Overview
Primary avascular necrosis (also called primary osteonecrosis) is a rare bone condition in which bone tissue dies because of a loss of blood supply. Unlike secondary avascular necrosis, which is caused by known risk factors such as steroid use, alcohol, or trauma, primary avascular necrosis occurs without an identifiable underlying cause. The condition most commonly affects the hip (femoral head), but it can also involve the knee, shoulder, ankle, or other joints. When blood flow to a section of bone is disrupted, the bone cells begin to die. Over time, the affected bone weakens and may collapse, leading to joint damage and arthritis. The main symptoms include joint pain that gradually worsens, stiffness, and reduced range of motion. In early stages, pain may only occur when putting weight on the affected joint, but it can progress to constant pain even at rest. Treatment depends on how far the disease has progressed. Early-stage disease may be managed with medications to reduce pain and inflammation, physical therapy, and procedures such as core decompression surgery, which aims to reduce pressure inside the bone and encourage new blood vessel growth. In advanced cases where the bone has collapsed and the joint is severely damaged, joint replacement surgery (such as total hip replacement) may be necessary. Research into newer treatments, including bone grafting techniques and regenerative therapies using stem cells, is ongoing but not yet standard care.
Also known as:
Key symptoms:
Joint pain, especially in the hip or kneePain that worsens with weight-bearing activitiesStiffness in the affected jointReduced range of motionLimping or difficulty walkingGroin pain (when the hip is affected)Pain at rest as the disease progressesJoint collapse in advanced stagesDifficulty climbing stairsPain that may spread to the buttock or thigh
Multifactorial
Caused by a mix of several genes and environmental factors
Adult
Begins in adulthood (age 18 or older)
FDA & Trial Timeline
1 eventData sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Primary avascular necrosis.
1 clinical trialare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Primary avascular necrosis.
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What stage is my avascular necrosis, and what does that mean for my treatment options?,Is there a known cause for my condition, or is it truly primary (idiopathic)?,What can I do to slow down the progression of the disease?,Am I a candidate for joint-preserving surgery like core decompression, or will I need a joint replacement?,Are there any clinical trials or newer treatments I should consider?,What activities should I avoid, and what exercises are safe for me?,Should my other joints be screened, since avascular necrosis can affect more than one joint?
Common questions about Primary avascular necrosis
What is Primary avascular necrosis?
Primary avascular necrosis (also called primary osteonecrosis) is a rare bone condition in which bone tissue dies because of a loss of blood supply. Unlike secondary avascular necrosis, which is caused by known risk factors such as steroid use, alcohol, or trauma, primary avascular necrosis occurs without an identifiable underlying cause. The condition most commonly affects the hip (femoral head), but it can also involve the knee, shoulder, ankle, or other joints. When blood flow to a section of bone is disrupted, the bone cells begin to die. Over time, the affected bone weakens and may colla
How is Primary avascular necrosis inherited?
Primary avascular necrosis follows a multifactorial inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Primary avascular necrosis typically begin?
Typical onset of Primary avascular necrosis is adult. Age of onset can vary across affected individuals.
Are there clinical trials for Primary avascular necrosis?
Yes — 1 recruiting clinical trial is currently listed for Primary avascular necrosis on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Primary avascular necrosis?
18 specialists and care centers treating Primary avascular necrosis are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.