Clinical profile of osteonecrosis in systemic lupus erythematosus – Experience from a tertiary care centre in South India

INTRODUCTION: Osteonecrosis or Avascular necrosis of bone (AVN) is a well recognized complication of systemic lupus erythematosus (SLE) leading to significant morbidity. METHODS: We did a cross sectional descriptive study in cohort of SLE patients, on regular follow-up at our Rheumatology OPD over a period of 5 years from 2012 to 2017. RESULTS: Of the total 415 SLE, 5.1% (n = 21) patients were diagnosed to have osteonecrosis. The mean age was 32.8 ± 7.6 years. Male: female were 1:4.2. Mean time interval between the onset of SLE and diagnosis of osteonecrosis was 4.1 ± 2.7 years. Pain (100%) was the most common presenting symptom followed by limping gait (42.8%). Most common site affected by osteonecrosis was femoral head (80.9%) (n = 17). 14.3% (n = 3) had multifocal involvement. The most common systemic involvement was musculoskeletal system (80.9%). In total 28.5% had secondary antiphospholipid syndrome. Mean SLEDAI-2K at the time of diagnosis of osteonecrosis was 5.3 ± 2.9. Hypertension 19%, hypothyroidism 9.5%, osteoporosis 24%, and chronic HCV infection 4.7% were the associated comorbidities. The most common stage by imaging at diagnosis was stage IV (38%), followed by 24% stage V, 19% stage III and 9.5% stage II and 9.5% stage VI. Medical management include bisphosphonates (100%), statins (90.4%) and anticoagulant therapy (28.5%), while 9.5% received core decompression surgery and 14.3% underwent total hip replacement. The mean daily dose of prednisolone at diagnosis of osteonecrosis was 8.5mg (range 5–20mg). CONCLUSION: This study described the prevalence and epidemiology of osteonecrosis in our cohort of SLE patients.