Synthetic biomaterials based on hydroxyapatite and tricalcium phosphate: analysis of current clinical trials

Introduction To date, a wide variety of synthetic materials, including metals, polymers and ceramics, have been proposed and used as a substitute for bone grafts in the field of traumatology/orthopedics, neurosurgery and oral and maxillofacial surgery (OMFS). However, the most studied materials are calcium phosphate ceramics (CPC), in particular hydroxyapatite and tricalcium phosphate, as well as their mixtures, called byphasic calcium phosphates. This interest stems from the fact that the main component of bone is the apatite mineral calcium phosphate. Hydroxyapatite and tricalcium phosphate are among the most commonly used and effective synthetic substitutes for bone grafts. They have not only osteoconductive properties, but also osteoinductive. These properties, combined with cell-mediated resorption, ensure complete regeneration of bone defects. This study will analyze existing clinical trials, registered on the clinicaltirals.gov website, on the use of hydroxyapatite and tricalcium phosphate in the field of traumatology and orthopedics, neurosurgery and OMFS.Aim To identify the potential for clinical use, as well as possible side effects, of CPC as a replacement for bone grafts.Materials and methods The search strategy was to use material from the clinicaltrials.gov website, which focused on key terms such as hydroxyapatite, tricalcium phosphate, hydroxyapatite and tricalcium phosphate, traumatology and orthopedics, maxillofacial surgery, dentistry, neurosurgery, bone, и diseases of the musculoskeletal system.Results and discussion As of November 2022, there were approximately 85 clinical trials with hydroxyapatite application, approximately 49 clinical trials with tricalcium phosphate, and approximately 16 clinical trials with the hydroxyapatite/tricalcium phosphate combination. Most of the studies were Phase 1-2, Phase 2, or Phase 4. Most focused on tibial trauma therapy, osteoporosis/osteopenia, alveolar bone resorption, and spinal surgery. It was found that full results were published only in 3, 7 and 2 clinical trials on the use of hydroxyapatite, tricalcium phosphate and their combination, respectfully. All clinical trials had similar preparation methods and all of those clinical trials produced positive results without serious side effects.Conclusion There is a wide potential for clinical use of CPC as synthetic bone graft substitutes without reports of serious side effects. Many preclinical and clinical studies are currently underway on the use of hydroxyapatite and tricalcium phosphate, and their future results will further explore their clinical potential.