A long-term in vivo bone strain measurement device

Area of Science:

• Biomedical Engineering
• Orthopedic Research
• Biomaterials Science

Background:

• Bone remodeling is influenced by mechanical strain, crucial for implant integration.
• Existing strain sensors lack long-term in vivo stability for studying bone remodeling.
• Developing durable in vivo strain sensors is vital for understanding implant osseointegration.

Purpose of the Study:

• To develop and evaluate a novel long-term in vivo strain sensor for bone.
• To assess the efficacy of a porous-surfaced gauge for stable attachment via tissue ingrowth.
• To compare the performance of the novel sensor against standard strain gauges in a long-term study.

Main Methods:

• A porous-surfaced metal tab was integrated with a standard strain gauge.
• The novel gauge and standard gauges were implanted onto greyhound femurs.
• Strain measurements were recorded over an 8-week period, followed by histological analysis.

Main Results:

• The porous-surfaced gauge remained attached and functional for 8 weeks.
• Standard gauges debonded within 3 weeks, losing functionality.
• Measurements from the porous gauge were lower, attributed to fibrous tissue ingrowth.

Conclusions:

• Porous-surfaced gauges offer a viable strategy for long-term in vivo strain sensing.
• Tissue ingrowth provides a stable attachment mechanism, but bone ingrowth is preferred for accurate readings.
• Further development is needed to ensure bone ingrowth for optimal sensor performance in bone remodeling studies.