Outcomes of symptomatic osteonecrosis in 95 patients with systemic lupus erythematosus.

OBJECTIVE

To describe the frequency and type of symptomatic osteonecrosis (ON) in a large cohort of patients with systemic lupus erythematosus (SLE) followed in a single center and to describe the outcome in terms of mortality and disability compared to SLE patients without ON.

METHODS

Patients with ON were identified from the University of Toronto Lupus Clinic Database. The diagnosis of ON was confirmed by radiographs, bone scans, tomograms, or magnetic resonance images. A comparison group of patients with SLE without ON was selected from the same database, matched by year of birth, sex, and year of entry to the clinic. Mortality, disability, and health related quality of life were compared between patients with and without ON.

RESULTS

Ninety-nine patients with ON were identified with 217 affected joints, the majority hips and knees, often in a bilateral distribution. There was no increase in mortality. Patients with ON had higher Health Assessment Questionnaire scores and lower SF-20 scores of physical functioning, suggesting increased disability. Hip joints that underwent surgery were more likely to have higher grades of ON at diagnosis.

CONCLUSION

Symptomatic ON occurred in 12.8% of 744 patients with SLE and often involved multiple joints. ON was not associated with increased mortality but was associated with physical disability. Radiological class of the hip jointsat diagnosis of ON was predictive of subsequent surgery.