From the Guidelines
The management of vascular necrosis, also known as osteonecrosis or avascular necrosis, should prioritize early diagnosis and treatment to prevent articular collapse and the need for joint replacements, with core decompression and bone grafting being potential invasive therapies for early-stage disease. The condition is defined as bone death due to inadequate vascular supply, with possible mechanisms including vascular interruption, occlusion, or extravascular intraosseous compression 1. Common sites of osteonecrosis include the femoral head, humeral head, tibial metadiaphysis, and talus, with risk factors such as trauma, corticosteroid therapy, alcohol use, and HIV 1.
Causes and Risk Factors
The exact pathophysiology of osteonecrosis is unknown, but it is thought to be a common condition affecting adults in their third to fifth decades of life, with an incidence of 10,000 to 20,000 new symptomatic cases per year in the United States 1. The true prevalence is likely underestimated due to many asymptomatic cases, particularly in metadiaphyseal locations 1. Risk factors for osteonecrosis are numerous and include:
- Trauma
- Corticosteroid therapy
- Alcohol use
- HIV
- Lymphoma/leukemia
- Blood dyscrasias
- Chemotherapy
- Radiation therapy
- Gaucher disease
- Caisson disease
Diagnosis and Staging
Early diagnosis of osteonecrosis is crucial to exclude other causes of pain and to allow for possible early surgical prevention 1. Imaging is important for preoperative planning, and many staging systems have been developed, including the Ficat and Arlet system, which remains the most commonly used 1. Other systems, such as the University of Pennsylvania (Steinberg), Association Research Circulation Osseous (ARCO), and Japanese Orthopedic Association systems, may also be used 1.
Management
Noninvasive therapy for osteonecrosis has limited supporting data, including statins, bisphosphonates, anticoagulants, extracorporeal shock wave therapy, and hyperbaric oxygen 1. Invasive therapies aim to prevent articular collapse and delay or prevent the need for joint replacement. 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 remains controversial 1. For late-stage femoral or humeral head osteonecrosis with articular collapse, resurfacing hemiarthroplasty or total joint arthroplasty may be necessary 1.
From the Research
Causes of Avascular Necrosis
- Avascular necrosis is an ischemic or cytotoxic necrosis of epiphyseal bone, responsible for joint pain, altered life quality and frequently affecting young patients 2
- Risk factors for avascular necrosis include corticosteroid treatment, hypercholesterolemia, sickle cell disease or alcohol abuse 2
- Direct vascular disruption, intravascular obliteration, or extravascular compression are factors that can contribute to avascular necrosis 3
Management of Avascular Necrosis
- MRI imaging is the main exploration for the diagnostic and staging of the disease, and should be performed in unexplained hip pain in young patients with normal X-rays 2
- In the earlier stages of the disease (stage I and II of the Arlet and Ficat classification), joint surface is preserved, and conservative treatment is recommended 2
- In the more advanced stages (III and IV of the Arlet and Ficat classification), the articular surface collapses and joint arthroplasty is the main treatment 2
- Joint-preserving surgery can be performed up to ARCO stage III, but a particular joint-preserving surgery currently cannot be recommended as preferred method 4
- Core decompression performed in stage ARCO I or stage ARCO II with medial or central necrosis with an area of less than 30 % of the femoral head shows better results than conservative therapy 4
- Bisphosphonates have been shown to prevent disease progression, bone collapse, and the requirement for surgery in avascular necrosis of femoral head 5, 6
- A combination of oral alendronate and intravenous zolendronic acid provides a pragmatic solution to non-femoral avascular necrosis, where no standard treatment exists 6
Treatment Options
- Joint arthroplasty is the main treatment for advanced stages of avascular necrosis 2, 4
- Core decompression, osteotomies, and bone grafting are other treatment options for avascular necrosis 4
- Bisphosphonate combination therapy is a potential treatment option for non-femoral avascular necrosis 6
- Mesenchymal stem cells may contribute to improve the bad functional prognosis of the disease in the future 2