Monitored impact loading of the hip: initial testing of a home-use device.

Many studies have been done involving exercise, impact loading, and the effect on BMD. In some of these studies, particularly those involving outpatient activity, compliance and the specific parameters of an individual's impact loading have been difficult to monitor effectively. In this study, an individual, home-use platform was used to record daily, specific, and reproducible impact forces generated during a heel drop exercise. At three centers over 24 months, we conducted a randomized, prospective study of 157 osteoporotic and osteopenic women, aged 60-85 years. A total of 99 patients used the home Osteocare device (OrthoGenesis Incorporated, Northborough, Massachusetts USA) to generate a reproducible and specific daily impact program (active group). Controls (32) performed a similar motion on the unit but without trying to trigger an impact force (sham group), and 26 patients did no prescribed heel drop exercise (control group). All groups had the same calcium and vitamin D supplementation. Hip DXA was performed at baseline and every 6 months during the entire study duration. Compliance with the 3-5 min routine was high, and patients were able to consistently achieve the specific targeted impact range. Pooled BMD results showed no significant differences between groups in overall BMD measurements. However, a classification model that looked at individual site-specific BMD changes showed that more than 75% of the active group responded (versus 62% for both the sham and the control groups) by maintaining or increasing site-specific hip BMD over the 2-year trial. In fact, at the end of the study, 45% of the actives were gainers versus 12% and 22% in the sham and control groups, respectively. This study suggests that hip BMD may be maintained through a brief, safe, at-home, monitored impact loading program.