The effect of screw type on the fixation of depressed fragments in tibial plateau fractures.

The ability of various screw types to stabilize depressed tibial plateau fractures was determined in a biomechanical study using a Sawbones model. Two sizes of both cancellous and cortical screws were evaluated for both supportfrom below and through the depressed fragment. As a general trend, cancellous bone screws provided a greater resistance to fragment displacement than cortical bone screws, and screws with a smaller thread diameter provided greater resistance to displacement than screws of the same thread type with a larger diameter. These results agree with the accepted standard that cancellous screws provide better fixation for tibial plateau fractures, but also are counterintuitive in that smaller screws provided greater fixation than larger screws of the same type.