There is a particular type of hip fracture that is often fixed with screws. This type of fracture is called an “impacted” femoral neck fracture. In this fracture, the femoral neck crumples slightly but does not break completely in half and the femoral head is still in a relatively normal position. A relatively minor surgical procedure is used to stabilize this fracture. Through several small incision on the side of the hip, 3 screws are inserted into the femur, bridging the fracture site and stabilizing the break so that normal healing can occur. Most surgeons who have been trained in the United States use an implant made by a swiss company called Synthes to fix this fracture. Therefore, it has become commonplace to refer to this type of an operation as 7.3mm cannulated screws because that is the diameter of the screws that are used to fix this fracture. It is also referred to as percutaneous screw fixation of the femoral neck because the screws are inserted through small incisions made in the skin.
Here are three pictures from a typical femoral neck fracture case treated in this manner. The patient is positioned on a fracture table in the supine positions — flat on their back. A type of surgical drape called a shower curtain prep is used to isolate the lateral side of the hip and create a sterile surgical field. Through three small separate incisions three screws are inserted into the femur across the fracture site. The most common pattern for screw insertion is an upside down triangle so that the base of the triangle is at the upper portion of the femoral neck.
This surgical procedure has the advantage of taking a minimal amount of time, involving a minimal amount of blood loss, and causes a minimal amount of tissue disruption. However, for the procedure to be successful, the fracture MUST heal. If the blood supply to the femoral head has been interrupted by the fracture then a devastating complication called avascular necrosis of the femoral head can occur. This complication tends to occur less than 10% of the time, so most patients have more than a 90% chance of having a successful outcome after this operation.
I always caution my patients that impacted femoral neck fractures in the elderly are often satisfactorily treated by percutaneous screw fixation but there is always the possibility that the fracture may not heal. I make sure that these patients are seen frequently so that I we can take X-rays on a regular basis to monitor fracture healing.