Measurements of stress and strain in live bone by electrical strain gage method.

Measurements of stress and strain in parts of musculokeletal system has been extensively studied in recent years. "In vitro" tests have contributed important information. The present study is an attempt to assess "in vivo" measurements using electrical extensometers attached to the bone with biocompatible adhesives permitting accurate measurements of strain over long periods of time. Even though its seems to be an adequate method there are some limitations to be considered. The problem involving tissue reaction, protections and isolation of the measuring unit, validity of measurements and determination of the principal directions of the strain are discussed. When adequately used the method may contribute to the knowledge and understanding of biomechanics of the musculokeletal system.