Epiphysiolysis is a hip condition that affects adolescents, especially pre-pubescent boys. Linked to an abnormality of the growth cartilage, it results in a sliding of the head of the femur (superior femoral epiphysis) relative to the neck of the femur. Surgical treatment should be undertaken as early as possible to avoid a potentially disabling major slip. 

Definition

Epiphysiolysis is a hip disease affecting children aged 9 to 18, especially during pre-pubertal growth spurts. It results in a sliding of the head of the femur (superior femoral epiphysis) relative to the neck of the femur. 

In this pathology, there is a deficiency of the growth cartilage – also called the growth cartilage – which in children separates the head from the neck of the femur and allows the bone to grow. As a result, the head of the femur tilts down, back, and in to the site of the growing cartilage. 

This movement can be rapid or gradual. We speak of acute epiphysiolysis when the symptoms set in quickly and push to consult in less than three weeks, sometimes following a trauma, and chronic epiphysiolysis when they progress slowly, sometimes over months. Some acute forms can also appear in a chronic context.

There are mild cases (angle of displacement <30 °), moderate (between 30 ° and 60 °) or severe (> 60 °) of epiphysis.

Epiphysis is bilateral – it affects both hips – in 20% of cases.

Causes

The causes of femoral epiphysis are not exactly known but probably involve mechanical, hormonal and metabolic factors.

Diagnostic

When the symptoms and risk factors give rise to suspicion of epiphysis, the doctor requests an X-ray of the pelvis from the front and especially of the hip in profile to establish the diagnosis.

The biology is normal.

A scan may be ordered before surgery to check for necrosis.

The people concerned

The frequency of new cases is estimated at 2 to 3 per 100 in France. They very rarely concern children under 000 years of age, epiphysis occurring mainly during the pre-pubertal period, around the age of 10 in girls and around the age of 11 in boys, who are two to four years old. three times more affected.

Risk factors

Childhood obesity is a major risk factor, as epiphysis frequently affects overweight children with delayed puberty (adipose-genital syndrome).

The risk is also increased in black children or children suffering from hormonal disorders such as hypothyroidism, testosterone deficiency (hypogonadism), global pituitary insufficiency (panhypopituitarism), growth hormone insufficiency or even hyperparathyroidism. secondary to renal failure.

Radiotherapy also increases the risk of suffering from epiphysis in proportion to the dose received.

Finally, certain anatomical factors such as retroversion of the femoral neck, characterized by kneecaps and feet oriented outwards, can promote the onset of epiphysis.

Pain

The first warning sign is often pain, of varying intensity from one subject to another. It can be a mechanical pain of the hip, but very often it is also not very specific and radiates in the region of the groin or the anterior surfaces of the thigh and the knee.

In acute epiphysis, the sudden sliding of the head of the femur can cause sharp pain, mimicking the pain of a fracture. Pain is more vague in chronic forms.

Functional impairment

Lameness is very common, especially in chronic epiphysis. There is also often an external rotation of the hip accompanied by a decrease in the amplitude of movements in flexion, abduction (deviation from the axis of the body in a frontal plane) and internal rotation.

Unstable epiphysiolysis is an emergency situation, in which acute pain, mimicking trauma, is accompanied by major functional impotence, with the inability to set foot.

Evolution and complications

Early osteoarthritis is the main complication of untreated epiphysis.

Due to impaired blood circulation, necrosis of the femoral head most often occurs after surgical treatment of unstable forms. It causes deformation of the femoral head, a source of osteoarthritis in the medium term.

Chondrolysis is manifested by the destruction of joint cartilage, resulting in stiffness of the hip.

The treatment of epiphysiolysis is always surgical. The intervention is intervened as soon as possible after the diagnosis, to prevent the slippage from worsening. The surgeon will choose the appropriate technique in particular according to the extent of the slip, the acute or chronic nature of the epiphysiolysis and the presence or absence of growth cartilage.

In the event of slight slippage, the femoral head will be fixed in place by screwing, under radiological control. Introduced into the neck of the femur, the screw passes through the cartilage and ends in the head of the femur. Sometimes a pin replaces the screw.

When the slippage is significant, the head of the femur can be repositioned on the neck. It is a heavier intervention, with a discharge of the hip by traction for 3 months, and a greater risk of complications.

Epiphysis cannot be prevented. On the other hand, worsening of the slippage of the head of the femur can be avoided thanks to a rapid diagnosis. Symptoms, even when they are moderate or not very typical (a slight lameness, pain in the knee, etc.) should therefore not be overlooked.