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Case Reports

Abstract

Hyaluronic acid (HA) is widely used for dermal augmentation and as a viscosupplement for osteoarthritis treatment. While typically well-tolerated, common adverse effects include localized pain and swelling. Vascular embolization is a well-recognized rare complication of dermal fillers, however, reports of HA embolization following intraarticular injections remain scarce. A 75-year-old woman presented with a non-healing necrotic wound on her right knee six weeks after receiving an intraarticular HA injection for osteoarthritis. Four days post-injection, she developed a painful, violaceous rash on the lateral knee, which progressed to ulceration. On examination, two necrotic eschars (1.5 × 1.0 cm) were noted on a background of retiform purpura with significant tenderness. Clinically, necrosis secondary to vascular infiltration of HA, vasculitis, and calciphylaxis were considered. Skin punch biopsy revealed basophilic amorphous nonpolarizable foreign material within the channels of small-caliber vessels in the dermis and subcutis. The findings were consistent with HA filler induced vascular occlusion. Von Kossa stain was negative, ruling out calciphylaxis. The proposed mechanisms for HA embolization following intraarticular injections are retrograde flow and inadvertent vascular entry. The clinical presentation of HA embolization includes livedo reticularis, pain, and necrosis, which often mimic vasculopathy or coagulation disorders. Histopathologic recognition is crucial, as HA intravascular emboli may be subtle and easily missed. Given the increasing use of HA injections for osteoarthritis, the awareness of this rare complication is prudent to ensure timely management.