Introduction
Although most bone disorders affecting children are similar to those affecting adults, there are some differences. Children's bones are continually growing and extensively reshaping themselves (remodeling). Growth proceeds from a vulnerable part of the bone called the growth plate. In remodeling, old bone tissue is gradually replaced by new bone tissue (see Section 5, Chapter 58). Children's bones can remodel more extensively than adults' can. Also, in children, bones heal more rapidly, and scarring and stiffening develop less often. Most childhood bone disorders are minor and do not cause permanent problems.
 See the sidebar Common Foot, Knee, and Leg Disorders in Infants and Young Children.
Causes
Bone disorders in children can develop from any of the causes that affect adults, such as injuries and infections. Causes that affect mainly children include gradually developing misalignment of bones. In children, the bones in the legs can be very curved, which usually results from the way the legs were positioned in the uterus before birth.
Poor blood supply can also damage the growth plate, as can separation from the rest of the bone or even minor misalignment. Damage to the growth plate suppresses the growth of bones, distorts the joint, and can cause long-standing joint damage (arthritis).
Certain rare hereditary disorders of connective tissue affect the bones, such as Marfan syndrome, mucopolysaccharidoses, osteogenesis imperfecta, chondrodysplasias, and osteopetroses (see Section 23, Chapter 279).
Symptoms and Diagnosis
Children usually experience the same symptoms as adults. Pain is common and may develop slowly, over weeks or longer. Infants and very young children may be unable to communicate their pain. Bone disorders sometimes cause painless deformities. Some deformities may affect a child's ability to walk or use the limbs. Diagnosis of bone disorders is similar in children and adults.
Treatment
Treatment of most bone disorders, such as fractures and infections, is usually similar in children and adults.
If the growth plate becomes damaged, surgery may help. Accurately realigning separated or misaligned ends of the growth plate surgically may restore normal bone growth. By decreasing the irritation caused by misalignment, surgery may prevent the development of arthritis in the joint.
If a bone disorder causes a physical deformity, the child may become anxious or depressed. Some treatments for bone disorders may also be psychologically difficult to accept. For example, adolescents may be reluctant to wear a back brace for treatment of scoliosis, because doing so makes them appear different from peers. Professional counseling may relieve anxiety or depression. Counseling may also help a child go through with difficult treatments.
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