Osteogenic protein 1 device increases bone formation and bone graft resorption around cementless implants

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Regenerative Medicine

Background:

• Hydroxyapatite-coated implants are used in orthopedic surgery.
• Bone grafting materials like allografts and synthetic substitutes are employed to enhance bone integration.
• Osteopontin (OP-1) is a protein involved in bone healing.

Purpose of the Study:

• To evaluate the effect of OP-1 on implant fixation and bone formation.
• To compare the efficacy of OP-1 with bone allograft versus a synthetic bone substitute (ProOsteon).
• To assess the impact of OP-1 on graft resorption and new bone formation around implants.

Main Methods:

• Hydroxyapatite-coated implants were placed in canine femoral condyles with a surrounding gap.
• Gaps were filled with bone allograft or ProOsteon, with or without OP-1.
• Implant fixation, bone volume, and graft resorption were analyzed after 3 weeks.

Main Results:

• OP-1 enhanced implant fixation by 800% in the ProOsteon group (p <0.05).
• OP-1 significantly increased woven bone formation around implants in both allograft (12% to 20%) and ProOsteon (6% to 25%) groups (p < 0.05).
• OP-1 accelerated bone allograft resorption, reducing its volume fraction from 29% to 9% (p < 0.05).

Conclusions:

• OP-1 significantly enhances new bone formation and implant fixation when used with bone allografts or ProOsteon.
• OP-1 accelerates the resorption of bone allografts, promoting integration with cementless implants.
• The use of ProOsteon alone is not supported for enhancing implant fixation in this model.