Vibration measurements predict the mechanical properties of human tibia

Abstract

Background Vibration analysis is a promising technique in diagnosing metabolic bone diseases such as osteoporosis and monitoring fracture healing. The aim of this study is to observe the structural dynamic property changes of the tibia extracted from the vibration analysis data. Methods In this study, bone mineral density and vibration measurements were made both in in vivo and in vitro conditions. The relationship between structural dynamic properties, obtained and bone mineral densities measured were investigated. Also, the effect of soft tissues on measured structural dynamic properties was analyzed. Findings Natural frequency of the tibia decreased with decreasing bone mineral density that presented a weak correlation with the bone mineral density values measured by dual energy X-ray densitometer of the femur. In the case of in vitro experiments, it was observed that the effect of muscles on measurement results is higher than that of the effect of the skin and the fibula which makes the modal identification procedure difficult. However, having very large percentage changes in the loss factors when mineral content and collagen are reduced is an encouraging result to believe that damping measurements may yield a promising technique in diagnosing progressing osteoporosis and monitoring fracture healing period. Interpretation The utilization of natural frequency alone as a diagnosing tool does not seem to be a sufficient method although there is a correlation between this parameter and bone mineral density. However, in vitro experiments showed that the identification of the loss factor is a promising technique in diagnosing progressing osteoporosis.