Metallic fragments on the surface of miniplates and screws before insertion

Particulate metal fragments have been identified histologically within the tissues adjacent to miniplates and screws after they have been removed. The se were thought to have been caused by corrosion and degradation of the met al. However, the particles may have originated from rough edges or from pro tuberances left on the metal surface after cutting and machining during man ufacture, and subsequently become detached. This study was undertaken to an alyse the incidence and distribution of metal fragments on the surface of m iniplates and screws before use. Fifteen miniplates and 60 screws sere exam ined by stereomicroscopy and scanning electron microscopy. Rough metal edge s or protuberances were identified on over half the samples, mostly in the countersink area of screw holes on the mini-plates. Fragments were detected within some of the cruciform screw heads and on some screw threads. We con clude that metal protuberances are present on the surface of mini-plate com ponents when they are received from the manufacturer. There is a risk that the fragments might be detached and deposited into the tissues during inser tion.