Strontium in the bone-implant interface

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Skeletal Tissue Engineering

Background:

• Total hip replacement revisions are increasing, necessitating improved implant longevity and fixation.
• Early implant instability and aseptic loosening are critical challenges, especially in revision surgeries requiring bone grafts.
• Strontium, a dual-action bone anabolic and anti-catabolic agent, may enhance osseointegration.

Purpose of the Study:

• To investigate the optimal delivery methods for strontium at the bone-implant interface.
• To evaluate strontium's potential to improve early osseointegration and implant fixation.
• To assess strontium's dual action (anabolic and anti-catabolic) in a canine hip replacement model.

Main Methods:

• Three studies utilized a cementless experimental gap model in canine subjects.
• Evaluated strontium delivery via hydroxyapatite (HA) coatings and bone graft extenders.
• Assessed osseointegration using histomorphometrical analysis and mechanical push-out tests.

Main Results:

• Strontium-substituted HA coating did not improve implant fixation at 4 or 12 weeks.
• Strontium-doped HA bone graft extender enhanced gap healing and protected allografts, but mechanical fixation results were inconclusive.
• Bioactive glass coatings failed; HA coatings demonstrated superior osseointegration and fixation.

Conclusions:

• Strontium delivered as a doping agent in HA bone graft extenders shows promise for improving bone-implant interface healing.
• Current strontium delivery methods require further investigation for effective application in hip implants.
• Experimental validation is crucial for novel applications of established therapeutic agents like strontium.