Patient-Specific Joint Arthroplasty Guide Template

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Solution Overview

Problem

Current joint arthroplasty techniques are invasive and often result in poor alignment and joint congruity, leading to instability, as existing tools fail to provide ideal cuts for surgical implantation, and biologic replacement materials struggle to achieve a morphologic arrangement similar to normal cartilage, with mechanical durability and long-term complications such as osteolysis.

Innovation Solution

A patient-specific guide template or mold is designed using electronic image data to engage the articular surface, allowing for precise cuts and alignment, and a method of producing articular replacement material that conforms to the measured dimensions of the joint, including cartilage replacement with non-pliable, solid materials that achieve a near anatomic fit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional joint arthroplasty tools are used, then surgical procedures can be performed, but poor alignment and joint congruity result leading to instability

Engineering Contradiction:
Improvecut alignment accuracyVSAvoidjoint stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

Patient-specific guide templates are manufactured preoperatively based on imaging data (CT/MRI) and surgical planning. These templates include contact surfaces that conform to the patient's actual joint anatomy and guide features that define precise cut orientations, allowing the surgeon to achieve accurate alignment without complex intraoperative adjustments

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The guide templates create a physical copy or replica of the patient's preoperative imaging data and planned surgical geometry. The contact surfaces replicate the anatomical features from the imaging data, while the guide features replicate the desired cut orientations from the surgical plan, transferring the virtual plan to the physical surgical field

Inventive Principle:
Principle #26Copying

2Strength

If biologic replacement materials are used, then cartilage repair is attempted, but morphologic arrangement similar to normal cartilage cannot be achieved, resulting in uncertain mechanical durability

Engineering Contradiction:
Improvemechanical durabilityVSAvoidmorphologic arrangement
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The invention transitions from biologic materials with uncertain mechanical properties to non-pliable solid materials (such as metal, ceramic, or highly cross-linked polymer) that provide predictable and durable mechanical properties. The solid material is shaped to replicate the load-bearing geometry of native cartilage while providing superior mechanical strength and wear resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The prosthesis may combine different materials (e.g., metal stem with polymer bearing surface, or ceramic with metal) to achieve both the mechanical durability of solids and the functional performance of cartilage-like surfaces, creating a composite structure that addresses both strength and morphologic requirements

Inventive Principle:
Principle #40Composite materials

3Reliability

If invasive joint arthroplasty procedures are performed, then joint replacement is achieved, but loss of underlying tissue and bone occurs leading to osteolysis and implant loosening

Engineering Contradiction:
Improveimplant retentionVSAvoidbone and tissue loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The prosthesis design preserves healthy bone and tissue by localizing the intervention to only the damaged cartilage area. The solid material replacement is confined to the specific defect geometry rather than requiring extensive bone resection, maintaining local bone stock and reducing the risk of osteolysis

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Preoperative imaging and planning identify the exact boundaries of cartilage damage, allowing the guide template to be designed with contact surfaces that engage only healthy tissue and guide features that define cuts limited to the damaged area, preventing unnecessary loss of bone and tissue

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If patient-specific guide templates are designed to engage osteophytes, then coverage of irregular joint surfaces is achieved, but template design complexity increases

Engineering Contradiction:
Improveengagement with irregular surfacesVSAvoidtemplate design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The complex task of adapting to irregular joint surfaces (including osteophytes) is performed preoperatively through imaging data acquisition and computer-aided design. The guide template is manufactured with the adapted geometry already incorporated, eliminating the need for complex intraoperative adjustments and simplifying the surgical procedure

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2710967B1Patient specific joint arthroplasty system
Publication Date: 2019.05.01 CONFORMIS INC
  • EP2710967B1 patent drawingFigure 1
  • EP2710967B1 patent drawingFigure 2~3A
  • EP2710967B1 patent drawingFigure 3B~4

AI summary

Disclosed herein are methods, compositions and tools for repairing articular surfaces repair materials and for repairing an articular surface. The articular surface repairs are customizable or highly selectable by patient and geared toward providing optimal fit and function. The surgical tools are designed to be customizable or highly selectable by patient to increase the speed, accuracy and simplicity of performing total or partial arthroplasty.