Silken Screws For Fixing Fractures

The tools doctors use to repair broken bones aren’t very different from those that carpenters use to fix broken boards. Screws and other fracture-fixation devices made of metal have been standard for healing rifts the body can’t repair on its own. But metal is not without its problems. Patients report stiffness, inflammation, and poor wound healing; in some cases, the metal implants need to be removed. In rare instances, doctors use fixation devices made from medical polymers. These can be resorbed by the body, but they can provoke an inflammatory response and tend to be more delicate than metal systems. A team led by Samuel J. Lin of Harvard Medical School and David L. Kaplan of Tufts University may have found a solution with surgical screws and plates made from silk protein (Nat. Commun. 2014, DOI: 10.1038/ncomms4385). The material is sturdy and biodegrades within the body. It also withstands temperatures of up to 200 °C, so it can be sterilized. The team prepared silk screws and tested them in rat femurs. The screws were so sturdy that there was no need to predrill holes for them, making implantation simpler.