Osteonecrosis and antiphospholipid syndrome

Area of Science:

• Orthopedics
• Rheumatology
• Hematology

Background:

• Osteonecrosis (ON), or avascular necrosis of bone, is often linked to reduced blood flow and associated with various systemic and local factors.
• Commonly implicated factors include corticosteroid therapy, systemic lupus erythematosus (SLE), alcohol abuse, and hypercoagulability states.
• The pathogenesis of ON is multifactorial, involving compromised bone vascularity.

Observation:

• A previously healthy young male presented with osteonecrosis of the femoral head, subsequently developing ON in the humeral head.
• This patient had no history of corticosteroid use or other typical risk factors for ON.
• Diagnostic workup revealed high levels of anticardiolipin antibodies (aCL), beta-2-glycoprotein 1 antibodies, and a positive lupus anticoagulant.

Findings:

• The patient's clinical presentation and laboratory findings were consistent with primary antiphospholipid syndrome (PAPS).
• The development of ON in the absence of other known risk factors in this patient suggests a potential association with PAPS.
• Antiphospholipid antibodies may contribute to ON pathogenesis through mechanisms such as thrombotic microangiopathy.

Implications:

• This case contributes to the controversial association between primary antiphospholipid syndrome (PAPS) and osteonecrosis (ON).
• It suggests that PAPS, potentially via thrombotic microangiopathy, could be an independent risk factor for ON in select individuals.
• Further research is warranted to elucidate the precise mechanisms linking PAPS to ON and to identify patients at risk.