Synonyms
Legg-Calvé-Perthes disease, ideopathic childhood femoral head necrosis
Definition
Perthes disease is a circulatory disorder of the child’s femoral head of unknown cause.
Age
3-12 years, mainly 5th -7th year of life
Gender distribution
BoysGirls 2 : 1 – 4 : 1, approx. 15 % – 50 % on both sides (depending on source)
Appearance
Occurrence approx. 1:1000 – 1:5000The blood circulation of the femoral head is critical from an anatomical point of view. The main part of the blood supply is from the femoral neck, an individually created artery radiates additionally into the femoral head (see picture on the right). The reason for this is assumed to be a reduced blood vessel supply. The extent of the circulatory disorder is decisive for the course of Perthes disease and for the regeneration of the femoral head.
Symptoms
The clinical signs of perthenic disease are often initially unspecific. In most cases, the first thing that is often noticed is a limping child. In the further course of the disease, 75% of all children with Perthes disease report pain in the area of the affected hip, 25% report pain in the knee and thigh remote from the hip joint.
The symptoms often change due to the stress and irritation of the joint. Pain is one of the non-specific symptoms of existing Perthes disease. On the one hand, the disintegration of the joint head leads to limping, which is the first indication of a disease of the locomotor system or a neurological problem.
The pain is often initially in the knee, which can lead to a misdiagnosis. For this reason, even children without hip pain but who have a limp should be considered for Perthes disease. If the joint head is gradually destroyed, pain in the affected hip also increases.
This pain occurs particularly during movement or stress. A pain picture that is very similar to the one we are familiar with is known as hip rhinitis (coxitis fugas). This is also a childhood disease of the hip joint.
If necessary, a differentiation can be made with the help of an X-ray image. In the early stages of Perthes disease, the clinical examination can often be unremarkable. As the disease progresses, the hip joint is increasingly restricted in its movement.
Especially the abduction and rotation are increasingly restricted. As can be seen above, the different stages can be easily distinguished from each other in the X-ray image. Only in the early stages can the diagnosis of Perthes disease be made with certainty using MRI (magnetic resonance imaging).
A side comparison shows the change in the left femoral head (right side of the image). X-rays play an important role in the diagnosis of suspected Perthes disease or in monitoring the course of a known disease. Only in early detection is the x-ray image displayed inferior to an MRI image of the hip.
X-rays can therefore be used both to diagnose and classify the disease. Each stage of Perthes disease is presented differently in the X-ray image and can be recognized by trained radiologists or (pediatric) orthopedic surgeons. In the first stage, the growth plate widens, which is difficult to see in X-rays and is therefore easier to visualize by MRI.
In the following condensation stage, the bone tissue thickens due to the pathological destruction of the substance. In the image, this is shown as a brightening, as the denser bone structures absorb more X-rays. The destroyed bone is now partially broken down in the fragmentation stage.
The X-ray image shows a decomposed head of the femur and the image darkens in the area of the joint due to the decrease in bone structures. In the repair stage, which usually continues seamlessly into the healing stage, the bone is formed again. X-rays show the reconstruction of the joint head and the normalization of the anatomical conditions.
If deformities occur during the healing process because the joint has been subjected to too much stress in this weak phase, this can also be shown on an X-ray. Typically, this pathological change is shown as a mushroom-shaped joint head. Perthes disease is classified according to the four degrees of Cattarall.
The different Catterall stages are classified according to the degree of femoral head involvement. In stage I only a small superficial part of the femoral head is affected.In stage II of Perthes disease, in contrast to stage I, larger parts of the femoral head are disturbed. The severity of the condition can be seen on the left edge of the picture.
The classification according to Catterall must not be confused with the Perthes stages. A prognosis of the course of the disease is difficult at any time and depends on many individual factors. A maximum of 50% of the femoral head is affected.
In stage III of Perthes disease, the entire femoral head is affected by the circulatory disorder. The prognosis is generally less favorable than the first two stages of Cattarall’s disease. Unfortunately, even in this stage it is not possible to make a prognosis about the further course.
A maximum of 75% of the femoral head is affected. In stage IV of Perthes disease, the femoral head is completely destroyed and there is a risk that the remaining femoral head will slip off the femoral neck. An anatomical reconstruction only occurs if the disease occurs at a very young age.
The entire femoral head is affected. Another important classification is the classification according to Herring. It is of decisive importance for the long-term prognosis.
The femoral head is divided into three pillars. The outer lateral pillar is of decisive importance. Group A: Lateral abutment is not affectedGroup B: > 50% of the height of the lateral abutment is affectedGroup C: < 50% of the height of the lateral abutment is retained, thus the worst long-term prognosis1.
Initial stage: This stage is often very difficult to detect on an X-ray image. Frequently, the growth plate is initially only widened. A higher significance of this stage can be achieved by magnetic resonance imaging (MRI).
2nd coding stage: Collapse of the skeleton of the bone structure results in radiological compression (in the X-ray image, a compression of the bone structure). This stage is reached approximately 2 to 6 months after the onset of the disease, depending on its severity. 3rd fragmentation stage: The cndensation stage is followed by the fragmentation stage.
Its maximum expression is reached after about 12 months. This stage is characterized by a loss of bone structure, hence the fragmentation. Especially in this stage, the femoral head has a reduced load bearing capacity.
4th repair stage: During the repair stage, the femoral head is rebuilt by the implantation of new vessels. This stage is reached after 2 – 3 years. This allows bone cells to settle again and form bone ground substance.
This leads to the reconstruction of the femoral head. 5. healing stage: The healing stage is the final result of the bony remodelling processes. If healing takes place in a deformity, i.e. in an unatomical final rounding of the femoral head, this remains for life.
As a result, there is a high risk of developing hip joint arthrosis. Healing occurs after 3 – 5 years. The aim of therapy must be to prevent deformation of the femoral head during the phase of reduced resilience.
If deformations have already occurred, the aim must be to restore the congruence of the joint. A therapy for Perthes disease must always be tailored to the individual patient and therefore no general therapy recommendation can be made. In the absence of risk factors, low Catterall stage and young age, it is sometimes possible to observe the course of the disease while putting full weight on the hip joint.
Since Perthes disease has a course of several years and thus the critical phase lasts for months, a consistent therapy of the affected children is often difficult. If an unfavorable course is indicated (risk signs after Cattarall or increasing movement restriction), the hip joint must be relieved by so-called orthoses (see picture on the left) during the critical phase. If there is a risk of the femoral head becoming deformed, there are various forms of therapy.
The aim of all procedures is to improve the so-called containment, the roofing of the femoral head, the apparent stimulation for an anatomical reconstruction. Only two established procedures should be mentioned here.
- The straightening correction of the femoral neck with the aim of better centring the femoral head in the acetabulum (intertrochanteric varisation osteotomy; IVO).
- The acetabular roof pivoting through a pelvic osteotomy according to Salter.
The prognosis for Perthes disease is primarily good.
There is of course no danger to life. However, the healing of the disease can lead to an unfavorable deformation of the femoral head, resulting in early hip arthrosis.In principle, however, it can be said that diseases before the age of 10 have a more favorable prognosis with regard to the deformity, since the body has a higher regenerative potential at a younger age. On the right, one can see an unfavorable healing result with typical cylindrical or mushroom-shaped deformation of the femoral head.
The original femoral neck is compressed, the angle between the shaft and the indicated femoral neck is statically unfavorable and too steep. Healing of Perthes disease in this malposition is very likely to lead to premature hip arthrosis. Unfavorable factors are
- Male sex
- Age of occurrence > 6 years
- Lateral external calcification in the X-ray image
- Pronounced restriction of movement
- Catterall stage 4
- Herring Group C
Perthes disease typically progresses in four to five stages.
The course of the disease is determined by the extent of the circulatory disorder. The individual stages of Perthes disease are described below. There are individual differences in the course of the disease.
Not all stages of Perthes disease necessarily occur in the form and extent described. The erection correction of the femoral neck is to be recognized. The result was fixed with a plate and screws.
This x-ray image shows the pelvic osteotomy according to Salter. Here the pelvis is swivelled over the femoral head.
