ROM Tensor Navigation for Knee Ligament Balancing Before Bone Cuts
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Solution Overview
Problem
Current total knee arthroplasty (TKA) surgeries have low patient satisfaction rates, primarily due to challenges in ligament balancing, which have not been adequately addressed by existing medical procedures and innovations.
Innovation Solution
A system and method utilizing a range-of-motion (ROM) tensor with a main body, arms, and a pin guide, coupled with navigation systems, allows for ligament balancing without bone cuts by pivoting about a pin as the tibia moves through its range of motion, sharing rotation between the femur and tibia to balance soft tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional TKA surgical procedures are used, then bone cuts are performed to install knee prosthesis, but patient satisfaction rate remains low at about 80% due to inadequate ligament balancing
Solution Approach 1:
The patent replaces traditional mechanical gap measurement methods with a navigation system that uses trackers and computer processing to detect and measure joint gaps. The tensor device incorporates electronic sensors and wireless communication to transmit gap data to a computer, substituting manual mechanical measurement with an automated optical-mechanical system that provides more accurate ligament balancing assessment.
Solution Approach 2:
The patent introduces a tensor device as an intermediary tool between the surgeon and the joint gap measurement. This device incorporates trackers that attach to bone surfaces and transmit positional information through a navigation system, serving as a mediator that enables precise measurement of gap changes during ligament balancing without requiring direct manual measurement by the surgeon.
2Measurement precision
If navigation systems are used for ligament balancing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The navigation system is designed to perform multiple functions: tracking bone position, measuring joint gaps, guiding instrument placement, and providing real-time feedback during the surgical procedure. The tensor device serves both as a mechanical tool for ligament tensioning and as a measurement device with integrated trackers, eliminating the need for separate measurement instruments and reducing overall system complexity.
3Manufacturing precision
If bone cuts are performed to achieve ligament balancing, then joint alignment is improved, but surgical time and complexity increase
Solution Approach 1:
The navigation system allows for preoperative planning and intraoperative visualization of the desired joint alignment before any bone cutting is performed. The system calculates optimal cutting parameters and provides real-time feedback during the procedure, enabling surgeons to achieve precise alignment in fewer steps and reduce surgical time by avoiding trial-and-error adjustments.
Data Source
AI summary
A system for ligament balancing including a range-of-motion (ROM) tensor. The ROM tensor of the system includes a main body, first and second arms, a pin guide and a pin. The main body has an elongate guide. The first and second arms are rigidly attached to and extends laterally from the main body and configured to be placed over an uncut tibia and below an uncut femur. The pin guide is slidably coupled to the elongate guide and has a through-hole for receiving the pin. The ROM tensor is designed to pivot about the pin while the tibia moves through its range of motion while the femur preferably remains stationary. A navigation system monitors the position of the tibia and femur as the tibia moves and the gap information derived from the position monitoring is displayed on a display device.