|Screws are the most common general purpose fixation devices.
They may be the only hardware used in reparative or reconstruction surgery. More commonly,
however, they are used with other hardware devices, particularly plates, to
fixate the associated device to bone. For fractures that have large well-defined
components, screws are used both to fixate plates and as standalone devices to
fixate the fracture fragments.
The main features of a screw are shown to the right along with the standard names for its parts. Each of the parts can be modified to produce screws with specific characteristics. The most common variations are differences in spacing between the threads (pitch), core diameter, and tip design. Screws can have hollow (cannulated) or solid central axes and can be fully or partially threaded. Screws tips are designed to be tapping or nontapping (see glossary). Screws are often referred to by the outer diameter of the threaded portion, 3.5, 4.5, and 6.5 mm screws being the most common.