Floating Locking Insert With Asymmetric Collar For Bone Fixation

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Solution Overview

Problem

Existing screw-and-plate systems for osteosynthesis or arthrodesis have limited resistance to compression stresses and difficulty in aligning fasteners accurately, leading to suboptimal fixation of bone fragments.

Innovation Solution

A fixation system comprising a plate with a unique insert design featuring a collar with varying radial distances and stopper surfaces, allowing for precise alignment and locking of fasteners at desired angles, enhancing the system's resistance to compression and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If radial offsets are extended along the entire arcuate surface of the insert, then friction is increased to enhance locking, but control of the insert during angle setting is diminished

Engineering Contradiction:

Improvelocking strengthVSAvoidinsert alignment control

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The collar features localized radial offsets at discrete positions rather than continuous offsets along the entire arcuate surface. This creates localized friction zones that provide locking strength at specific angular positions while leaving other portions of the collar surface free to rotate smoothly, thereby maintaining control during angle setting.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the insert allows polyaxial movement for angle selection, then versatility is improved, but precision in maintaining the desired angle is reduced

Engineering Contradiction:

Improveangle selection flexibilityVSAvoidangle alignment precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The collar acts as an intermediary mechanism between the insert and the plate aperture. It provides a controlled degree of polyaxial movement that allows angle selection while its interaction with the plate aperture's inner wall serves as a guiding constraint that maintains precision in the final angular position.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If the collar has varying radial distances, then alignment precision is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvealignment precisionVSAvoidcollar structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The collar incorporates asymmetric radial offsets at specific positions, creating varying radial distances from the longitudinal axis. This asymmetric geometry provides precise alignment features while being manufacturable through standard machining processes for asymmetric components.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS20250099146A1Floating Locking Insert

Publication Date: 2025.03.27 STRYKER EUROPEAN OPERATIONS HOLDINGS LLC

AI summary

An insert for receipt within a plate aperture having an inner wall along the plate aperture includes a body and collar. The body has inner and outer surfaces. The inner surface defines an insert aperture having a longitudinal axis. The collar extends from the outer surface in a first radial direction perpendicular to the longitudinal axis and extends along only a portion of the outer surface in a second radial direction transverse to the first radial direction and the longitudinal axis. The collar defines a first radial distance from the longitudinal axis at a first position of the collar and a second radial distance from the longitudinal axis at a second position of the collar that differs from the first radial distance. A fixation system includes the plate and insert which is receivable within the plate aperture such that the collar contacts and is slideable along the inner wall.