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.
Diagnosis
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.
Treatment
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 orthopaedic surgeon which option he or she recommends and why.
- Traction. 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.
- Casting. 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.
- Plating. 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 or fractured shinbone (tibia) is the most common long-bone injury. Several types of fractures can occur, ranging from the hairline stress fractures common in runners to severe open fractures (where the skin is broken) resulting from motor vehicle crashes.
Toddler's fracture
A toddler (1 to 3 years of age) can fracture the shinbone when he or she trips over a toy or falls down a stair while learning to walk. These fractures usually do not break the skin, and the bone stays fairly well-aligned. There will be acute pain and possibly some swelling. The toddler may refuse to get up and walk again. The area of the fracture may be very tender.
It may be difficult to see this type of fracture on an X-ray, and your physician may request a bone scan to verify the diagnosis. These fractures heal quickly and can be treated with only a short leg weightbearing cast.
Growth plate fractures
Growth plate fractures are more common in older children and adolescents. These injuries occur near the ends of the bones at the ankle or knee. Bones do not grow from the center out, but from these growth plate areas. A fracture can disrupt the bone's development, leading to unequal limb length.
Growth plate fractures need to be identified early and watched carefully until the child reaches skeletal maturity to ensure that there is no shortening of the limb. The orthopaedic surgeon may need to use internal fixation devices, such as screws or nails, to stabilize the bone.
Stress fractures
Stress fractures are overuse injuries that occur when fatigued muscles can no longer absorb shock and transfer the load to the bone. More than 50 percent of all stress fractures occur in the lower leg. Stress fractures can develop gradually, with swelling and pain during activity. The most important treatment for stress fractures is rest. It takes 6 to 8 weeks for most stress fractures to heal. During that time, the individual should not participate in the activity that caused the fracture, but can participate in other pain-free activities.
Closed fractures
In a closed fracture, the skin is not broken. Closed fractures may be classified in several different ways, depending on the force of the injury, the stability of the bone, and the type and location of the break. The mechanism of the injury, such as a direct blow to the bone or an indirect twisting injury, can also cause soft-tissue damage.
Many stable closed fractures can be aligned without surgery, immobilized in a cast, and later supported by a fracture brace until healing is complete. However, if there is severe soft-tissue injury or if the fracture is grossly unstable, the orthopaedic surgeon may not be able to manipulate the bone into alignment and surgical treatment may be necessary. Surgical treatment may also be needed if the bone is fragmented into 3 or more pieces.
Open fractures
Because the shinbone is so close to the skin surface, a high-energy direct force may push the bone through the skin, resulting in an open fracture. All open fractures have an increased risk of infection and require surgical exploration and treatment. Open fractures are also often associated with trauma elsewhere in the body.
The use of small-diameter, interlocking nails to stabilize the fracture can result in less deformity, improved limb function, and shorter healing times. External fixators, such as a frame constructed around the leg, may also be used for the more severe, contaminated fractures, although these generally have higher rates of infection, poor alignment, or nonunion. In severe cases, amputation may be necessary.
