What is a varus deformity also known as? Genu Varum and Bow-Leggedness Explained

Approximately one in ten children are born with some degree of bow-leggedness, which is what is a varus deformity also known as, particularly when affecting the knees. Medically referred to as genu varum, this condition describes an inward angulation of a bone or joint, giving the legs a bowed appearance.

Quick Summary

A varus deformity is medically known as genu varum or commonly referred to as bow-leggedness, a condition characterized by the outward curvature of the legs.

Key Points

• Genu Varum: The medical term for a varus deformity of the knee, also known as bow-leggedness, describing an inward angulation of the leg bones.

• Inward Angle: The defining characteristic of a varus deformity is the inward angle of the distal part of a limb relative to the joint.

• Common vs. Severe Causes: Bow legs in infants are often physiological and resolve naturally, but in older children or adults, it can indicate conditions like Blount's disease, rickets, or osteoarthritis.

• Valgus is Opposite: The opposite condition, a valgus deformity, is known as knock-kneed, where the limb deviates outward from the midline.

• Diagnosis is Key: Diagnosis involves a physical exam, and potentially X-rays or blood tests, to determine the cause and severity of the condition.

• Treatment Options Vary: Treatment ranges from simple observation for infants to corrective surgery like osteotomy for severe cases in adults.

• Potential Complications: If left untreated, severe varus deformity can lead to pain, instability, and premature osteoarthritis.

Understanding the Varus Deformity

A varus deformity is a medical term used to describe a specific type of angulation in a bone or joint. The term describes an inward-pointing angle of a bone segment distal to a joint. While a varus deformity can affect various joints, including the hips (coxa vara), ankles (talipes varus), and elbows (cubitus varus), it is most commonly discussed in relation to the knees. In this context, the condition is referred to as genu varum, or more commonly, bow-leggedness.

This bowing occurs when the tibia, or shin bone, is angled inward in relation to the femur, or thigh bone. When a person with genu varum stands with their ankles together, a distinct, noticeable gap exists between their knees. This misalignment can shift the body's weight-bearing axis towards the inner side of the knee joint, increasing stress on the medial compartment of the knee.

Medical and Common Terminology for Varus Deformity

While the clinical term is "varus deformity," several other names are used, depending on the affected area and context.

• Genu Varum: This is the precise medical term for a varus deformity of the knee. "Genu" is Latin for knee, and "varum" signifies the inward turn. This term is used by healthcare professionals to describe the bow-legged condition.
• Bow-Leggedness / Bow Legs: This is the most common colloquial term. It vividly describes the visual appearance of the legs, resembling an archer's bow.
• Bandy-Leg: An older, less common term for the same condition, derived from the bend in a leg.
• Tibia Vara: A specific type of genu varum caused by a growth disorder affecting the tibia, known as Blount's disease. Tibia vara typically results in more progressive and severe bowing than physiological genu varum.

Common Causes of Varus Deformity

Several factors can contribute to the development of a varus deformity, ranging from normal developmental stages to serious underlying medical conditions.

• Physiological Bowing: In infants and toddlers, it is perfectly normal to be bow-legged due to their position in the womb. This condition is known as physiological genu varum and typically corrects itself by 18 to 24 months of age as the child begins to walk and bear weight.
• Blount's Disease: This growth disorder affects the shinbone (tibia) near the knee, causing the growth plate to develop abnormally. It is more common in children who are overweight or who started walking early.
• Rickets: A deficiency in vitamin D, calcium, or phosphate can cause bones to soften and weaken, leading to bowed legs. While rare in developed countries, it remains a concern in regions with poor nutrition.
• Osteoarthritis: In adults, severe osteoarthritis can cause the cartilage on the inside of the knee to wear away, leading to a gradual collapse of the joint and a resultant varus deformity.
• Bone Dysplasia: Various genetic disorders that cause abnormal bone development can lead to a varus deformity.
• Trauma: Poorly healed fractures or injuries affecting the growth plates can result in a varus angulation.

Symptoms and Diagnosis

The primary symptom of a varus deformity is the characteristic bowing of the legs, where the knees remain apart when the ankles are touching. Depending on the severity and cause, other symptoms may include:

• Knee, hip, or ankle pain, especially during or after physical activity.
• An uneven gait or limp.
• Instability in the knee joint.
• Difficulty walking or running.

Diagnosis typically begins with a physical examination by a healthcare provider. For children, the doctor will observe the child walking and standing. If the bowing appears severe, is asymmetric, or persists beyond the age of three, further tests may be ordered. These tests often include:

1. X-rays: To view the bones and measure the exact angle of the deformity.
2. Blood Tests: To check for vitamin D deficiency, especially in suspected cases of rickets.
3. Specialized Imaging: In complex cases, a CT scan or MRI may be used to get a more detailed look at the bone and joint structure.

Treatment Options for Varus Deformity

Treatment for a varus deformity varies based on the underlying cause, the patient's age, and the severity of the condition.

Non-Surgical Treatments

For physiological bowing in young children, no treatment is usually necessary, as the condition resolves naturally. For other cases, non-surgical options may be considered:

• Observation: Close monitoring by a healthcare provider for young children to ensure the condition is improving.
• Bracing or Orthotics: Custom leg braces or shoe orthotics can be used, particularly in early-stage Blount's disease, to help guide proper bone growth.
• Physical Therapy: Exercises can strengthen the surrounding muscles, improve joint stability, and manage pain, although they cannot correct the underlying bone alignment.
• Nutritional Supplements: In cases caused by rickets, vitamin D and calcium supplements are prescribed to strengthen bones.

Surgical Treatments

For severe cases, for those where non-surgical options fail, or for deformities in adolescents and adults, surgery may be the best course of action.

• Osteotomy: This is a common procedure for older children and adults. The surgeon cuts and reshapes the bone (usually the tibia) to correct the alignment and then secures it with plates and screws. This procedure is effective in preventing the progression of osteoarthritis.
• Guided Growth Surgery: A technique used in growing children where a small plate or staple is placed on one side of the growth plate. This slows growth on the unaffected side, allowing the bowed side to straighten naturally over time. Learn more about the latest orthopedic techniques.

Varus vs. Valgus: A Comparison

Understanding the distinction between varus and its opposite, valgus, is critical in orthopedic medicine. While varus is an inward angulation, valgus is an outward angulation, leading to a different appearance and set of symptoms.

Feature	Varus Deformity (Genu Varum)	Valgus Deformity (Genu Valgum)
Common Name	Bow-leggedness	Knock-kneed
Joint Angle	Distal segment turns inward (medially)	Distal segment turns outward (laterally)
Knee Appearance	Knees point outward, wide gap when standing with ankles together	Knees touch or overlap when standing with ankles apart
Affected Joint Area	Medial (inner) compartment of the knee is stressed	Lateral (outer) compartment of the knee is stressed
Common Cause in Adults	Osteoarthritis of the inner knee	Rheumatoid arthritis, injuries
Corrective Surgery	High Tibial Osteotomy	Distal Femoral Osteotomy

Conclusion

Recognizing that what is a varus deformity also known as can be the first step toward addressing a potentially serious medical issue. Whether it's the innocent physiological bowing of a toddler or a symptom of progressive osteoarthritis in an adult, understanding the terminology and causes is key. While many cases resolve naturally, persistent or symptomatic varus deformities warrant medical attention. Early diagnosis and appropriate intervention, whether through non-surgical management or corrective surgery, can significantly improve outcomes, reduce pain, and prevent long-term joint damage.

Frequently Asked Questions

What is the medical name for a varus deformity of the knee?

The medical name for a varus deformity, specifically at the knee, is genu varum. This condition is what is commonly known as bow-leggedness.

Is a varus deformity always a problem?

Not necessarily. In infants and toddlers, a varus deformity is often a normal developmental stage called physiological bowing and resolves on its own. However, if it persists past age three or is accompanied by pain, it should be evaluated by a doctor.

What is the difference between a varus and valgus deformity?

The key difference is the direction of angulation. A varus deformity involves an inward angulation (bow-leggedness), while a valgus deformity involves an outward angulation (knock-kneed).

Can a varus deformity be corrected without surgery?

For mild cases or cases caused by nutritional deficiencies, non-surgical treatments like observation, bracing, physical therapy, or supplements may be effective. However, significant or progressive deformities often require surgical intervention for correction.

What is Blount's disease?

Blount's disease is a growth disorder that affects the growth plate of the shinbone (tibia) near the knee, causing an abnormal and progressive varus deformity. It is a more serious cause of bow-leggedness, especially in children.

How is a varus deformity diagnosed?

Diagnosis typically begins with a physical examination. The doctor may also order X-rays to assess the degree of the deformity and identify any underlying bone issues. For children, vitamin levels may be checked to rule out rickets.

Can adults develop a varus deformity?

Yes, adults can develop a varus deformity, most commonly due to the progression of osteoarthritis in the medial (inner) compartment of the knee joint. This causes the leg to bow gradually over time.