[Diagnostic accuracy of conventional X-ray imaging for assessment of trapeziometacarpal joint osteoarthritis]. / Genauigkeit der konventionellen Röntgendiagnostik bei der Beurteilung der Daumensattelgelenkarthrose.

BACKGROUND: Osteoarthritis of the trapeziometacarpal joint is a common and painful affliction that can be diagnosed using conventional X­ray imaging as well as arthroscopy and if necessary treated; however, the X­ray 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 X­ray imaging compared to arthroscopy for osteoarthritis of the trapeziometacarpal joint. MATERIAL AND METHODS: The preoperative conventional X­ray 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 X­rays. 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 X­ray 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.