The genu valgum designates a deviation of the knees inward. It is said to be physiological before 7-8 years old, and pathological when it persists. In everyday language, we sometimes speak of “legs in X”. The knees come together as the ankles move apart. Certain treatments may be considered in the event of pathological genu valgum.

Definition of genu valgum

The genu valgum refers to a deviation of the knees that sets in during growth. At birth, the axis of the lower limbs is not yet fully established. The newborn naturally presents a genu varum, that is to say a deviation of the knees outward. Gradually, the axis of the lower limbs will be reversed. The genu varum is then replaced by a genu valgum, a deflection of the knees inward.

The characteristic deviation of the genu valgum usually reaches its maximum around 3-4 years. In the years that follow, it subsides. The knees gradually align with the physiological axis of the adult.

In some cases, genu valgum can persist beyond 7-8 years. It is said to be pathological, in opposition to the physiological genu valgum which occurs during the first years of children. The pathological genu valgum can have many explanations which are detailed below.

Cause you genu valgum

Between 2 and 6 years on average, the genu valgum is considered physiological. It is a stage in the child’s growth and disappears naturally. The knees are gradually positioned on the physiological axis of the adult. They are aligned with the ankles and hips.

The genu valgum is considered pathological if it does not subside or becomes asymmetric from 7-8 years old. There are two types: essential genu valgum and secondary genu valgum. The first can be either familial and well tolerated, or caused by overweight. Secondary pathological genu valgum can be the consequence of different growth disorders:

• an overgrowth of the tibia following a fracture of the proximal tibia;
• post-traumatic epiphysiodesis, which is a growth disorder with trauma to the cartilage;
• vitamin D deficiency rickets or vitamin-resistant rickets, which results in defective or delayed bone mineralization;
• pseudoachondroplasia, which is a rare disease resulting in severe growth retardation;
• osteochondrodysplasia which is a group of rare and inherited diseases affecting the bones.

Diagnostic du genu valgum

It is based on a clinical examination. In particular, the healthcare professional will measure:

• the inter-malleolar distance, that is to say the distance between the internal protuberances located at the ankles;
• the femoro-tibial angle, that is to say the angle between the femur (single bone of the thigh) and the tibia (bone of the leg).

In the majority of cases, the diagnosis of genu valgum is made in children. This should be placed in a standing position with the knees extended and the kneecaps facing forward. If the child refuses, the examination can be performed while lying down.

To deepen the diagnosis and identify the cause of genu valgum, additional examinations may be performed. The healthcare professional may in particular request:

• medical imaging examinations;
• a dosage of vitamin D.

Genu valgum can be seen in many children between the ages of 2 and 6. It then constitutes a stage of normal growth.

The pathological genum valgum is rarer. It occurs when the deviation of the knees persists after 7-8 years. It is usually diagnosed in children but also sometimes in adults.

Risk factors for pathological genu valgum

Several factors can increase the risk of pathological genu valgum:

• a hereditary predisposition;
• early overweight or obesity;
• deficiencies, especially vitamin deficiencies;
• trauma such as a fracture or shock to the joints.

Knee deflection inward

In a genu valgum, the knees come together while the ankles move apart. In everyday language, we sometimes speak of “legs in X”. Depending on the case, the deviation of the knees can be:

• unilateral or bilateral;
• more or less severe;
• symmetrical or asymmetrical.

Discomfort when walking

When it persists, the genu valgum can tend to disrupt the movements of the lower limbs. Sometimes the discomfort can be accompanied by pain in the knees and stiffness.

Risk of complications

Pathological genum valgum can lead to progressive destruction of cartilage. This constitutes a risk factor for gonarthrosis (osteoarthritis of the knee).

Occurring between 2 and 6 years on average, a physiological genu valgum does not require any treatment. This is a normal growth stage. The deviation of the knees fades naturally.

On the other hand, treatment can be considered in certain cases of pathological genu valgum. It depends on the identified cause and the perceived symptoms:

• vitamin D supplementation in case of deficiency;
• an osteotomy which is a surgical operation aimed at repairing bone and joint deformities;
• deepiphysiodesis, which is a surgical procedure to reduce epiphysiodesis (growth disorder with trauma to the cartilage);
• orthopedic treatment with, for example, the wearing of splints and / or insoles;
• physiotherapy sessions;
• anti-inflammatory and analgesic treatment for severe pain in the knees.

Some cases of genu valgum cannot be prevented, especially those of hereditary origin. On the other hand, other cases are linked to preventable risk factors. In particular, it is necessary to:

• prevent and fight against overweight in children;
• maintain a balanced and varied diet to avoid nutritional deficiencies in children.