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Preliminary development of a hydroxyapatite-backed strain gauge
J A Szivek1, R G Gealer, F P Magee
1Harrington Arthritis Research Center, Phoenix, AZ 85006.
Journal of Applied Biomaterials : an Official Journal of the Society for Biomaterials
|October 1, 1990
Summary
Hydroxyapatite-backed strain gauges enable long-term in vivo bone strain sensing. This novel method overcomes limitations of traditional adhesives, accurately measuring bone deformation for over four months without adverse tissue response.
Area of Science:
- Biomedical Engineering
- Orthopedic Research
- Materials Science
Background:
- Long-term in vivo strain sensing is crucial for understanding bone remodeling around implants.
- Conventional cyanoacrylate adhesives limit strain gauge implantation duration to less than one month due to biodegradation.
- Hydroxyapatite (HA) is a biocompatible material used for bone implant fixation.
Purpose of the Study:
- To develop and evaluate a novel method for long-term in vivo strain sensing on bone.
- To assess the efficacy of hydroxyapatite-polysulfone composite as an adhesive for strain gauges.
- To determine the biocompatibility and accuracy of HA-backed strain gauges over an extended period.
Main Methods:
- Developed HA-polysulfone composite coatings for strain gauges.
- Tested three HA-polysulfone surface morphologies in preliminary bench-top experiments.
- Implanted the optimized HA-backed strain gauges onto a greyhound femur for four months.
- Compared in vivo strain measurements with contralateral femur data and analyzed tissue response via microradiography.
Main Results:
- The single-layer pressed HA-polysulfone surface morphology demonstrated superior performance in bench-top tests.
- HA-backed strain gauges maintained accurate strain measurements for four months in vivo.
- Microradiographs revealed no adverse tissue reactions to the HA-backed gauges on endosteal or periosteal surfaces.
Conclusions:
- Hydroxyapatite-polysulfone composite provides a viable, biocompatible adhesive for long-term in vivo strain gauge applications.
- This technique overcomes the limitations of conventional adhesives, enabling extended monitoring of bone strain.
- The developed HA-backed strain gauges accurately measure bone deformation during remodeling without eliciting adverse tissue responses.