Avascular necrosis

Avascular necrosis, also called osteonecrosis, occurs when reduced blood flow causes bone tissue to weaken and die, most often in the hip, knee or shoulder. Left untreated, it can lead to joint collapse and painful arthritis. Novant Health orthopedic specialists offer timely diagnosis and personalized treatment to help protect your joints and relieve pain.

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A 3D model of a human body showing joints highlighted, indicating pain areas.

Anatomy of the hip, knee and shoulder

Healthy bones rely on a steady supply of blood to deliver oxygen and nutrients that keep bone tissue strong and able to repair itself. When that blood supply is disrupted by injury, medical conditions or other factors, bone cells begin to die and the bone can lose its normal shape and strength.

Avascular necrosis most often develops in the hip, but it can also affect the shoulder, knee or ankle. When it occurs near a joint, the smooth cartilage covering the bone can break down too. This creates uneven surfaces that increase friction inside the joint, accelerating cartilage damage and leading to arthritis-like symptoms.

Overview

Symptoms

In its early stages, avascular necrosis may cause only mild discomfort that's easy to overlook. As the condition progresses, you may notice:

Pain in the hip, knee or shoulder that increases with activity or weight-bearing
Stiffness or reduced range of motion
Discomfort that worsens with standing, walking or exercise
A deep, dull ache or throbbing pain that may persist at rest
Difficulty with daily activities such as climbing stairs, walking long distances or lifting

As bone collapse begins, pain may become constant and interfere with sleep or rest.

Causes

Avascular necrosis can develop gradually or appear suddenly, depending on the underlying cause. Common causes include:

Trauma or fractures that damage nearby blood vessels
Joint dislocations, particularly in the hip or shoulder
Long-term corticosteroid use, which can interfere with blood flow in small arteries
Excessive alcohol use, which may increase fat deposits that block circulation
Medical conditions such as sickle cell disease, lupus, diabetes or HIV
Radiation or chemotherapy treatments that affect bone health

In some cases, no clear cause can be identified. Identifying the underlying cause when possible helps our specialists develop a treatment plan that addresses both symptoms and future bone protection.

Risk factors

Certain factors may increase your likelihood of developing avascular necrosis, though having one or more risk factors doesn't mean you'll develop the condition. These include a history of joint trauma or dislocation, long-term steroid use, heavy alcohol use and underlying medical conditions such as sickle cell disease, lupus or diabetes. Talk with your physician about your personal risk factors and what they mean for your health.

Diagnosis

Our orthopedic specialists take a thorough, patient-centered approach to diagnosing avascular necrosis. Your evaluation may include a detailed medical history and review of risk factors, a physical exam to assess pain, motion and joint stability, and imaging tests. X-rays help identify structural changes or bone collapse, while MRI scans are highly sensitive for detecting early bone damage.

In some cases, CT scans or bone scans may be used to assess blood flow and the extent of the condition. We take time to explain your results clearly so you understand what's happening and how treatment can help.

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