Knock Knees: Causes, Diagnosis, and Latest Treatment Methods

Knock Knees: Causes, Diagnosis, and Latest Treatment Methods

The Cliff News | November 2, 2026

Knock knees, medically known as genu valgum, is a condition where the knees touch or overlap when a person stands with their feet and ankles close together. The space between the ankles becomes abnormally wide, making the legs appear in the shape of the English letter 'X'.

This condition can be a normal part of physical development in childhood. However, it can also stem from congenital deformities, bone diseases, injuries, or problems with the growth plate. According to orthopedic specialists, factors such as the patient's age, the severity of the deformity, the mechanical axis of the lower limbs, and remaining bone growth potential determine the treatment approach.

In infants and young children, knock knees are often a normal developmental phase. They typically begin to appear around two to three years of age, peaking between three and four years old. As children grow and their bones develop, this knee bowing naturally corrects itself.

For most children, the leg alignment becomes close to normal by seven to eight years of age. If the condition is symmetrical in both legs and does not cause pain or difficulty walking, it is considered normal and usually requires no specific treatment.

Congenital and Developmental Causes

Congenital genu valgum, as the name suggests, is present from birth. Its root cause can be congenital abnormalities in the femur (thigh bone), tibia (shin bone), or the overall skeletal structure. Conditions like skeletal dysplasia, where bone development and shape are abnormal, can lead to this problem.

In such cases, a thorough examination of leg length, overall body proportions, and other potential bone deformities is necessary to pinpoint the underlying issue. Careful assessment is required to reach the root of the problem.

Acquired or Pathological Deformities

Knock knees can also develop due to various diseases and traumas, termed acquired or pathological genu valgum. Severe vitamin D deficiency leading to rickets, which softens and weakens bones, is a primary cause. Kidney diseases can also affect bone health, leading to conditions like osteodystrophy.

Additionally, injuries to the growth plate, infections, or improper healing of fractures can cause knock knees. Obesity is also a significant factor, as it increases mechanical stress on the knees, potentially worsening the condition. In some children, abnormal or uncontrolled activity in one part of the growth plate leads to imbalanced bone growth, resulting in knock knees.

Diagnosis Process

The diagnosis of genu valgum involves a detailed physical examination. The physician carefully assesses the patient's gait, the position of both knees, differences in leg length, the distance between the ankles, and the angle of knee deviation.

To understand the severity and cause, a full-leg X-ray (from hip to ankle) is performed in specific situations while standing. This X-ray helps determine the mechanical axis deviation of the lower limbs, the angles between the femur and tibia, and the precise location of the deformity.

If rickets or another metabolic bone disease is suspected, blood tests are conducted to check levels of calcium, phosphorus, vitamin D, and other necessary parameters. Further investigations are carried out as needed.

Modern Treatment Methods

Treatment for knock knees primarily depends on the patient's age and the cause of the deformity. For typical developmental genu valgum, regular monitoring is sufficient. There is no reliable scientific evidence to support the effectiveness of special shoes, exercises, or braces in correcting developmental deformities, so such measures are generally not recommended.

If vitamin D deficiency or other bone diseases are identified, the underlying conditions are treated first. For children with severe or progressively worsening deformities whose growth plates are still active, guided growth surgery, also known as hemi-epiphysiodesis, is an effective approach. This procedure involves temporarily inhibiting growth in specific parts of the growth plate to guide bone growth in the desired direction, gradually correcting knee alignment.

When bone growth is complete and the deformity is severe, corrective osteotomy is performed. This involves surgically cutting and repositioning the bone at a specific angle to realign the mechanical axis of the legs.

Importance of Timely Diagnosis

It is crucial to consult a specialist orthopedic surgeon immediately if a child's knee bowing persists beyond seven to eight years of age, is progressively worsening, affects one leg more than the other, or is accompanied by knee pain and difficulty walking.

Timely diagnosis and appropriate treatment not only improve leg alignment but also enhance knee function and help maintain long-term joint health. Early intervention is key to better outcomes.