Medically reviewed by: Dr. Ralph J. Napolitano Jr., DPM, CWSP, FACFAS
A lack of blood flow to a region causes severe damage to the tissues around it. For example, when an occlusion occurs in the heart’s coronary arteries, blood flow is restricted, and that tissue begins to die. The ischemia due to the lack of blood flow causes chest pain, and if that occlusion is not cleared, the tissue the artery supplies will be non-functional. This is commonly called a heart attack.
But what is the exact mechanism of tissue death due to a lack of blood flow?
Blood carries essential nutrients and is crucial for gas exchange. Without a blood supply, the tissues do not receive the nutrients needed to nourish them, nor do they have the potential to receive oxygen, which keeps the tissues alive. Without these basic needs, the tissues become ischemic or oxygen deprived and experience death.
A disruption in blood flow can also occur to the vessels that supply the bone. This is termed “avascular necrosis” (dead bone), literally meaning bone tissue death due to a lack of blood flow. This is common in joints such as the hip, ankle, knee, and shoulder.
At the shoulder joint, multiple blood vessels enter the humerus and branch to the periphery, supplying the head of the proximal humerus (upper arm bone) in the shoulder joint. If a segment of these blood vessels is blocked, the region it supplies will die. On a larger scale, many times the humeral head collapses, which causes deterioration of the joint surface and causing abnormalities in joint functioning.
If you have questions about avascular necrosis of the shoulder and would like more information, schedule a consultation with our expert orthopedic surgeons at OrthoNeuro. We take pleasure in caring for our patient’s concerns by providing our patients with accurate and helpful information. Call us today or book an appointment online!
Avascular necrosis of the shoulder does have some risk factors associated with it. One common cause of avascular necrosis is fractures. A fracture at the shoulder joint may impact the small vessels that provide blood to the head of the humerus, therefore resulting in avascular necrosis.
Another risk factor includes taking corticosteroids due to their ability to block calcium absorption and cause bones to break down. Excessive alcohol intake is also a risk factor, as well as bone marrow and kidney transplants. Blood clots are also risk factors for avascular necrosis, as they may block the blood flow to the humeral head.
Avascular necrosis of the humeral head is suspected originally due to clinical presentation. Patients with avascular necrosis will present with constant pain without alleviation but typically worse at night and with activity.
Early stages of the disease must be diagnosed with magnetic resonance imaging (MRI), which may not even detect early disease. MRI will detect a bright segment on imaging as the disease progresses, indicating dense, necrotic bone. Further, the MRI may show collapsed bone and cartilage, further suggesting the condition. At this progressed disease state, radiographs, or X-rays, may be enough to diagnose avascular necrosis.
First-line treatment of avascular necrosis of the shoulder is thought to be avoiding further injury. Additional treatment for avascular necrosis depends on the cause of injury and its progression. For example, alcoholics and patients on corticosteroids are typically taken off these things to prevent further damage and preserve the joint.
Other mechanisms of injury may need further intervention because if more vessels are impacted, the joint will deteriorate further. The surgical management of avascular necrosis may include joint preservation to improve blood flow to the bone. Once the bone damage has progressed to a significant stage, and the bone has collapsed, shoulder replacement may be required.
The shoulder joint can either be replaced with an anatomic or reverse prosthesis. An anatomic shoulder replacement includes a metal ball to replace the humeral head and a plastic piece to replace the socket. In the reverse prosthesis, the metal ball is placed on the socket side of the joint, while the plastic ball-shaped socket is on the humeral end of the prosthesis.
The anatomic shoulder replacement is recommended in patients with avascular necrosis of the shoulder. The reverse replacement would be indicated if there was cartilage damage or rotator cuff damage, which is not common in avascular necrosis of the shoulder.
Preservation of the shoulder joint is almost always indicated before a shoulder replacement due to the complications that may arise with this kind of invasive operation. The most common complication is instability, rotator cuff tear, periprosthetic fracture, and infection. Replacement is indicated when the joint cannot be salvaged due to humeral head collapse.
Currently, avascular necrosis of the shoulder is a treatable ailment. Current research is investigating the preservation mechanisms of patients with this disease and mechanisms to prevent bone breakdown due to disease progression. With this goal in mind, shoulder replacements also have an excellent prognosis with a high success rate and the ability to regain quality of life.
Our highly skilled orthopedic surgeons can answer your questions about conditions that can result in bone necrosis. Schedule a consultation with us today at OrthoNeuro, for a preventative treatment plan that is customized to you.
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