The thighbone (femur) is the longest and the strongest bone in the body. To break the thighbone across its length (shaft) takes a great deal of force, as might occur in a motor vehicle accident or a fall from a high place. Because of this, a broken thighbone is often associated with potentially life-threatening injuries to other body systems. In children younger than 3 years of age, a thighbone fracture is often an indicator of abuse.
A broken thighbone is usually obvious, even if the bone does not break through the skin. Severe pain, inability to move the leg, deformity and swelling are characteristic. The injured thigh may be shorter than the uninjured one because the strong thigh muscles may force the broken edges of bone out of alignment (displacement). The injury may disrupt the rich blood supply to the muscles of the thigh, resulting in extensive bruising and loss of blood.
If the fracture resulted from high-energy trauma such as a motor vehicle accident, the patient might not be conscious and may have other injuries. It is important that emergency medical personnel tend to the injury and transport the individual to a hospital.
The physician will examine the injury and evaluate the circulatory and nervous systems, as well as the fracture. Several X-rays may be required, including the leg, knee, hip and pelvis, to determine the extent of injury to the adjacent joints.
As with all broken bones, a broken thighbone will need to be “reduced” or returned to alignment and immobilized until it heals. There are several methods that can be used, depending on the patient’s degree of skeletal maturity, the amount of displacement, the type of break and the presence of associated injuries. If you are the parent of a child with a broken thighbone, ask your orthopedic surgeon which option he or she recommends and why.
- Traction is the traditional method of treating thighbone fractures. The leg is placed in a cast and sticky tape (skin traction) or a metal pin (skeletal traction) is used to attach a series of strings that connect to weights. X-rays are used to monitor the position of the bone so that the traction can be adjusted. Although traction is effective, it requires a lengthy hospital stay. Because research has confirmed the importance of early mobility in reducing complications and promoting successful healing, other methods of fixation are now more popular than traction.
- Very young children (under 8 years of age, depending on their size and weight) with an isolated fracture to the shaft of the thighbone can be treated with casting. A spica cast, which goes up over the hips and includes the other leg, may be used. A child with a spica cast can be cared for at home.
- In some cases, the surgeon may apply a metal plate to the side of the thighbone across the break. The plate is held in place with screws. The plate helps bear weight and makes early mobilization possible. However, the plate may also shield the bone from stress, which is not necessarily a good thing. Because some stress on the bone is necessary to strengthen it as it heals, this stress-shielding may leave the bone with a residual weakness. This generally disappears as the patient resumes normal activities. However, one concern is that when the plate is removed, the still-weakened bone may break again, but this is an infrequent occurrence. Plate-and-screw fixation can be an ideal choice for a patient with open growth plates or a nerve injury.
- External fixation. Although less frequently used for thighbone fractures, external fixation is an option if there are severe soft-tissue injuries along with the fracture. A frame around the leg is attached to the bone with pins. This has the advantage of allowing early mobilization, but caring for the pin insertions is difficult and infections are common. Nevertheless, external fixation may be appropriate for children with open growth plates and for patients with contaminated wounds.
- Internal intramedullary fixation. Internal intramedullary fixation (placing a rod inside the bone) is usually recommended for people who have attained skeletal maturity. The thighbone is like a tube, with a soft center surrounded by hard (cortical) bone. During a surgical procedure, a special rod (intramedullary nail) is inserted into the thighbone. The insertion may be near the hip or just above the knee. The rod extends into the middle of the bone and across the fracture site. It is locked in place with screws that pass through the bone and across the rod. This enables early movement and good stabilization of the fracture. After the fracture heals, the nail is removed.
A broken thighbone is a serious injury that takes a long time (3 to 6 months) to heal. Any delay in diagnosis or treatment could result in problems later. A child who has a thighbone fracture should be watched carefully and any changes in condition should be brought to the physician’s attention immediately. Oddly enough, because of the plentiful blood supply to the thighbone, the injured leg may grow longer than the uninjured one in some children. If, however, the bone is not properly aligned, the opposite could occur, with the injured leg being shorter.
A fracture that breaks the skin (open fracture) is susceptible to infection. In high-energy trauma cases, other injuries (including injury to the muscles and nerves around the thighbone) may make treating the fracture difficult.