Knock Knees (Genu Valgum) – Diagnosis & Treatment

What is Knock Knee (Genu Valgum):

• A child with Knock knee (Genu Valgum) will have large gap between both feet without any gap between both knees when they stands.
• Medial side of knee will touch each other during standing and walking.
• As part of natural growth, child will develop bowing of tibia which correct by the age 2 year then child leg will start going in valgus. Valgus will be evident in most of the children around 4 year age which will disappear by the age of 7 year.
• Slight genu valgus continue in adult but it don’t cause any problem if it is very mild.
• If it is sever then child can have pain & difficulty in walking. Arthritis may start in adults.

What are the Causes of Knock Knees:

Knock knee is very common in healthy children between the age of 3 to 7 year as part of their growth & development. Leg will be straighten as they grow but some time they persist forever then we need to worry.

Cause of know knee which do not improve (pathological):

Rickets:

Deficiency of vitamin D & calcium can cause rickets. Because of deficient mineralization in rickets, bone are weak so easily bend in genu valgus. As child grow, it don’t recover by itself.

Obesity:

Due to excessive load soft bone get deformed

Trauma:

Trauma to growth plate near knee joint.

Infection:

Infection affecting distal femoral physis:

Skeletal dysplasia

What are the Symptoms of Knock Knees:

• Touching of medial side of knee.
• Awkward wide-based gait,
• Pain in knee joint
• Easy fatigue & difficulty in running, limping, repeated fall
• In long term if not managed then arthritis of the knee

How Knock Knees can be Diagnosed:

• Genu valgus can be easily identifiable by anyone.
• It can be diagnosed just by visualising large gap between both ankles joint on standing with knee together.
• The normal distance between medial malleolus is less than 8 cm but if it is more, then treatment should be started.

Tests needed for Knock Knees:

• Full-length X-ray both lower limb AP view is needed in standing position to confirm the diagnosis & to measure the angle of deformity.
• Vitamin D assessment is required to see the status of Vit-D deficiency.

When you need to take medical consultation:

Usually knock knee is the part of natural growth of leg in children but if you find any of these finding then you need to consult your doctor:

• Distance between both ankle joint is more than 8 cm while standing with knee together
• Deformity is progressively increasing with age
• Age of child is more than 7 year or less than 2 year
• Only one side is affected
• Symptom like knee pain, limping, difficulty in running
• Problem develop in adult
• Any other problem in body.

Treatment for Knock Knees

Knock Knees Treatment depends on the cause and severity of the condition. Knee Knock problem is physiological between 3-6 years of age and it correct naturally with age.

Non surgical treatment :

• Due to vitamin D deficiency, its severity may be exaggerated so rapid progression in early age may indicate some other problem. Children with Vit D deficiency should be supplemented with VIt-D. Dose and duration will be decided by a paediatric orthopaedic surgeon or paediatrician.
• Many braces are prescribed but child may not be comfortable to wear. This braces has to be used during 20 hours in a day so most of time it is not feasible.
• If genu valgus appear in teen age or later then non-surgical method don’t help.

Surgical Treatment:

Indication:

• Progressive genu valgus beyond the age of 7 year
• Sever genu valgus deformity even in younger age
• First-time develop in teen age or adult
• Only one side
• Pain in knee join with genu valgus deformity

Type of surgery:

Guided Growth:

• In this operation growing area (distal femoral physis) of thigh bone near knee joint is being modulated by the use of plate / screw.
• This operation is being done by very minute incision and small plate of two hole will be placed.
• This plate will be removed once deformity get corrected.
• This surgery can only be done in when sufficient growth is remaining with child.
• This surgery cannot be done growth of bone slow down.
• Child can start walking within 2 days once his pain subside? Child can join school / sport with in week.

Osteotomy:

• In osteotomy, small wedge of bone will be removed after cutting the bone.
• Bone will be fix with plate and screw.
• This surgery is performed in adult and teenager with insufficient growth remaining (> 14 year age).
• In this surgery patient are advised take rest for few months till bone unite.
• Physical therapy will be done to regain movement after surgery.

Reference Links :

• https://kidshealth.org/en/parents/knock-knees.html
• https://en.wikipedia.org/wiki/Genu_valgum
• https://www.medicalnewstoday.com/articles/319894#treatment
• https://www.hss.edu/condition-list_knock-knee.asp

Frequently Asked Questions