What is knock-knee and bowleg?
Knock-knee, or genu valgum, is a problem that causes your child’s feet to be far apart when they stand with their knees together.
Bowleg is a condition that also occurs around the knees, causing the legs to bow outwards when your child is in a standing position with their feet together. Its proper name is genu varum.
Common signs and symptoms of knock-knee and bowleg
It is normal for most children to have some degree of knock-knee or bowleg within acceptable limits. In children, the rate at which they are growing in their first few years of life can cause them to bowlegged from birth up to around age 3. After age 3, they can become knock-kneed until around age 5, with the legs finally straightening into a more normal position by around age 7.
The changing phases that children go through with knock-knee and bowleg do not usually present any cause for concern in parents, as the appearance is not severe. In some cases, however, parents do tend to become worried if the condition becomes more obvious.
Knock-knee and bowleg does not usually cause any symptoms and the only sign of it tends to be the obvious appearance of the legs when in the standing position. However, in more severe or complicated cases, your child might have symptoms such as:
- Pain or a limp whilst walking
- Signs of Blout’s disease (a growth disorder of the shin bone)
- Rickets (a skeletal disorder)
There is a chance that other disease syndromes and their symptoms may be associated with knock-knee or bowleg.
Common causes of knock-knee and bowleg
Whilst the general cause of knock-knee and bowleg is due the normal rate of growth in young children, there can also be more severe cases which may be linked to other causes:
- Blount’s disease – this condition affecting the growth of the shinbone can cause severe bowleg in children. It is more common in black children and may require surgery
- Growth disturbance – when your child stops growing in the normal way, knock-knee or bow leg can develop
- Trauma – if your child suffers an injury to the knee, it may cause damage to the growth plate, resulting in knock-knee or bowleg as your child grows
- Rickets – if your child does not get enough vitamin D or has trouble metabolizing vitamin D due to kidney disease, a growth disturbance can occur which affects the bones of the body, including the knees
Diagnosing knock-knee or bowleg
As mentioned, knock-knee and bowleg can be considered a normal impact of growth within certain ages. Diagnosis is usually based on the physical appearance. In young children, if the distance between the feet is less than 2 inches (in knock-knee) or the distance between the knees is less than 2 inches (in bowleg), then there is no need for concern. Checking these measurements periodically is all that is required in order to monitor the condition.
In certain circumstances, further investigations, such as x-rays and blood tests, may be required:
- If knock-knee or bowleg appears outside of the normal range, such as bowleg occurring in children above age 3 and knock-knee occurring in children above age 7
- If it affects one leg / knee only
- If the distance between the feet and knees is more than 2 inches when standing with feet or knees together
- If the distance between the feet or knees is increasing rapidly, by more than half an inch within six months.
- If pain or a limp, or signs of other conditions, such as Blout’s disease or rickets is present
Treating knock-knee and bowleg
Whilst it is very unlikely that your child may need treatment for knock-knee or bowleg, in severe or complicated cases, such as where Blout’s disease is present, your doctor may suggest treatment. The type of treatment will depend on your child’s condition and may be non-surgical or surgical.
Your doctor may suggest the use of knee braces, splints or orthotic shoes. Physiotherapy may also be recommended.
Where surgery is required, it is usually postponed until certain bone maturity has been reached, at around 10 years old. Surgery consists of cutting, straightening and then holding the bones of the knee in place while they heal with metal implants, including pins, plates and screws.
Even though surgery is not a common treatment for these conditions. An extended recovery period involving physiotherapy is required before fully returning to regular activities and sports.