Plating of Fractures

Because of the large number of locations where fractures occurs and the different bones involved there is a variety of plates available. The dynamic compression plate or DCP allows a sliding technique to be used because of the screw holes being angled away from a central point. Once the screws are inserted and tightened they apply an inwards compression force, bringing the fragments into stronger contact. The ulna and the ankle lateral malleolus are fixed with thin plates of about one mm in thickness which can be shaped to the area required. Fractures close to a joint need specially designed plates to facilitate fixation and reduce impingement.

Ninety-five degree angled plates are typically used in fixation of fractures of the upper femoral areas so that the normal alignment of the bone can be restored. Surgeons need to be three dimensional thinkers to insert this kind of fixation and accurately recreate the anatomical relationships in the area. Pelvic and acetabular fractures are more often fixed with reconstruction plates as they are thinner than dynamic compression plates and more easily mouldable. Fractures often occur close to or just below the prostheses of joint replacements and they may be fixed by bigger plates and cerclage wiring.

Plate fixation along with good anatomical reduction and compression of the fragments against each other provide high levels of stability to the fracture. The fracture will undergo primary healing if there is no gap and the fixation is very stable. The dead bone close to the fracture site is absorbed by the osteoclasts, bone absorbing cells, followed by the growth of blood vessels into the area, followed by osteoblasts which are bone producing cells. Some osteoporosis of the area under the plate may be produced due to disruption of the blood flow locally by the plate and when the plate is removed the lowered bone density and the screw holes needs to be borne in mind when planning rehabilitation.

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.

More modern plating techniques include the LISS (Less Invasive Surgical Stabilisation) which makes less contact with the bone surface along its length, limiting potential disturbance in the membranous blood supply. Locking screw methods are typical newer designs, which offer great advantages over older systems by adhering to bony contours better also. These designs should allow greater forces to be tolerated while the fracture is still being held in the desired position. These are of particular use in fractures of the distal and proximal humerus, distal femur, distal radius and distal tibial fractures.

Less unstable fractures such as of the humeral, ulna and radial shafts have room to fix more easily and unite well with normal techniques. Locking screws are used where the options to fix are limited or the bone is osteoporotic. Locking capability will likely be the default option as plating develops and the costs, now much higher than conventional screws, reduces. However, if malunion occurs with conventional plating and the fixation needs to be revised the expense of the newer locking systems looks less prohibitive.

Nails

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.