Valgus knee, commonly known as “knock-knee,” is a lower limb deformity where the knee joint angles inward, causing the knees to touch or come close together while the ankles remain apart when standing. This condition can affect individuals of all ages, from children to adults. While often a normal part of development in young children, persistent or acquired valgus knee can lead to various physical challenges and discomfort.
Understanding Valgus Knee
Valgus knee is a lower leg deformity where the knee joint angles inward, causing the knees to touch or come close together while the ankles remain apart. A valgus angle, often referred to as the Q angle, exceeding 10 degrees, is indicative of this condition.
The altered alignment in valgus knee shifts the weight-bearing axis of the leg. Weight distribution shifts from the center of the knee to the outer (lateral) compartment. This uneven distribution can increase stress on the lateral meniscus and other outer knee structures. The condition can also impact the alignment and function of the entire leg, potentially leading to internal hip rotation and excessive foot pronation.
Common Causes
Valgus knee can arise from developmental patterns or acquired conditions. In many young children, particularly between the ages of two and four, valgus knee is a normal part of growth and often corrects itself by around age seven or eight. This physiological valgus is not a cause for concern.
However, valgus knee can persist or develop later in life. Acquired causes include injuries or infections affecting the knee or leg, and metabolic bone diseases like rickets, which stem from severe deficiencies in vitamin D and calcium. Obesity is another contributing factor, as increased body weight places additional stress on the knee joints, worsening the condition, especially in adolescents. Arthritis of the knee, especially rheumatoid arthritis, can also lead to valgus deformity.
Identifying Valgus Knee
Individuals with valgus knee might observe an altered walking pattern, sometimes described as a “waddle,” as the body attempts to compensate for the misalignment. Common symptoms include discomfort or pain in and around the knees, especially during physical activity or prolonged standing. This pain can extend to the hips, ankles, or feet due to abnormal weight distribution.
Medical professionals typically diagnose valgus knee through a physical examination, observing the alignment of the legs while the patient stands and walks. The examination may also include assessing knee stability, range of motion, and checking for any leg length discrepancies. Imaging tests, such as full-length, weight-bearing X-rays, are often used to confirm the diagnosis and accurately measure the degree of the valgus angle.
Approaches to Management
Management strategies for valgus knee depend on the underlying cause, the severity of the condition, and the individual’s age. For mild cases or physiological valgus in children, observation may be sufficient as the condition often resolves spontaneously. For persistent or symptomatic cases, non-surgical interventions are typically the first line of approach.
Non-surgical management often involves physical therapy, focusing on exercises to strengthen knee, hip, and thigh muscles like quadriceps, hamstrings, and glutes. Specific stretches may also be recommended to improve flexibility and address muscle imbalances. Bracing or orthotics can be used to help realign the knee joint and provide support. Weight management is also important, as reducing excess body weight can alleviate stress on the knees.
When non-surgical methods are not effective or for more severe cases, surgical interventions may be considered. One common procedure is an osteotomy, which involves cutting and reshaping the bone, often the femur or tibia, to correct the alignment and redistribute stress across the knee joint. For adults with severe arthritis and significant deformity, total knee replacement surgery may be an option to restore function and relieve pain.