Document Type: Review Article
Materials and Chemistry department, Esfarayen University of technology, Iran
Ferdowsi University of Mashhad, Engineering Faculty, Materials Science and Engineering Department, Mashhad, Iran
One of the popular orthopedic implants is fixation screws which have been utilized for fixation of Anterior Cruciate Ligament (ACL) grafts to secure the graft into femur and tibia. Currently, these screws are made of titanium or bioabsorbable ones. In this respect, the bioabsorbable screws were generated in order to overcome some of the potential problems attributed to metallic screws. However, the bioabsorbable ones have been also suffered from some drawbacks such as bone ingrows features as well as good in vitro and in vivo mechanical properties. The bimechanical results of ACL screws demonstrate that the ultimate failure loads and yield point loads are varied between 800-1500 N and 600-1000 N, respectively. Moreover, the in vivo degradation behaviors evaluations show the near complete or fully complete resorption of ACL screws from 6 month up to 2 years. Incorporation of biceramics such as hydroxyapatite (HA), β-tricalcium phosphate (β-TCP) and calcium carbonate (CC) into pure polymeric ACL screws may help to enhance the osteogenesity of bone after full resoprption of screws and act as buffering agents to decrease the acidity of screw adjacent resulted of degradation by products as well as improving in mechanical properties of ACL screws. In this article we are going to discuss the latest bioabsorbable ACL screws which are currently available for graft fixation in orthopedic markets. A brief review of the literature regarding the physical, biological and mechanical properties of bioabsorbable ACL screws is studied.