Is avascular necrosis painful?

Avascular Necrosis and Pain

Yes, avascular necrosis is typically painful, particularly when it progresses to later stages with subchondral fracture and articular collapse, often requiring surgical intervention for disabling symptoms. 1

Pain Presentation and Progression

Avascular necrosis (also called osteonecrosis) presents with varying pain patterns depending on the stage of disease:

• Early stages:

  • May be asymptomatic in approximately 5% of patients 1
  • When symptomatic, presents as pain in the affected joint (commonly hip)
  • Pain may be insidious in onset as edematous bone marrow develops 2

• Advanced stages:

  • Pain becomes severe and persistent
  • Weight-bearing becomes difficult or impossible when involving the hip
  • Pain is often the trigger for diagnostic imaging studies 1

Anatomical Considerations

The location of avascular necrosis affects pain presentation:

• Hip (femoral head): Most common site (>75% of cases), with pain typically in the groin, buttock, or referred to the knee 3
• Other common sites: Humeral head, knee, scaphoid, lunate, and talus 1
• Weight-bearing joints: Generally more symptomatic due to mechanical stress

Diagnostic Approach for Painful Avascular Necrosis

MRI is the preferred diagnostic method for detecting avascular necrosis, especially in early stages when X-rays may appear normal 4, 5:

• Should be performed in young patients with unexplained joint pain and normal X-rays 3
• Can detect early bone marrow edema before structural collapse
• Allows staging and assessment of lesion size/location, which correlates with prognosis 5

Pain Management

Pharmacological Management

1. First-line analgesics:

   • Regular paracetamol (acetaminophen) administration 4
   • NSAIDs with caution, especially in elderly or those with renal dysfunction 4

2. Advanced pain control:

   • Opioids for severe pain, used cautiously with reduced dosing in renal dysfunction 4
   • Avoid codeine due to side effects including constipation 4

Disease-Modifying Approaches

1. Bisphosphonates:

   • May improve bone density and prevent progression 4
   • Require calcium and vitamin D supplementation 4

2. Monitoring:

   • Regular assessment of pain response to treatment
   • Vigilance for complications like expanding hematoma or infection 4

Surgical Interventions for Painful Avascular Necrosis

Surgical options depend on disease stage:

• Early stages (Ficat stages I-II): Joint-preserving procedures may be considered 3

  • Osteotomy in young adults with symptomatic hip avascular necrosis 4

• Advanced stages (Ficat stages III-IV):

  • Total joint replacement for patients with refractory pain and disability 4
  • Currently the most definitive treatment for severe pain 6

Special Considerations

• HIV patients: Diagnoses of osteonecrosis are usually made when imaging studies are performed in response to patient's complaints of pain 1

• Post-transplant patients: Avascular necrosis can cause severe pain, often requiring surgery for disabling symptoms 1

• Sickle cell disease: AVN is one of the most common causes of severe chronic pain in this population 6

Pitfalls in Management

• Delayed diagnosis: Pain may be attributed to other causes, especially when X-rays are normal
• Asymptomatic disease: Remember that 5% of cases may be asymptomatic despite MRI findings 1
• Multifocal involvement: Pain in one joint should prompt consideration of other affected sites
• Limited treatment options: Current therapeutic approaches for pain control remain suboptimal, particularly in conditions like sickle cell disease 6

Physical therapy and gentle mobilization should be encouraged once acute pain subsides to restore normal gait and function 4.