Efficacy and safety of porous hydroxyapatite/type 1 collagen composite implantation for bone regeneration: A randomized controlled study

Background Porous hydroxyapatite/collagen composite (HAp/Col) is a bioresorbable bone substitute composed of nano-scale HAp and porcine type 1 collagen. In this study, the efficacy and safety were assessed in comparison to commercially available porous β-tricalcium phosphate (β-TCP). Methods Patients with bone defects caused by benign bone tumors, fractures, or harvesting of autografts were randomly allocated for implantation of porous HAp/Col (n = 63) or porous β-TCP (n = 63). X-ray images were scored and used to evaluate the efficacy of the implantation until 24 weeks after surgery. Blood tests and observation of the surgical site were also performed to evaluate the safety of the implants. In total, 59 and 60 cases were analyzed in the porous HAp/Col and β-TCP groups, respectively. Results At 18 and 24 weeks after surgery, the highest grade of bone regeneration was more frequent in the porous HAp/Col group than in the porous β-TCP group (p = 0.0004 and 0.0254 respectively). Wilcoxon's rank sum test confirmed the superiority of porous HAp/Col from early time points onward (p = 0.0084, 4 w; p = 0.0037, 8 w; p = 0.0030, 12 w; p < 0.0001, 18 w; and p = 0.0316, 24 w). The incidence of adverse effects was higher in the porous HAp/Col group than in the β-TCP group. However, no serious adverse events were reported and no cases needed to drop out of the clinical trial. Conclusions The superiority of porous HAp/Col for bone regeneration in comparison to an established porous β-TCP was confirmed. Although the incidence of side effects associated with the porous HAp/Col implant was higher than that in the β-TCP group, no serious adverse events occurred that resulted in rejection of the implants.