Bone Regeneration and Integration Following Implantation of Octacalcium Phosphate/Gelatin Composite After Benign Bone Tumor Surgery.

Bone defect reconstruction following benign bone tumor curettage remains challenging due to limitations of traditional grafts. Autologous bone provides excellent osteoconductivity and osteoinductivity, but it causes donor site morbidity. In contrast, allogeneic and xenogeneic grafts are limited by infection risk and restricted availability. Synthetic substitutes such as hydroxyapatite and β-tricalcium phosphate offer osteoconductivity but lack osteoinductive potential. Octacalcium phosphate (OCP), a precursor of biological apatite, possesses both osteoconductivity and intrinsic osteoinductivity and exhibits greater resorbability than conventional materials. The OCP/gelatin composite (OCP/Gel) was recently approved for clinical use in Japan. This prospective study investigated seven patients who underwent OCP/Gel implantation after curettage of benign bone tumors. No internal fixation was required, and no complications related to the material occurred. Radiographic follow-up demonstrated a gradual decrease in radiolucency at the graft site, and computed tomography at six months confirmed trabecular bone formation in all cases. These findings suggest that OCP/Gel is progressively replaced by new bone and can promote early bone regeneration after tumor curettage. Despite the small sample size, single-center design, and limited defect size, OCP/Gel appears to be a safe and effective bone substitute. Further multicenter studies are warranted to confirm its long-term efficacy and optimal clinical indications.