Osteonecrosis of the shoulder — also called avascular necrosis (AVN) — is a condition in which part of the bone in the shoulder loses its blood supply and begins to die. It affects the humeral head, the ball at the top of the arm bone, and after the hip it’s the second most common site in the body. Left untreated, it can lead to collapse of the joint surface and arthritis. So what causes osteonecrosis of the shoulder, and how do we treat it?

What is osteonecrosis of the shoulder?

The humeral head has a rich but somewhat vulnerable blood supply. That’s why we also call this condition humeral head osteonecrosis. When that blood supply is interrupted, the bone cells beneath the joint surface die — a process called osteonecrosis, or avascular necrosis. Over time, the weakened bone can develop tiny fractures, the joint surface can collapse, and the shoulder can go on to develop arthritis.

The same process affects the hip more often than any other joint — see our guide to osteonecrosis of the hip — but the shoulder is the next most common site. Because it often affects younger, active people, and because catching it early can change the outcome, an accurate and timely diagnosis matters.

What causes osteonecrosis of the shoulder?

Osteonecrosis develops in people with a genetic predisposition who are then exposed to one or more risk factors. Whatever the trigger, the final common pathway is the same: a disrupted blood supply, raised pressure within the bone, and bone death.

The recognised risk factors include:

  • Corticosteroid (cortisone) use — high-dose or long-term steroid treatment is by far the commonest cause of atraumatic shoulder osteonecrosis
  • Heavy alcohol intake
  • Sickle cell disease and other blood disorders such as thalasemia 
  • Previous trauma — a fracture or dislocation that damages the blood supply
  • Deep-sea diving (decompression, or “dysbaric”, osteonecrosis)
  • Some medical conditions — including lupus (SLE), Gaucher’s disease, and pancreatitis
  • Smoking
  • Certain chemotherapy and radiation treatments
  • Pregnancy (an uncommon association)

In a proportion of cases no cause is found, and the condition is called idiopathic. It’s also worth knowing that osteonecrosis can affect more than one joint — so if it’s found in the hip or knee, the shoulders are sometimes worth checking too.

Symptoms of AVN shoulder 

The symptoms of AVN shoulder can be surprisingly vague in the early stages, and some people have very little pain even when a scan shows advanced changes. Typical features include:

  • A deep, poorly localised shoulder pain, which can radiate down towards the elbow
  • Pain that comes and goes, often worse with use of the arm
  • A painful click or catch, if fragments of bone or cartilage have become loose
  • Stiffness and loss of movement, which tends to appear only in the later stages once the joint surface has collapsed

Because there are no symptoms unique to osteonecrosis, a degree of suspicion — particularly in someone with a risk factor such as steroid use — is what leads to the diagnosis. Often, symptoms can be similar to those of frozen shoulder or early shoulder joint arthritis. 

How is avascular necrosis shoulder diagnosed?

Diagnosis combines the history and examination with imaging. The two imaging tests that matter most are the X-ray and the MRI, and they do different jobs.

  • X-ray — the first-line test, and the main tool for staging AVN shoulder. Early on, though, the X-ray can look completely normal.
  • MRI — the most sensitive test, and the one that detects osteonecrosis in the early stages when X-rays are still normal. It shows the tell-tale signal changes in the bone (including a characteristic “double-line sign” adn subchondral fracture). It helps predict the outlook by showing how large the affected area is and where it sits.

How is osteonecrosis of the shoulder treated?

Treatment of AVN shoulder depends on the stage, symptoms, age and activity level, and underlying cause. The overall aim is to relieve pain, preserve the joint, and prevent — or delay — collapse.

Non-surgical treatment (early signs)

For early-stage disease with imaging showing swelling of the bone but no collapse, non-surgical treatment is preferred and may reduce the risk of progression:

  • Activity modification — reducing the load through the shoulder to protect the weakened bone
  • Pain relief and physiotherapy — to manage symptoms and maintain movement
  • Addressing the cause — for example, reviewing steroid dose and duration with the prescribing doctor where it’s safe to do so, and managing alcohol intake or an underlying condition
  • Statin treatment has been suggested to lower the risk in people who must remain on high-dose steroids – the effect is thought to be related to reducing fat levels in the serum. 

It’s worth being honest about the evidence here: high-quality trials of drug treatments are lacking, and conservative measures don’t always halt the disease. Some newer approaches — such as stem-cell (mesenchymal stromal cell) therapy, or hyaluronic acid or PRP injections — have shown promise or anecdotal benefit but aren’t yet supported by strong evidence, so they aren’t part of routine care.

Joint-preserving surgery

Where the disease is progressing but the joint surface hasn’t yet collapsed, joint-preserving surgery may be considered. Most commonly, core decompression, which drills into the humeral head to reduce the pressure inside the bone and encourage new blood vessels to grow. It works best in the earlier stages (before significant bone collapse). Its success falls as the stage advances. Arthroscopic (keyhole) surgery can be used to tidy up the joint, remove loose fragments, and assist decompression.

Joint replacement (advanced stages)

Once the humeral head has collapsed, the treatment shifts towards resurfacing or replacing the joint. Options include partial resurfacing, a partial replacement (hemiarthroplasty), or a total shoulder replacement, depending on whether the socket is involved. These reliably reduce pain and improve function in advanced disease.

Where does injection treatment fit in?

Sport Doctor London is an ultrasound-led sports medicine practice, so it’s worth being clear about the role of injections here. Osteonecrosis itself is a problem of bone blood supply, and it is not cured by a cortisone injection — indeed, cortisone is one of the causes of the condition, so it isn’t a treatment for it.

Sometimes, a few doctors trial other injections such as hyaluronic acid or PRP. However, evidence for these injecitons is lacking, so they are not routinely used. 

Frequently asked questions about avascular necrosis shoulder

What is the main cause of osteonecrosis of the shoulder?

By far the commonest cause of avascular necrosis shoulder is corticosteroid (cortisone) use, particularly high-dose tablets over a long period. Heavy alcohol intake and sickle cell disease are other important causes. It can also follow trauma such as a fracture. In some people no cause is found. Because steroid-related osteonecrosis can affect several joints, the shoulders are sometimes screened when it’s found in the hip or knee.

Can humeral head osteonecrosis be treated without surgery?

Yes, in the early stages. Before the joint surface collapses, non-surgical treatment is preferred and may slow the disease. Where it progresses despite this, joint-preserving surgery (such as core decompression). In advanced cases, joint replacement may be needed. Early diagnosis is what keeps the non-surgical options open.

Is avascular necrosis shoulder the same as arthritis?

They’re related but not the same. Osteonecrosis is bone death from a loss of blood supply, whereas arthritis is wear of the joint surface. The link is that untreated osteonecrosis leads to collapse of the humeral head, which then causes secondary arthritis of the shoulder. Catching osteonecrosis early — before collapse — is what can prevent it from progressing to arthritis.

How is osteonecrosis of the shoulder diagnosed early?

With MRI. In the early stages an X-ray can look completely normal. This is why anyone with unexplained shoulder pain and a risk factor — such as long-term steroid or alcohol use — should be assessed properly. And it’s why people who develop osteonecrosis in the hip or knee are sometimes screened for it in the shoulder too.

Does a cortisone injection help AVN shoulder?

No. Osteonecrosis is a problem of the bone’s blood supply, not inflammation, and cortisone is actually one of its causes. So a cortisone injection isn’t a treatment for it. Other injections, such as hyaluronic acid or PRP, may have a role in the early stages. 

Final word from Sport Doctor London about osteonecrosis of the shoulder

Osteonecrosis of the shoulder is an important, and often overlooked, cause of shoulder pain — particularly in people who have taken long-term steroids. The key is early diagnosis with MRI, because treatment before the humeral head collapses aims to save the joint. If you have unexplained shoulder pain and a risk factor for osteonecrosis, it’s worth being assessed properly and promptly.

If you have persistent shoulder pain, Dr Masci can assess you in London, including ultrasound in clinic and the right imaging. Contact the team here or call +44 (0) 203 488 0350.

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