BONE mineral density (BMD) assessment using radiofrequency echographic multispectrometry (REMS) shows that age, sex, and BMI remain the strongest determinants of bone health, even in the context of total hip replacement surgery. A new study found that metal implants contribute minimally to measured changes in femoral neck BMD.
In this prospective analysis, REMS was performed in 50 patients with advanced hip osteoarthritis before and shortly after total hip arthroplasty. The cohort included 27 women and 23 men aged between 49 and 84 years. BMD was measured at the proximal femur in all patients and additionally at the lumbar spine in a subset of male participants.
Results demonstrated a strong correlation between femoral neck BMD values obtained before and after surgery. Postoperative measurements revealed a modest decrease of 0.021 g/cm², equating to a 2.8 percent reduction compared to preoperative values. This decline reached statistical significance but was largely explained by patient characteristics rather than the surgical intervention itself.
Regression models confirmed that approximately 90 percent of the variability in REMS-BMD at the femoral neck could be attributed to age, sex, and BMI. No evidence of systematic measurement bias emerged when comparing pre- and postoperative assessments. Variations in measured BMD were also observed at the femoral neck and lumbar spine when values were recalculated under different assumptions of age, height, and weight.
These findings suggest that REMS provides consistent and reproducible results across clinical settings and that prosthetic hip components exert little influence on the measurement itself. The study underscores the importance of patient-related factors in determining bone density and highlights the need for additional research to clarify whether REMS-BMD reflects areal or volumetric density, and how backscattered ultrasound signals shape measurement accuracy.
Reference: Bobelyak M et al. Bone mineral density assessment using radiofrequency echographic multispectrometry (REMS) in patients before and after total hip replacement. Osteoporos Int. 2025. doi: 10.1007/s00198-025-07685-w
