Patient selection: childhood-onset SLE (onset prior to 18th birthday)
Outcome: symptomatic avascular necrosis (AVN). MRI can detect AVN in more patients but this can be asymptomatic.
Presentation of symptomatic AVN:
(1) rapid onset of swelling in 1 or more large joints
(2) groin pain
(3) joint pain out of keeping with current disease activity level
(4) restricted range of joint movement
Risk factors for symptomatic AVN:
(1) major organ involvement (CNS, nephritis)
(2) higher maximal daily dose of prednisone in mg/kg (0.89 to 1.61 with AVN, 0.18 to 1.24 without AVN)
95% of patients with AVN after the onset of puberty.
Most patients with symptomatic AVN had symptoms in 2 or more sites. Hips, knees and ankles were the most commonly affected joints.
