Multifocal avascular osteonecrosis despite appropriate anticoagulation therapy in a patient with systemic lupus erythematosus and antiphospholipid syndrome.

Multifocal avascular osteonecrosis (AON) is a serious manifestation of systemic lupus erythematosus (SLE). Prothrombotic factors, especially antiphospholipid antibodies (aPL), have been associated with the development of AON; therefore, attenuating the procoagulant state while balancing the haemorrhagic risks might have a rationale when managing this condition. We report a case of a 37-year-old patient with SLE, treated with low doses of corticosteroids and immunosuppressive therapy, who was started on vitamin K antagonist following an episode of deep vein thrombosis while having persistent positivity for aPL. After 2 years, he presented with multifocal AON, involving both femurs and shoulders. The patient underwent a bilateral hip replacement, but despite appropriate anticoagulation therapy after 2 years, he developed another episode of AON at both distal epiphyses of the femurs and proximal epiphyses of the tibias. Multifocal AON should be suspected, especially in the presence of aPL positivity. Its aetiology is still unknown and is most likely multifactorial. Its management is challenging and requires combined approaches.