Robotic Joint Soft Tissue Evaluation for Precise Ligament Balancing
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Solution Overview
Problem
Traditional manual evaluation of soft tissue during partial or total joint replacement surgeries leads to complications such as joint imbalance, discomfort, and the need for revision surgeries, as surgeons lack precise methods to achieve balanced joint results.
Innovation Solution
A robotic ligament evaluator system with force-torque sensing capabilities and encoders, integrated with a computer-assisted surgery system, allows for precise evaluation and balancing of soft tissues by replicating and adjusting joint positions, using local tracking systems and ultrasound transducers for continuous registration, and providing modes for fixed and repositioning during surgical procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual evaluation methods are used by surgeons, then the surgical procedure is simple to perform, but the measurement precision and manufacturing precision of soft tissue balancing deteriorate
Solution Approach 1:
The patent replaces manual mechanical evaluation by surgeons with an automated robotic system that uses force-torque sensors and encoders to objectively measure joint mechanics. The robotic device applies controlled forces and torques to the joint while sensors measure the resulting movements, eliminating subjective manual assessment and providing precise quantitative data for soft tissue balancing.
Solution Approach 2:
The robotic evaluation system performs self-measurement by automatically applying forces, sensing responses, and calculating soft tissue characteristics without requiring surgeon manipulation. The system autonomously executes evaluation protocols, records data, and provides feedback for surgical decision-making, reducing dependency on manual skill variability.
2Reliability
If traditional manual testing methods are used, then the ease of operation is maintained, but the reliability of achieving balanced joint results deteriorates
Solution Approach 1:
The robotic system incorporates real-time feedback through force-torque sensors that continuously monitor joint responses during evaluation. The system provides immediate quantitative feedback on ligament tension and joint stability, allowing surgeons to objectively assess soft tissue balance and make informed decisions about necessary adjustments, thereby improving reliability of balanced joint outcomes.
3Measurement precision
If manual soft tissue evaluation is performed, then the device complexity remains low, but the measurement precision and objectivity deteriorate
Solution Approach 1:
The patent employs force-torque sensors and encoders within the robotic system to objectively measure ligament tension and joint mechanics, replacing subjective manual palpation and testing. These sensors provide precise quantitative measurements of forces and torques applied to and generated by the joint, enabling accurate assessment of soft tissue characteristics that cannot be obtained through manual evaluation alone.
Data Source
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AI summary
A method of robotically evaluating soft tissue characteristics of a joint includes measuring, by a robotic device, information about a joint during a controlled range of motion manipulation of the joint; determining a motion limit of the joint, using the information about the joint measured during the controlled range of motion manipulation of the joint, wherein the motion limit is at least one of a displacement limit or a force limit of the joint; and replicating, using a joint positioner controlled by the robotic device, the controlled range of motion manipulation of the joint while introducing perturbations to the joint, wherein the replicated range of motion manipulation is controlled, at least in part, based on the motion limit. The method further includes using data obtained by the computer-assisted surgery system during the range of motion manipulation with perturbations to characterize the constraints of a soft tissue envelope of the joint.