Flush Cam-Locking Bone Plate Cable Fixation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional bone fixation systems using cable and plate methods are bulky, difficult to work with, and require special tools, with components often projecting from the bone plate, making them cumbersome and hard to install.

Innovation Solution

A cam-locking system with a flush-mounted cam mechanism that allows for easy installation of a cable loop around a bone, using a through-bore and groove system on the bone plate, where a cam with a concave profile is rotated to lock the cable in place without requiring special tools and ensuring the system is flush with the plate surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional cable and plate fixation systems are used, then bone fixation can be achieved, but the system becomes bulky and components project from the bone plate

Engineering Contradiction:
Improvebone fixation stabilityVSAvoidsystem bulk
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The cam mechanism is nested within the bone plate structure, with the cam body positioned in a recessed cavity of the plate. When activated, the cam rotates within this nested space to deploy its locking function, eliminating the need for external projecting components while maintaining fixation stability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from a three-dimensional external cable system to a two-dimensional planar cam mechanism that operates within the plane of the bone plate. The cam's rotation and locking action occur in a different dimensional space, allowing the system to achieve the same fixation function with minimal volume.

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

2Stability of the object's composition

If conventional cable and crimp systems are used, then bone fixation can be achieved, but special tools are required for installation

Engineering Contradiction:
Improvebone fixation stabilityVSAvoidinstallation ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The cam mechanism is designed to be self-actuating through a simple rotational motion that directly engages the cable locking feature. The cam's geometric profile automatically converts rotational input into the necessary clamping force on the cable, eliminating the need for specialized crimping tools or complex installation procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Instead of using a tool to crimp or deform the cable onto the bone, the invention inverts the approach by using a rotating cam to apply controlled pressure that secures the cable in place. This reverse engineering of the locking mechanism simplifies the installation process to a basic rotational action.

Inventive Principle:
Principle #13The other way round (Inversion)

3Stability of the object's composition

If conventional cable systems with projecting components are used, then bone fixation can be achieved, but the system is hard to work with and cumbersome

Engineering Contradiction:
Improvebone fixation stabilityVSAvoidsurgical maneuverability
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The invention extracts the cam mechanism from the external environment and integrates it directly into the bone plate structure. By removing the need for separate external components and their associated installation tools, the system becomes much easier to manipulate during surgery while maintaining all necessary fixation functions.

Inventive Principle:
Principle #2Taking out (Extraction)

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 cam-locking system provides a user-friendly, tool-free method for securing cables around bones, ensuring a secure and stable fixation without any components projecting from the bone plate, enhancing surgical efficiency and ease of use.

Implementation Method 1

Rotation of the cam results in the cam surface squeezing the cable between concave cam surface and walls of the opening, thereby locking the cable in the tightened state

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP2197375B1Cam-locking of cable for fracture plate
Publication Date: 2015.12.02 STRYKER EUROPEAN HOLDINGS I LLC
  • EP2197375B1 patent drawingFigure 1
  • EP2197375B1 patent drawingFigure 2A~2C
  • EP2197375B1 patent drawingFigure 3

AI summary

A bone plate (20) mounted on a bone (22) having at least one opening (24) for receiving a flush mounted cam (30, 134). A through-bore (46) passes from a side surface to opposing side surface of the bone plate (20) and has a diameter sized to allow insertion of a cable (54). A portion of the through- bore (46) intersects with a peripheral portion of the opening (24). A second opening (48) also passes from the side surface to opposing side surface. A cable (54) may be inserted in the second opening (48), wrapped around the bone (22) and its free end inserted in the through-bore (46, 48). The cable (54) may be tightened around the bone (22). The flush mounted cam (30) can be rotated in place, resulting in the cam surface squeezing the cable (54) between concave cam surface and walls of the opening, thereby locking the cable (54) in the tightened state.