31 Osteonecrosis: prevention and treatment

Osteonecrosis (ON) is a well-known component of damage accrual in patients with systemic lupus erythematosus (SLE), it frequently causes disability and considerably affects patients’ quality of life. The increased incidence of ON in SLE patients as compared to the general population, patients with other autoimmune diseases, or diseases requiring high doses of corticosteroids (CS) suggest that the disease itself and/or the underlying genetic background of the patients might dictate the susceptibility in its occurrence.1–5 Several modifiable risk factors have been associated with an increased risk of ON, such as alcohol intake, cigarette smoking, high triglyceride levels, and heavy physical work. The use of CS has been recognized as a major risk factor for the development of ON. The average daily dose of CS, its highest dose, and the total cumulative CS dose, as well as the use of pulse therapy, and the presence of Cushingoid appearance have all been associated with ON. The prevalence of ON in patients with SLE ranges between 5–15% but it may be as high as 40% when patients with silent patterns are included. The clinical presentation of ON is variable, being related to the size and location of the affected bone(s). The hip and knee are the most frequently affected joints followed by ankle and shoulder. Multifocal ON has been reported in up to half of patients with SLE. The early diagnosis of ON is challenging because it frequently occurs silently; there is often a time lag between the development of ON and the onset of symptoms. Preventing ON involves controlling modifiable risk factors. Corticosteroids, if needed, should be prescribed at the lowest possible dose and for the shortest period of time, regardless of patient’s disease manifestations. Anticoagulant therapy, and statins/lipid-lowering drugs, may reduce the incidence of CS-induced ON. The therapeutic approach depends largely on the joint involved and the extent of the injury. Immobilization has a role for small lesions that will spontaneously heal. Various medications have been used anecdotally with some benefit, including lipid-lowering drugs, anticoagulants, vasodilators, and bisphosphonates. Stem cell treatment of femoral head ON has been reported as useful therapy; however, this therapeutic approach has not been standardized and will need to be studied further. The type of surgical therapy is based on the severity of joint damage. For early ON, core decompression and percutaneous debridement and drilling is recommended. For ON lesions prior to bone collapse, bone grafting and osteotomies are also a possibility. Once subchondral fracture collapse is evident, bone grafting, hemi-resurfacing and total hip arthroplasty are the treatment options. Learning Objectives Describe the epidemiology and clinical presentations of ON in patients with SLE Explain the modifiable and non-modifiable risk factors for ON in patients with SLE Discuss the preventive measures for ON in patients with SLE Describe how patients with SLE and ON should be treated References Gurion R, Tangpricha V, Yow E, et al. Avascular necrosis in pediatric systemic lupus erythematosus: a brief report and review of the literature. Pediatric Rheumatol. 2015;13:13-. Gladman DD, Dhillon N, Su J, Urowitz MB. Osteonecrosis in SLE: prevalence, patterns, outcomes and predictors. Lupus. 2018;27(1):76–81. Nawata K, Nakamura J, Ikeda K, et al. Transitional changes in the incidence of osteonecrosis in systemic lupus erythematosus patients: focus on immunosuppressant agents and glucocorticoids. Rheumatology (Oxford). 2018;57(5):844–9. Hussein S, Suitner M, Beland-Bonenfant S, et al. Monitoring of Osteonecrosis in Systemic Lupus Erythematosus: A Systematic Review and Metaanalysis. J Rheumatol. 2018;45(10):1462–76. Kallas R, Li J, Petri M. Predictors of osteonecrosis in systemic lupus erythematosus: A prospective cohort study. Arthritis Care Res (Hoboken). 2020.