Bone Resection Planning From Ligament Laxity in Joint Balancing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing joint surgeries, such as joint replacement procedures, face challenges in accurately calculating and adjusting ligament laxity and joint subluxation to achieve proper joint balance, leading to potential complications and reduced procedure efficiency.

Innovation Solution

A method and system for assessing a joint using image processing techniques to identify bone portions and ligaments, determining adjustment parameters through linear equations based on cross-sectional areas and ligament laxity, and outputting these parameters for bone resection and implant adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional manual methods are used to calculate and adjust ligament laxity and joint subluxation, then surgeon experience and judgment are required, but accuracy and consistency in joint balancing are reduced

Engineering Contradiction:
Improvejoint balancing accuracyVSAvoidligament laxity data accuracy
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces manual mechanical measurement and calculation methods with an automated image processing and computational system. The system uses images captured during surgery, applies image processing techniques to identify bone portions and ligaments, and automatically calculates ligament laxity and joint subluxation parameters through linear equations, eliminating reliance on surgeon experience and manual measurement errors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables self-service by automatically performing measurements, calculations, and recommendations without requiring external expert intervention. The image processing system autonomously identifies anatomical structures, computes laxity values, and generates bone resection recommendations based on the captured images and pre-stored linear equations specific to each patient's anatomy.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If complex image processing and multiple measurements are performed to accurately determine ligament laxity and bone resection parameters, then joint balancing accuracy is improved, but procedure time increases

Engineering Contradiction:
Improveligament laxity measurement accuracyVSAvoidprocedure time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-storing linear equations specific to each patient's anatomy before surgery. During the procedure, the system only needs to capture images and apply the pre-prepared equations, significantly reducing computation time. The complex image processing algorithms and measurement protocols are prepared in advance, allowing rapid execution during surgery.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces time-consuming manual measurement and calculation processes with an automated computational system that rapidly processes images and applies linear equations. The system efficiently performs multiple measurements and calculations simultaneously through computer algorithms, reducing the time required compared to sequential manual methods while maintaining high measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If standard bone resection procedures are performed without personalized adjustment based on individual ligament laxity, then procedure simplicity is maintained, but post-surgery complications increase

Engineering Contradiction:
Improvepost-surgery outcome reliabilityVSAvoidprocedure planning complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing personalized bone resection recommendations specific to each patient's unique ligament laxity and bone geometry. The system uses pre-stored linear equations tailored to individual patient anatomy to calculate precise resection depths and angles, ensuring that each patient receives customized treatment rather than standardized procedures, thereby improving post-surgery outcomes.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system implements feedback by using images captured during surgery to automatically calculate ligament laxity and joint subluxation, then providing real-time recommendations for bone resection adjustments. This closed-loop feedback mechanism allows the surgeon to make informed decisions based on actual intraoperative measurements, improving the reliability of surgical outcomes while managing complexity through automated computation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4652953A1Devices, systems, and methods for bone balance adjustment based on ligament laxity
Publication Date: 2025.11.26 MAKO SURGICAL CORP
  • EP4652953A1 patent drawingFigure 1
  • EP4652953A1 patent drawingFigure 2
  • EP4652953A1 patent drawingFigure 3

AI summary

A method of assessing a joint may include identifying a first bone portion in an image of the joint. The method may further include identifying a cross-sectional area of the first bone portion and identifying a medial ligament in extension value, a lateral ligament in extension value, a medial ligament in flexion value, and a lateral side in flexion value; determining a lateral ligament laxity based on the lateral ligament in extension value; and determining one or more adjustment parameters based on the identified cross-sectional area and the lateral ligament laxity. The determining the adjustment parameters may include a predicted change in soft tissue laxity after the identified first bone portion is removed. The adjustment parameters may include an adjustment to a planned bone resection and/or an adjustment to a planned thickness of an implant. The method may further include outputting the determined adjustment parameters to a display.