Knock knees, known medically as genu valgum, is a condition where the knees angle inward, causing them to touch or nearly touch while the ankles remain apart when standing. This alignment can create an “X-shaped” appearance of the legs. It is a common orthopedic presentation, particularly noticeable in children.
Understanding Valgus Deformity
Genu valgum can manifest as either physiological or pathological, with the distinction determining the need for intervention. Physiological knock knees are a normal part of childhood development, often peaking between ages 2 and 4, and typically self-correct by age 7 or 8. During this phase, the inward angling is considered a natural variation in bone growth.
Pathological genu valgum does not resolve on its own and may worsen. It can stem from various underlying causes, including metabolic bone diseases (like rickets due to vitamin D or calcium deficiency), genetic conditions (such as skeletal dysplasias), or acquired issues (like growth plate injuries). Obesity, joint hypermobility, muscular imbalances, or leg length differences can also contribute.
Medical attention is warranted if knock knees are asymmetrical, cause pain, progress rapidly, or persist beyond age 7 or 8. A visible limp, difficulty walking, or height significantly below age-appropriate averages also warrant evaluation. These signs may indicate a more complex underlying issue.
Non-Surgical Management
Conservative approaches are often the first step for managing genu valgum, especially in mild cases. Physical therapy can strengthen muscles around the knee and improve leg function. Exercise programs may include activities to enhance balance and posture. These efforts support proper alignment and alleviate discomfort.
Bracing is sometimes recommended for children with mild to moderate knock knees. Orthotic devices, such as knee-ankle-foot orthotics (KAFOs), provide stability and guide bone growth. However, research indicates braces and shoe inserts may not consistently speed resolution. These methods are generally more effective for physiological knock knees or to support recovery, rather than fully correcting severe structural deformities.
Surgical Correction Options
Surgical intervention may be considered for more pronounced or persistent genu valgum. Procedure choice depends on the patient’s age and active growth plates. For growing children and adolescents, guided growth surgery (hemiepiphysiodesis) is a common option. This minimally invasive procedure involves implanting small metal plates or screws, often called an “eight-plate,” on one side of the knee’s growth plate.
The implanted device temporarily slows growth on one side of the bone, allowing the other side to continue growing and gradually straighten the leg. This guides the bone into alignment over several months to a year. Guided growth surgery is typically an outpatient procedure, with patients often able to bear weight immediately.
For adolescents nearing skeletal maturity or adults, osteotomy is the primary surgical method. This procedure involves cutting and reshaping the thigh bone (femur) or shin bone (tibia) to realign the leg. A bone wedge may be removed or added, and segments are secured with plates and screws. Osteotomy aims to redistribute weight-bearing forces across the knee joint, reduce pain, improve function, and potentially delay arthritis progression.
Recovery and Outlook
Recovery timelines vary by procedure and individual factors. After guided growth surgery, children typically return to normal activities within 2 to 3 weeks. Pain usually subsides within weeks, and most patients can return to sports within 2 to 4 weeks once the surgical site heals. Bones gradually straighten over 6 to 18 months, requiring follow-up visits to monitor progress. Once alignment is achieved, plates are removed in another outpatient procedure.
Osteotomy recovery is generally more extensive due to bone cutting and realignment. Patients often stay in the hospital for 1-2 days. Crutches are typically needed for weeks, and full weight-bearing may not begin until 6-8 weeks post-surgery, once initial bone healing is confirmed. Complete recovery, including a return to full activity, can take 6-12 months.
Physical therapy is important after both surgeries, helping restore strength, flexibility, and balance. Long-term outcomes for corrected genu valgum are favorable, with improved leg alignment, reduced pain, and enhanced function. Adherence to post-operative instructions and consistent follow-up care optimizes recovery and results.