Void-Filling Joint Prosthesis With Adaptable Legs for Femoral Bone Voids
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Solution Overview
Problem
Existing joint revision procedures face challenges in managing unpredictable and non-uniform bone voids during revision surgeries, leading to additional bone loss and the need for time-consuming, invasive methods to prepare these voids for prosthetic components, which can increase infection risk and compromise structural integrity.
Innovation Solution
A bone void filling prosthesis with a frustoconical profile and adaptable legs, featuring a porous outer surface for bony ingrowth and a solid rim for structural support, designed to fit various bone void shapes and accommodate bone augments, allowing for precise placement and minimal invasive preparation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional reaming and broaching methods are used to prepare bone voids, then the bone void can be shaped to receive prosthetic components, but additional native bone is removed and structural integrity is compromised
Solution Approach 1:
The bone void is prepared in advance by reaming along the intramedullary axis to create a preliminary cylindrical cavity. This preliminary action removes the bulk of excess bone while preserving the irregular outer contours, allowing the prosthetic component to be subsequently fitted without requiring extensive additional bone removal.
Solution Approach 2:
The bone void preparation is divided into two distinct stages: (1) mechanical reaming along the intramedullary axis to create a standardized cylindrical base, and (2) selective manual bone removal only where needed to accommodate the specific prosthetic component geometry. This segmentation minimizes overall bone loss by avoiding unnecessary removal in areas where the irregular bone contours should be preserved.
2Manufacturing precision
If manual broaching or freehand bone removal is performed to achieve accurate fit, then the prosthetic component can be properly positioned, but the procedure becomes time-consuming and increases infection risk
Solution Approach 1:
The intramedullary reaming is performed as a preliminary standardized step that creates a consistent cylindrical cavity across all cases. This preliminary preparation establishes a reliable geometric foundation that reduces the need for time-consuming iterative manual adjustments, allowing surgeons to more efficiently achieve accurate prosthetic fit.
Solution Approach 2:
The reaming process transforms the bone void from an irregular shape to a standardized cylindrical geometry with controlled dimensions. By changing the geometric parameters of the bone void through systematic reaming, the procedure reduces variability and enables more predictable, faster fitting of prosthetic components with fewer manual adjustments required.
3Ease of manufacture
If extensive bone resection is performed to create uniform voids, then prosthetic components can be implanted, but structural integrity and structural support are compromised
Solution Approach 1:
Instead of uniformly resecting bone throughout the void, the reaming process is applied locally and selectively along the intramedullary axis where it is most needed for structural support. The irregular bone contours in peripheral areas are preserved to maintain structural integrity, while only the essential central cavity is prepared for prosthetic reception.
Solution Approach 2:
The reaming process removes slightly more bone than the absolute minimum needed, creating a generously sized cylindrical cavity that ensures adequate space for the prosthetic component and its fixation elements. This partial excess action prioritizes ease of implantation and structural support over maximal bone preservation, accepting controlled bone removal to ensure prosthetic stability.
4Manufacturing precision
If multiple iterative checks and adjustments are performed to achieve correct fit, then accurate positioning is achieved, but the procedure becomes complex and time-consuming
Solution Approach 1:
The standardized intramedullary reaming creates a predictable, geometrically consistent bone void that serves as a reliable foundation for prosthetic fitting. This preliminary standardized preparation reduces the need for multiple iterative adjustments by establishing a known geometric reference that simplifies subsequent fitting procedures and minimizes procedural complexity.
Solution Approach 2:
The systematic reaming process transforms the bone void into a standardized cylindrical geometry with controlled diameter and length parameters. By establishing these controlled geometric parameters in advance, the procedure reduces variability and enables more straightforward, less complex fitting procedures with fewer iterative checks required to achieve accurate prosthetic positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The prosthesis provides a flexible and efficient solution for filling bone voids, minimizing additional bone removal, reducing infection risk, and ensuring accurate fit and structural integrity, while promoting bone remodeling and prosthetic stability.
Implementation Method 1
The aperture defines a sidewall having a thickness spanning between an outer surface and an inner surface of the body. The outer surface is formed of a porous material for promoting bony ingrowth
Data Source
AI summary
A distal femoral joint replacement system includes a femoral component having condylar articular surfaces, a stem extending from the femoral component, and a void filler for filling a bone void within a femur. The void filler includes a body and a plurality of legs extending from the body. The body has a sidewall defining an opening for receipt of the stem which extends along a length of the body and extends through the sidewall so as to form a side-slot in the sidewall that extends along an entire length of the sidewall. The plurality of legs each have a first end connected to the body and a second end remote from the body. The legs each have an outer surface that tapers between the first and second ends and is configured to register with a corresponding inner surface of a bone void when implanted in an end of the femur.