Implant Stability Sensing for Measuring Bone-Implant Micromotion
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Solution Overview
Problem
Existing orthopedic implant surgeries face challenges in determining the stability and fit between implants and bones, particularly in cementless procedures, which can lead to issues like osteolysis and premature loosening due to inadequate bone integration, especially in younger patients with good bone quality.
Innovation Solution
A system and method for detecting relative motion between an implant and bone using a bone locator, implant attachment, and a motion detector, which includes a camera and torque wrench to apply forces and measure stability, providing an indication of implant movement based on relative motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cementless fixation is used to eliminate cement-related complications, then long-term reliability is improved, but implant stability assessment becomes difficult leading to potential fixation failure
Solution Approach 1:
The patent introduces a sensor system as an intermediary between the implant-bone interface and the surgeon. The sensor includes a sensor head with accelerometer and magnetometer that indirectly measure implant stability by detecting motion and orientation changes, translating complex biological fixation processes into measurable electrical signals.
Solution Approach 2:
The patent replaces traditional mechanical stability assessment methods (visual inspection, tactile feedback) with electronic sensing systems. The accelerometer and magnetometer detect mechanical motion and orientation, converting physical implant-bone interface conditions into electrical signals for quantitative analysis.
2Reliability
If cemented fixation is used to ensure immediate stability, then short-term reliability is improved, but long-term durability deteriorates due to cement breakdown and osteolysis
Solution Approach 1:
The patent implements real-time feedback through the sensor system that continuously monitors implant stability and transmits data to the surgeon's device. This allows dynamic assessment of fixation quality throughout the surgical process, enabling informed decisions about whether cemented or cementless fixation is appropriate based on actual measured stability rather than preoperative assumptions.
3Reliability
If cementless fixation is used for younger patients with good bone quality, then long-term outcomes are improved, but implant stability assessment becomes critical yet difficult
Solution Approach 1:
The patent adds a new dimension to stability assessment by using three-dimensional motion tracking with the accelerometer and magnetometer. The sensor head measures acceleration along three axes and magnetic field orientation, creating a multi-dimensional data set that provides precise quantitative measurement of implant stability beyond traditional single-parameter assessments.
Data Source
AI summary
A system for detecting motion between an implant and a bone that can optionally include: a bone locator means configured to be coupled to the bone, an implant attachment means configured to be coupled to the implant, and a data analysis means. The implant attachment means includes a detection means, and the implant attachment means defines one or more apertures or surfaces for receiving a force from a force inducing means.