Primary cancellous bone formation with BMP and micro-chambered beads: experimental study on sheep

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Regenerative Medicine

Background:

• Cancellous bone defect reconstruction in the locomotor system remains a significant surgical challenge.
• Existing methods often result in prolonged healing and incomplete bone regeneration.

Purpose of the Study:

• To evaluate micro-chambered ß-tricalcium-phosphate (ß-TCP) beads for their ability to create a stable scaffold via capillary action.
• To assess the efficacy of recombinant human bone morphogenetic protein (rhBMP) in enhancing bone defect healing, remodeling, and ß-TCP resorption.
• To investigate the protective role of gentamicin-loaded ε-caprolactone against implant infection.

Main Methods:

• Sheep were used to create standardized patella-groove and tibial head bone defects.
• Implants included micro-chambered ß-TCP beads with rhBMP-7 or demineralized bone matrix (DBM) paste, and plain ß-TCP beads.
• Gentamicin-loaded ε-caprolactone was added, and outward diffusion was prevented; healing was assessed via micro-casting, μ-CT, and microscopy at various time points.

Main Results:

• Micro-chambered ß-TCP beads exhibited strong capillary action, resorbing blood and bone marrow to form a stable, load-bearing scaffold.
• rhBMP-7 significantly accelerated bone healing, shortened resorption, and improved remodeling compared to DBM and plain ß-TCP implants.
• The combination of ß-TCP beads and rhBMP-7 facilitated faster and more complete bone regeneration.

Conclusions:

• Micro-chambered ß-TCP beads serve as effective bone-forming elements, with rhBMP significantly enhancing defect healing and remodeling.
• The BMP-loaded implants demonstrated superior outcomes in bone reconstruction and ß-TCP resorption compared to DBM and plain implants.
• This approach offers a promising strategy for accelerated and enhanced bone defect repair in orthopedic surgery.