Knee Arthroplasty Implants With Trabecular Bone-Ingrowth Fixation
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Solution Overview
Problem
Existing knee arthroplasty procedures face challenges with bone cement failures, such as weak bonding, cement fracture, and surgical complications, necessitating the development of cementless femoral and tibial implants with improved fixation mechanisms.
Innovation Solution
The development of femoral and tibial implants with trabecular structures and fixation pegs that promote bone healing and interdigitation, along with specialized instrumentation for cementless implantation, utilizing materials like titanium and polyethylene for enhanced stability and reduced procedural risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bone cement is used to secure femoral and tibial implants, then initial fixation is achieved, but the risk of cement failure, fracture, and complications increases
Solution Approach 1:
The patent removes bone cement from the surgical procedure entirely, extracting the harmful element that causes failures. The invention uses cementless implants with trabecular structures and fixation pegs that provide strength through bone ingrowth and mechanical interlocking, eliminating cement-related risks while maintaining fixation reliability
Solution Approach 2:
The patent employs trabecular structures with porous characteristics in the implant design. These porous materials allow bone to grow into and through the implant structure, creating strong biological fixation without requiring bone cement. The trabecular pattern provides both structural integrity and bone ingrowth pathways
2Reliability
If cementless implants with trabecular structures are used, then cement-related complications are eliminated, but the complexity of implant design increases
Solution Approach 1:
The patent divides the implant into multiple functional components: trabecular structures for bone ingrowth, fixation pegs for mechanical anchoring, and articulating surfaces for joint movement. This segmentation allows each component to perform its specific function while working together to provide reliable cementless fixation
Solution Approach 2:
The patent uses composite construction combining metallic materials (such as titanium or cobalt-chromium) for the implant body with porous trabecular structures. This composite approach integrates multiple functions—structural strength, bone ingrowth, and mechanical fixation—into a single cohesive implant design
3Strength
If fixation pegs with bulleted profiles are added, then initial fixation and bone ingrowth surface area are increased, but manufacturing complexity increases
Solution Approach 1:
The fixation pegs are pre-formed with their bulleted profiles and fins during the implant manufacturing process. This preliminary action of creating the peg geometry in advance allows for standardized production and simplifies the surgical procedure, as the pegs are ready for immediate insertion without requiring complex intraoperative fabrication
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 cementless implants provide improved fixation and stability through bone ingrowth, reducing procedural time and complications associated with bone cement, while ensuring long-term integration and mechanical integrity.
Implementation Method 1
The inner surface of the femoral implant and the distal surface of the tibial tray define a trabecular structure, which provides a scaffold for bone healing and interdigitation
Implementation Method 2
The implants may include one or more fixation pegs with bulleted profiles to provide initial fixation and increase the surface area for bone ingrowth
Data Source
AI summary
Knee arthroplasty implants, instruments, systems, and methods of implanting the same. The knee arthroplasty implants may include a femoral implant and a tibial tray implant, each with trabecular surfaces configured to contact bone to provide a scaffold for bone healing and interdigitation. The implants may also include fixation pegs with bulleted profiles to increase the surface area for bone ingrowth. An inserter instrument may include a sliding rack, which is incrementally extended with a rotatable shaft, thereby allowing for quick lock and release of various tibia trays.