Management of Avascular Necrosis of the Hip

Diagnostic Approach

CT scan can also be used for diagnosis when MRI is performed in response to patient complaints of hip or spine pain 1, 2
Asymptomatic disease with positive MRI findings occurs in approximately 5% of at-risk patients 1, 3

Common risk factors include corticosteroid treatment, according to the Centers for Disease Control and Prevention 1, 2
Alcohol abuse is a risk factor for avascular necrosis of the hip, as reported by the American College of Physicians 1, 3
Hemoglobinopathies, including sickle cell disease, are risk factors for avascular necrosis of the hip, as stated by the American College of Physicians 1, 3
Hyperlipidemia is a risk factor for avascular necrosis of the hip, according to the American Heart Association 1, 2
Hypercoagulability states are a risk factor for avascular necrosis of the hip, as reported by the American College of Chest Physicians 1, 3

Late presentation is a major negative prognostic factor, according to the American College of Radiology 4, 5
Untreated avascular necrosis inevitably leads to early degenerative joint disease, as stated by the American College of Radiology 4, 5
Avascular necrosis is estimated to cause up to one-third of all total hip arthroplasties performed in patients under 60 years of age, according to the American Academy of Orthopaedic Surgeons 4, 5
The most serious complication of treatment is iatrogenic avascular necrosis, as reported by the American College of Radiology 4, 5

Magnetic resonance imaging (MRI) is the preferred diagnostic method for avascular necrosis (AVN) of the hip, especially in patients presenting with persistent hip pain with normal standard radiologic studies, and both sides of the hip should be imaged, as AVN can be bilateral 6, 7

Weight reduction and use of walking aids (canes or walkers) may help reduce symptoms in early stages, and pharmacological treatments such as bisphosphonates can be used to prevent bone collapse 6, 7, 8

For young adults with symptomatic hip AVN, especially with dysplasia or varus/valgus deformity, joint-preserving procedures such as osteotomy may be considered, and for elderly patients with poor bone quality, cemented femoral fixation should be considered to reduce periprosthetic fracture risk 8

NSAIDs and analgesics can provide symptomatic pain relief for patients with avascular necrosis, although they do not alter disease progression, as recommended by the American Society of Anesthesiologists 9

For younger patients with dysplasia or varus/valgus deformity, osteotomy and other joint-preserving procedures should be considered, according to the European League Against Rheumatism 10
Cemented arthroplasty improves hip function and is associated with lower residual pain compared to uncemented arthroplasty, especially in elderly patients, as reported by the American Society of Anesthesiologists 9, 11

Protected weight-bearing is recommended for patients with pre-symptomatic avascular necrosis with MRI changes only, as suggested by the American Society of Anesthesiologists 11
Osteotomy may be considered for young patients with specific anatomical abnormalities, such as dysplasia or varus/valgus deformity, according to the European League Against Rheumatism 10

HIV infection and antiretroviral therapy have been associated with an increased risk of avascular necrosis (AVN) 12

Radiography should be performed as the initial imaging study for suspected AVN to exclude other causes of pain such as fracture, primary arthritis, or tumor, according to the American College of Radiology 13, 14
Radiographs are less sensitive for detection of early AVN but can show findings of secondary osteoarthritis in late-stage disease, as noted by the American College of Radiology 13
Anteroposterior, lateral, and oblique views are recommended to exclude subchondral collapse in cases of epiphyseal osteonecrosis, as suggested by the American College of Radiology 13

The American College of Radiology recommends CT without contrast for determining the extent of necrosis, which is the main determining factor in outcome, particularly in Freiberg's infraction 15, 16
CT is well-suited to assess trabecular bridging at fracture sites, nonunion, malunion, and the sclerosis and fragmentation of avascular necrosis, according to the American College of Radiology 16
Bone scintigraphy has been largely replaced by MRI due to poor spatial resolution, low specificity, and inability to quantify the size of necrotic lesions, as stated by the American College of Radiology 13, 14
Single-photon emission CT (SPECT) may improve the accuracy of bone scintigraphy but is not commonly performed for detection of AVN, as noted by the American College of Radiology 13