Dual Energy X-Ray Absorptiometry of the Distal Femur May Be More Reliable than the Proximal Tibia in Spinal Cord Injury

Morse LR, Lazzari AA, Battaglino R, Stolzmann KL, Matthess KR, Gagnon DR, Davis SA, Garshick E. Dual energy x-ray absorptiometry of the distal femur may be more reliable than the proximal tibia in spinal cord injury.ObjectiveTo evaluate the precision of dual energy x-ray absorptiometry scanning at 2 skeletal sites at the knee (proximal femur and distal tibia) in people with SCI.DesignCross-sectional.SettingVeterans Affairs Medical Center.ParticipantsSubjects (N=20) with chronic SCI.InterventionsNot applicable.Main Outcome MeasuresPrecision as determined by root mean square coefficient of variation (RMS-CV) and root mean square standard deviation (RMS-SD).ResultsAt the distal femur the root RMS-CV was 3.01% and the RMS-SD was 0.025g/cm2. At the proximal tibia the RMS-CV was 5.91% and the RMS-SD was 0.030g/cm2.ConclusionsPrecision at the distal femur is greater than at the proximal tibia and we recommend it as the preferred site for the longitudinal assessment of bone mineral density at the knee in chronic SCI.