Emerging Insights On Fixation For Austin/Chevron Bunionectomies
The use of human bone allografts has been gaining popularity in the surgical community and is increasingly utilized in a variety of surgical procedures of the lower extremity. The Musculoskeletal Transplant Foundation reports that more than 900,000 allograft procedures occur each year in the United States.15 The product has predominately been in use as bone filler for tumors that are excised or as grafts to assist in bone healing from postsurgical or post-traumatic non-unions. Although disease transmission is rare, a careful understanding of the tissue processing bank and its procedures is critical to allow the surgeon to provide patients with the tools to make an informed decision, and be an active participant in their surgical plan of care.
There are several physiological properties of bone grafts that directly affect the success or failure of graft incorporation. These properties include osteoconduction, osteoinduction and creeping substitution.
Osteoconduction occurs when the bone grafting material acts as scaffolding for new bone growth, which the native bone perpetuates. Osteoblasts utilize the bone grafting material as a framework to spread and generate new bone formation.16
Osteoinduction involves the stimulation of osteoprogenitor cells to differentiate into osteoblasts that subsequently begin the formation of new bone.17 Bone grafting materials that display both osteoconductive as well as osteoinductive properties will serve as scaffolding for currently existing osteoblasts and trigger the formation of new osteoblastic activity, theoretically promoting faster integration of the implanted graft.17
Creeping substitution is the process of bone remodeling by osteoclastic resorption and creation of new vascular channels with osteoblastic bone formation, resulting in new haversian systems. This is the method by which strong cortical bone forms from grafted material.18
Advantages of using allograft bone include its availability in plentiful supply, its limited risk of transmission of infectious organisms including hepatitis and HIV, and that it provides an osteoconductive scaffold as well as structural support.19,20 The goal of using allograft bone is to initiate a healing response from the host that will produce new bone at the host-graft interface and within the porous bone of the graft material. Some disadvantages to its use include delayed vascular penetration, slow bone formation, accelerated bone resorption, and delayed or incomplete graft incorporation.20
A Closer Look At A New Allograft Product
With the development and introduction of the TenFUSE Nail allograft (Solana Surgical), we begin a new generation of fixation. The TenFUSE Nail allograft nail (which complies with the Food and Drug Administration, American Association of Tissue Banks, and state regulatory requirements for donor screening and testing) is a cortical allograft fixation device that is partially demineralized to maintain osteoinductive and osteoconductive properties.
The goals with the development of this novel fixation device include:
• ease of availability and a long shelf life with no additional preparation;
• a reliable sterility assurance rate of 106, conforming with industry standards for implants;
• compatibility with host bone and possibly other additional hardware;
• ease of insertion;
• a patented design to resist migration or rotation;
• disposable drill guides and insertion sleeves; and
• a variety of lengths and diameters.