Larsen grades in evaluating the first carpometacarpal joint

Objective To illustrate different Larsen grades for CMC I. Methods In the Heinola Follow-up Survey of Arthritis 103 seropositive patie nts with rheumatoid arthritis (RA) were followed prospectively over 20 year s. Hand radiographs were taken at onset and at 1, 3, 8, 15, and 20 years fr om entry. One female patient was selected to demonstrate Larsen grades for CMC I, as she presented all the different grades of destruction during the progression of RA. Interobserver and intraobserver errors in grading of CMC I were tested. Results Radiographs of the different grades with schematic presentation are illustrated. Interobserver and intraobserver errors were in the Weighted K appa test 0.75 and 0.82, respectively. Conclusion We emphasise the importance of following the destruction of CMC I separate from the entire carpus during the course of RA.