The effect of hip rotation on bone mineral density of the proximal femur measured by dual energy X-ray absorptiometry

Objectives: The aim of this study was to compare the effect of lower extremity position changes on hip bone mineral density measured by dual energy X-ray absorptiometry. Patients and methods: Sixty-nine healthy university students (30 men, 39 women; mean age 21.9 +/- 1.6; range 20 to 25 years) participated in this study. Participants were evaluated in two groups as male and female. A special positioning device was produced and used during bone mineral density measurements. Measurements were performed in positions of external 30 degrees, external 15 degrees, neutral 0 degrees, internal 15 degrees, and internal 30 degrees of hip rotations. Measurements were evaluated at shaft, wards and trochanteric region of proximal femur. Differences between positions at shaft, wards, trochanter and total values were compared using repeated measures of analysis of variance. Results: External rotation significantly increased bone mineral density values measured by dual energy X-ray absorptiometry in both male and female. The lowest bone mineral density value was measured at 30 degrees internal rotation in both sexes. There were slight differences between neutral, 15 degrees and 30 degrees internal rotation positions, but these differences were not statistically significant. Conclusion: Our findings suggest that position differences are important in adult healthy male and female during bone mineral density measurements of proximal femur using dual energy X-ray absorptiometry.