Management of Osteonecrosis of the Humeral Head

Initial Diagnostic Approach

The American College of Radiology recommends beginning with plain radiographs to exclude other causes of shoulder pain, though radiographs are less sensitive for early osteonecrosis 1
MRI is the gold standard for early detection and staging of osteonecrosis, as it can identify disease before radiographic changes appear and quantify the size of the necrotic lesion 1
CT imaging is essential for surgical planning when intervention is considered, showing precise location and extent of the necrotic lesion 2

Lesion size is the most critical prognostic factor, with lesions involving <30% of the humeral head having <5% progression to collapse, while lesions >30% have 46-83% risk of progression 3
Risk factors that worsen prognosis include corticosteroid therapy, alcohol use, HIV, blood dyscrasias, chemotherapy, radiation, age >40 years, BMI >24 kg/m², joint effusion, and increased bone marrow edema 1, 3
Screening for bilateral disease is necessary, as 70-80% of nontraumatic cases are bilateral 3
Assessment for multifocal involvement is also necessary, as osteonecrosis can affect multiple sites including knee, ankle, and hip 3

The American College of Radiology recommends noninvasive therapy as the first line of treatment for early-stage disease, though supporting data remains limited 1
Core decompression is the surgical intervention of choice for early-stage disease when conservative measures fail, with success rates of 94% for Stage I and 88% for Stage II disease 1
Arthroplasty is the definitive treatment for advanced disease, with hemiarthroplasty for late-stage osteonecrosis with articular collapse but preserved glenoid, and total shoulder arthroplasty for severe secondary osteoarthritis involving both humeral head and glenoid 1

Early detection is crucial, as delay in diagnosis can lead to articular collapse and reduce treatment options 1, 3
Core decompression should not be performed on Stage IV disease, as success rates are poor (14%) and arthroplasty is indicated 1
Evaluation of the contralateral shoulder is necessary, as bilateral involvement occurs in 70-80% of nontraumatic cases 3
MRI is necessary for detection of early disease, as radiographs are less sensitive 1