From the Guidelines
The workup for avascular necrosis (AVN) should begin with a thorough history and physical examination, followed by plain radiographs, and then MRI as the gold standard diagnostic tool, as recommended by the most recent study 1. The diagnosis of AVN is crucial, and early detection is vital to prevent articular collapse and the need for joint replacements.
- Key risk factors to focus on during the history and physical examination include corticosteroid use, alcohol consumption, trauma, and underlying conditions like sickle cell disease or systemic lupus erythematosus.
- Plain radiographs should be obtained first, though they may appear normal in early disease, as noted in the study 1.
- MRI is the preferred method of diagnosis, especially for patients presenting with persistent hip pain who have normal standard radiologic studies, and both sides should be imaged, as suggested by the study 1.
- Additional imaging may include CT scans to assess bone architecture and bone scans to evaluate for multifocal disease.
- Laboratory tests should include complete blood count, comprehensive metabolic panel, coagulation studies, and specific tests based on suspected underlying causes, such as hemoglobin electrophoresis for sickle cell disease or antiphospholipid antibodies for autoimmune conditions.
- Bone biopsy is rarely needed but may be considered in unclear cases.
- Once AVN is diagnosed, staging is important for treatment planning, with the Ficat and ARCO classification systems commonly used to determine disease progression based on imaging findings, as discussed in the study 1.
- Early diagnosis is crucial, as treatment outcomes are significantly better when AVN is identified before collapse of the femoral head or other affected bones occurs, highlighting the importance of prompt and accurate diagnosis, as emphasized by the study 1.
From the Research
Diagnostic Approaches for Avascular Necrosis
- The diagnosis of avascular necrosis (AVN) can be achieved through various imaging modalities, including MRI, CT scans, and bone scintigraphy 2, 3, 4.
- MRI is considered the most sensitive diagnostic imaging procedure for AVN, allowing for early diagnosis and monitoring of therapy 2, 3.
- CT scans can be useful in excluding subchondral fractures and visualizing calcification and new bone formation in later stages of AVN 3, 4.
- Bone scintigraphy may be used in exceptional cases, but its use is restricted due to its lower specificity compared to MRI 2, 3.
Imaging Characteristics of Avascular Necrosis
- Early stages of AVN are characterized by localized subchondral edema, joint effusion, and necrosis of bone marrow and bone cells 4.
- Later stages of AVN may demonstrate calcification, new bone formation, and microfractures, which can be visualized using plain X-rays and CT scans 4.
- The use of contrast-enhanced MRI can help outline the number of repair mechanisms and return of fatty marrow 4.
Treatment and Management of Avascular Necrosis
- Early detection and treatment of AVN are crucial to prevent progression of the disease and improve outcomes 2, 5.
- Treatment strategies for AVN may include conservative approaches, surgical interventions, and emerging therapies such as regenerative therapies 5.
- A multidisciplinary approach involving orthopaedic specialists, rheumatologists, and physical therapists is recommended for the management of AVN 5.
- Percutaneous vertebroplasty (PVP) has been shown to be an effective and safe procedure for the treatment of avascular necrosis of the vertebral body, providing quick pain relief 6.