Knock Knees- Everything you need to know

Knock knees are angular deformities in the knee where the head of the deformity is inward. When the knees of a standing child touch but ankles do not is usually said to have knock knees. However, you do not have to worry, knock knees are a stage in your child’s normal development and growth (physiologic valgus).

After birth and for 18 months, it is usual to have an alignment that is outward-turning (varus) from hip to knee to ankle. After 18 months, this alignment starts to become neutral. At the age of 2-5, your child will have a normal inward-turning (valgus) alignment. This alignment will return to neutral as your child grows.

Causes of knock knees

Knock knees are a part of the normal development and growth of the lower extremities. However, if your child is 6 years or older, it can be a sign of an underlying disease in the bones, such as rickets or osteomalacia. Your child might be overweight, which can also contribute to knock knees.

While growing all children develop normal alignment of their lower extremities for some time. More than 20 per cent of children who are 3 years old have at least a 5-centimetre gap between their ankles. When they reach age 7, only 1 per cent of children have this gap.

Symptoms of knock knees

When your child is growing, knock knees help them to maintain balance, especially when they begin walking. When a child has knock knees, both knees usually lean inward symmetrically. One knee, however, may “knock” less than the other or may even remain straight.

A standing child of average weight whose knees come in contact, but ankles do not, is considered to have knock knees. It becomes apparent when your child is 2 to 3 years old, and it may become severe until age 4.

Knock knees usually self-corrects when your child is 7 or 8 years old. However, if this condition does not appear until your child is 6 or older, it could be a symptom of an underlying disease.

Sometimes knock knees continue into adolescence. The condition is a bit more common in girls, but boys can develop it, as well.

How are knock knees diagnosed?

Knock knees become apparent when your child stands with straight legs and toes pointing forward. Your paediatric orthopaedic doctor can find out the severity of your child’s knock knees by observing the alignment of the legs. They will monitor the position of the knees and ankles, also measure the gap between the inner ankle bones. Knock knees are more severe if there is a wide gap between the ankles.

Your orthopaedic doctor may use these exams for diagnosing knock knees:

• Measurements of your child’s height and length
• Measurements of body mass index (BMI) and weight
• Measurements of rotations and knee extensions
• assessment of leg-lengths and leg symmetry 
• Observation and examination of gait

If your child is of average age for knock knees, they would have a regular exam with a typical appearance and no functional issues. However, if your child is older than the usual age range or their legs are not symmetrical; your doctor will go for standing x-rays.

Treatment options for knock knees

Doctors treat children who have knock knees with close observation. Since this condition is a natural part of a child’s growth (typically ages 2 to 5), it corrects itself with time. As your child grows, walking patterns will become standard by age 7 to 8 or in some cases when they reach their teens.

Non-surgical options for knock knees

Sometimes the valgus can be severe and may not self-correct. Splints and other devices are not usually required for a child at a normal stage of valgus till age 7. 

These devices are useful if your child’s normal valgus does not straighten out by the time they reach 7 or 8 years old. Splints and other tools can also be used if your child’s valgus has an underlying metabolic or systematic condition.

If your child has severe, unresolved knock knees, doctors may suggest:

• A night brace, especially if there is a family history of knock knees. These brace work by attaching them to a shoe and pulling the knee up to a straight position
• Orthopaedic shoes, which are equipped with a heel wedge and sometimes an arch pad

Surgical options for knock knees

In a rare condition when natural growth, braces or shoes do not correct knock knees in your child, the doctor may recommend surgery.

Your child’s pediatric orthopedic surgeon may perform surgeries that influence bone growth (called a “guided growth” procedure. They may also cut and straighten the thigh or shin bone (osteotomy of the femur or tibia).

Guided growth surgery means negating the growth on the bent side of your child’s bone (for knock knees, the inside of the knee). Your doctor performs this surgery by implanting small metal devices that tie’s the inside part of the growth centre around the knee. This allows the outer part to grow and straighten out the knee.

Your child can take a guided-growth surgery when they are approaching puberty (age 11 in girls and 13 in boys). This gives the child’s bones time to continue straightening on their own while they are growing. Guided growth surgery is a minimal procedure, where your child does not need to take a break from daily activities.

Your doctor may perform Osteotomy surgery if deformities are severe or after the child’s growth has finished. After surgery, your child will have to stay in the hospital for some days. They will be given pain medications and kept under observation. 

When your child goes home after this surgery limit their weight-bearing activities. Crutches or a walker is required for 6 to 8 weeks. Also, you can go for physical therapy which will help restore muscle strength. After 6 months of surgery, your child can resume normal activities, including sports.

In 99 per cent of cases knock knees are self-correcting. The long-term scenario is very optimistic for most children. For children who require surgery for severe forms of knock knees, the outlook is also excellent. The surgery procedures are very safe — and children’s bones heal faster and much better than adults. 

Children with surgically fixed knock knees caused by an underlying condition may develop risks of arthritis, pain, or dislocation in adulthood.