Orthopaedic Stem Protrusions for Bone Fragment Stabilization

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Solution Overview

Problem

Current shoulder prostheses often fail to effectively reduce and promote healing of condylar fractures, particularly in the humerus, as the greater and lesser tuberosities may not be adequately secured to the humerus, leading to insufficient fracture reduction and union.

Innovation Solution

A modular orthopaedic prosthesis with protruding fingers made of materials like titanium, nitinol, or memory metal, which apply constant pressure to the bone fragments, using spikes, sutures, cables, and screws to secure the fragments to the humerus, minimizing soft tissue irritation and promoting anatomical alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional shoulder prosthesis are used, then the basic joint replacement function is achieved, but the fracture reduction and stabilization of bone fragments (greater and lesser tuberosities) is insufficient

Engineering Contradiction:

Improvefracture reduction and stabilizationVSAvoidprosthesis structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The prosthesis is divided into distinct functional segments: the main stem portion for intramedullary insertion, and separate protrusion elements (fingers) that extend outward to contact and stabilize the greater and lesser tuberosities. This segmentation allows each component to perform its specific function independently while contributing to overall fracture stabilization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protrusions are integrated into the overall prosthesis structure, with the fingers extending from the main stem body. The modular design allows the protrusions to be attached to or integrated with the stem, creating a nested configuration where the stabilization elements are contained within the overall prosthesis assembly.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If protrusions are added to secure bone fragments, then fracture stabilization is improved, but soft tissue irritation may increase

Engineering Contradiction:

Improvebone fragment fixationVSAvoidsoft tissue irritation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protrusions are designed with specific local characteristics: rounded or contoured surfaces that conform to the bone anatomy, and selective placement that avoids soft tissue structures. The geometry and surface properties of each protrusion are optimized to contact bone while minimizing contact with surrounding soft tissues, thus reducing irritation while maintaining fixation effectiveness.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If modular design with multiple components is used, then adaptability to different fracture patterns is improved, but device complexity and surgical procedure difficulty increase

Engineering Contradiction:

Improvefracture pattern accommodationVSAvoidnumber of components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The prosthesis design incorporates universal features that allow it to address multiple fracture patterns and anatomical variations. The stem portion can be inserted into the medullary canal while the protrusions can accommodate different tuberosity configurations. This multi-functional design enables a single prosthesis type to serve various clinical scenarios, reducing the need for multiple specialized implants.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If constant pressure is applied to bone fragments, then healing and union are promoted, but the risk of fragment displacement or damage increases

Engineering Contradiction:

Improvefracture healingVSAvoidbone fragment integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The protrusions are designed with specific geometric parameters including surface area, curvature, and contact point distribution that optimize the pressure application. By adjusting these parameters, the design achieves sufficient compressive force to promote healing while distributing the load to prevent fragment damage. The material properties and structural configuration are also optimized to provide appropriate pressure characteristics.

Inventive Principle:

Principle #35Parameter changes

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 effectively reduces and stabilizes fractures by applying continuous pressure, facilitating healing and union of bone fragments, and can be used in various long bones, including the humerus, femur, tibia, fibula, ulna, or radius.

Implementation Method 1

A modular orthopaedic prosthesis with protruding fingers made of materials like titanium, nitinol, or memory metal, which apply constant pressure to the bone fragments

Methodology Applied

Scientific EffectConstant pressure: Compression

Data Source

PatentUS9211191B2Orthopaedic stem with protrusion and associated surgical procedure

Publication Date: 2015.12.15 DEPUY SYNTHES PROD INC

AI summary

A method of performing joint arthroplasty on a patient with a bone fragment of a bone at least partially separated from the bone in one embodiment includes providing a prosthetic component with a bone connecting portion and a bone fragment portion, implanting the bone connecting portion of the prosthetic component in the bone, and attaching the bone fragment to the bone using the bone fragment portion.