When is surgery indicated for avascular necrosis?

From the Guidelines

Surgery is indicated for avascular necrosis when the necrotic volume of epiphyseal osteonecrosis is greater than 30%, or when there is evidence of subchondral fracture, secondary osteoarthritis, or articular collapse, as these conditions are associated with a high risk of disease progression and poor outcomes 1.

Indications for Surgery

The decision to proceed with surgery for avascular necrosis depends on various factors, including the stage of the disease, the location and size of the necrotic lesion, and the patient's symptoms and overall health.

• Early surgical intervention is often recommended for patients with moderate to severe symptoms or those with evidence of femoral head collapse on imaging.
• Core decompression is typically used for early-stage disease (Ficat stages I-II) to reduce intraosseous pressure and improve blood flow 1.
• For more advanced disease with femoral head collapse (Ficat stages III-IV), joint-preserving procedures like osteotomy or vascularized bone grafting may be considered in younger patients.
• Total joint replacement becomes necessary when significant joint destruction has occurred, offering reliable pain relief and functional improvement.

Disease Staging and Surgical Options

The Ficat and Arlet staging system, as well as other systems like the University of Pennsylvania (Steinberg), Association Research Circulation Osseous (ARCO), and Japanese Orthopedic Association systems, can be used to guide surgical decision-making 1.

• Patients with a necrotic angle <90 in the humeral head may not require immediate surgery, as the risk of collapse is lower 1.
• However, patients with a necrotic volume >30% in the femoral head are at high risk of collapse and may benefit from early surgical intervention 1.

Importance of Early Diagnosis and Treatment

Early diagnosis of osteonecrosis is crucial to prevent articular collapse and the need for joint replacements 1.

• Imaging plays a critical role in preoperative planning and staging of the disease.
• Patients should be aware that conservative measures like protected weight-bearing and medications may temporarily manage symptoms but typically do not halt disease progression, making surgical evaluation important when pain persists or function deteriorates despite non-operative management.

From the Research

Indications for Surgery in Avascular Necrosis

Surgery is indicated for avascular necrosis (AVN) in certain stages and conditions, as outlined below:

• Up to ARCO stage III, joint-preserving surgery can be performed 2
• Core decompression is recommended for stage ARCO I (reversible early stage) or stage ARCO II (irreversible early stage) with medial or central necrosis with an area of less than 30% of the femoral head 2
• For ARCO stage III with infraction of the femoral head, core decompression can be used for short-term pain relief 2
• In ARCO stage IIIC or stage IV, core decompression should not be performed, and the indication for implantation of a total hip replacement should be checked 2

Factors Influencing Surgical Outcomes

The outcomes of surgical treatment for AVN can be influenced by various factors, including:

• The extent of necrosis 2
• The presence of avoidable risk factors, such as corticosteroids, smoking, alcohol consumption, blood pressure elevation, and hypercholesterolemia 3
• The patient's age, with younger patients being at higher risk for revision 2
• The underlying disease, with certain conditions such as sickle cell disease, Gaucher disease, or kidney transplantation associated with higher revision rates 2

Alternative Treatment Options

Conservative management, including bisphosphonates, Hyper Baric Oxygen Therapy (HBOT), Extracorporeal Shock Wave Therapy (ESWT), and electrical stimulation modalities like Pulsed Electro Magnetic Field (PEMF), can be considered for early stages of AVN 4

• Bisphosphonates are easily available, cost-effective, and do not require hospital resources, making them a potential initial line of treatment for patients with early stages of AVN 4

Surgical Techniques

Various surgical techniques, including core decompression, osteotomies, and total hip replacement, can be used to treat AVN 2, 5, 6

• Core decompression with cancellous bone grafting is a safe and effective procedure for the treatment of early AVN of the femoral head 5
• Multiple small drilling and adjunctive therapeutics, such as tantalum rods, bone-grafting, and orthobiologic, have been studied as alternative techniques 6