From the Guidelines
Avascular necrosis, also known as osteonecrosis, is a condition that requires prompt medical attention to prevent disease progression and improve outcomes, with early diagnosis and treatment being crucial to prevent articular collapse and the need for joint replacements. Avascular necrosis is defined as bone death due to inadequate vascular supply, and it is sometimes also called “aseptic necrosis” when involving epiphysis or “bone infarct” when involving metadiaphysis 1. Common sites include the femoral head, humeral head, tibial metadiaphysis, femoral metadiaphysis, scaphoid, lunate, and talus 1.
The condition develops when blood flow to a section of bone is interrupted, causing the bone tissue to die and eventually collapse. Common causes include:
- Traumatic injury
- Long-term use of high-dose steroids
- Excessive alcohol consumption
- Certain medical conditions like HIV, lymphoma/leukemia, blood dyscrasias, chemotherapy, radiation therapy, Gaucher disease, and Caisson disease 1. Symptoms typically begin with joint pain that worsens with weight bearing and may eventually lead to severe pain even at rest.
Treatment depends on the stage of the disease and may include:
- Medication for pain management
- Physical therapy to maintain joint mobility
- Surgical interventions such as core decompression, bone grafting, or joint replacement in advanced cases 1. Early diagnosis is crucial for preventing disease progression, with imaging being important for preoperative planning and excluding other causes of patient’s pain. Risk reduction strategies include limiting alcohol consumption, avoiding high-dose steroid use when possible, and properly managing conditions that increase risk.
In terms of specific treatment options, core decompression can be performed in various locations, including the femoral head, humeral head, and talus, and can be supplemented with injection of autologous bone marrow cells, vascular fibular grafting, or electric stimulation 1. However, the overall efficacy of core decompression at preventing eventual articular collapse remains controversial. For late-stage femoral or humeral head osteonecrosis with articular collapse, resurfacing hemiarthroplasty may be needed, whereas total joint arthroplasty is performed in cases of severe secondary osteoarthritis 1.
Overall, avascular necrosis requires a comprehensive treatment approach that takes into account the stage of the disease, the location of the affected bone, and the patient's overall health status, with the goal of preventing disease progression and improving outcomes 1.
From the Research
Definition and Treatment of Avascular Necrosis
- Avascular necrosis (AN) is a condition characterized by the death of bone tissue due to a lack of blood supply 2.
- The treatment of AN aims to improve blood support in the avascular area, but there is no uniformly accepted treatment that alleviates pain and retards its progression 2.
Surgical Treatment of Avascular Necrosis
- Joint-preserving surgery can be performed up to ARCO stage III, but a particular joint-preserving surgery cannot be recommended as a preferred method 3.
- Core decompression can be used for short-term pain relief in ARCO stage III with infraction of the femoral head, but it should not be performed in ARCO stage IIIC or stage IV 3.
- Total hip replacement is a viable option for advanced stages of avascular necrosis, with cemented and cementless fixation techniques showing comparable results 3.
Use of Bisphosphonates in Avascular Necrosis
- Bisphosphonates have been shown to prevent disease progression, bone collapse, and the requirement for surgery in avascular necrosis of the femoral head 2, 4.
- A combination of oral alendronate and intravenous zolendronic acid has been found to provide a pragmatic solution for non-femoral avascular necrosis, with significant pain relief and reduction in analgesic requirement 4.
Risk Factors and Pathophysiology of Avascular Necrosis
- Glucocorticoid use is a significant risk factor for avascular necrosis, with the cumulative dose of glucocorticoid being a determining factor 5.
- The pathogenesis of glucocorticoid-induced avascular necrosis is not fully understood, but it is thought to involve fat hypertrophy, fat emboli, and intravascular coagulation 5.
- Compromised subchondral microcirculation is a common pathophysiological pathway in osteonecrosis, with decreased femoral head blood flow occurring through various mechanisms 6.