Ligament Elastography for Preoperative Joint Replacement Planning
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Solution Overview
Problem
Conventional methods for characterizing ligament properties in orthopedic surgeries, such as total knee arthroplasty, lack objectivity and require intraoperative measurements, increasing procedure time and risk, while bone cuts limit corrective measures.
Innovation Solution
The use of elastography for preoperative and intraoperative characterization of ligament behavior through a computer-assisted surgical system, enabling objective assessment and planning before bone cuts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional gap-balancing techniques are used to characterize soft tissues, then intraoperative measurements can be obtained, but procedure time increases and surgical risk increases
Solution Approach 1:
The elastography imaging is performed preoperatively to characterize ligament properties before surgery. This preliminary assessment provides objective baseline data on ligament stiffness and strain distribution, eliminating the need for time-consuming intraoperative measurement procedures while preserving the ability to make informed surgical decisions.
Solution Approach 2:
The patent replaces mechanical tensioning devices and manual gap-balancing techniques with elastography imaging technology. This substitution uses non-contact ultrasound-based elastography to measure ligament mechanical properties, eliminating the need for physical manipulation devices and reducing procedural time and risk.
2Measurement precision
If mechanical tensioning devices are used for intraoperative measurement, then ligament properties can be characterized, but procedure complexity and infection risk increase
Solution Approach 1:
The patent replaces invasive mechanical tensioning devices with non-contact elastography imaging. This eliminates the need to introduce mechanical instruments into the surgical site, thereby reducing infection risk while maintaining the ability to characterize ligament mechanical properties through ultrasound-based strain measurement.
Solution Approach 2:
The elastography system acts as an intermediary between the surgeon and the ligament tissue. Instead of direct mechanical contact with tensioning devices, the system uses ultrasound waves to indirectly assess ligament properties, reducing direct exposure and infection risk while providing objective measurement data.
3Productivity
If bone cuts are performed before ligament characterization, then implant placement can proceed, but corrective measures are limited
Solution Approach 1:
The elastography assessment is performed before bone cuts and implant placement. This preliminary characterization of ligament properties allows the surgical plan to be optimized in advance, ensuring that bone cuts and implant selections are appropriate for the patient's specific ligament mechanics, thereby maintaining full corrective options without requiring reoperation.
Solution Approach 2:
The preoperative elastography provides feedback on ligament stiffness and strain distribution that informs surgical planning. This feedback loop allows surgeons to adjust their surgical approach, bone cut depths, and implant selections based on objective ligament data, maintaining adaptability while proceeding efficiently through the surgical workflow.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate preoperative planning and intraoperative adjustment of ligament tension, reducing procedure time and risk, and preserving options for implant selection and surgical precision.
Implementation Method 1
an ultrasound transducer is positioned against a patient's skin to emit sound waves that propagate through soft tissue
Implementation Method 2
elastography to estimate the stiffness and strain distribution in ligaments
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
Methods and system for characterizing ligament properties using elastography are disclosed. An ultrasound system capable of performing shear wave elasticity imaging and/or supersonic shear imaging may retrieve one or more images from a proposed surgical site. The one or more images may be provided to a surgical planning system that identifies one or more properties of ligaments proximate to the surgical site. Musculoskeletal simulations may be performed using the identified properties to preoperatively identify a surgical plan. Preoperative identification of a surgical plan may enable a surgeon to select from more fine-tuning options for a joint replacement than conventional systems.