Current concepts to reduce mechanical stiffness in locked plating systems: a review article

Nikhil Nanavati, Marcus Walker Scunthorpe General Hospital, Scunthorpe, North East Lincolnshire, UK Abstract: Locking plates can be used in a bridging mode to treat fractures by means of secondary bone healing. This requires stimulation by interfragmentary micromotion. Recent data suggest that up to 20% of fractures fixed with locking plates may encounter suboptimal fracture healing. Three main systems have been developed to improve bone healing, thereby reducing the risks of delayed or nonunion: overdrilling the near cortex; far cortical locking (FCL) screw; and dynamic locking screw (DLS). Overdrilling the near cortex offers a cheap alternative to screw technology by reducing construct stiffness; overdrilling potentially causes repetitive loading and thus has consequences postoperatively such as failure and fatigue. FCL screws reduce construct stiffness and maintain construct strength but cannot be used in dynamic compression mode and therefore, require adequate fracture reduction. DLS is a new generation of locking screw, amalgamating locking technology with dynamic motion with the aim of improving interfragmentary motion at the near cortex. Keywords: dynamic locking screw, locking plates, bone healing, construct stiffness, dynamic compression