Acceleration of second and fourth metatarsal fracture healing with recombinant human bone morphogenetic protein-2/calcium phosphate cement in horses.
Authors: Perrier Melanie, Lu Yan, Nemke Brett, Kobayashi Hirohito, Peterson Anna, Markel Mark
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Accessory metatarsal bone fractures in horses present a clinical challenge, particularly when surgical stabilisation leaves significant defects requiring biological support for healing. Researchers at Iowa State University compared three treatment approaches in a controlled model: surgically created defects in the second and fourth metatarsal bones of nine horses were either left untreated, treated with recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with calcium phosphate cement, or grafted with autogenous cancellous bone. Over the 12-week study period, both rhBMP-2 and autogenous bone graft significantly improved radiographic union scores compared to untreated controls (P<0.0001 and P=0.004 respectively), with rhBMP-2–treated defects in the second metatarsal demonstrating superior torsional strength at failure compared to both grafted and control limbs (P=0.011). Histological examination confirmed that rhBMP-2 and autogenous bone both promoted accelerated bone formation with more mature bone organisation at the defect site relative to untreated controls. For practitioners managing accessory metatarsal fractures surgically, rhBMP-2/calcium phosphate cement offers a potentially superior biological augmentation strategy to autogenous bone grafting, with the added benefits of eliminating donor-site morbidity and reducing operative time—though further clinical validation in naturally occurring fractures remains warranted before widespread adoption.
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Practical Takeaways
- •rhBMP-2/calcium phosphate cement may offer a viable alternative to autogenous bone grafting for treating accessory metatarsal bone defects, potentially reducing surgery time and donor site morbidity
- •This biologic approach can accelerate radiographic union and improve mechanical strength of healing bone compared to no treatment, improving prospects for return to soundness
- •Consider this treatment option particularly for larger or contaminated bone defects where graft harvest would be impractical or when faster healing is critical
Key Findings
- •rhBMP-2/calcium phosphate cement produced significantly greater radiographic union scores at 12 weeks compared to untreated controls in both MT2 and MT4 bones (P<0.0001 and P=0.004)
- •rhBMP-2-treated MT2 bones demonstrated greater maximum torque to failure in torsion than both autogenous cancellous bone graft and control groups at 12 weeks (P=0.011)
- •Histologic analysis showed increased bone formation and more mature bone at ostectomy sites for MT2 in rhBMP-2 and CBG groups versus untreated controls
- •rhBMP-2/calcium phosphate cement was equivalent or superior to autogenous cancellous bone graft for accelerating early bone healing