What is the definition of Knock Knees?

Knock knees are condition in which the knees touch, but the ankles do not touch. The legs turn inward.

What are the alternative names for Knock Knees?

Genu valgum

What are the causes for Knock Knees?

Infants start out with bowlegs because of their folded position while in their mother's womb. The legs begin to straighten once the child starts to walk (at about 12 to 18 months). By age 3, the child becomes knock-kneed. When the child stands, the knees touch but the ankles are apart.

By puberty, the legs straighten out and most children can stand with the knees and ankles touching (without forcing the position).

Knock knees can also develop as a result of a medical problem or disease, such as:

  • Injury of the shinbone (only one leg will be knock-kneed)
  • Osteomyelitis (bone infection)
  • Overweight or obesity
  • Rickets (a disease caused by a lack of vitamin D)

What are the current treatments for Knock Knees?

Knock knees are not treated in most cases.

If the problem continues after age 7, the child may use a night brace. This brace is attached to a shoe.

Surgery may be considered for knock knees that are severe and continue beyond late childhood.

What is the outlook (prognosis) for Knock Knees?

Children normally outgrow knock knees without treatment, unless it is caused by a disease.

If surgery is needed, the results are most often good.

What are the possible complications for Knock Knees?

Complications may include:

  • Difficulty walking (very rare)
  • Self-esteem changes related to cosmetic appearance of knock knees
  • If left untreated, knock knees can lead to early arthritis of the knee

When should I contact a medical professional for Knock Knees?

Call your provider if you think your child has knock knees.

How do I prevent Knock Knees?

There is no known prevention for normal knock knees.


Demay MB, Krane SM. Disorders of mineralization. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 71.

Kliegman RM, Stanton BF, St. Geme JW, Schor NF. Torsional and angular deformities. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 675.

Pomeranz AJ, Sabnis S, Busey SL, Kliegman RM. Bowlegs and knock-knees. In: Pomeranz AJ, Sabnis S, Busey SL, Kliegman RM, eds. Pediatric Decision-Making Strategies. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 49.

  • Condition: Coronal Genu Angular Deformities in Children less than 10 Years Old
  • Journal: BMC musculoskeletal disorders
  • Treatment Used: Temporary Hemiepiphysiodesis
  • Number of Patients: 66
  • Published —
The study researched the outcomes of temporary hemiepiphysiodesis for treating coronal genu angular deformities in children less than 10 years old.
  • Condition: Patellar Instability with Skeletal Immaturity
  • Journal: Eklem hastaliklari ve cerrahisi = Joint diseases & related surgery
  • Treatment Used: Combined Tibial Tubercle Ventromedialization and Proximal Tibial Closing Wedge Osteotomy
  • Number of Patients: 1
  • Published —
This case report described treating a patient with a patellar instability born from a skeletal immaturity using a combined tibial tubercle ventromedialization and proximal tibial closing wedge osteotomy.

There are no recent clinical trials available for this condition. Please check back because new trials are being conducted frequently.