Dual-Function Cutting Instrument for Osteochondral Plug Sizing

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Solution Overview

Problem

Current osteochondral grafting procedures face challenges in accurately sizing and securing osteochondral plugs for implantation, leading to potential graft rotation, tissue damage, and poor integration due to the lack of precise cutting and trimming tools that can handle the plugs without causing further damage.

Innovation Solution

A dual-function cutting instrument with a cutting block that allows for both length and cross-sectional sizing of osteochondral plugs, featuring a bore for secure placement, a paring slot for length adjustment, and trimming channels for precise cross-sectional trimming, enabling accurate preparation without removing the plug from the instrument.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional osteochondral grafting procedures are used without precise cutting instruments, then the procedure is simpler to perform, but the graft sizing accuracy deteriorates leading to rotation or loosening

Engineering Contradiction:

Improvegraft sizing accuracyVSAvoidcutting instrument complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cutting instrument is divided into distinct functional components: a cutting block with bore for initial sizing, a paring slot for length adjustment, and trimming channels for cross-sectional sizing. This segmentation allows each component to perform its specific function precisely while maintaining overall system manageability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The instrument performs preliminary sizing actions in a specific sequence: first the bore provides initial cylindrical sizing, then the paring slot adjusts length, and finally the trimming channels refine cross-sectional dimensions. This preliminary action sequence ensures accurate graft preparation before implantation

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the host site opening is made larger to accommodate the graft, then implantation is easier, but tissue damage to the graft increases

Engineering Contradiction:

Improveimplantation easeVSAvoidtissue damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The instrument employs a press-fit mechanism where the precisely sized graft is inserted into the host site opening and compressed to achieve intimate seating. This hydraulic-like pressing action secures the graft without requiring excessive opening size that would cause tissue damage

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The instrument replaces rough mechanical insertion with precise mechanical sizing followed by controlled press-fit. The cutting block, paring slot, and trimming channels collectively prepare the graft to exact dimensions, allowing gentle insertion and secure fitting without tissue trauma

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the graft is trimmed to precise dimensions using multiple separate instruments, then sizing accuracy improves, but the number of handling steps increases causing more damage

Engineering Contradiction:

Improvedimensional accuracyVSAvoidnumber of instruments

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cutting block, paring slot, and trimming channels are merged into a single integrated instrument. This allows all trimming operations (length and cross-sectional) to be performed on the graft while it remains secured in the bore, eliminating the need to transfer the graft between multiple instruments and reducing handling damage

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The instrument serves multiple functions within a single device: the bore provides initial cylindrical sizing and secure holding, the paring slot enables length trimming, and the trimming channels facilitate cross-sectional sizing. This multi-functionality consolidates what would traditionally require multiple separate instruments

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7955336B2Cutting instrument and method of use for preparing an osteochondral plug for implantation

Publication Date: 2011.06.07 WARSAW ORTHOPEDIC INC

AI summary

A cutting instrument and method of use for preparing an osteochondral plug for implantation into a bone defect site. The instrument includes a dual function cutting block, a base holder, a rod mechanism and a trimming mechanism. The cutting block has a bore sized to receive the plug, at least one trimming channel and a transverse paring slot. The cutting block functions to hold the plug within the bore to allow for length and cross-sectional sizing. The base holder is constructed to fix the cutting block in a first orientation that allows the rod mechanism to position the plug within the cutting block for accurate length sizing. The base holder is also constructed to fix the cutting block in a second orientation which aligns the cutting block with the trimming mechanism so that an angled blade may engage the trimming channel and cut at least two sides of the plug.