Magnetic Hip Prosthesis With Rotatable Femoral Head for Dislocation Control

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Solution Overview

Problem

Existing total hip replacement (THR) prostheses face high dislocation rates due to misalignment of the femoral and acetabular components, leading to complications such as impingement, wear, and osteolysis, with conventional stabilization methods limiting motion or causing additional issues.

Innovation Solution

A hip prosthesis design featuring an acetabular component with magnets and a rotatable spherical magnet on the femoral component, generating an attractive force to maintain stability throughout the hip's range of motion, reducing the risk of dislocation and associated complications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional stabilization methods (posteriorly oriented rim, larger femoral component heads, constrained femoral head-polyethylene liner, mobile polyethylene component) are used to reduce dislocation, then stability is improved, but complications such as impingement, wear, osteolysis, loosening, restricted range of motion, and locking mechanism failure increase

Engineering Contradiction:

ImprovestabilityVSAvoidimpingement, wear, osteolysis, loosening

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces conventional mechanical stabilization methods (physical constraints like posteriorly oriented rims, constrained liners, and mobile polyethylene components) with a magnetic field-based stabilization system. Magnets embedded in the acetabular component and femoral component generate magnetic attraction forces that stabilize the joint without mechanical contact, eliminating impingement and wear associated with traditional mechanical constraints.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state of stabilization from mechanical contact forces to magnetic field forces. By embedding magnets in both components, the system creates a non-contact magnetic attraction that provides stability without the harmful mechanical interactions (impingement, wear, osteolysis) that occur with conventional mechanical stabilization methods.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional stabilization methods are used to reduce dislocation, then stability is improved, but range of motion is restricted

Engineering Contradiction:

ImprovestabilityVSAvoidrange of motion

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The magnetic stabilization system replaces mechanical constraints (constrained liners, posteriorly oriented rims) with magnetic field forces that can act across the full range of motion without physical contact. This allows the femoral component to move freely within the acetabular component while maintaining stable alignment through magnetic attraction, preserving natural range of motion.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If larger femoral component heads are used to improve stability and reduce dislocation, then head-to-neck ratio is improved, but liner wear and corrosion at the femoral head-neck interface increase

Engineering Contradiction:

ImprovestabilityVSAvoidliner wear, corrosion

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent eliminates the mechanical contact between the femoral head and acetabular liner by introducing magnetic fields as the stabilization mechanism. Magnets embedded in both components create magnetic attraction forces that stabilize the joint without requiring mechanical contact, thereby eliminating liner wear and corrosion at the femoral head-neck interface that result from larger femoral component heads.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provides enhanced stability and reduces the incidence of dislocation, impingement, and osteolysis while maintaining a full range of motion, avoiding complications associated with conventional stabilization methods.

Implementation Method 1

The acetabular component comprises one or more magnets and the femoral component comprises a spherical magnet. The spherical magnet is rotatable within the spherical head. An attractive force is generated between the one or more magnets of the acetabular component and the spherical magnet of the femoral component.

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentUS20260076802A1Total hip replacement system with rotatable femoral magnet

Publication Date: 2026.03.19 FELLOWSHIP OF ORTHOPAEDIC RESEARCHERS LLC

AI summary

A hip prosthesis that comprises an acetabular component and a femoral component. The acetabular component comprises a shell and optionally a liner. The shell has an approximate shape of a hollowed spherical cap, in which the shell comprises one or more magnets. The femoral component comprises a stem portion, a neck portion that is joined to the stem portion, and a spherical head that is affixed to the neck portion and comprises a spherical magnet that is rotatable within the spherical head. The acetabular component is configured to receive all or a portion of the spherical head of the femoral component. Further, the one or more magnets of the acetabular component and the spherical magnet of the spherical head of the femoral component are oriented to generate an attractive force therebetween.