Intramedullary (IM) rods are used to align and stabilize fractures. IM rods are inserted into the bone marrow canal in the center of the long bones of the extremities. They may be used in the femur (thigh bone) or tibia (shin bone), for example. They are also called intramedullary nails.
One of the significant advantages of IM rods over other methods of fracture fixation is that IM rods share the load with the bone, rather than entirely supporting the bone. Because of this, patients are able to use the extremity more quickly.
IM rods cannot be used for all fractures, and there are often associated complaints of pain and other symptoms at the site the IM rods are inserted. For this reason, a second operation may be needed to remove the IM device if you have painful symptoms. Otherwise, the IM rod is designed to stay inside your bone forever.
Bone Healing and Intramedullary Rods
It's important to note that these types of implants don't really speed bone healing and they don't take the place of bone healing. Any metal implant used to stabilize a fracture is designed to hold the fracture in proper alignment while the normal healing process takes place.
While bone healing may not speed up, some IM rods are designed to have sufficient strength to carry the load of the body, and that is why people can often place weight on the extremity sooner than if you had to wait for full healing of the bone.
Uses of Intramedullary Rods
A femoral shaft fracture (broken thigh bone) is often treated with intramedullary nailing. Usually, the rod is made of titanium and they come in different lengths and diameters to fit patients of different ages and heights. A small incision is made at either the hip or the knee and the rod is inserted into the marrow canal. Screws are used to hold it in position at each end.
Shinbone fractures are also commonly treated with intramedullary nailing. It is inserted down the marrow canal of the tibia from the knee, crossing the area of the fracture for full-length fixation. Screws are placed on both ends to keep it in position during healing. The rod ensures that the position will be maintained better than just using a cast or external fixation. However, this is usually avoided in children because the rod would cross the bone's growth plates and could have an effect on the length of the leg.
Intramedullary rods may also be used in cases of metastatic bone disease in cancer to fixate and support a bone after tumor removal. This may be done for bones that are at risk for fracture.
In the genetic disorder osteogenesis imperfecta or brittle bone disease, rodding surgery may be used to prevent fractures and progressive deformity of the long bones. Telescoping rods may be used for growing children. They lengthen as the bone grows.