Erosive inflammatory osteoarthritis (EIOA) sits in uncomfortable territory between two well-mapped diseases. It shares the mechanical wear of classical osteoarthritis but also carries the synovial inflammation more typical of rheumatoid disease.

If you have been diagnosed with localized nodular tenosynovitis (LNTS), you have probably already heard the standard narrative: it is a benign tumor of the tendon sheath, surgery is the answer, and there is not much else to discuss.