The bioactive bone graft substitute at least as good as the real thing
Bone grafting is second only to blood transfusion as the most performed tissue transplantation procedure worldwide, with approximately 4 million operations each year. While artificial materials, and bone from bone banks, are possible, the preferred option is an autograft – bone from the patient themselves. “But transplanting bone harvested from another part of the body can be painful and risks complications in up to 50 % of cases, 20 % of which can be major,” according to Kaarlo Paakinaho, project coordinator of the ADAPTOS project. To offer a better alternative, the EU-funded ADAPTOS project has developed more adaptable bioactive artificial bone grafts. Already launched in the veterinary market, Adaptos® already benefited over 1 500 animals to date. “With its unique mechanical properties, we are confident that ours is the graft that most closely resembles cancellous bone,” adds Paakinaho.
The flexible yet robust porous composite
Adaptos® is a porous composite material – comprising beta-tricalcium phosphate, bioactive glass (45S5) and poly-L-lactide-co-ε-caprolactone (a copolymer of polylactide) – discovered somewhat serendipitously. “While experimentally mixing different materials in the lab, I created a polymer composite with high ceramic content. When used to create a polymer composite matrix and foamed with supercritical CO2 processing, the combination offered the perfect blend of versatility and robustness,” explains Paakinaho from Biomendex, the project host. The resulting high ceramic composition, alongside its porous structure, meant that bioactive ceramic could be even more effective than before. The composite material allows bone to grow on it (osteoconductive), while also promoting the healing process (osteoinductive) – when combined with bone marrow aspirate or autologous bone, the graft stimulates bone-regenerating cells. The bioactive composite comes in different forms – including granules, plates and cylinders – offering surgical flexibility for the perfect repair fit. The granules can be sculpted into irregularly shaped surgical sites by compressing and expanding them but resisting breakage or crumbling, while the porous structure accommodates the bone marrow aspirate. Project pilots found that the degradation rate of the tissue regeneration scaffolding – important for repairs to be as natural as possible – was similar in both in vitro and in vivo environments. Additionally, foreign body reactions – such as swelling, fluid accumulation, sinus tract formation or abnormal tissue formation – were not seen. “We are extremely pleased with how our synthetic material not only mimics the porosity of natural bone, but has handling and modification properties which sometimes even surpass a natural bone graft,” says Paakinaho.
Introducing the innovation to more surgical settings
Now that Adaptos® has proven successful in the veterinary market, Biomendex plans to widen its availability to human surgery, initially prioritising the orthopaedic market. In Finland, Biomendex is currently undergoing randomised, controlled, partially blinded, multicentre clinical trials for more general orthopaedic surgery, specifically evaluating use of an Adaptos wedge in knee surgery. Meanwhile, analysis is under way of a clinical study already conducted with over 70 patients looking at the use of Adaptos® granules for dental implants. “We anticipate that Adaptos® will help maintain the alveolar ridge height and bone regeneration in the jaw bone, providing more stability for a tooth implant,” says Paakinaho. To date, Biomendex has been granted manufacturing method and unique structure patents in Australia, China, Finland, Japan and the United States. While patents are pending for the EU and Canada.
Keywords
ADAPTOS, bone, graft, veterinary, ceramic, bioactive, osteoconductive, osteoinductive, regeneration, surgery