Bone Model Updating for Prosthesis Removal Bone Loss

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Solution Overview

Problem

The challenge in orthopedic revision surgeries is accurately predicting and adapting to bone loss caused by the removal of an existing orthopedic prosthesis, which complicates the surgical planning and registration of 3D models with real-world bones due to mismatched landmark locations.

Innovation Solution

A surgical assistance system generates a pre-revision model of the bone, obtains intra-revision imaging data to identify damaged and intact parts, and modifies the model to exclude damaged areas, enabling a revised surgical plan and improved registration with the actual bone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a pre-revision 3D model of the bone is used for surgical planning, then the surgical plan can be prepared in advance, but the model becomes inaccurate due to bone loss during prosthesis removal

Engineering Contradiction:
Improvesurgical planning timeVSAvoidbone model accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The system transitions from a static pre-revision bone model to a dynamic intra-revision bone model that is updated during surgery. The intra-revision model is generated from real-time imaging data captured after prosthesis removal, allowing the model to adapt to actual bone conditions and maintain accuracy throughout the surgical procedure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback by comparing the pre-revision model with actual intra-revision imaging data. This feedback loop identifies discrepancies caused by bone loss and enables generation of corrected intra-revision models that reflect the true bone geometry, improving subsequent surgical guidance accuracy.

Inventive Principle:
Principle #23Feedback

2Ease of repair

If the existing prosthesis is removed during revision surgery, then the damaged prosthesis can be replaced, but bone loss occurs that complicates surgical planning

Engineering Contradiction:
Improveprosthesis replacementVSAvoidsurgical planning complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by generating the pre-revision bone model and surgical plan before prosthesis removal. This allows surgeons to prepare implant selection and surgical approach in advance, even though the final plan may be adjusted based on intra-revision findings.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes parameters by transitioning from pre-revision to intra-revision modeling. This parameter change captures the actual bone geometry after prosthesis removal, including any bone loss or damage, enabling accurate measurement and planning for the replacement prosthesis.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If intra-revision imaging data is obtained during surgery, then accurate bone geometry can be captured, but the surgical process is extended

Engineering Contradiction:
Improvebone geometry accuracyVSAvoidsurgical duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system maintains continuity by integrating intra-revision imaging and model generation into the existing surgical workflow. The imaging and model updating occur during normal surgical steps without requiring separate dedicated time for model creation, keeping the surgical process flowing continuously.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4106655B1Computer-implemented surgical planning based on bone loss during orthopedic revision surgery
Publication Date: 2026.01.28 HOWMEDICA OSTEONICS CORP
  • EP4106655B1 patent drawingFigure 1
  • EP4106655B1 patent drawingFigure 2
  • EP4106655B1 patent drawingFigure 3

AI summary

A surgical assistance system may obtain a pre-revision model of a bone of a patient. The pre-revision model of the bone represents a pre-revision state of the bone after a prior orthopedic surgery on the bone. In this example, an orthopedic prosthesis was attached to the bone during the prior orthopedic surgery. Additionally, the surgical assistance system may obtain intra-revision imaging data of the bone. The intra-revision imaging data represents an intra-revision state of the bone during the orthopedic revision surgery after removal of the orthopedic prosthesis from the bone. The surgical assistance system may determine, based on the intra revision imaging data, damaged and intact parts of the bone. The surgical assistance system may then generate a second intra-revision model of the bone by modifying the pre-revision model of the bone to exclude damaged parts of the bone.