Bowlegs

Disease Description (Causes and Symptoms)

Genu varum (bow legs, O-shaped legs) is a condition in which the center of the knee joint bends inward from the straight line connecting the hip, knee, and ankle joints, causing the space between the knees to widen.
Main causes and pathophysiology:

• Physiological factors: Physiological genu varum is common in infancy, particularly before 1 year of age, and usually improves between 18–24 months.
• Growth abnormalities/bone metabolism disorders: Rickets (vitamin D deficiency/resistance), renal rickets, and other conditions can cause widespread softening and deformity of the bones.
• Localized growth plate disorders: Blount disease (a disorder of the medial growth plate of the tibia), or epiphyseal plate damage caused by trauma or infection, can lead to progressive or unilateral genu varum.
• It may also result from malunion after trauma or fracture, congenital deformity, obesity, and in adults, osteomalacia, osteitis deformans, hyperparathyroidism, and other conditions.
  Main symptoms:
• Increased distance between the knees when standing (interfemoral or intertibial distance; several centimeters in mild cases and 7.5 cm or more in severe cases, for example).
• Weight bearing concentrated on the outer sides of both feet when walking, waddling gait, and toes pointing inward.
• Pain is usually mild in the early stages, but as the condition progresses, pain on the inside of the knee, arthritis symptoms, lower back pain, or gait abnormalities may occur.
  Diagnostic points (brief):
• Medical history: Age at onset, whether it is progressive (increasing/decreasing), pain, fever, systemic symptoms, obesity, and previous trauma or surgery.
• Physical examination: Length of both lower limbs, distance between the knees (ankle together, measure intercondylar distance), and gait observation.
• Imaging: Weight-bearing (standing) AP long-leg X-ray (full-length lower-extremity radiograph) to measure the lower-limb axis (mechanical axis) and angles; MRI/CT if necessary.
• Blood tests: If rickets is suspected, bone metabolism tests including Ca, P, ALP, and 25(OH) vitamin D.

Treatment Methods

• Observation (conservative)
  • For physiological genu varum, particularly in children under 2 years of age, and mild nonprogressive cases, regular observation is recommended to monitor changes with growth. Weight management and proper posture and activity are recommended.
• Braces/physical therapy
  • For moderate cases (the middle level in classifications based on the distance between the knees), stretching, muscle strengthening, and, if necessary, braces (corrective braces for children during specific growth periods) may be considered. Weight loss is recommended for people with obesity.
• Medication (correction of the underlying condition)
  • If the cause is a bone metabolism disorder such as rickets, medical treatment such as vitamin D and calcium supplementation should be provided first. The mechanical deformity should be reassessed after treating the underlying condition.
• Surgical treatment
  • Children with open growth plates: Guided growth (hemiepiphysiodesis) — temporarily inhibiting part of the growth plate (using a plate, staple, or similar device) to achieve gradual correction. This is effective for progressive deformities such as Blount disease.
  • After growth is complete (adults or after skeletal maturity): Corrective osteotomy is performed to remove and correct the deformity, followed by fixation with a metal plate and screws or an external fixation device. External fixation (such as the Ilizarov method) may be considered for complex deformities.
• Determining the timing of treatment
  • In general, detailed evaluation is needed if the condition persists after age 2, is unilateral, or is progressive. For severe cases (a large distance between the knees, or cases expected to persist after growth), surgical correction should be considered at an appropriate time.
    Precautions and self-care
• Reduce joint stress through obesity management (weight loss).
• Avoid folk remedies such as forcibly immobilizing the legs with bandages.
• Immediate specialist evaluation is needed if pain, unilateral progression, gait problems, or delayed growth is present.

Checklist Before an Outpatient Visit (Including Example Questions)

Items to prepare/bring:

• A list of currently taken medications and supplements, including dosage and duration of use.
• Previous relevant test results and imaging, if available (X-ray, MRI files, or photographs).
• A record of when symptoms began and how they have progressed (whether they have improved or worsened), as well as the presence and characteristics of pain.
• Recent weight and height (a growth chart is helpful), and, if possible, photographs or videos of walking or standing.
• Family history, including similar lower-limb deformities and metabolic or endocrine diseases.
  Items to submit/organize for the outpatient visit:
• When it began, whether it affects one side or both sides, and the rate of progression (rapid/slow)
• Presence of pain and its impact on daily life (gait problems, exercise limitations, etc.)
• Whether previous treatments were received (braces, physical therapy, surgery)

Examples of General Questions to Ask the Doctor

• "How severe is my (or my child's) genu varum currently, and is observation alone sufficient?"
• "Which tests do you recommend (blood tests, weight-bearing X-ray, etc.), and why?"
• "How likely are braces or physical therapy to be effective?"
• "If surgery is recommended, what are the expected benefits and risks (complications)?"
• "Are there any particular precautions regarding daily life, exercise, or weight management?"

Examples of Condition-Specific Questions

• Regarding children around age 2: "My child's genu varum has persisted after age 2. What additional tests are needed to rule out Blount disease or rickets?"
• When considering surgery: "If you recommend surgery that could affect the growth plate (epiphyseal plate), such as hemiepiphysiodesis, could you explain the timing and possible long-term side effects, such as growth imbalance?"