Anatomical Guide for Trochlear Groove Bone Resection

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Solution Overview

Problem

Current patellofemoral joint replacement systems lack anatomically guided instrumentation for precise bone preparation and implantation, leading to inconsistent results and poor fit, which affects patellar tracking and overall knee kinematics.

Innovation Solution

A system comprising a prosthesis with angled protrusions and an annulus for secure bone contact, along with templates and guides for precise alignment and resection, ensuring accurate bone preparation and implant sizing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If free-hand instruments (rongeur, osteotome, rasp, saw, burr) are used for bone removal in the trochlear groove region, then the surgeon has flexibility in handling, but precision and reproducibility of the trochlear groove restoration are poor

Engineering Contradiction:
Improvesurgeon flexibility in handling instrumentsVSAvoidprecision of trochlear groove restoration
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent introduces an anatomical guide as an intermediary device between the surgeon and the bone removal instruments. The guide includes template members with reference points that contact specific anatomical landmarks on the femur, creating a mediator system that translates surgeon intent into precise, reproducible bone removal while preserving surgeon flexibility in instrument selection and handling

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by pre-establishing the anatomical guide on the femur before any bone removal begins. The guide templates are positioned and secured to reference points on the femoral anatomy, pre-defining the precise locations and orientations for all subsequent bone removal activities, ensuring that precision is built into the process from the start rather than attempted during instrument manipulation

Inventive Principle:
Principle #10Preliminary action

2Productivity

If current PFJ replacement systems use free-hand instrumentation, then procedure duration may be reduced, but the results are inconsistent and patellar tracking is compromised

Engineering Contradiction:
Improveprocedure durationVSAvoidconsistency of surgical results
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The anatomical guide is established as a preliminary structure before bone removal begins, pre-defining all critical parameters for trochlear groove reconstruction. This preliminary positioning of templates with reference points ensures that when bone removal proceeds, it follows pre-determined precise paths, achieving both efficiency and consistency without requiring prolonged surgical time for repeated measurements and adjustments

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent incorporates feedback mechanisms through the anatomical guide's reference points that contact specific femoral landmarks. These reference points provide continuous feedback during the procedure, allowing the surgeon to verify positioning and maintain consistency. The guide's fixed geometry provides inherent feedback on whether bone removal is proceeding along the correct trajectory, ensuring reliable results while maintaining procedural efficiency

Inventive Principle:
Principle #23Feedback

3Device complexity

If asymmetric implant designs with few sizing options are used, then device complexity is reduced, but anatomic fit is poor

Engineering Contradiction:
Improveimplant design varietyVSAvoidanatomic fit
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by providing multiple template members with varying dimensions, offsets, and configurations that correspond to different implant sizes and anatomical variations. The system includes templates with different reference point spacings, distances from the femoral axis, and angular orientations, allowing precise adaptation to diverse patient anatomies while maintaining a unified guide design framework

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The anatomical guide system is segmented into multiple interchangeable template members, each designed for specific implant sizes or anatomical configurations. This segmentation allows the surgeon to select and attach the appropriate template module to match the patient's anatomy and chosen implant size, achieving customized anatomic fit without requiring completely different guide systems for each implant variant

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2958522B1Anatomically guided instrumentation for trochlear groove replacement
Publication Date: 2017.11.29 STRYKER CORP
  • EP2958522B1 patent drawingFigure 1A
  • EP2958522B1 patent drawingFigure 1B
  • EP2958522B1 patent drawingFigure 2

AI summary

A method for replacing a joint surface, which includes resecting a first portion (2004) of the joint surface to create a wall surface (2006) and inner resected surface (2007). The wall surface (2006) separates the inner resected surface (2007) and a non-resected portion of the joint surface. Further included in the method is cutting a concave groove (2008) having a first radius into the wall surface (2006), and engaging the concave groove (2008) with a periphery (2102) of a joint prosthesis (2100). The periphery (2102) includes a second radius that is substantially the same as the first radius of the concave groove (2008).