Enhancement of bone healing through the direct injection of osteogenic and maintenance media concurrent with hydroxyapatite in a rat model of radial bone defects.

Background: Healing critical bone defects remains a major challenge for orthopedic surgeons. Numerous studies have explored ways to enhance bone regeneration. Aims: This study aimed to evaluate the healing potential of osteogenic and maintenance cell culture media when applied directly to the defect site, either alone or in combination with hydroxyapatite (HA) granules. Methods: Seventy male Wistar rats were divided into seven groups: empty defect (n=10, negative control), autograft (n=10, positive control), HA (n=10), osteogenic medium (OM) (n=10), maintenance medium (MM) (n=10), MM+HA (n=10), and OM+HA (n=10). A 5 mm radial diaphyseal gap was created as a critical-sized defect. Culture media were injected transcutaneously into the gap on the fourth day post-surgery. Radiological evaluations were conducted on postoperative days 14, 28, 42, and 56. Histopathological assessments were performed on days 28 and 56. Results: OM and MM, both alone and combined with HA, demonstrated significant bone healing capacity. Radiologically, all treatment groups showed superior healing compared with the negative control. Bone regeneration in the OM group was comparable to the autograft group on days 42 and 56. Histopathologically, all groups exhibited advanced healing on days 28 and 56, except the HA group. Notably, bone healing in HA+OM and HA+MM on day 28, and in OM and MM on both days 28 and 56, was similar to that observed with autografts. Conclusion: Osteogenic and maintenance media exhibit promising bone regenerative properties and may serve as effective treatments for bone defects, provided that suitable delivery and support systems are developed.