• Cellular bone death due to vascular insufficiency
    • Can be either traumatic or nontraumatic
  • Also known as:
    • Avascular necrosis (AVN)
    • Ischemic necrosis
    • Idiopathic osteonecrosis
    • Lunatomalacia/Kienböck disease (lunate bone)
    • Subchondral fracture
    • Aseptic necrosis
    • Legg-Calvé-Perthes syndrome (idiopathic necrosis of the femoral head)
    • Osteonecrosis of the jaw (ONJ)


  • Primarily involves the epiphysis of long bones (most commonly femoral head, humeral head, and the femoral condyles), but any bone may be affected
  • System(s) affected: musculoskeletal


  • Predominant age: 3rd to 5th decades
  • Predominant sex: varies depending on comorbidities and etiology

  • 10,000 to 20,000 new cases per year in the United States (1)
  • Osteonecrosis is the most common cause for total hip replacement in young adults. It represents about 10% of all hip replacements (1).
  • Disease is bilateral in at least 50% of all nontraumatic cases and in 75–95% of cases associated with steroid use (1).
  • Hip: occurs in 10% of undisplaced femoral neck fractures, 15–30% of displaced femoral neck fractures, and 10% of hip dislocations
  • Jaw: Over the past 10 years, ONJ has been reported in 5% of cancer patients receiving high-dose IV bisphosphonates.
  • Glucocorticoid-induced osteonecrosis develops in 9–40% of patients on long-term therapy.
  • Osteonecrosis occurs during early postoperative period in 20–25% of patients after renal transplant.

Etiology and Pathophysiology

  • Pathophysiology is multifactorial and not fully understood. The final common pathway is the interruption of blood flow to the bone.
  • Vascular insufficiency leads to demineralization, trabecular thinning, subchondral plate fracture, and fatigue/fracture of the necrotic segment (1).
  • Traumatic: disruption of blood supply due to vessel injury as the result of fracture or dislocation
  • Nontraumatic
    • Impedance of blood flow due to vascular compression/vasospasm
    • Intraluminal obstruction from thromboembolism, nitrogen bubbles (diving), fat emboli, intravascular coagulation, or vascular stasis (1)
    • Long-term high-dose corticosteroid therapy
    • In many, the cause of interrupted blood flow is unknown.

Risk Factors

  • Primary risk factors are a history of trauma, prolonged corticosteroid use, or alcoholism.
  • Other risk factors include bisphosphonate use, sickle cell disease, diabetes mellitus, hyperlipidemia, oral contraceptives, pregnancy, chemotherapy, decompression sickness (“bends”; “caisson disease”), chronic pancreatitis, Crohn disease, gout, myeloproliferative disorders, radiation treatment, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), chronic renal failure and hemodialysis, chronic liver disease, Gaucher disease, organ transplant, trauma, tobacco use, HIV, hypercoagulable states, fat embolus syndrome, developmental hip dysplasia, and slipped capital femoral epiphysis (SCFE).

General Prevention

  • Limit alcohol use. There is a dose-dependent relationship with alcohol consumption. The relative risk (RR) is 3.3 for <400 mL/week and 17.9 for >1,000 mL/week.
  • Smoking cessation: Smokers have RR of 3.9 versus nonsmokers.
  • Limit corticosteroid use: Serum corticosteroid concentration is cumulatively associated with osteonecrosis.
  • Consider screening bone density for high-risk patients.
  • Consider preventive dental checkup before high-dose bisphosphonate use in chemotherapy patients.



Consider osteonecrosis in individuals presenting with bone pain who have a history of trauma or other risk factors.

  • Hip/femoral head: dull, aching groin/hip pain that is progressive and worsens with weight-bearing
  • Knee: dull, aching knee pain that worsens with weight-bearing, stair climbing, and at night
  • Humeral head: shoulder pain that is severe and poorly localized, worsens at night and with activity
  • Lunate (Kienböck disease): pain and stiffness of dorsal wrist of dominant hand
  • Jaw: exposed bone in the mouth that fails to heal despite appropriate intervention

Physical Exam

  • Hip/femoral head
    • Decreased and painful hip range of motion, especially in rotation and abduction
    • Antalgic or Trendelenburg gait
  • Knee
    • Pseudolocking secondary to pain, effusion, or muscle contracture
  • Humeral head
    • Active motion inhibited by pain
    • Passive motion and strength preserved
  • Lunate
    • Dorsal swelling with tenderness over radiocarpal joint
    • Restricted and painful dorsiflexion of wrist with weakness of grip

Differential Diagnosis

  • Hip/femoral head
    • Osteoarthritis (OA), femoral neck fracture, labral tear, osteomyelitis, muscle strain, transient synovitis, bone marrow edema syndrome
  • Knee
    • OA, septic arthritis, meniscal tear, bone bruise, transient osteopenia of the knee, pes anserine bursitis, osteochondritis dissecans
  • Humeral head
    • Adhesive capsulitis, rotator cuff tear/tendonitis, osteomyelitis
  • Lunate (Kienböck disease)
    • TFCC injury, tenosynovitis of extensor compartments, RA, degenerative joint disease, occult ganglion, other carpal bone injury
  • No specific physical findings or laboratory tests reliably establish the diagnosis.
  • Clinically suspected osteonecrosis can be confirmed only by diagnostic imaging or biopsy.

Diagnostic Tests & Interpretation

Initial Tests (lab, imaging)

Consider testing for sickle cell disease (Hb electrophoresis), hyperlipidemia (fasting lipid profile), and coagulopathies (protein C, protein S, factor V Leiden) with atraumatic etiology.

  • Plain radiographs (first line)
    • Early stages: unremarkable
    • Mild to moderate AVN: mild bone density changes followed by sclerosis, cyst formation
    • Advanced disease: bony deformities and loss of contours, subchondral lucency (crescent sign), and osseous collapse
    • Specific views based on location
      • Hip/femoral head: anteroposterior (AP) and frog-leg lateral views of both hips
      • Knee: AP, lateral, and tunnel view of knee
      • Humeral head: AP, true AP, and axillary views of shoulder
      • Lunate: standard wrist films
  • MRI without contrast: gold standard for diagnosis (sensitivity and specificity >98%); obtain if x-ray findings are normal and clinical suspicion is high:
    • Early stages: decreased signal intensity of the subchondral region on both T1- and T2-weighted images (water signal)
    • Mild to moderate: high signal intensity line within two parallel rims of decreased signal intensity on T2-weighted scans (double-line sign)
    • Advanced: deformity and calcification of the articular surface
      • Bone marrow edema on MRI is a marker of disease progression and elevated risk for collapse of the femoral head.
  • Bone scan: single photon emission computed tomography (SPECT):
    • Central area of decreased uptake surrounded by an area of increased uptake (doughnut sign)
    • Not as sensitive as MRI
  • Staging: Several different staging systems are available for the femoral head (2).
  • Original Ficat-Arlet classification based on radiographic findings
  • ARCO classification (3)[C]
    • Stage 0: normal diagnostic testing
    • Stage 1: X-rays are normal; positive MRI and biopsy
    • Stage 2: X-rays may show osteopenia, sclerosis, or subchondral cysts but no collapse.
    • Stage 3: X-rays will show a subchondral radiolucent fracture line (crescent line). Flattening of the femoral head may also be present.
    • Stage 4 (end stage): X-rays will show joint space narrowing and other degenerative changes similar to OA.
  • Steinberg stages 0 to 6 are based on imaging and subdivided into categories based on percentage of the femoral head affected. They are a modification of the Ficat-Arlet stages based on imaging studies (4)[B].


  • Early diagnosis is important.
  • Treatment depends on the age, location, stage of the disease, and overall health of the patient.
  • The goal of therapy is to preserve the native joint.

General Measures

  • Usually managed as an outpatient; inpatient care if surgery indicated
  • Crutches or other assistive devices to avoid weight-bearing (if weight-bearing joint is affected)


  • No medical treatment has been proven effective for arresting the disease process.
  • NSAIDs and other analgesics, as needed, for pain relief
  • Prophylactic alendronate may help prevent osteonecrosis with corticosteroid use; lipid-lowering agents help prevent steroid-induced osteonecrosis (5)[B].

Issues For Referral

Refer to orthopedics for surgical opinion.

Surgery/Other Procedures

  • Surgical options are controversial and depend on severity and site of disease. Joint-preserving procedures are preferred when possible. Severe disease may require total joint replacement.
  • Hip/femoral head:
    • Early stages (precollapse) treated surgically with bone decompression and possible bone graft
    • Later stages (postcollapse) treated with total hip arthroplasty
  • Knee: arthroscopy, osteochondral grafts, high tibial osteotomy, core decompression, unicompartmental/total knee arthroplasty
  • Humeral head: arthroscopy, core decompression, hemiarthroplasty, total shoulder arthroplasty
  • Lunate (Kienböck disease): lunate excision with/without replacement, joint-leveling procedures, intercarpal fusions, revascularization, salvage procedures

Complementary and Alternative Medicine

Noninvasive modalities including electrical stimulation, shock wave therapy, electromagnetic field therapy, and hyperbaric oxygen are undergoing trials. Some studies show improvement in pain, function, or outcomes, but evidence remains limited.

Ongoing Care

Physical therapy and occupational therapy as adjuncts

Patient Education

  • Physicians prescribing bisphosphonates should alert patients to potential oral complications, and advise patients to notify their oral health provider that they are taking these drugs.
  • Patients at high risk for osteonecrosis should be educated about typical symptoms and advised to present early for care should any symptoms develop.


  • Poor prognostic factors include age >50 years, advanced disease at time of diagnosis, necrosis of >1/3 of the femoral head weight-bearing area, lateral femoral head involvement, and the presence of nonmodifiable risk factors.
  • Progression of asymptomatic osteonecrosis of the femoral head is proportional to lesion size. Small lesions (<15% involvement) are unlikely to progress, whereas large lesions (>30% involvement) are much more likely to progress.
  • >50% of patients with osteonecrosis require surgical treatment within 3 years of diagnosis.


  • Surgical complications include nonunion, malunion, peroneal nerve palsy, deep venous thrombosis, intraoperative fracture, and postoperative dislocation.
  • Progression of disease can also lead to OA of the involved joint (6).

Additional Reading

  • American College of Radiology (ACR) Appropriateness Criteria for avascular necrosis of the hip. National Guideline Clearinghouse. 2010;31:15734.
  • Mont MA, Hungerford DS. Non-traumatic avascular necrosis of the femoral head. J Bone Joint Surg Am. 1995;77(3):459–474. [PMID:7890797]
  • National Institute of Arthritis and Musculoskeletal and Skin Diseases. Osteonecrosis. www.niams.nih.gov/health_info/osteonecrosis/. Accessed March 27, 2018.
  • Reid IR, Cornish J. Epidemiology and pathogenesis of osteonecrosis of the jaw. Nat Rev Rheumatol. 2011;8(2):90–96. [PMID:22124271]
  • Ribeiro GH, Chrun ES, Dutra KL, et al. Osteonecrosis of the jaws: a review and update in etiology and treatment [published online ahead of print June 24, 2017]. Braz J Otorhinolaryngol. doi:10.1016/j.bjorl.2017.05.008. [PMID:28712852]

See Also

Avascular Necrosis ; Legg-Calvé-Perthes Disease ; Osteoarthritis



  • M87.00 Idiopathic aseptic necrosis of unspecified bone
  • M87.059 Idiopathic aseptic necrosis of unspecified femur
  • M87.08 Idiopathic aseptic necrosis of bone, other site
  • M87.09 Idiopathic aseptic necrosis of bone, multiple sites
  • M87.10 Osteonecrosis due to drugs, unspecified bone
  • M87.159 Osteonecrosis due to drugs, unspecified femur
  • M87.188 Osteonecrosis due to drugs, other site
  • M87.19 Osteonecrosis due to drugs, multiple sites
  • M87.20 Osteonecrosis due to previous trauma, unspecified bone
  • M87.256 Osteonecrosis due to previous trauma, unspecified femur
  • M87.28 Osteonecrosis due to previous trauma, other site
  • M87.29 Osteonecrosis due to previous trauma, multiple sites
  • M87.3 Other secondary osteonecrosis
  • M87.88 Other osteonecrosis, other site
  • M87.89 Other osteonecrosis, multiple sites
  • M87.9 Osteonecrosis, unspecified


  • 733.40 Aseptic necrosis of bone, site unspecified
  • 733.41 Aseptic necrosis of head of humerus
  • 733.42 Aseptic necrosis of head and neck of femur
  • 733.43 Aseptic necrosis of medial femoral condyle
  • 733.44 Aseptic necrosis of talus
  • 733.45 Aseptic necrosis of bone, jaw
  • 733.49 Aseptic necrosis of bone, other


  • 17926002 Aseptic necrosis of medial femoral condyle
  • 203482000 Idiopathic aseptic necrosis of bone (disorder)
  • 29281007 Aseptic necrosis of head AND/OR neck of femur
  • 398199007 Aseptic necrosis of bone (disorder)
  • 43453000 Aseptic necrosis of talus
  • 441809006 aseptic necrosis of bone of jaw (disorder)
  • 710186007 Osteonecrosis due to trauma (disorder)
  • 83453001 Aseptic necrosis of head of humerus (disorder)

Clinical Pearls

  • Trauma, alcohol abuse, and prolonged glucocorticoid use are the most common risk factors for developing osteonecrosis.
  • Suspect osteonecrosis in high-risk patients presenting with dull bony pain.
  • Order joint-specific plain films initially and proceed to MRI if needed for definitive diagnosis.
  • Patients on chemotherapy are at higher risk for mandibular osteonecrosis.


Vicki R. Nelson, MD, PhD


  1. Lafforgue P. Pathophysiology and natural history of avascular necrosis of bone. Joint Bone Spine. 2006;73(5):500–507.  [PMID:16931094]
  2. Kaushik AP, Das A, Cui Q. Osteonecrosis of the femoral head: an update in year 2012. World J Orthop. 2012;3(5):49–57.  [PMID:22655222]
  3. Gardeniers JWM. Report of the Committee of Staging and Nomenclature. ARCO Newsletter. 1993;5(2):79–82.
  4. Steinberg ME, Hayken GD, Steinberg DR. A quantitative system for staging avascular necrosis. J Bone Joint Surg Br. 1995;77(1):34–41.  [PMID:7822393]
  5. Lai KA, Shen WJ, Yang CY, et al. The use of alendronate to prevent early collapse of the femoral head in patients with nontraumatic osteonecrosis. A randomized clinical study. J Bone Joint Surg Am. 2005;87(10):2155–2159.  [PMID:16203877]
  6. Mankin HJ. Nontraumatic necrosis of bone (osteonecrosis). N Engl J Med. 1992;326(22):1473–1479.  [PMID:1574093]

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