (lateral positioning, rotational control, depth limitation) into one component, achieving the same shaped space accuracy with significantly reduced device complexity and a single reaming step.
Solution Approach 2:
The patent merges multiple reaming functions (positioning, orientation, depth control, and shaping) into a single integrated guidepost-reamer system. The asymmetric guidepost combines what would otherwise require separate positioning devices and multiple reaming steps, thereby achieving manufacturing precision while reducing device complexity to its essential elements.
4Manufacturing precision
If rigid guideposts are used to control reamer movement, then precise bone modification is achieved, but the system cannot accommodate variable trajectories or angled paths
Solution Approach 1:
The patent applies dynamics by allowing the guidepost and reamer to move relative to each other in multiple directions (axial, lateral, and rotational). The asymmetric guidepost geometry provides precise control while enabling dynamic adjustment of the reaming path, thereby achieving both manufacturing precision and adaptability to variable trajectories and angled paths.
Data Source
AI summary
Systems and methods for reaming an intramedullary canal of a long bone comprise a trial stem configured to extend into the long bone along an insertion axis and a guide device comprising an adapter configured to couple to the trial stem and a reaming guidepost extending from the adapter along a guide axis, wherein the guide axis and the insertion axis are non-aligned. A method of reaming an intramedullary canal of a long bone to form a complex shaped socket can comprise inserting a stem into the intramedullary canal along an insertion axis, connecting a guide device to the stem, the guide device comprising a guidepost extending along a guide axis and guiding a cannulated reamer along the guidepost to remove bone from the intramedullary canal to form the complex shaped socket, wherein the guide axis and the insertion axis are non-aligned.