When a bone is fractured, the broken pieces must be set back in their proper place and held together in order to heal correctly. The process of setting broken bones is called reduction. Setting a fracture without surgery is called closed or external reduction. When surgery is required, the process is referred to as open or internal reduction. When mechanical devices such as glue, pins, plates, screws or rods are used to hold the pieces of bone together, the procedure is labeled osteosynthesis.
Wrist fractures are the most common bone fractures, especially in active young people. If the bones remain properly aligned, or can be maneuvered into place externally, then stabilization with a cast or other external fixture is generally adequate. If the fracture is severely misaligned, however, osteosynthesis is recommended. Surgery can involve placing temporary screws, or a combination of plates and screws, into the joint to stabilize it during the healing process.
Hip fractures are usually repaired with osteosynthesis. The hip can be broken in three areas; the femoral neck, the narrow area where the ball and socket of the joint meet; the intertrochanteric area, the portion of the hip directly beneath the ball and socket joint; and the subtrochanteric area, the lower portion of the hip which reaches the upper leg. If the break occurs in the femoral neck, the surgeon can either replace the joint altogether, or stabilize it with surgical screws. Repair is the preferred method in younger patients or those in good physical condition because these patients experience less side effects and can usually return to full activity once the fracture has healed.
Hip fractures which do not occur in the femoral neck are generally repaired using plates and screws. These are easier to repair using osteosynthesis than femoral neck breaks, and generally do not require hip replacement surgery. Some surgeons use a metal plate placed along the outside of the hip and held in place by screws to stabilize the bone. Another option involves the use of a long rod with holes which is driven into the shaft of the bone. Screws are then placed through the bone and the holes in the rod, stabilizing the fractured area.
Surgical pins are often used in osteosynthesis of bones involving joints. These are made of non-magnetic materials such as stainless steel or titanium. In most cases, the pins are temporary and will be removed once the bone has healed sufficiently. Surgical rods and plates may be removed or left in place, depending upon the type of injury, placement and degree of stabilization.
Biodegradable pins and anchors have also been developed which will dissolve as the bone heals. These are currently made from polymer materials which can be resorped by the bone, although research is being conducted on the use of surgical implants made from magnesium alloys, which are also capable of biodegrading in the surgical site. One advantage of using these devises for osteosynthesis is that they generally cause less irritation to the surrounding tissue then metal. Avoidance of a second procedure to remove the pins is an additional advantage.