Hydrogel Scaffold for Bone Defect Regeneration in Rabbits: Characteristics and Healing Stimulation Evaluation

Segmental bone defects represent a significant clinical challenge in orthopedic medicine, often resulting from trauma, infection, or tumor resection. Traditional treatments frequently fail to achieve adequate bone regeneration in large defects. This study evaluated the regenerative potential of a novel composite biomaterial combining Wollastonite, β-tricalcium phosphate (β-TCP), and polyethylene glycol dimethacrylate (PEGDMA) for treating segmental bone defects. The composite hydrogel was synthesized using 80% Wollastonite, 20% β-TCP, and PEGDMA polymeric matrix through foam replication and UV-curing techniques. Twelve New Zealand rabbits underwent surgical creation of 5 mm radius segmental defects. Animals were randomly assigned to implant group (GI, n=6) receiving the composite biomaterial or control group (CG, n=6) with standard plate fixation only. Both groups received identical stabilization with locked plates and screws. Comprehensive evaluation included clinical monitoring, radiographic imaging, computed tomography, and histopathological analysis over 120 days. The composite demonstrated excellent biocompatibility with no adverse reactions observed. Radiographic analysis revealed significant differences in biological activity scores between groups (GI: 3.0±0 vs CG: 1.6±0.51, p<0.05 at 120 days). Tomographic evaluation showed superior tissue neoformation (2.8±0.4 vs 2.0±0.63, p<0.05) and mineralization (2.6±0.51 vs 1.5±0.54, p<0.05) in the implant group. Histomorphometric analysis demonstrated dramatically enhanced tissue proliferation in treated animals (4798.33±151.32 μm vs 2408.33±148.51 μm, p<0.01 at 120 days). Complete bone consolidation was achieved in the implant group at 120 days, while control group showed persistent defects. The Wollastonite-β-TCP-PEGDMA composite hydrogel effectively promotes bone regeneration in segmental defects, demonstrating superior osteoinductive and osteoconductive properties compared to natural healing. This innovative biomaterial represents a promising therapeutic approach for challenging bone reconstruction scenarios.