Avascular Necrosis of Femoral Head

Avascular necrosis (also know as osteonecrosis)  is a disease in which bone death occurs.

While the exact cause is unknown there are known risk factors which include alcoholism, excessive steroid use, trauma and vascular compression.

Avascular  necrosis (AVN) primary affects shoulders, knees and hips with death of the bone.  In addition there is often degeneration of the joint articular surfaces which result in pain and restriction in range of motion.

The Regenexx procedure, which allows patients to use their stem cells has been used in the treatment of AVN of the hip. Instead of surgery patients had their own expanded mesenchymal stem cells into the area of necrosis in the bone via x-ray guidance.  The Regenexx procedure with much less downtime than even a surgical CORE decompression and certainly less invasive than a hip replacement surgery.

Preliminary review of the data was significant.  Of the 27 patients treated to date, 4 were lost to follow-up (couldn’t get outcome information), and 3 went on to hip replacements so their data was removed as any results might be due to the hip replacement.  All patients were between 3 months and more than a year out from their stem cell injection.  Of the 20 remaining patients, approximate mean reported improvement was 50%.  This data requires more work.   We will be examining outcomes with regard to the disease severity( ARCO grade I, II, III, IV).  More to follow.

Early Detection of Avascular Necrosis of Femoral Head

Avascular necrosis of the femoral head is a disease where the blood supply to the hip bone ( femoral head) gets disrupted leading to loss of bone integrity and eventual death (necrosis) of the femoral head. There are 4 stages of AVN characterized by radiographic findings.  Early detection is associated with better outcomes.  Late detection typically results in total hip replacement.  MRI is used to perform staging.

Normal MRI of femoral head

Stage I consists of an asymptomatic hip and slight changes on a bone scan.

Stage II Avascular Necrosis

In Stage II, the hip is asymptomatic to mildly symptomatic and the shape of the femoral head is preserved. The necrosis appears as an area of increased density.

In Stage III, the patient is symptomatic, the femoral head is flattened  subtly and a crescent sign is present caused by fracture through dead bone.

Stage III Avascular Necrosis

In Stage IV, there is an increase in pain, flattening  of the femoral head and articular collapse.

Why is this significant?  Gangji demonstrated that when patients with Stage I & II  had areas of necrosis decompressed and injected with specific bone marrow cells, two years later only 10% of the patients had progressed to Stage III .  Hernigou conducted a study with 189 hips which were treated with decompression and injection of autologous bone marrow cells and followed for 5-10years.  In patients who were Stage I & II at the time of therapy, only 6% eventually required hip replacement.  Unfortunately in patients who were Stage III or IV at the time of  therapy, 57% of them went on to receive a hip replacement.

Early detection is essential.  At the Centeno-Schultz Clinic,  a thorough evaluation is the cornerstone of our practice.   Current therapies for AVN include decompression with mononucleated bone marrow cells  alone or in combination with autologous stem cells.

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Avascular Necrosis

Avascular Necrosis (AVN) is an unfortunate disease where the blood supply to the hip bone (femoral head) is disrupted with loss of bone integrity and eventual collapse of the femoral head and joint. 

Trauma, use of steroids, alcohol abuse, damage from radiation, high blood pressure and sickle cell anemia have all been identified as causative factors.   Unfortunately the cause is often never identified.   AVN is also known as osteonecrosis, aseptic bone necrosis and ischemic bone necrosis. It affects people between 30 and 50 years of age.

Diagnosis is typically made by MRI which demonstrates areas of bone necrosis.  Collapse of subchondral bone is referred to as a crescent sign and is indicative of advanced disease.

The most common treatment of  avascular necrosis of the femoral head is total hip replacement. Other treatments include core decompression, where the internal bone pressure is relieved by drilling a hole into the head of the femur.  Gangji demonstrated that injection of bone marrow mononuclear cells can reduce the progression of the disease when performed during the early stages of AVN.  Centeno et. al., in a single case study demonstrated articular surface regeneration  following the intra- articular  injection of bone marrow cells.

Combining bone marrow cells with stem cells is new novel technique.  The Centeno-Schultz Clinic offers a needle-in, needle-out treatment with mononucleated bone marrow cells alone or in combination with expanded mesenchymal stem cells for treatment of early stage avascular necrosis.

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