Thanks for posting your query.
The second fall might have injured your already osteopenic bone.
The air bubble like sensation is called crepitus and indicates fracture
or severe ligament injury
I would like you to get a review to your orthopedician and tell you problem as such. A good local physical examination and repeat Xray would help in diagnosis and management.
I hope this answers your query.
In case you have any follow up queries or doubts, you can forward them for me, and I shall be glad to help you.
Please accept my answer in case you do not have further queries.
Wishing you good health.