SLR - March 2012 - Andrew M. Hall
Reference: Siddhant K. Mehta, Eric A. Breitbart, Wayne S. Berberian, and Sheldon S. Lin. Current Orthopedic Practice: May/June 2010 - Volume 21 - Issue 3 - pp 245-250
Scientific Literature Review
Reviewed by: Andrew M. Hall, DPM, PGY-2
Residency Program: Southern Arizona VA Healthcare System
Podiatric Relevance:
A facet of current orthopaedic research has focused on the molecular aspects of the healing process, which has led to the development of several agents that serve as adjunctive therapy to conventional treatment and have the potential to maximize the healing process in the foot and ankle.
Methods:
The authors aimed to describe the basic science and current clinical data available to better understand the potential role of growth factors in foot and ankle surgery.
Platelet-Rich Plasma
PRP is derived from autologous blood that contains, on average, a five-fold increase above physiologic levels. When activated, platelets release growth factors which have been shown to initiate healing and regenerate musculoskeletal tissue. These growth factors include platelet-derived growth factor (PDGF), transforming growth factor (TGF), insulin-like growth factor (IGF), vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF). Their roles in healing include hematoma formation, chemotaxis of inflammatory cells, proliferation and differentiation of mesenchymal cells, remodeling, angiogenesis, and extracellular matrix formation.
Examples of current literature
- PRP reduced the time to union in ankle syndesmotic fractures in total ankle replacement. (Barrow, Pomeroy)
- Supplementation of locally implanted allograft bone chips with bone marrow aspirate containing pluripotential stromal cell in combination with PRP significantly enhanced healing rates in patients undergoing tibial osteotomy. (Dallari, et al)
- Using a rabbit model, results suggest that PRP may accelerate the tendon healing process by enhancing angiogenesis. (Lyras, et al)
Bone Morphogenic Proteins
BMPs are the key initiators of osteoprogenitor and mesenchymal cells during osseous healing. BMPs induce new bone formation by endochondral ossification and in high concentration can even form new bone by intramembranous ossification.
Examples of current literature
- A significant increase in vascularity was observed in the defects of femurs treated with rhBMP-2 compared with those treated with a saline buffer. (Azad, et al)
- Significantly more mineralized callus was observed in rat femoral defects with those treated with rhBMP-2 than those treated without. (Chen, et al)
Platelet-Derived Growth Factor
PDGFs are a family of growth factors released from platelets and macrophages in response to tissue injury. PDGF has been shown to promote the synthesis and release of several other growth factors and to stimulate various mesenchymal-derived cells to further enhance DNA synthesis, augment collagen deposition, and increase synthesis of extracellular matrix.
Examples of current literature
- rhPDGF-BB significantly enhanced bone healing in osteoporotic and diabetic animal models. (Al-Zube, et al)
- There was no statistical difference in torsional strength of fractured tibia treated with rhPDGF-BB compared with the non-fractured contralateral tibiae, while non-treated groups showed significant reduction in torsional strength. (Hollinger, et al)
Conclusions:
Reconstructive foot and ankle surgery continues to be a challenge especially when operating on high risk patients with decreased healing ability. Growth factors, such as PRP, BMPs, and PDGF, may contribute significantly to achieve more favorable outcomes, reduce complication rates, and improve patient satisfaction. Although there is considerable research that has shown the potential benefit of these agents, more randomized studies will be necessary to determine their efficacy and safety before they are used in mainstream treatment.