The thighbone (femur) is the largest and strongest bone in the body. It can break when a child experiences a sudden forceful impact.

Statistics

The most common cause of thighbone fractures in infants under 1 year old is child abuse, which accounts for approximately 70% of the fractures. Child abuse is also a leading cause of thighbone fracture in children between the ages of 1 and 4 years, but the incidence is much less in this age group.

In adolescents, motor vehicle accidents (either in cars, bicycles, or as a pedestrian) are responsible for the vast majority (up to 90%) of femoral shaft fractures.

Risk

Events with the highest risk for pediatric femur fractures include:

• Falling hard on the playground
• Taking a hit in contact sports
• Being in a motor vehicle accident
• Child abuse

Femur fractures vary greatly. The pieces of bone may be aligned correctly (straight) or out of alignment (displaced), and the fracture may be closed (skin intact) or open (bone piercing through the skin). An open fracture is rare.

Specifically, thighbone fractures are classified depending on:

• Location of fracture on the bone (proximal, middle, or distal third of the bone shaft)
• Shape of the fractured ends — bones can break all kinds of ways, such as straight across (transverse), or angled (oblique)
• Position of the fractured edges (angulated or displaced)
• Number of fractured parts: Two parts or Several fractured parts (comminuted)

A thighbone fracture is a serious injury. It may be obvious that the thighbone is fractured because:

• Your child has severe pain
• The thigh is noticeably swollen or deformed
• Your child is unable to stand or walk, and/or
• There is a limited range of motion of the hip or knee allowed by the child because of pain.

Take your child to the emergency room right away if you think he or she has a broken thighbone. Explain exactly how the injury occurred. Tell Dr. Backe if your child had any disease or other trauma before it happened.

The doctor will give your child pain relief medication and carefully examine the leg, including the hip and knee. A child with a thighbone fracture should always be evaluated for other serious injuries.

To treat a child’s thighbone fracture, the pieces of bone are realigned and held in place for healing. Treatment depends on many factors, such as your child’s age and weight, the type of fracture, how the injury happened, and whether the broken bone pierced the skin.

A young child in a hip spica cast to immobilize a femoral shaft fracture.

In some thighbone fractures, Dr. Backe may be able to manipulate the broken bones back into place without an operation (closed reduction). In a baby under 6 months old, a brace (called a Pavlik Harness) may be able to hold the broken bone still enough for successful healing.

Spica casting. In children between 7 months and 5 years old, a spica cast is often applied to keep the fractured pieces in correct position until the bone is healed.

There are different types of spica casts, but, in general, a spica cast begins at the chest and extends all the way down the fractured leg. The cast may also extend down the uninjured leg, or stop at the knee or hip. Your doctor will decide which type of spica cast is most effective for treating your child’s fracture.

Dr. Backe will sedate your child for the closed reduction, and apply a spica cast immediately (or within 24 hours of hospitalization) to keep the fractured pieces in correct position until healing occurs.

A thighbone fracture before and immediately after treatment with a spica cast. The femur will remodel over time so that it appears normal.

When a bone breaks and is displaced, the pieces often overlap and shorten the normal length of the bone. Because children’s bones grow quickly, Dr. Backe may not need to manipulate the pieces back into perfect alignment. While in the cast, the bones will grow and heal back into a more normal shape.

In general, for the best results, the broken pieces should not overlap more than 2 cm when in the cast. The growth of the thighbone may be temporarily increased by the trauma. The mild shortening from the overlap will resolve.

Traction. If the shortening of the bones is too much (more than 3 cm) or if the bone is too crooked in the cast, it may be helpful to put the leg in a weight and counterweight system (traction) to make sure the bones are properly realigned.

Doctors generally agree that displaced femur fractures that have shortened more than 3 cm are not acceptable and require treatment to correct at least a portion of the shortening.

Left, Preoperative X-ray of a child with a fracture through the midshaft of the left femur. Right, Postoperative X-ray of the same child shows that the fracture was treated with internal flexible nailing to restore stability and allow early mobilization.
In some more complicated injuries, Dr. Backe may need to surgically realign the bone and use an implant to stabilize the fracture.

Doctors are treating pediatric thighbone fractures more often with surgery than in previous years due to the benefits that have been recognized. These include earlier mobilization, faster rehabilitation, and shorter time spent in the hospital.

In children between 6 and 10 years old, flexible intramedullary (inside the bone) nails are often used to stabilize the fracture. Over the past decade, this treatment method has gained great acceptance.

Occasionally, the broken bone has too many pieces and can not be treated successfully with flexible nails. Other options that can lead to successful outcomes in this situation include:

A plate with screws that “bridges” the fractured segments
An external fixator — this is often used if there has been a large open injury to the skin and muscles
Prolonged traction with a pin temporarily placed into the thighbone

External fixation is often used to hold the bones together when the skin and muscles have been injured.

As the child nears the teenage years (11 years to skeletal maturity), the most common treatment choices include either flexible intramedullary nails or a rigid locked intramedullary nail. The rigid nail is particularly useful when the fracture is unstable. Both types of nails allow for the child to begin walking immediately.