Lag Screws & Surgery

For a patient with a broken bone or who requires reconstructive surgery, surgical implants could be required to hold bones in place and stabilize them as they heal. Surgeons have several tools available to them, including lag screws.

Function

• Lag screws are tools that orthopedic and plastic surgeons use to provide internal stabilization for patients' bones. They hold bones in place and can be used to stabilize bone fractures as well as to provide stability after reconstructive surgery so bones heal correctly. A lag screw differs from other screws in that it has threads only along the lower portion of the shank, while other screws have threads along their entire lengths, according to the book "Oral and Maxillofacial Surgery: Trauma." Lag screws may or may not have to be removed later.

Other Tools

• Lag screws can be used on their own or in conjunction with other surgical tools like wires and plates. During surgery to repair a broken bone, a surgeon places a metal plate along the length of the fractured bone that needs to be stabilized. She then uses a lag screw to hold the plate in place against the bone. When a lag screw is used in combination with a metal plate, it is important that they both be made of the same metal to avoid possible breakdown of the implants later, according to "McGlamry's Comprehensive Textbook of Foot and Ankle Surgery."

Surgeries

• Surgeries in which lag screws are frequently used include those to repair mandibular fractures, both along the sides of the jaw and near the chin. Surgeons also use lag screws to hold bones in place when working with fractures in the area below the nose or near the eyes, according to "Facial Plastic and Reconstructive Surgery." If a surgeon is working with multiple fractures in a broken ankle, he can use lag screws during surgery to hold those fractured bones in place.

Complications

• Potential complications of using lag screws in surgery include the risk of wound infection. A patient could develop an infection in the bone around the site where the lag screw was inserted. There is a risk that the screw could shift out of place, which would lead either to the bone fracture's not healing or to its healing with the bone not in proper alignment.

Considerations

• Lag screws function by causing bone compression and pressing the two portions of a fracture together so they heal correctly. If a fractured bone has a gap defect and a portion is missing, lag screws cannot be used. If carefully placed by a surgeon, a fully threaded screw can function as a lag screw.