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Down syndrome is one of the most common genetic disorders. According to the Centers for Disease Control and Prevention, it affects about 1 baby in every 691 births.
Children with Down syndrome have varying developmental delays and medical problems. They may have special medical problems of the heart, stomach, eyes, and other parts of the body. Many children have problems that involve the bones and joints. These musculoskeletal problems may affect movement and coordination, and may worsen later in life.
Anticipating and addressing the musculoskeletal issues that occur in childhood can greatly improve the health and function of people with Down syndrome.
The severity of developmental delay varies in children with Down syndrome. A child with Down syndrome will eventually reach the same growth milestones as other children, however, he or she may be slower to turn over, sit, stand, walk, and do other physical activities.
The most common musculoskeletal effects of Down syndrome include weak muscle tone (hypotonia) and ligaments that are too loose (ligament laxity). This leads to excessive joint flexibility.
Children with Down syndrome may have hip, knee, and other joints that slip out of place or become dislocated.
- Hip instability. The hip is a "ball-and-socket" joint. In a normal hip, the ball of the upper end of the femur (thighbone) fits firmly into the acetabulum (socket). Because the ligaments and muscles that help hold the bones in place are loose in children with Down syndrome, the femur is more likely to slip out of place. Over time, this instability may lead to repeated hip dislocations, in which the femur pops completely out of the socket, without any outside force or injury.
- Kneecap instability. Patellofemoral (kneecap) instability is a common musculoskeletal problem in children with Down syndrome. The kneecap normally rests in a small groove at the end of the thighbone. The kneecap slides up and down within the groove when the knee bends and straightens. Due to weak muscle tone, the kneecaps of a child with Down syndrome may slip out of the groove. This instability will cause the knees to look deformed, but may not cause any other symptoms. Many children will continue to walk, while others may experience pain and frequent falls.
In many children with Down syndrome, the muscles and ligaments that support the neck are weak and loose. This can potentially cause spinal cord compression, in which the small bones in the neck (vertebrae) press on the spinal cord. Compression may lead to reduced muscle coordination, numbness, and weakness.
Spinal cord compression does not occur in most children with neck instability. However, any progressive physical changes in a child with Down syndrome should be brought to your doctor's attention. These changes may include:
- Weakness, clumsiness, and tripping
- Walking with stiff legs
- Having a stiff neck, neck pain, and headaches
Your doctor may recommend taking x-rays of your child's neck to look for joint laxity. In some cases, a child may be kept out of contact sports or other activities that put stress on the neck, such as high jumping, diving, gymnastics, and using a trampoline.
A child with Down syndrome may have flat feet, bunions, and other foot conditions. These problems can cause foot pain, and impact the child's gait and balance.
Getting early medical care and treatment can improve the health of a child with Down syndrome.
Your doctor will consider many factors when planning treatment, including your child's age, remaining years of growth, symptoms, and any physical disabilities caused by the orthopaedic problem.
There are a number of things that can be done nonsurgically to help a child with Down syndrome.
- Physical therapy. Exercise and strengthening activities may improve weak muscle tone and help protect against problems that may result from excessive joint flexibility. Your doctor may recommend a special program of physical therapy when your child is very young. Early intervention can help a child with Down syndrome achieve developmental skills and build muscle tone and coordination. It can also give extra stimulation and encouragement to help the child achieve his or her full potential in life.
- Immobilization. Children with hip instability may temporarily be treated with a spica cast that is designed to hold the hip bones in proper position and allow the ligaments around the joint to become more stable.
- Assistive devices. Some children may need splints or other devices to relieve pain and make physical activity easier. Orthotics, arch supports, customized shoes, and braces can be helpful for problems due to joint instability.
- Adopting a healthy lifestyle. A child with Down syndrome should be encouraged to be physically active and eat a healthy, well-balanced diet. This will help them avoid excess weight gain and other health problems like high blood pressure and diabetes. Your doctor can help develop a well-rounded exercise routine that includes aerobic activity, strength training, and stretching exercises.
If the child's musculoskeletal problems do not respond to nonsurgical treatments such as bracing, orthotics, and physical therapy, your doctor may recommend surgery.
- Spinal fusion. Occasionally, a child with severe cervical instability may require a spinal fusion procedure to stabilize the bones in the neck and decrease pressure on the spinal cord. Spinal fusion is essentially a "welding" process. The goal of the surgery is to fuse together the vertebrae so that they heal into a single, solid bone.
- Other procedures. Surgery on bones, soft tissues like ligaments, or both may also be needed to manage looseness of the hip and knee joints, and looseness of the joints in the feet.
People with Down syndrome are living longer, in large part due to advances in treatment for heart conditions. As a result, musculoskeletal problems that are present in childhood may worsen in adulthood, often resulting in arthritis and loss of mobility. Early diagnosis and treatment during childhood may prevent pain and disability in adults with Down syndrome.
Source: Parker SE, Mai CT, Canfield MA, Rickard R, Wang Y, Meyer RE, Anderson P, Mason CA, Collins JS, Kirby RS, and Correa A; for the National Birth Defects Prevention Network. (2010). Birth Defects Res A Clinical Molecular Teratology. 88(12):1008-16. Retrieved from the Centers for Disease Control and Prevention.
Reviewed by members of POSNA (Pediatric Orthopaedic Society of North America)
The American Academy of Orthopaedic Surgeons
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