Variable-Width Orthopaedic Implant Fixation for Bone Stress Reduction
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Solution Overview
Problem
Conventional orthopaedic implants face issues with securing to bone tissue due to unnecessary stress from internal and external forces, and the use of multiple fastening devices can damage surrounding tissue or lack sufficient fixation points.
Innovation Solution
An orthopaedic implant with a D-shaped body featuring a fixation feature that tapers along its length, allowing it to be pressed into a fixation bore in the bone, and optional expandable or peg-like designs with adjustable widths to enhance fixation without damaging the bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional fastening devices (bone screws and pins) are used to secure the implant, then the implant can be firmly fixed to the bone, but unnecessary stress is placed on the fastening devices due to internal and external forces
Solution Approach 1:
The patent removes the conventional fastening devices (screws and pins) from the fixation system. Instead, it uses a fixation feature with variable width that presses against the inner surface of the fixation bore, extracting the stress-bearing function from discrete fasteners and distributing it across the implant-bone contact surface.
Solution Approach 2:
The fixation feature has non-uniform width along its length, with different portions having different widths. This local variation in geometry allows the feature to conform to the fixation bore geometry, distributing contact stresses more evenly across the interface rather than concentrating them at discrete fastening points.
2Strength
If multiple conventional fastening devices are used to securely fasten the implant, then the implant can be firmly secured, but the surrounding tissue may be damaged
Solution Approach 1:
The patent eliminates the need for multiple discrete fastening devices that penetrate and damage surrounding tissue. The fixation feature achieves secure attachment through pressure distribution across a larger area, removing the harmful effect of tissue penetration while maintaining fixation strength.
Solution Approach 2:
The fixation feature's width varies along its length, creating a gradient that allows gradual engagement with the fixation bore. This parameter change enables the feature to expand or conform to the bore geometry, achieving strong fixation through controlled pressure rather than aggressive tissue penetration.
3Strength
If multiple bone screws and pins are used to fasten the implant, then secure fixation can be achieved, but the implantation site may not have enough potential locations for receiving these fastening devices
Solution Approach 1:
The fixation feature serves multiple functions simultaneously: it provides fixation, distributes stress, and adapts to varying bone geometries. This single feature replaces the need for multiple specialized fastening devices, making the implant adaptable to different implantation sites without requiring specific locations for screws or pins.
Solution Approach 2:
The variable width of the fixation feature allows it to adapt to different fixation bore geometries. By changing its dimensional parameters along its length, the feature can engage effectively with bones of varying shapes and sizes, enhancing the implant's adaptability to different surgical sites.
Data Source
AI summary
A method for implanting an orthopaedic implant includes: forming a resected surface in a bone of a patient; forming a fixation bore in the resected surface; implanting the orthopaedic implant, the orthopaedic implant including an implant body having a first surface and a second surface opposite the first surface, the second surface including a fixation feature, the fixation feature configured to have a variable width; and pressing the fixation feature of the implant into the fixation bore.