Pediatric Tibia and Fibula Fractures
Tibial fractures represent the third-most fractured long bone in kids. They happen in 15 percent of pediatric fractures. The average age of fracture is 8 years of age. Thirty percent of these fractures are also associated with fibular fractures on the same side. Boys get this fracture more than girls by a 2:1 margin. It is commonly fractured in children who are victims of child abuse.
Half of all injuries happen as a result of motor vehicle accidents. In tibial fractures unassociated with fibular fractures, the fracture is usually caused by a rotational force. Kids between the ages of one and four tend to get this fracture from a bicycle spoke injury. Older kids tend to get the fracture from a motor vehicle accident or athletic injury.
A full trauma evaluation is necessary because many of these fractures are associated with other trauma. Patients with this fracture cannot walk on the leg and there is painful range of motion of the knee or ankle. Neurovascular damage can happen so this needs to be evaluated. Compartment syndrome is possible. The entire area should be assessed to rule out an open fracture.
X-rays should be done of the front and side of the leg and should include the knee. The ankle should also be x-rayed. An MRI scan can identify an occult fracture.
Proximal Tibial Fractures
These are uncommon and represent only 11 percent of tibial fractures. The peak incidence is between 3 and 6 years of age. The most common mechanism of injury is a lateral force applied to the extended knee. The fibula usually does not get fractured. The patient usually presents with pain, tenderness, and swelling of the affected area. The knee is painful and the child does not want to walk on the leg. There may be a valgus deformity.
Nondisplaced fractures can be treated in a long leg cast with the knee extended. Displaced fractures need realignment under general anesthesia with a long leg cast applied after that. The cast needs to be in place for 6-8 weeks with frequent x-rays to rule out a new displacement. Normal activities are possible after the knee and ankle motions are restored and the fracture site does not hurt.
If the fracture cannot be reduced using closed measures, surgery needs to be done. After surgery, a long leg cast is applied with the knee extended for 6-8 weeks. Open fractures are also treated with surgery. External fixation may be necessary to keep an eye on the open area with debridement as necessary.
Complications include progressive angulation in the valgus direction. There may also be premature closure of the proximal tibial physis.
Fractures of the Tibial and Fibular Diaphysis
These fractures usually involve the middle third of the tibia. About a third of tibial fractures also involve fractures of the fibula. Isolated fibular fractures are rare and come from a direct lateral blow to the fibula. The main mechanism of injury is a direct blow from a pedestrian-motor vehicle accident. Indirect injuries from torsional forces can happen in younger kids. These lead to spiral and oblique fractures of the tibia.
The child usually refuses to walk on the leg and there is swelling and tenderness to the affected area. Motion about the knee is painful. Stress fractures of the tibia can happen in children. Compartment syndrome can happen in severe fractures.
Treatment can be nonoperative and involve closed reduction and placement in a long leg cast. If the fracture is displaced, it can be reduced under general anesthesia with a long leg cast applied with the ankle slightly flexed. This is done for 2-3 weeks. As the muscles atrophy, the fracture can become out of alignment and realignment under general anesthesia may need to be done at about 3 weeks after the injury. Surgery is only required in about 5 percent of cases. Surgery is done if there is:
- An open fracture
- Lack of stability after closed reduction
- Vascular injury
- Compartment syndrome
Surgery is done if there is a femoral fracture resulting in a floating knee, an open fracture that is grossly contaminated, or vascular compromise. Sometimes percutaneous pins are used; other times an intramedullary rod or plates and screws are used to hold the fracture fragments together. After surgery, a long leg cast is applied for up to 16 weeks.
Complications include having an angular deformity, malrotation of the tibia, premature proximal physeal closure, delayed union, and nonunion.
Fractures of the Distal Tibial Metaphysis
These involve about half of all pediatric tibial fractures. The peak age at incidence is between 2 and 8 years of age. The mechanism of injury involves a fall from a great height. Direct injuries can occur when a kid gets his foot caught in the spokes of a bicycle.
Patients with this fracture cannot walk on the leg or walk with a great deal of pain. There is usually not a great deal of deformity. The leg and foot must be evaluated for other injuries and open fractures. Compartment syndrome is possible as is neurovascular injury. If the injury is due to a bicycle spoke injury, the foot and ankle need evaluation, too.
Treatment can involve nonoperative means. In such cases, the child is placed in a long leg cast. After 3-4 weeks if healing is taking place, a short leg walking cast can be used. A child with a bicycle spoke injury should be admitted because the extent of the soft tissue injury might be delayed. Surgery is required if there is an open fracture or if there is an unstable distal tibial fracture. Pins and wires are used to hold the fracture ends together.
This is a spiral fracture of the distal tibia seen in toddlers. The average age at the time of the fracture is 27 months. The fracture occurs when there is external rotation of the foot with the knee in a fixed position. The child will often not want to walk on the leg and will be irritable. X-rays can show the fracture in most cases but sometimes it doesn’t show up for about 7-10 days. Technetium bone scans can be used to pick up occult fractures of the distal tibia.
The treatment involves using a long leg cast for about 2-3 weeks followed by the change to a short leg cast for another 2-3 weeks. It is rarely necessary to manipulate these fractures as they are usually in acceptable alignment.