Dear Mrs Estavillo,
There seems to be some trouble involving the soft tissues and not the bones. It could be the ligaments, meniscus
, synovium or the joint capsule. Since X-rays are normal, the possibility of an injury
to bone can not be ruled out. To be more specific you need an MRI
done for your husband. Avoid medicines till a diagnosis is established.
Mail the MRI reports to firstname.lastname@example.org