Bone Abstracts

Background: Osteonecrosis (ON) has emerged as a debilitating complication of acute pediatric lymphoblastic leukemia (pALL), with severe pain and poor functional outcome. ON affecting weight bearing joints may eventually need arthroplasty, with large juxta-articular lesions being at highest risk. Intravenous Pamidronate (IV-PAM) is postulated to reduce pain and prevent joint collapse in ON.

Objective: To study if IV-PAM was effective in 1) preventing joint ON progression and need for surgical intervention and in 2) reducing ON related pain in pALL.

Methods: All consecutive pALL patients (0–18 years) who developed bone pain were assessed for ON with a whole body MRI (WB-MRI). Patients with confirmed ON received two 9-month courses (induction and maintenance) of once/monthly IV-PAM (first dose 0.5 mg/kg; all others 1 mg/kg per dose; maximum dose 11.5 mg/mg per year). Visual analogue score for pain (VAS), with ‘0’ being ‘no-pain’ and ‘10’ being ‘the worst possible pain’ was administered at baseline, 3, 6 and 12 months and yearly. The radiologic outcome was assessed by serial WB-MRIs.

Results: Out of 40 pALL patients referred for assessment of bone pain, all had osteoporosis and 24/40 had ON (9F:15M). ON was multisite in 24/24; with 10/24 having upper limb and 20/24 having lower limb lesions. ON affected 26 large joints (shoulders [10], hips [4] and knees [12]). Four hips, knees and ankles had >50% articular surface involvement by ON. The mean duration of follow-up was 7 (range 3–15) years. None of the large joint ON required surgery: two femoral heads developed minor collapse, while other ON lesions remained stable or resolved. The mean pain VAS pre-pamidronate was 8.5/10 (range 8–10/10; 0.1/10 (range 0–1/10) at 6 months, and unchanged at 0. 08/10 (range 0–1/10) at 12 months and at final follow-up.

Conclusions: Our results suggest that IV-PAM is effective in controlling ON related pain and may prevent joint ON progression and orthopedic surgery.

Disclosure: The authors declared no competing interests.