Bone Fracture Fixation Clamp Anti-Loosening Nut

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Solution Overview

Problem

Periprosthetic fractures, which occur around previously implanted metal prostheses, pose challenges in bone fixation due to the preclusion of certain bone fixation devices, necessitating the use of alternative methods like clamps and compression plates.

Innovation Solution

A bone fixation clamp system comprising first and second clamp members, a stud, and a locking nut with an anti-loosening feature, designed to securely stabilize the bone by threading over the stud, preventing post-operative loosening, and facilitating stabilization of periprosthetic fractures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking nut is threaded over a stud to fix clamp members, then the clamp members are secured over the bone, but the locking nut may loosen post-operatively

Engineering Contradiction:
Improvefixation stabilityVSAvoidlocking nut stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The locking nut includes an anti-loosening feature that proactively prevents loosening before it can occur. The deformable portion is pre-configured to deform and create interference with the stud threads, establishing a preventive mechanism against post-operative loosening rather than reacting to loosening after it occurs.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The locking nut utilizes deformation of its deformable portion to change its physical state and create interference with the stud threads. This parameter change from a rigid to a deformed state creates the anti-loosening effect by generating friction and mechanical interference that prevents thread rotation and loosening.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the stud and opening are correspondingly sized and shaped for non-rotatable reception, then rotational stability is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improverotational stabilityVSAvoidstud and opening dimensional tolerance
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The stud and opening include asymmetric features such as flats or non-circular cross-sections that prevent rotational movement. This asymmetric geometry ensures that the stud can only be inserted in a specific orientation and cannot rotate within the opening, providing inherent rotational stability through shape complementarity rather than relying solely on tight dimensional tolerances.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If the deformable portion deforms to interfere with threading, then anti-loosening effect is enhanced, but the threading process becomes more complex

Engineering Contradiction:
Improveanti-loosening effectivenessVSAvoidlocking nut structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking nut incorporates a deformable portion made from a flexible or elastically deformable material that can bend or deform during the threading process. This flexible portion deforms to create interference with the stud threads, and the material's elasticity allows it to maintain this deformed state, providing a continuous anti-loosening effect without requiring complex mechanical structures.

Inventive Principle:
Principle #30Flexible shells and thin films

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 clamp system effectively stabilizes periprosthetic fractures by securely fixing the clamp members over the bone, preventing loosening and providing stability, thus addressing the challenges posed by pre-existing metal prostheses.

Implementation Method 1

The locking nut includes an anti-loosening feature which, when the locking nut is threaded over the stud, results in an interference with threading along the stud

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a locking nut threadable over the stud to fix the first and second clamp members over the bone

Methodology Applied
Scientific EffectMechanical Fastening: Mechanical Fastener

Data Source

PatentEP4110210B1Bone fracture fixation clamp
Publication Date: 2024.12.11 DEPUY SYNTHES PROD INC
  • EP4110210B1 patent drawingFigure 1~2
  • EP4110210B1 patent drawingFigure 3~4
  • EP4110210B1 patent drawingFigure 5~7

AI summary

A bone fixation clamp includes first and second clamp members, a stud, and a locking nut. The first member extends along a curve corresponding to an outer surface of a first portion of bone and includes an opening extending therethrough along an axis extending adjacent to the bone. The second member extends along a curve corresponding to an outer surface of a second portion of bone. The stud is receivable within the opening of the first member. The nut includes a threaded channel threadedly engaging a portion of the stud so that, when the first and second members are in the operative configuration, the nut is threadable over the stud to fix the first and second members over bone. The nut includes an anti-loosening feature which, when the nut is threaded over the stud, results in an interference with threading along the stud.