Bowlegs: Duration, Causes, Complications, and Treatment Options

How long do Bowlegs last?

The duration of bowlegs (genu varum) is highly dependent on its underlying cause and the individual's age. While most cases in infants are physiological and resolve spontaneously by toddlerhood, bowlegs caused by pathological conditions or those appearing later in life typically persist or worsen without appropriate medical intervention.

Understanding Bowlegs (Genu Varum)

Bowlegs, medically known as genu varum, is a condition characterized by an outward curvature of the legs, where the knees remain wide apart even when the ankles are touching. This results in a "bowed" appearance of the lower limbs. While often a normal part of development in infants, persistent or progressive bowing can indicate an underlying medical issue requiring attention.

Causes of Bowlegs

The origin of bowlegs varies significantly, influencing its potential duration and prognosis:

• Physiological Bowlegs (Infantile Bowlegs): This is the most common cause in infants and toddlers. It's a normal developmental stage, where the slight bowing is due to the position of the legs in the womb. It is almost always symmetrical and resolves spontaneously as the child grows and begins to walk.
• Blount's Disease (Tibia Vara): This is a pathological condition involving abnormal growth of the upper part of the tibia (shin bone), near the knee. It can affect one or both legs, often worsening with age and weight. Blount's disease does not resolve on its own and typically requires medical intervention.
• Rickets: A condition caused by a severe and prolonged deficiency of Vitamin D, calcium, or phosphate, leading to softening and weakening of bones. This can cause bone deformities, including bowlegs, in growing children. Nutritional rickets can be corrected with supplementation, but severe cases may require surgery.
• Skeletal Dysplasias: Genetic conditions that affect bone and cartilage growth, leading to various skeletal abnormalities, including severe bowlegs. Examples include achondroplasia.
• Trauma: Injuries to the growth plates around the knee in children can disrupt normal bone development and lead to angular deformities like bowlegs.
• Bone Tumors or Infections: Though rare, certain bone pathologies can affect bone growth and alignment.
• Osteoarthritis: In adults, severe osteoarthritis, particularly in the medial compartment (inner side) of the knee, can lead to or worsen a bowed leg appearance due to cartilage loss and bone changes.
• Obesity: Excessive weight can place increased stress on developing bones, potentially exacerbating or contributing to the progression of bowlegs, especially in conditions like Blount's disease.

Natural Progression and Duration in Children

The duration of bowlegs in children is highly dependent on whether the cause is physiological or pathological.

• Infants (Birth to 2 years): Physiological bowlegs are common and considered normal. The bowing is typically most noticeable around 6-12 months of age. In the vast majority of cases, it spontaneously begins to straighten as the child grows and places weight on their legs, resolving completely by 18-24 months of age, and certainly by age 3.
• Toddlers (2-3 years): If bowlegs persist beyond age 2 or 3, or if they appear to be worsening, it is a strong indicator that the cause is likely pathological (e.g., Blount's disease, rickets) rather than physiological. These cases will not resolve on their own and will typically persist or progress without intervention.
• Preschoolers (3+ years): By this age, most children's legs should be straight or even slightly knock-kneed as part of normal development. Persistent bowlegs at this age are almost always indicative of an underlying condition that requires medical evaluation and potentially treatment.

Bowlegs in Adolescents and Adults: When Do They Persist?

Bowlegs that persist into adolescence or adulthood are invariably due to an underlying pathological cause, or they represent a mild, uncorrected physiological bowing that did not fully resolve.

• Persistent Pathological Causes: Conditions like untreated Blount's disease, consequences of rickets, or skeletal dysplasias will remain present and may worsen over time. These structural deformities do not spontaneously correct in older individuals.
• Adult-Onset Bowing: New onset of bowlegs in adults is typically related to degenerative conditions such as severe osteoarthritis of the knee. In these cases, the bowing is a result of cartilage loss and bone remodeling, and it will persist and often progress as the underlying arthritis advances, unless surgically corrected.

Potential Complications of Persistent Bowlegs

Uncorrected or persistent bowlegs, especially those of pathological origin, can lead to several long-term issues:

• Increased Risk of Osteoarthritis: The uneven distribution of weight across the knee joint places excessive stress on the medial (inner) compartment, significantly increasing the risk of early-onset and progressive osteoarthritis.
• Pain: Chronic knee pain, particularly on the inner side, is a common complaint.
• Gait Abnormalities: An altered walking pattern can develop, leading to compensatory movements and stress on other joints (hips, ankles, spine).
• Instability: The altered biomechanics can lead to feelings of instability in the knee.
• Functional Limitations: Difficulty with activities requiring full knee extension or flexion, or prolonged standing/walking.
• Cosmetic Concerns: The visual appearance of bowed legs can be a significant source of distress for some individuals.

Diagnosis and Assessment

Accurate diagnosis is crucial to determine the cause and expected duration of bowlegs.

• Physical Examination: A thorough evaluation of leg alignment, gait, and measurement of the intercondylar distance (distance between the knees when ankles are together).
• Medical History: Information on family history, nutritional status, and developmental milestones.
• Imaging Studies:
  • X-rays: Standing long-leg X-rays are essential to assess the degree of bowing, identify the location of the deformity (tibia vs. femur), and evaluate the growth plates in children.
• Blood Tests: May be ordered to rule out metabolic conditions like rickets (e.g., Vitamin D, calcium, phosphate levels).

Treatment and Management Options

Treatment depends entirely on the cause, severity, and the patient's age.

• Observation (for Physiological Bowlegs): For infants with physiological bowlegs, the primary approach is observation with regular follow-up appointments to ensure the condition is resolving as expected.
• Bracing: For certain pathological conditions like Blount's disease in younger children, or rickets, specialized braces (orthoses) may be used to guide bone growth and correct the deformity.
• Nutritional Correction: If rickets is diagnosed, supplementation with Vitamin D and calcium is crucial to normalize bone metabolism.
• Surgery:
  • Guided Growth (Hemiepiphysiodesis): In growing children, a minor procedure can be performed to temporarily slow growth on one side of the growth plate, allowing the other side to catch up and correct the deformity over time.
  • Osteotomy: For more severe deformities, or in adolescents and adults where growth plates are closed, an osteotomy involves surgically cutting and realigning the bone (usually the tibia) to correct the angle.
  • Joint Replacement: In adults with severe osteoarthritis and significant bowing, total knee replacement may be considered.
• Physical Therapy: While not directly corrective for structural bowing, physical therapy can help manage symptoms, improve muscle strength, flexibility, and gait mechanics, especially post-surgery or for osteoarthritis.

Prognosis and Long-Term Outlook

The long-term outlook for bowlegs varies widely:

• Physiological Bowlegs: The prognosis is excellent. These cases resolve completely on their own, with no long-term complications.
• Pathological Bowlegs (Treated Early): With timely and appropriate intervention (bracing, nutritional correction, guided growth surgery), the prognosis is generally good, with significant correction of the deformity and reduced risk of future complications.
• Pathological Bowlegs (Untreated or Severe): If left untreated, pathological bowlegs will persist, often worsen, and significantly increase the risk of chronic pain, gait issues, and early-onset, severe osteoarthritis.
• Adult-Onset Bowing: Prognosis depends on the underlying cause (e.g., osteoarthritis) and the effectiveness of its management. Surgical correction can improve alignment and function.

When to Seek Professional Advice

It is important to consult a pediatrician or orthopedic specialist if you observe any of the following:

• Bowlegs are still present in a child over the age of 2.
• The bowing appears to be worsening over time.
• The bowing is asymmetrical (one leg is more bowed than the other).
• The child experiences pain, limping, or difficulty walking.
• The child is unusually short for their age.
• New onset of bowlegs in an adolescent or adult.