Modular Stem Extension With Porous Sleeve
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Solution Overview
Problem
Current orthopedic implants face challenges in securely anchoring modular components within bones, particularly in preventing pistoning and rotation, while existing solutions require complex manufacturing processes and additional stability measures.
Innovation Solution
A modular orthopedic component design featuring a stem with a highly porous biomaterial sleeve that directly contacts the bone, facilitating bony ingrowth and osteointegration, and is retained using a taper lock or adhesive, allowing for independent production of the stem and sleeve components, reducing manufacturing complexity and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stem includes an integral head with porous surfaces for tissue ingrowth, then bone integration is facilitated, but the head surface is separated from the osteotomized bone, reducing direct contact and stability
Solution Approach 1:
The implant is divided into separate components: a stem with head assembly and a discrete sleeve component. The sleeve is made of porous biomaterial and is received on the exterior of the head, allowing the head to be formed without porous material while the sleeve provides the tissue ingrowth function at the bone interface.
Solution Approach 2:
The porous sleeve acts as an intermediary component between the head and the bone. It is positioned at the interface where direct bone contact is needed, facilitating tissue ingrowth while allowing the head to be manufactured separately without special protection or masking.
2Adaptability or versatility
If the stem is designed as a modular prosthesis system, then adaptability to specific femur configurations is improved, but the number of components and assembly complexity increases
Solution Approach 1:
The modular system includes a stem with head that can be independently sized, and a separate porous sleeve that can be selected based on bone quality and ingrowth requirements. This segmentation allows customization while keeping the overall system manageable.
Solution Approach 2:
The porous sleeve serves multiple functions: it facilitates tissue ingrowth, provides structural support at the bone interface, and can be used with different stem/head combinations. This multi-functionality reduces the need for multiple specialized components.
3Ease of manufacture
If the porous biomaterial sleeve is formed as an independent component, then manufacturing complexity and cost are reduced, but additional retention mechanisms (taper lock or adhesive) are required
Solution Approach 1:
The sleeve is manufactured as a separate component from the stem and head, allowing each part to be optimized for its specific function. The stem and head can be formed using standard manufacturing processes without the complexity of creating porous structures, while the sleeve is专门 manufactured with porous biomaterial.
Solution Approach 2:
The retention of the porous sleeve is achieved through chemical bonding (adhesive) or mechanical interlocking (taper lock) rather than complex mechanical fastening systems. This substitution simplifies the overall assembly while ensuring secure retention.
4Reliability
If the sleeve directly contacts the osteotomized bone to facilitate boney ingrowth, then stability and osteointegration are improved, but the intramedullary canal may require sealing
Solution Approach 1:
The sleeve is made of highly porous biomaterial that allows bone tissue to grow through and integrate with the implant structure. This porous structure facilitates osteointegration by providing a scaffold for bone ingrowth while maintaining structural integrity.
Solution Approach 2:
The sleeve merges the functions of bone contact, tissue ingrowth facilitation, and potential canal sealing into a single component. By positioning the porous sleeve at the bone interface, it simultaneously provides structural support, promotes osteointegration, and can help seal the intramedullary canal through the boney ingrowth it facilitates.
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 design enhances stability by promoting bone integration, prevents pistoning and rotation, and reduces manufacturing costs by simplifying production processes.
Implementation Method 1
the sleeve facilitates bony ingrowth and osteointegration of the bone with the modular stem component
Implementation Method 2
results in the sleeve directly contacting the osteotomized bone to facilitate boney ingrowth
Data Source
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AI summary
The modular stem component (10) may include a shaft portion (12), a head (14), and a sleeve (16). The shaft portion (12) is configured for receipt within the intramedullary canal of a bone and the head (14) is configured to receive another component of a modular prosthetic system, such as a femoral neck, thereon. In one exemplary embodiment, the head extends radially around at least a portion of the stem and includes a rib (50) defining a flange (50) extending therefrom. The sleeve (16), which is formed as an independent part of the modular stem component and is made at least partially of a highly porous biomaterial, includes opposing ends (66,67) and has a bore extending therethrough. The bore is configured to facilitate sliding receipt of the sleeve on the head.