The thighbone, also known as the femur, is the largest and strongest bone in the body. However, it can break when a child experiences an abrupt, forceful impact.

Statistics

Child abuse is the most common cause of thighbone fractures in infants below 1 to 4 years old. The incidence is higher for infants under the age of 1.

As for adolescents, motor vehicle accidents, either cars, bicycles or as a pedestrian, are the cause of most femoral shaft fractures.

Risk

Below are some events with the highest risk for pediatric femur fractures:

• Child abuse
• A motor vehicle accident
• Getting hit in contact sports
• A hard fall at the playground

There are various different types of femur fractures. In certain fractures, the pieces of bone may be straight and aligned while in others, they are displaced and out of alignment. In some cases, the fracture may be closed with skin intact whereas, in others, the fracture may be an open one, meaning the bone pierces through the skin. An open fracture, however, is rare.

Femur fractures are classified specifically depending on:

• Where the fracture is on the bone (proximal, middle, or distal third of the bone shaft)
• What shape the fractured ends are — bones can break in all types of ways, such as straight across (transverse), angled (oblique), or spiralled (spiral)
• What position the fractured edges are in (angulated or displaced)
• How many fractured parts there are, whether two or several (comminuted)

A femur fracture is serious. There are several telling signs of a femur fracture:

• Severe pain
• Bruising, where the skin changes colour
• Noticeable swelling or deformity in the thigh
• Inability to stand or walk
• Limited range of motion in the hip or knee because of pain

If a broken thighbone is suspected, the child must be taken to the emergency room immediately.

It is crucial for the doctor to know how the injury occurred in detail. One should also inform the doctor of any previous diseases or trauma.

The child will be given pain relief medication and have their leg, hip and knee examined carefully. Other serious injuries should also be looked out for with a thighbone fracture.

Imaging tests

X-rays of the injured leg will be required in order to observe the broken bone for classification. The healthy leg may also be X-rayed for comparison purposes.

The X-ray will also be used to check for any damage to the growth plate towards the end of the femur. This is the part that allows the child’s bone to grow. If needed, surgery can help to restore the growth plate’s function. On top of that, regular X-rays may be taken for several months to track the growth of the bone.

To treat a pediatric femur fracture, the pieces of bone have to be realigned and held in place for healing. Treatment may vary depending on several factors. Such factors include the type of fracture, the child’s age and weight, how the injury occurred and whether the broken bone has pierced through the skin.

Nonsurgical treatment

In certain femur fractures, the broken bones may be successfully manipulated back into place without an operation. This is known as a closed reduction. For babies under 6 months old, a brace called a Pavlik Harness may be able to hold the broken bone still enough to heal successfully.

Spica casting

For children between 7 months and 5 years of age, a spica cast is typically applied. This is to keep the fractured pieces in the correct position until the bone heals.

Generally, a spica cast begins at the chest and extends all the way down from the fractured leg. There are various kinds of spica casts. Some may also extend down the uninjured leg or stop at the knee or hip. The doctor will determine which kind of spica cast is the most effective in treating the fracture.

First, the child will be sedated for closed reduction. Next, a spica cast is applied immediately or within 24 hours of hospitalisation to fix the fractured pieces in the right place until they heal.

When a bone is broken and displaced, the pieces usually overlap and shorten the normal length of the bone. Because children’s bones grow quickly, the pieces may not need to be manipulated back into perfect alignment. The bones will grow and heal back into a more normal shape while in the cast.

For the best results, the broken pieces should generally not overlap over 2cm in the cast. The growth of the thighbone may be temporarily increased by the trauma, and the mild shortening from the overlap will resolve.

Traction

In some cases, the shortening of the bones may be too much (over 3 cm) or the bone may be too crooked in the cast. In such events, it may be helpful to place the leg in a weight and counterweight system, also known as traction. This is to ensure the bones are correctly realigned.

Surgical treatment

Generally, displaced femur fractures that have shortened over 3 cm are deemed unacceptable and require treatment to correct at least some part of the shortening.

In certain cases of more complex injuries, the bones may need to be surgically realigned and an implant may be used to stabilise the fracture.

In recent years, more pediatric femur fractures have been treated with surgery due to its increasingly recognised benefits. Such benefits include a shorter hospital stay, faster rehabilitation and earlier mobilisation.

For children between the ages of 6 and 10, flexible intramedullary (inside the bone) nails are commonly used to stabilise the fracture. This treatment method has gained a great deal of acceptance, especially over the past decade.

Once in a while, the bone has been broken into too many fragments and cannot be treated effectively with flexible nails. In such situations, there are other options that can bring about successful outcomes:

• A plate with screws that “bridges” the fractured pieces
• An external fixator, which is typically used if there has been a large open injury to the muscles and skin
• Prolonged traction with a pin temporarily placed into the thighbone

For children nearing their teenage years (11 years to skeletal maturity), the most common treatment options include either flexible intramedullary nails or a rigid locked intramedullary nail. The rigid nail, in particular, is useful for unstable fractures. Both kinds of nails allow the child to begin resume walking straight away.

Most of the time, children who sustain a femur fracture will heal well, regain normal function and have legs that are equally long. However, if the intramedullary nails are causing irritation of the skin and tissues underneath, they may need to be removed.

Although uncommon, children may sometimes require further treatment early on or in subsequent years. This is if they have an infection, a significant difference in leg length, abnormal rotation of the healed bone, unacceptable angulation of the healed bone or (rarely) if the thighbone fracture persists (also known as a nonunion).

However, one need not be too concerned, as these problems can almost always be resolved with extra treatment.