Knock-knee

Knock-knee

Knock-knee, also known as genu valgum, is a condition where the knees angle in and touch one another when the legs are straightened. This condition is common in children and often corrects itself as they grow. However, in some cases, it can persist into adulthood and may require medical intervention.

Etiology

Knock-knee can be caused by a variety of factors, including:

• Physiological development: It is a normal stage of growth in children between the ages of 2 and 5.
• Genetic factors: Family history can play a role in the development of genu valgum.
• Nutritional deficiencies: Lack of vitamin D, calcium, or phosphate can lead to bone deformities such as rickets, which can cause knock-knee.
• Injury or infection: Trauma to the growth plate or infections such as osteomyelitis can result in angular deformities.
• Underlying medical conditions: Conditions such as osteogenesis imperfecta, renal osteodystrophy, or skeletal dysplasias can contribute to the development of knock-knee.

Clinical Presentation

Patients with knock-knee may present with:

• Gait abnormalities: Affected individuals may have a waddling gait or difficulty walking.
• Knee pain: Due to abnormal stress on the knee joint.
• Difficulty with physical activities: Such as running or jumping.
• Cosmetic concerns: The appearance of the legs may be a concern for some patients.

Diagnosis

Diagnosis of knock-knee is primarily clinical, based on physical examination. Key diagnostic steps include:

• Physical examination: Assessing the alignment of the legs and measuring the intermalleolar distance (the distance between the ankles when the knees are together).
• Radiographic evaluation: X-rays may be used to assess the degree of angulation and to rule out underlying bone abnormalities.
• Laboratory tests: Blood tests may be conducted to check for nutritional deficiencies or metabolic disorders.

Management

The management of knock-knee depends on the underlying cause and severity of the condition:

• Observation: In children, observation is often sufficient as the condition may resolve with growth.
• Orthotic devices: Braces or orthotic devices may be used to guide bone growth in children.
• Physical therapy: Exercises to strengthen the muscles around the knee and improve alignment.
• Surgical intervention: In severe cases, surgical options such as osteotomy or guided growth surgery may be considered.

Prognosis

The prognosis for knock-knee is generally good, especially in children where the condition often resolves spontaneously. In adults, treatment can alleviate symptoms and improve function.

Also see

• Genu varum
• Rickets
• Osteogenesis imperfecta
• Orthopedic surgery