Quantitative ultrasound of the calcaneus reflects the mechanical properties of calcaneal trabecular bone.

Abstract

To provide new information about the potential role of quantitative ultrasound (QUS) in fracture risk prediction, we assessed whether QUS and densitometric variables derived from measurements of intact cadaveric feet were associated with the mechanical properties of calcaneal trabecular bone. We obtained 31 intact cadaveric feet from the local anatomic gifts program, including 13 men and 18 women, with a mean age of 77 years (range 50-91 years). Broadband ultrasound attenuation (BUA) and ultrasound transit velocity (SOS) were assessed in the intact cadaveric feet using a water-based ultrasound system. In addition, we measured the bone mineral density (BMD) of the posterior calcaneus using dual-energy X-ray absorptiometry. Cubes of trabecular bone were then removed from the calcaneus at approximately the same location as the QUS measurements were obtained, and the elastic modulus and ultimate strength of the trabecular bone specimens were measured by compressing them in the mediolateral direction. We found that QUS variables were moderately to strongly correlated with the mechanical properties of calcaneal trabecular bone (r2 = 0.48-0.63, p < 0.001 for all). However, the strongest associations with the mechanical properties trabecular bone were provided by calcaneus BMD and trabecular bone apparent density (r2 = 0.66-0.88). BUA and densitometric measurements were independently associated with elastic modulus, but not with ultimate strength. Our results indicate that QUS measurements of the intact heel are associated with the mechanical properties of calcaneal trabecular bone and, in some cases, provide information in addition to that provided by BMD or density measurements.