Congenital Pseudarthrosis of the Tibia
What is Congenital Pseudarthrosis of the Tibia (CPT)?
Congenital pseudarthrosis of the tibia is a shin bone fracture in children that has not healed. It normally presents before a child turns two years old. Typically the child gets a shin bone fracture that either happens spontaneously, or results from when the child experiences a minor trauma, and the fracture will not heal. It is a rare condition that occurs in 1 out of every 250,000 children. It stems from the periosteum, a membrane that covers the bone, being abnormal and preventing proper bone healing. Since the bone has not healed correctly, it is unstable and there is mobility at the false joint which should be solid, stable bone.
Congenital pseudarthrosis of the tibia is challenging to treat because it is very difficult to get the fractured bone to heal. Even if it does heal, it is hard to preserve that union. Refracture is common. The poor healing is due to the irregular periosteum, abnormally hyperactive osteoclasts (cells that remodel bone), and the mechanical challenge of stabilizing very small bone fragments in children. Some studies suggest that the periosteum is abnormal because its cells form too tightly around the small blood vessels that supply its oxygen and nutrients.
Who gets congenital pseudarthrosis of the tibia?
Congenital pseudarthrosis of the tibia is usually associated with neurofibromatosis (NF-1) which has many other serious potential manifestations. However, congenital pseudarthrosis of the tibia is also seen in fibrous dysplasia, osteofibrous dysplasia, cleidocranial dysostosis, and sometimes spontaneously (“idiopathic”).
How is congenital pseudarthrosis of the tibia diagnosed?
To diagnose congenital pseudarthrosis of the tibia, doctors use X-rays and also look for the signs of the associated conditions (see above).
What will happen during a clinic visit for congenital pseudarthrosis of the tibia?
The doctor will evaluate the patient for neurofibromatosis, a genetic disorder that causes tumors to form on nerve tissue which occurs in 40-50% of patients. The doctor will also ask for a history of previous fractures and examine the leg to determine the range of motion of the false joint. X-rays will be taken to determine the quality of the bone, the condition of the joints, the amount of limb length discrepancy and the severity of any bone abnormalities.
How is congenital pseudarthrosis of the tibia treated?
The primary treatment goal of congenital pseudarthrosis of the tibia is to achieve union of the shin bone (tibia) and to maintain that union. Treatment also addresses the resulting limb length discrepancies and bone deformities. To treat congenital pseudarthrosis of the tibia, the International Center for Limb Lengthening has a combined multimodal, comprehensive treatment program that addresses both the biological and mechanical issues. Many doctors use various elements of our protocol, but we strongly believe that the combined multimodal approach is the most effective.
What happens in surgery for congenital pseudarthrosis of the tibia?
- Two to four weeks before surgery, the patient receives an infusion of bisphosphonate that promotes bone healing.
- The abnormal periosteum is removed from the tibia (shin bone).
- The tibia is cut so the part closest to the knee has a V-shaped notch like an old-fashioned wooden clothespin. The part of the tibia closest to the foot is then cut so it can fit into the notch. Minimal bone is removed.
- The tibia and fibula (bone behind the shin bone) bones are stabilized with intramedullary rods or wires.
- Healthy periosteum and a bone graft are harvested from the pelvis.
- The healthy periosteum is wrapped around the bone ends of the congenital pseudarthrosis of the tibia site, bridging between the tibia and the fibula to create a cross-union.
- The bone graft is placed around the congenital pseudarthrosis of the tibia site.
- An external fixator is applied to the leg to provide rotational stability and to compress the bone ends while they knit. Alternatively, an internal plate and screws can be used instead of an external fixator.
- Inserting an intramedullary nail in the shin bone and the fibula increases the union rate and reduces the refracture rate. Intramedullary nailing also reduces the severity of any future fractures.
What happens after congenital pseudarthrosis of the tibia surgery?
Patients return monthly for follow-up visits until the bone heals. Three or four months after surgery, another infusion of bisphosphonate is done to prevent the bone graft from resorbing (melting away). After the bone has healed, patients return annually for checkups. Even after solid healing, there is still a risk for additional fractures until adulthood. Bracing reduces the number and severity of these fractures. We have seen very successful results with this combined treatment, even in patients who are younger than five years of age. After skeletal maturity, the bone becomes more normal and does not have as much tendency to fracture again.
Additional surgery may be needed in the future for limb lengthening or to insert longer rods to accommodate growth. Ankle deviations are common and may require realignment surgery. While our success rate with the multimodal approach is very high, nothing is 100%. We have found that some children require a second surgery to achieve union or to treat a refracture.
What is the “unbroken” congenital pseudarthrosis of the tibia?
Some children with congenital pseudarthrosis of the tibia are born with the leg crooked, but not broken. In such cases, we recommend bracing to prevent fracture. However, if fracture does occur, then our standard multimodal protocol is followed. On rare occasions, we will electively cut the bone at one or two levels to correct severe deformities.
Why come to the International Center for Limb Lengthening for treatment of congenital pseudarthrosis of the tibia?
Limb lengthening and deformity correction are complex processes. Your doctor at the International Center for Limb Lengthening will take the time to make sure you understand all of your options and then will customize your treatment to meet your specific needs. Our patients benefit from our team-centered approach with world-renowned pediatric and adult orthopedic surgeons and specialized physician assistants, nurses and physical therapists. We help patients with congenital pseudarthrosis of the tibia achieve their best possible result.