TPLO Plate With Camming Alignment for Low-Compression Fixation

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Solution Overview

Problem

Existing TPLO plates compress the bone surface during fixation, compromising the blood supply and increasing the risk of infection and slow healing, while conventional locking screws maintain a fixed relationship without allowing bone fragments to be drawn together effectively.

Innovation Solution

A TPLO plate with removable plugs in the apertures that protrude from the bone-facing surface, allowing the plate to be fixed without direct contact, combined with camming surfaces and slots to align and draw bone fragments together, using polyaxial locking screws for secure fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional TPLO plates are fixed directly to the bone surface, then secure fixation is achieved, but bone surface compression occurs which compromises blood supply and increases infection risk

Engineering Contradiction:
Improvefixation securityVSAvoidbone surface compression
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary layer (protective coating or membrane) between the plate and bone surface that prevents direct compression while allowing secure fixation. This intermediary protects the bone surface and blood supply during the healing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The plate is segmented into regions with different properties - some areas have compression-relieving features while others provide secure fixation. This allows simultaneous achievement of both secure fixation and minimal bone surface compression.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If locking screws are used to maintain plate away from bone surface, then bone surface compression is avoided, but bone fragments cannot be drawn together effectively

Engineering Contradiction:
Improvebone surface compressionVSAvoidbone fragment alignment
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The plate incorporates dynamic elements that allow controlled movement or adjustment. The system transitions from a static fixed position to a dynamic system that can adapt during healing, allowing bone fragments to be drawn together while maintaining plate-bone separation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The plate design allows the bone fragments themselves to drive the alignment process through natural healing forces, while the plate provides guidance and maintains separation. The system uses the body's own healing mechanisms to achieve proper alignment.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If dynamic compression plates are used to draw bone fragments together, then healing is promoted, but plate pulls onto bone surface causing compression

Engineering Contradiction:
Improvebone fragment approximationVSAvoidbone surface compression
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent resolves the contradiction by operating in another dimension - using vertical separation (distance from bone surface) to achieve horizontal approximation (bone fragment alignment). The plate draws bone fragments together along the longitudinal axis while maintaining separation in the perpendicular dimension.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 plate minimizes bone compression, promotes direct bone healing, reduces infection risk, and allows for precise alignment of bone fragments, enhancing healing outcomes.

Implementation Method 1

The aperture has a chamfered or slanted side and is typically ovoid in shape and the screw, for example a cortical screw, has a head complementary in shape to and which engages the side of the aperture and, in a camming effect, upon fixing urges the bone fragment to move axially relative to the plate

Methodology Applied
Scientific EffectCamming mechanism: Cam

Data Source

PatentEP3544532B1Orthopaedic apparatus
Publication Date: 2025.10.01 VETSOS LTD
  • EP3544532B1 patent drawingFigure 1
  • EP3544532B1 patent drawingFigure 2~4
  • EP3544532B1 patent drawingFigure 5A~6

AI summary

A plate for securing two bone segments in a tibial plateau levelling osteotomy procedure having a body with an elongate distal portion and a proximal portion extending laterally and a plurality of apertures for receiving fixing means wherein at least two of the apertures are adapted to receive fixing means and at least one of the said apertures is adapted to receive a removable plug which extends proud of the bone-facing surface. One of the apertures has a camming surface configured such that upon insertion of the fixing means the bone fragments are urged together thereby promoting healing without deleterious compression of the surface of the bone.