Loss of bone mass after total hip replacement: preliminary data

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Bone Metabolism

Background:

• Cemented total hip replacement is a common procedure for coxarthrosis.
• Understanding the long-term effects of hip prostheses on bone mineral density (BMD) is crucial for patient outcomes.
• Prosthetic stem loosening is a potential complication affecting implant longevity and bone health.

Purpose of the Study:

• To evaluate bone mineral density (BMD) in the femur and ischium of females with cemented total hip replacement.
• To compare BMD between operated and contralateral sides in patients with and without prosthetic stem loosening.
• To investigate the relationship between BMD and time since surgery, and the impact of prosthetic stem loosening on bone resorption.

Main Methods:

• Dual ray photonic absorbimetry was used to measure BMD in 37 females with cemented total hip replacements.
• Regions of interest (ROI) were selected on the femoral cortex (4 cm below lesser trochanter) and ischium bilaterally.
• Statistical analysis, including Student's "t" test, was employed to compare BMD between groups and sides.

Main Results:

• Patients with hip replacements showed significantly lower BMD in the operated femur and ischium compared to the contralateral side (p < 0.001).
• Femoral BMD in the operated leg was significantly higher in patients with stable prostheses than in those with prosthetic stem loosening (p < 0.000).
• BMD loss in the femoral cortex was significantly greater with prosthetic stem loosening than with stable implants over time.

Conclusions:

• Cemented total hip replacement is associated with significant bone resorption in the proximal femur and ischium on the operated side.
• Prosthetic stem loosening may exacerbate bone loss in the femoral cortex, indicating compromised implant fixation.
• BMD measurements provide valuable insights into the biomechanical effects of hip prostheses and complications like loosening.