What causes knock knees in adults

What are Knock Knees (Genu Valgum)?

Knock knees, medically known as genu valgum, is a condition where the knees angle inward and touch or nearly touch when the legs are straightened. While common in young children and often resolving naturally as they grow, it can persist into adulthood or develop later in life. In adults, knock knees can cause discomfort, pain, and affect mobility, often stemming from underlying issues.

Causes of Knock Knees in Adults

The causes of knock knees in adults are varied and can often be linked to specific medical conditions or events:

1. Obesity

Excess body weight is one of the most common and significant contributing factors to the development or worsening of knock knees in adults. The increased load on the knee joints puts abnormal stress on the cartilage and ligaments, leading to abnormal alignment over time. This extra pressure can accelerate wear and tear, exacerbating pain and instability.

2. Arthritis

Various forms of arthritis can lead to knock knees. Osteoarthritis, the most common type, involves the breakdown of cartilage in the knee joint. As the cartilage wears away unevenly, especially on the inner side of the knee, the joint space narrows, causing the knees to bow inward. Rheumatoid arthritis, an autoimmune disease, can also cause inflammation and damage to the knee joint, potentially leading to valgus deformity.

3. Rickets and Osteomalacia

Rickets in children and osteomalacia in adults are conditions caused by severe vitamin D deficiency, which is essential for bone health. These conditions lead to softening and weakening of the bones, making them prone to deformities. If not treated, rickets in childhood can result in permanent skeletal changes, including knock knees, that persist into adulthood. Osteomalacia in adults can also cause bone pain and weakness, potentially contributing to changes in leg alignment.

4. Previous Injuries

Traumatic injuries to the knee, femur (thigh bone), or tibia (shin bone) can disrupt the normal alignment of the leg. Fractures that don't heal properly, ligament tears (especially those affecting the stability of the knee), or damage to the growth plates in adolescents can all lead to the development of knock knees later in life. Surgical interventions for knee injuries can also, in rare cases, alter the biomechanics of the joint and leg alignment.

5. Developmental Issues and Genetics

While most childhood knock knees resolve by age 7-8, some cases may persist. In some instances, there might be an underlying genetic predisposition that causes the bones to develop in a way that favors valgus alignment. Certain rare congenital conditions affecting bone development can also manifest as knock knees.

6. Neuromuscular Conditions

Conditions affecting the nerves and muscles around the knee can influence joint stability and alignment. For example, conditions that cause muscle weakness or spasticity might indirectly contribute to the development of knock knees over time.

7. Other Medical Conditions

Less common causes can include certain bone diseases, metabolic disorders, or tumors that affect the bones of the leg or knee joint.

Symptoms Associated with Knock Knees

Beyond the visible inward angling of the knees, adults with knock knees may experience:

• Pain in the knees, hips, or ankles
• Difficulty walking or performing physical activities
• Increased risk of sprains and ligament injuries
• Development of arthritis due to uneven joint wear
• Instability in the knees
• A 'waddling' gait

Diagnosis and Treatment

A healthcare professional will typically diagnose knock knees through a physical examination, observing the leg alignment while standing and walking. X-rays are often used to assess the degree of deformity, check for arthritis, and rule out other bone conditions. Treatment depends on the underlying cause and severity and may include:

• Weight management to reduce stress on the knees
• Physical therapy to strengthen muscles and improve flexibility
• Orthotics or shoe inserts to help with alignment
• Pain management strategies
• In severe cases, surgery to realign the bones or reconstruct the knee joint.

It's important for adults experiencing symptoms associated with knock knees to consult a doctor for an accurate diagnosis and personalized treatment plan.