[Inclined plate screws - in vitro measurement of the stability of transverse osteotomy of tibia].

A compression plate which is exactly contoured to the bone surface produces asymmetric compression: only part of the cortex near the plate is compressed. Therefore a compression plate is not meant to be used selfstanding, it will rather be combined with additional means. Two of these have been studied: the increased stability provided by the use of lagging, inclined plate screws was compared to the one provided by the spring effect of a plate prebent for central elevation. 7-hole dynamic compression plates (DCP) and 4.5 mm cortex screws were used to stabilize transverse osteotomies in human tibiae in vitro. Flexural and torsional testing revealed that the use of an inclined lag screw or a prebent plate increases stability compared to the one achieved with an exactly contoured plate alone. Preliminary tests suggest, that a combination of plate lag-screw and prebending offers stability up to high loads.