LAUSR

BACKGROUND Osteoarthritis of the trapeziometacarpal joint is a common and painful affliction that can be diagnosed using conventional X‑ray imaging as well as arthroscopy and if necessary treated; however, the X‑ray classification often does not sufficiently demonstrate the cartilage damage found in arthroscopy. OBJECTIVE The aim of the study was to evaluate the diagnostic accuracy of conventional X‑ray imaging compared to arthroscopy for osteoarthritis of the trapeziometacarpal joint. MATERIAL AND METHODS The preoperative conventional X‑ray images of 23 patients were presented to 10 experienced hand surgeons who were blinded to the arthroscopy results. Their ratings were compared to the results found with arthroscopy. RESULTS Of the patients 11 were found to have grade 4 cartilage lesions according to the Outerbridge classification, 8 grade 3 lesions, 4 grade 2 lesions and no grade 1 lesions. Overall, 43% (95% confidence interval, CI 37-49%) of the cartilage lesions were diagnosed correctly using conventional X‑rays. For grade 4 lesions 73% (95% CI 65-81%) of the surgeons made the correct diagnosis, in the case of grade 3 lesions 38% (95% CI 27-49%) and in grade 2 lesions 13% (95% CI 3-23%). CONCLUSION This study presents an arthroscopy classification system that is specific for osteoarthritis of the trapeziometacarpal joint and provides an additional method of assessment if the X‑ray grading of osteoarthritis according to Eaton and Littler is too unspecific. Arthroscopy can be used to safely differentiate the treatment-relevant stage and also includes treatment options.