Allograft Hip Arthroplasty Device for Osteolysis Reduction

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Solution Overview

Problem

Current methods for reconstructing the hip joint, such as total joint arthroplasty, face challenges like osteolysis, implant loosening, and bone density loss due to metal implants, and lack a biological solution for restoring hyaline articular cartilage.

Innovation Solution

A specialized device for preparing graft acetabular and femoral head bones for a total hip allograft replacement, using a tower to achieve uniform thickness and architecture, allowing for biological total hip arthroplasty with optional metal or ceramic resurfacing implants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional total joint arthroplasty with metal implants is used, then joint replacement is achieved, but osteolysis, implant loosening, and bone density loss occur

Engineering Contradiction:

Improvejoint replacement stabilityVSAvoidosteolysis and bone density loss

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the material parameter of the implant from metal to biological allograft tissue, fundamentally altering the interaction between implant and host bone. The allograft undergoes biological remodeling where donor bone is gradually replaced by host bone, eliminating the foreign body effect that causes osteolysis while maintaining structural integrity throughout the healing process

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The allograft implant represents a composite structure combining donor bone tissue with the host's biological remodeling capacity. The implant consists of cortical bone outer shell providing structural strength and cancellous bone interior allowing vascular ingrowth and osteogenic cell migration, creating a biologically active composite that integrates with host tissue

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If metal implants are used for hip replacement, then joint function is restored, but metal ion release and debris generation occur

Engineering Contradiction:

Improvejoint function restorationVSAvoidmetal ion release and debris

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The allograft implant is designed as a temporary structure that fulfills its load-bearing function during the healing period and then is completely replaced by host bone tissue. Unlike permanent metal implants that continuously generate debris, the allograft is intentionally designed to be transient, serving its purpose and then being biologically assimilated without leaving harmful residues

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the material composition parameter from metal alloys to biological bone tissue, fundamentally eliminating the source of metal ion release and particulate debris. The allograft's organic composition allows for biological degradation and replacement rather than permanent presence with continuous wear

Inventive Principle:

Principle #35Parameter changes

3Reliability

If fresh osteochondral allografts are used, then cartilage repair is achieved, but uniform thickness and architecture control is difficult

Engineering Contradiction:

Improvecartilage repair successVSAvoidgraft thickness uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The allograft is prepared in advance with predetermined thickness and architectural characteristics before implantation. The donor bone is processed to achieve uniform cortical shell thickness and appropriate cancellous bone density, ensuring consistent performance and fit before being implanted into the recipient site

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention controls the physical parameters of the allograft including cortical bone thickness, cancellous bone porosity, and overall dimensions through standardized processing protocols. These parameters are optimized to ensure mechanical strength while allowing biological integration, creating a predictable and reliable implant

Inventive Principle:

Principle #35Parameter changes

4Reliability

If the entire femoral head is removed for traditional hip replacement, then joint replacement is complete, but stress-shielding and bone density loss occur

Engineering Contradiction:

Improvejoint replacement completenessVSAvoidproximal femur bone density

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The allograft implant is segmented into distinct regions: a cortical bone outer shell that provides structural strength and load-bearing capacity, and a cancellous bone interior that allows vascular ingrowth and biological integration. This segmentation preserves the femoral head structure while providing the necessary joint replacement function

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8439921B2Device and method for allograft total hip arthroplasty

Publication Date: 2013.05.14 JAMALI AMIR

AI summary

Method and apparatus for preparing bone and cartilage transplants for the reconstruction of the acetabulum, femoral head, or both with tissue engineered osteochondral constructs or and osteochondral allograft transplant.