Enthesopathy as you correctly defined is inflammation where the tendons and ligaments attach onto bone. It commonly affects areas such as the achilles tendon insertion onto the heel or the plantar fascia insertion on the heel. It is a feature of the seronegative spondyloarthroapthies whihc include ankylosing spondylitis, psoriatic arthritis, reactive arthritis (Reiter’s) and enteropathic arthritis. The inflammation causes calcification in these areas, and rarely causes bony erosions. The calcifications on the tendons can cause the popping or grating sensation that you describe. Unlike the studies with RA, there have not been formal studies with medications on prevention of erosions and joint damage in these diseases. But, presumably, drugs like methotrexate, and the TNF inhibitors will be disease modifying in these diseases similar to their role in RA.
About Alan Matsumoto, M.D.
Part-time Faculty, Division of Rheumatology
Johns Hopkins University