Scintigraphic evaluation of the osteoblastic activity of rabbit tibial defects after HYAFF11 membrane application.

BACKGROUND: An unfavorable condition for bone healing is the presence of bone defects. Under such conditions, a material can play a role to cover fractured or defective bone. Technological advances now allow for the use of such material. Hyalonect(®) (Fidia Advanced Biopolymers SLR, Italy), a novel membrane comprising knitted fibers of esterified hyaluronan (HYAFF11) can be used to cover fractured or grafted bone and can also serve as a scaffold to keep osteoprogenitor cells in place. The aim of this study was to compare osteoblastic activity by the use of scintigraphic methods in defective rabbit tibias during early-phase bone healing with or without a hyaluronan-based mesh.

METHODS: Two groups (A and B) of New Zealand albino rabbits were used; each group included 10 animals. Operations on all rabbits were performed under general anesthesia. We also resected 10-mm bone segments from each animal's tibial diaphysis. After resection, tibias with defects were fixed using Kirschner wires. In group A, no hyaluronan-based mesh was used. In group B, tibial segmental defects were enclosed with a hyaluronan-based mesh. The rabbits were followed up for 4 weeks postoperatively, after which bone scintigraphic studies were performed on each animal to detect and compare osteoblastic activity.

RESULTS: The mean count in the fracture side of the hyaluronan-based mesh group was significantly higher compared to that of the group A (p = 0.019). However, there was no significant difference between group B and control rabbits with respect to the mean count on the intact bone side (p = 0.437). The bone defect (fracture)/intact bone mean count ratio was significantly higher in group B compared to group A (p = 0.008).

CONCLUSIONS: A hyaluronan-based mesh plays a role in promoting osteoblastic activity. Hyalonect(®) is suitable for restoring tissue continuity whenever the periosteal membrane is structurally impaired or inadequate. Our results demonstrated that, during early-phase bone healing, osteoblastic activity was increased in bone defect sites when a hyaluronan-based mesh was also used. The most important aspect of this study concerns its scintigraphy-based design. This study is the first to use a scintigraphic method to demonstrate the effectiveness of hyaluronic acid-based material for bone healing.