| Because current resorbable fracture fixation devices experience problems with implantation technique and negative host response, there is a need for new devices that have multifunctional features. These include immediate fracture stabilization upon implantation, complete degradation to avoid need for hardware removal, robust mechanical properties to allow for implantation, and ability to resterilized and reused to save on costs. The goal of this study was to prepare and characterize a new family of resorbable screws and plates from silk protein for craniomaxillofacial (CMF) repair. The screws and plates were prepared using a solvent-based process, treated with methanol to induce crystalline, beta sheet structures for stability then machined to the desired geometries. The silk material was evaluated in dry and in hydrated environments to mimic implantation as well as in vivo fixation conditions. The silk biomaterials compared favorably with the mechanical properties of current poly-lactic-co-glycolic acid (PLGA) resorbable fixation systems, while offering a number of advantages including ease of implantation, conformal fit to the repair site, easy sterilization by autoclaving and non-inflammatory response. Assessment of the screws in vivo in a rat femur model showed they were self-tapping, remained fixed in the bone for a 4 week trial, exhibited biocompatibility, and showed signs of normal bone remodeling. These silk screws and plates exhibit potential for resorbable fixation systems due to their mechanical strength, ease of implantation, ability to degrade, tunable properties with autoclaving, and potential to be resterilized and reused if opened but not used in the operating room. |
