Musculoskeletal Disorders: Knees

Description

Two of the most common knee problems in children are knock knees and bow legs:

• Knock knees is when a child's legs curve inward abnormally so that the distance between her knees seems smaller than expected. Knock knees are less common than bow legs, and are most often seen in children 3 to 6 years of age. Knock knees may correct themselves, without treatment, by the time a child is between 6 and 8 years of age.
• Bow legs is where a child's legs curve outward abnormally, so that the distance between the knees seems greater than expected. Having bow legs is normal in children less than 2 years old. In older children, bow legs can be caused by many different problems, including abnormal bone growth in the legs, leg injury, infection, severe vitamin D deficiency and other problems of the bone or cartilage.

Symptoms and Signs

Both bow legs and knock knees are usually noticed by parents and can be checked for using the tests described below. Either bowlegs or knock-knees, if not treated, can cause osteoarthritis in the knees later in life.

Diagnosis and Treatment

To check for knock knees, have the child lie on his/her back and straighten out the legs. Bring the knees together and then measure the distance between the insides of her ankles. The distance should be less than 10 centimetres (about 4 inches). Children with knock knees usually grow out of the problem by the time they are 8 years old. Rarely, if a teen has severe knock knees, doctors will correct the problem with surgery.

To check for bow legs, have the child lie on his/her back and straighten out the legs.. Bring the insides of the ankles together and then measure the distance between the insides of the knees. The distance should be less than 10 centimetres (about 4 inches).
After age 2, a child's bow legs should be checked by your doctor. After a physical exam, your doctor may order x-rays of your child's legs. Less often, your child may need an MRI scan or other tests to check the cartilage in the knees. Once the reason for the bow legs is found, it can be treated, either with surgery (in more severe cases) or with an orthopaedic appliance.

The information in this page is presented in summarised form and has been taken from the following source(s):
1. Intelihealth.com, Children's Health Section: http://www.intelihealth.com/