Knock knees, also known as genu valgum. It is a common condition that occurs when a child (or adult) stands up straight with their knees together, but their feet and ankles stay apart. The opposite type of alignment, called bowlegs. Often, young children may appear as if standing in this position with legs turned inwards.
The condition is common from infancy till the age of 2 or 3 years. It may increase in severity until about age 4. Besides, it gets self-corrected by 7 or 8 years old. However, in rare cases when knees begin to knock after the age of 6 years. This can be an indicator of an underlying bone disorder.
Knock knees are usually assessed by directly measuring the angle of the shin bone to the thigh bone. Measurement can also be the distance between the ankles. Sometimes x-rays help to calculate these measures.
What causes knock-knees?
Knock knees are normal in young children. But if the problem persists or appears later in life, there may an underlying medical cause. Some of the causes that can contribute to knock knees include:
- Neurological conditions, such as cerebral palsy or spina bifida. This is as a result of the altered muscle pull on the bones.
- Overweight or obesity
- Injury to the growth area of the shin bone (tibia). This may result in just one knocked knee.
- Rickets (a disease caused by a lack of vitamin D)
- Bone infection such as rickets
- Adults may show knock knees due to a previous injury. It can also be due to a joint condition such as osteoarthritis or rheumatoid arthritis.
What are the symptoms of knock knees?
Knock knees are most commonly a normal stage of growth in young children. However, if they persist beyond a particular age, they may cause discomfort and pain in the legs. They typically become apparent when a child is 2 to 3 years old. Other symptoms include:
- More than 10 cm of gap between both ankles
- Changes in gait patterns
- A standing child of average weight whose knees touch, but whose ankles do not.
- Excessive inward angle of knees
- Pain at the anterior part of the knee, in severe cases
How are knock knees diagnosed?
Knock knees become apparent when a child stands with legs straight and toes pointed forward. Your doctor will perform a thorough physical examination. He or she will also review your child’s medical history. In addition, he may doctor observe the positions of the your lower legs, ankles and knees. He may also measure the distance between the inner parts of the ankle joints to assess the severity of the condition.
The doctor may also evaluate certain other factors including:
- Height, weight and body mass index (BMI)
- Walking and standing pattern
- Skeletal alignment of the lower leg
- Range of motion of the lower leg
What are the treatment options for knock knees?
Knock knees occur naturally in growing children. Therefore observation is necessary during early years. The condition usually corrects itself with time. As a child grows, walking patterns become normal or near-normal by 7 to 8 years of age. However, if the condition does not subside your doctor may recommend the following treatment:
Wearing a brace during night-time may help to straighten and restore the normal alignment of the knees. The brace attaches to a shoe and works by pulling the knee up into a straight position. Depending upon the severity of the condition, the doctor may recommend a customized knee brace for effective results.
Performing certain exercises, as prescribed by the physical therapist. For example, strengthening exercises, which help to realign and stabilize the knees. Perform these exercises in 10 repetitions for each leg and gradually with weights. They may also help to strengthen the knee muscles so that they are better able to bear the weight of the body.
In severe cases, the patient may be recommended to undergo any of the following surgical treatment.
This involves manipulating the knee bones to bring the joint back to their normal position. The procedure also helps in even distribution of weight through the knee. After surgery, your child will probably stay in the hospital for a couple of days. When your child goes home, limit weight-bearing activities. Crutches or a walker may be needed for a six to eight weeks. Physical therapy will help restore muscle strength. Typically, after six months, full activities, including sports may be resumed.
Guided Growth Surgery
This surgery slows down the growth of knee bone. Guided growth surgery is usually recommended for children who are in their developmental stage. This allows time for the child’s bones to continue to straighten on their own during the remaining growing years. This is a minimal day-surgery procedure with immediate weight bearing and a rapid return to sports allowed.