Purpose of study: ALL is the commonest childhood malignancy and current survival rates reach 80%. Consequently adverse effects of therapy may have significant long-term implications. Treatment is risk stratified with the higher intensity regimens B and C receiving more Dexamethasone and Methotrexate, both of which are known to have significant bony effects. The skeletal morbidity associated with ALL and its treatment, particularly AVN, is being increasingly identified. AVN is rare in paediatric practice. Its pathophysiology is largely unknown, although it is probably related to corticosteroid use.

Method: The records of a series of 7 out of 53 children treated with chemotherapy for ALL as per MRC ALL 99/01 and ALL 2003 protocols in a single tertiary paediatric oncology centre were reviewed. All 7 cases (3 male) had MRI confirmation of AVN (2 normal x-rays). All cases had been treated on higher intensity chemotherapy regimens and were at least 6 months from commencement of anti-leukaemic therapy. All presented with transient limb pain.

Results: The AVN was multi-focal (median 4 sites) and was associated with significant other bony abnormalities, including joint collapse, fracture, osteomyelitis and septic arthritis. In this series the dose of steroids did not correlate with the severity of the AVN. Treatment options were limited with all cases receiving conservative treatment

Conclusions: Careful consideration must precede a recommendation to stop steroids as this may compromise leukaemic cure. Although the long-term consequences of AVN on bone health are unknown, we recommend a high index of suspicion in professionals who are treating these children to ensure prompt diagnosis.