Hey Esther-
There has been a ton of recent research suggesting that osteonecrosis can be a rare side effect to bisphosphonate (the class of drugs zometa belongs to) use.
Just go to pubmed and type in zoledronic+osteonecrosis and you'll find stuff like:
http://www.ncbi.nlm.nih.gov/entrez/query.f...7925&query_hl=1
all the best,
Jeff