Orthopedic Broach Tooth Layout for Proximal Press-Fit Stability
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Solution Overview
Problem
Existing orthopedic broaches fail to adequately prepare the intramedullary canal for hip stem implants, leading to improper fit, micromotion, and potential implant failure due to distal fixation and lack of rotational stability.
Innovation Solution
An orthopedic broach with a differential tooth pattern, including diamond, compaction, and extraction teeth, is designed to optimize the preparation of the intramedullary canal, minimizing distal fixation and ensuring a proper press-fit at the proximal region while providing rotational stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a uniform tooth pattern is used on the broach, then the manufacturing process is simple, but the fit and stability of the hip stem implant are compromised due to inadequate preparation of the intramedullary canal
Solution Approach 1:
The broach is divided into multiple segments along its longitudinal axis, with each segment featuring a different tooth pattern (cutting teeth, compaction teeth, extraction teeth). This segmentation allows each region to perform a specific function: cutting teeth remove bone to create clearance, compaction teeth densify bone for press-fit, and extraction teeth remove debris. The segmentation resolves the contradiction by enabling precise control over bone preparation at different locations, achieving superior implant fit and stability while maintaining a systematic manufacturing approach.
Solution Approach 2:
Different tooth patterns are applied to different regions of the broach based on the specific preparation needs of each intramedullary canal zone. The proximal region receives compaction teeth for dense bone preparation and press-fit, while the distal region receives cutting teeth for clearance creation. This local differentiation of tooth quality resolves the contradiction by optimizing each region's bone interaction characteristics, achieving both precise implant fit and rotational stability without requiring a uniformly complex design throughout.
2Stability of the object's composition
If the broach creates a tight fit throughout the intramedullary canal, then initial stability is improved, but distal fixation occurs which prevents proper proximal loading and may lead to implant failure
Solution Approach 1:
The broach creates differential fit characteristics through segmented tooth patterns: a preferential press-fit is generated in the proximal region using compaction teeth, while the distal region maintains clearance using cutting teeth. This segmentation resolves the contradiction by localizing the tight fit to only where it is needed (proximal for initial stability) while preventing distal fixation, thereby enabling proper proximal loading and long-term implant reliability through stress transfer to the bone.
Solution Approach 2:
The broach applies different bone interaction qualities at different locations: compaction in the proximal region creates dense bone for press-fit and initial stability, while cutting in the distal region maintains clearance to prevent fixation. This local differentiation resolves the contradiction by ensuring initial stability where required without creating harmful distal fixation, allowing proper load transfer and long-term implant survival.
3Productivity
If the intramedullary canal is not properly prepared, then the broaching process is faster, but micromotion occurs between the implant and bone leading to implant failure
Solution Approach 1:
The broach performs preliminary bone preparation actions in a specific sequence: cutting teeth first remove bone to create clearance and basic canal shape, then compaction teeth densify the bone to create the preferential press-fit envelope. This preliminary action sequence resolves the contradiction by efficiently preparing the canal in stages, achieving both process productivity and reliable implant stability through systematic bone modification before implant insertion.
Data Source
AI summary
An improved orthopedic broach used to prepare an intramedullary canal of a patient's bone such as, for example, a patient's femur, to receive an orthopedic implant such as, for example, a hip stem implant. The broach has differential teeth or tooth patterns. In one preferred example, the broach includes three different types of teeth including diamond teeth, compaction teeth, and extraction teeth. The different teeth patterns being specifically arranged on the sides of the broach to optimize bone removal and bone compaction for a subsequently implanted hip stem implant. In addition, the different teeth patterns and locations enhancing rotational stability. As such, the broach is configured to compact bone in certain areas while removing bones in other areas, all while maintaining broach rotation.