Flexural wave propagation velocity and bone mineral density in females with and without tibial bone stress injuries

Study Design: Case-control nonexperimental design. Objectives: To compare flexural wave propagation velocity (FWPV) and tibial bone mineral density (BMD) in women with and without tibial bone stress in juries (BSIs). Background: Physical therapists, particularly in military and sports medici ne settings, routinely diagnose and manage stress fractures or bone stress injuries. improved methods at preparticipation quantification of tibial str ength may provide markers of BSI risk and thus potentially reduce morbidity . Methods and Measures: Bone mineral density, FWPV, bone geometry, and histor ical variables were collected from 14 subjects diagnosed with tibial BSIs a nd 14 age-matched controls; all 28 were undergoing military training. Results: No difference was found between groups in FWPV and tibial BMD when analyzed with t tests (post hoc power = 0.89 and 0.81, respectively). Furt hermore no difference was found in tibial length, tibial width, femoral nec k BMD, and lumbar spine BMD among the groups. There were no differences bet ween the 2 groups in smoking history, birth control pill use, and onset of menarche. Finally sensitivity and positive likelihood ratios for FWPV (0.14 and 0.63), tibial BMD (0.0 and 0.0), and lumbar BMD (0.18 and 2.0) were lo w, while specificity was high (0.77, 0.93, and 0.91, respectively). Conclusion: Current bone analysis devices and methods may not be sensitive enough to detect differences in tibial material and structure; local stress es on bone may be more important in the development of BSIs than the overal l structural stiffness.