The various bones and fracture positions dictate the different types of plate available. The DCP or dynamic compression plate and the screw holes allow compression of the fracture site to be applied as the screws are tightened up in the angled screw holes. Small plates are used to fix the lateral malleolus of the ankle and the wrist end of the ulna forearm bone and for this job they are often very thin at an easily mouldable one millimetre. Other plates have been designed for use in fractures close to joints and these have reduced device size and thickness and added options for the flexibility in fixation required.
Fractures of the upper femur are fixed by using plates with a 95 degree angle so that the mechanical axis of the upper femur can be restored at this angle. Inserting this kind of fixation requires that the surgeon thinks in three dimensions as are all must be correctly aligned to restore normal anatomy. Reconstruction plates are less thick than dynamic compression plates and can be contoured in three dimensions for the acetabulum and pelvis. Fractures close to or next to prostheses such as hip replacements or knee replacements are fixed with larger plates with the addition of cerclage wires.
High levels of fracture stability can be provided by compression of the fragments and a good restoration of anatomical alignment by the fixation. If firmly stabilised and without any fragment gap then the fracture will heal by primary healing. Absorption of the dead bone at the site of fracture occurs by the action of osteoclasts, with blood vessels growing into the region and then bone producing cells proliferating. Disruption of the blood supply by the plate can produce some osteoporosis under the plate, leading to reduced bone strength from this and the screw holes once the plate is removed, necessitating careful decisions about the amounts of force to be applied to the area.
Internal fixation with a plate involves opening up the fracture site and removing the blood clot, reducing the fragments to an anatomically acceptable alignment. A fracture interrupts the blood supply across and around a fracture and the remaining blood supply is provided by the periosteal bone lining. The periosteum should be preserved and not stripped away during the operation or healing could be delayed from reduced vascular supply. Unstable comminuted fractures are more difficult to fix and bridge plates are used to fix the two main parts and keep the important aspects of the bone in line, the rotation, alignment and length of the bones. However this form of weaker fixation cannot tolerate any significant level of load.
The Less Invasive Surgical Stabilisation plating system (LISS) is a modern fixation system which limits the contact between the metal and the bone, lowering the risks of the blood supply in the damaged area becoming compromised. These designs are more mouldable to the bony contours and have the ability to apply locking screws, allowing these designs to keep the desired bony alignment whilst simultaneously managing to resist significant forces during the period of healing. Choice of these newer designs is indicated in managing fractures of the end of bones such as the radius, humerus and femur.
Conventional plating techniques are adequate to fix fractures where access to the areas is easy and in cases where the fractures are of a stable type, incorporating fractures of bony shafts such as the ulna, humerus and radius. With osteoporotic bone and difficult fixation options the locking systems will be more appropriate. As they are much more expensive than the conventional systems they are not yet the default choice in all cases but look likely to be more widely used as the cost comes down. They may well be cost effective if cases of malunion which require revision are taken into account.
It was in the 1930s that Kuntscher refined the intramedullary nailing technique which then became the treatment of choice for shaft fractures of the femur. Humeral and tibial fractures as well as femoral breaks nearer the bone ends were the next progression. Early joint movement and weight bearing walking is allowed by this.