Biomechanical and surface physico-chemical analyses of used osteosynthesis plates and screws--potential for reuse in...

Reprocessing of single-use devices is an upcoming issue in the Western world, but has been for many years in developing countries. In developing countries, the number of bone fractures due to traffic or industrial accidents is high. Patients often need an osteosynthesis with plates and screws, but most patients, however, cannot afford this because of the costs involved and have to rely on the application of used plates and screws. This study aims to determine whether used plates can be safely reused in another patient from a biomechanical, surface physico-chemical, and biological point-of-view. Osteosynthesis plates weakened in a predictable way during use, regardless of the history, presumably because tests were conducted under extreme conditions in the absence of clinically applied load-sharing between bone and plate. Surface physico-chemical analyses indicated that used plates and screws were more hydrophilic than new ones; had increased amounts of calcium-phosphates at their surfaces; and possessed higher number of scratches. Pitting corrosion could be seen on SEM micrographs. Simple cleaning methods, as available in developing countries, including toothbrush, water, detergent and bleach yielded elemental surface compositions, and hydrophobicities similar to those of new ones, while biologically thus cleaned screws were not cytotoxic according to ISO-10993-5 and endotoxin release according to USP-27-NF-22 was within the requirements of the FDA. It is concluded that the reuse of osteosynthesis plates and screws is not necessarily unsafe, although preferably a register should be kept of all previous users to limit the number of reuses as mechanical weakening does occur.