Pediatric Femoral Shaft Injuries
These make up about 1.6 percent of all pediatric fractures. Boys are more commonly injured than girls. There is a peak incidence between 2-4 years of age and in middle adolescence. Most occur during the summer months due to increased activity. In children who do not walk, the number one reason behind a fractured femoral shaft is child abuse. In adolescence, more than 90 percent of femoral shaft fractures occur because of motor vehicle accidents.
The main mechanisms of injury are direct trauma in a car accident, pedestrian accident, fall or child abuse. Indirect trauma from rotational injuries can also cause femur fractures. Many femoral shaft fractures are pathological fractures in patients with osteogenesis imperfecta, fibromas, bone cysts, and bone tumors.
A child with a suspected femur fracture should undergo a full trauma evaluation. The child is usually unable to walk on the leg and there can be swelling at the site of the fracture. Open fractures need to be looked for as soon as possible. There can be a great deal of blood loss from a femur fracture. Compartment syndrome is uncommon and usually results from severe hemorrhaging. The hip and knee need to be evaluated any time there is a femoral shaft fracture because they can be injured as well.
X-rays of the front and side of the femur should be taken along with hip and knee x-rays. It is usually unnecessary to do a CT or MRI but they can help if there is a hidden fracture not seen on x-ray but still suspected.
The treatment of femoral shaft fractures depends on the patient’s age. If less than 6 months, the fracture is treated with a Pavlik harness or posterior leg splint. Between 6 months and 4 years, spica casting is used in 95 percent of cases. Traction may be necessary with a spica cast to follow if the length cannot be maintained in the fracture. In children aged 4-12, surgery is done using flexible intramedullary nails. If the fracture is open or comminuted, then bridge plating may be necessary or external fixation. If the fracture is stable, a spica cast may be applied. In ages 12 through adulthood, intramedullary fixation or interlocked nails are used to hold the fracture together. If there are multiple injuries or an open fracture, external fixation may be possible.
A certain degree of angulation and shortening is acceptable depending on the age of the patient. The younger the patient, the more angulation and shortening is tolerated because the bones usually heal well.
Surgery is necessary if the following situations apply:
- Open fracture
- Multiple other traumas
- Vascular damage
- Pathologic fracture
- Large body habitus that interferes with spica casting
- The patient is uncooperative
The options for surgery to the femoral shaft include flexible elastic nails, or reamed and locked intramedullary nails. Plate fixation can be done using nails or screws to hold the fracture ends together.
Complications include malunion of the fracture, nonunion of the fracture, muscle weakness following repair, leg length discrepancy, overgrowth of the fracture, and osteonecrosis, especially of the proximal femoral area.