The panel is now urging the FDA to add a special alert to that effect on the drugs' labeling.
The drugs, known as bisphosphonates, were first approved for the treatment of osteoporosis in 1995.
Millions of people, mostly women, have been treated with them.
The panel says the threat of these fractures is very unusual but there is still concern patients could have them.
The findings are published in the Journal of Bone and Mineral Research.
The FDA says it is now considering label revisions.
