What is Congenital Pseudoarthrosis of the Tibia?
Congenital pseudoarthrosis of the tibia is a rare condition that usually occurs in the first 2 years of life. In this condition, the tibia or shinbone is weak and undergoes fractures spontaneously or due to minor injury. The break does not heal properly forming an unstable fibrous joint (pseudoarthrosis) that can lead to complications. Congenital pseudoarthrosis is often associated with another condition called neurofibromatosis. It may also be associated with fibrous dysplasia.
Causes of Congenital Pseudoarthrosis of the Tibia
The disease process is present in the outer layer of bone called the periosteum which helps form new bone when a fracture occurs. The cause of this condition is unclear, but it may be due to decreased blood supply to the periosteum resulting in poor oxygenation. In this condition, a layer of scar tissue forms around the bone. Decreased activity of osteoblasts (bone-forming cells) and increased activity of osteoclasts (bone-resorbing cells) have also been noted resulting in the production of poor quality bone which does not heal well.
Symptoms of Congenital Pseudoarthrosis of the Tibia
Pseudoarthrosis of the tibia causes problems with pain and mobility and can affect the growth of the limb leading to deformity such as bowing and differences in limb length. The pseudoarthritic joint may be stiff or mobile and usually affects one side of the body. The bone is weak and has a tendency to fracture or refracture until your child reaches skeletal maturity, but fractures can even occur afterward.
Diagnosis of Congenital Pseudoarthrosis of the Tibia
Your doctor will review your child’s medical history and perform a physical examination assessing limb structure and function. X-rays, a CT scan or MRI are obtained to visualize the extent of the pseudoarthrosis or other abnormalities. Any associated condition is evaluated.
Treatment of Congenital Pseudoarthrosis of the Tibia
Congenital pseudoarthrosis of the tibia may be treated with a combination of surgery and medication. Bisphosphonate therapy is administered before surgery to reduce bone loss by inhibiting osteoclast activity. The fibrous tissue and diseased periosteum are surgically excised and an intramedullary rod is passed through the tibial bone. Bone grafts including a periosteal graft may be used to strengthen and heal the union. An external fixation device or other hardware may be used for further stability and to correct deformities. Additional procedures may be necessary to improve alignment and correct deformity. A non-invasive treatment using electrical stimulation may also be recommended.
Though congenital pseudoarthrosis of the tibia can be difficult to treat, newer treatments and technologies have shown improved outcomes. Amputation of the limb is however sometimes necessary for severe cases or repeated surgical failures.