Necrosis of the Femoral Head

What is Femoral Head Necrosis?

In femoral head necrosis, bone cells die due to degenerative changes in the tissue. Because of its complex blood supply, the femoral head is susceptible to necrosis.

The upper portion of the femoral head is supplied by a different artery than the lower portion. This creates a so-called watershed area, i.e., an area where two differently supplied areas adjoin each other. In such a watershed area, circulation disorders occur most frequently.

Inside the femoral head, this leads to damage to the bone, which loses strength and stability and can collapse. Since the femoral head is located directly on the joint, these degenerative processes also affect the hip joint, and hip osteoarthritis may result without proper treatment.

The femoral head can also be affected by necrotic damage in childhood; this condition is Perthes' disease. In most cases, no cause can be identified, but the chances of recovery are better than in adulthood.

Symptoms and Causes

The cause of the undersupply of the femoral head is an occlusion of one of the blood vessels, which interrupts the blood supply and the high demand of the bone cells. These usually undertake a steady build-up and breakdown of bone material, which can no longer be adequately met.

There are numerous causes for such an occlusion of essential blood vessels. In addition to accidental damage to the vessels, excessive alcohol consumption, certain medications (cortisone, chemotherapeutic agents), radiation therapy, and metabolic diseases (diabetes mellitus) can also be responsible.

Frequently, however, no specific cause can be identified for the finding, in which case it is referred to as idiopathic femoral head necrosis.

Patients initially complain of mild pain in the groin, which worsens massively as the condition progresses and spreads to the knee or buttock region, for example. In addition, hip joint mobility is severely restricted, and many patients adopt a protective posture.

Diagnosis: How Is Femoral Head Necrosis Detected?

A precise diagnostic procedure is important to first differentiate between femoral head necrosis and other clinical pictures and record the necrosis's progress on the femoral head. First, a comprehensive patient interview provides information about possible risk factors and pain symptoms. Then, physical examination of the hip joint with a precise analysis of mobility, muscle strength, and certain pain-provoking positions is often sufficient to make an initial diagnosis.

This is followed by diagnostic radiology, which reveals damage to the bone tissue.

Necrosis of the Femoral Head MRI

MRI examination is a central component for early diagnosis and planning the correct therapy. It confirms the initial findings on the one hand and determines the exact extent of the femoral head necrosis and possible joint involvement.

During such MRI examination, patients are transported on a movable couch into a unique tube inside which a magnetic field is produced. In the human body, this magnetic force aligns all water molecules in parallel to point in one direction. Complex processes in the MRI device subsequently change the magnetic field and automatically analyze the movement of the water molecules back to their normal state. Each tissue reacts differently to this external influence. So the computer-guided MRI device can precisely calculate the individual structure of the organs and identify, among others, inflammations, injuries, or other diseases. The doctor now analyzes the result in slice-like images and thus precisely recognizes the exact extent of the dead bone tissue in the femoral head. In addition, the MRI examination makes it possible to check whether the hip joint is still intact or has already been damaged by necrotic changes.

Osteonecrosis of the Femoral Head Progression and Stages

Osteonecrosis of the femoral head can manifest differently in each patient and is divided into five stages based on pain symptoms and clinical diagnosis. In the first two stages, 0 and 1, patients usually experience no pain at all or only mild pain in the groin region, which can manifest as an unpleasant pulling sensation and is therefore relatively nonspecific.

Stage 0 diagnoses are atypical and can only be achieved by special tissue sampling, but stage 1 MRI scans can diagnose early.

Typically, femoral head necrosis progresses and manifests as more severe pain in stage 2, leading to diagnosis based on diagnostic radiography or MRI.

In the subsequent stage 3, the pain worsens, and imaging techniques already reveal damage to the articular surface. The final stage 4 means strong wear of the hip joint combined with massive pain, which can usually only be eliminated by implanting an artificial hip joint.

Osteonecrosis of the Femoral Head Treatment: When to Operate?

First of all, the patient's age significantly influences the therapy, and medical treatment is usually not necessary for femoral head necrosis in childhood (Perthes' disease), as the disease is very likely to heal on its own.

In adulthood, in addition to the patient's general condition, treatment depends mainly on the stage of the disease, i.e., how far the femoral head necrosis has progressed.

In the early stages, conservative treatment can provide relief and even enable a complete recovery. In particular, strengthening exercises or physiotherapy, sparing through relieving supports, and pain-relieving medications are used. However, surgery is absolutely necessary for the later stages when the joint surface has already been affected.

From Stage 3, Surgery Is Necessary

In stage 3, so-called microfracture surgery is an option. This involves using fine wires to drill minimal holes in the hip bone down to the damaged cartilage layer, allowing increased blood and stem cells to migrate into the necrosis zone and form a secondary cartilage replacement layer.

Another option is joint-preserving osteotomy, mainly considered for joint surfaces that are still in good condition in healthy patients. In this operation, the position of the femoral head is realigned by removing necrotic parts and screwing healthy parts of the joint to create a new articular surface. However, it should be noted that these two therapies usually only delay complete degeneration, and in the long term, an artificial hip joint will be essential.

In stage 4 and patients of advanced age, the most promising option is an artificial hip joint (total hip replacement, TEP). This involves surgical removal of the femoral head's articular surfaces and the pelvic bone's acetabulum and replacement with artificial articular surfaces.

Healing and Prognosis

As a general rule, the earlier femoral head necrosis is detected, the better the chances of recovery. This means for stages 0 and 1 that, complete self-healing can occur.

However, in the subsequent stages, the bone can no longer recover on its own, and therapy is inevitably required. However, proper treatment can preserve natural joint function for a long time and delay the need for a prosthesis.

Finally, the use of an artificial hip joint is the right choice. In recent years, the development of modern surgical techniques and innovative materials has contributed to tissue-conserving and durable hip prostheses that immediately improve the lives of many patients. In addition, an adequate lifestyle and avoidance of strenuous activities can allow decades of trouble-free daily life with an artificial joint.

Which Doctors Are Specialists in Osteonecrosis of the Femoral Head?

Patients suffering from hip pain should see an orthopedic specialist with a surgical focus on hip surgery.

We can help you find an expert for your condition. All listed doctors and clinics have been reviewed by us for their outstanding specialization in femoral head necrosis and are awaiting your inquiry or treatment request.