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 injuries (BSIs). BACKGROUND: Physical therapists, particularly in military and sports medicine settings, routinely diagnose and manage stress fractures or bone stress injuries. Improved methods of preparticipation quantification of tibial strength may provide markers of BSI risk and thus potentially reduce morbidity. METHODS AND MEASURES: Bone mineral density, FWPV, bone geometry, and historical variables were collected from 14 subjects diagnosed with tibial BSIs and 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). Furthermore, no difference was found in tibial length, tibial width, femoral neck BMD, and lumbar spine BMD among the groups. There were no differences between 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 low, 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 stresses on bone may be more important in the development of BSIs than the overall structural stiffness.

Phonophoretic delivery of 10% hydrocortisone through the epidermis of humans as determined by serum cortisol concentrations.

BACKGROUND AND PURPOSE: The purpose of this investigation was to determine whether application of hydrocortisone phonophoresis enhances transcutaneous delivery of topically applied hydrocortisone in humans, as determined by blood cortisol levels. SUBJECTS: The subjects were 16 men and women, between the ages of 18 and 33 years (X = 25, SD = 2.74), without symptoms of any ongoing inflammatory condition. METHODS: A gel coupling medium containing 10% hydrocortisone acetate was used. Ultrasound was delivered over a 50-cm2 area for 5 minutes at an intensity of 1.0 W/cm2 and a frequency of 1.0 MHz. Each subject received a control treatment (ultrasound alone) and an experimental treatment (hydrocortisone phonophoresis) on the volar aspect of the forearm 1 week apart. Blood was drawn, under both control and experimental conditions, from a cubital vein just proximal to the treatment site prior to each treatment and 0,5, and 15 minutes posttreatment. Serum cortisol concentrations were measured using a fluorescence polarization immunoassay. RESULTS: No rise in serum cortisol concentrations following hydrocortisone phonophoresis was detected. CONCLUSION AND DISCUSSION: These findings suggest that there was no penetration of hydrocortisone through the epidermis and into the underlying vasculature. Clinical implications regarding hydrocortisone levels within the subcutaneous tissues are discussed, and further research is suggested.