Precision of the Larsen and the Sharp methods of assessing radiologic change in patients with rheumatoid arthritis

Abstract

Objective: To compare the sensitivity of Sharp's and Larsen's radiographic scoring methods for detecting change in rheumatoid arthritis (RA) over time.

Methods: Radiographs of the hands and wrists were taken at the beginning and at the end of a 2-year followup period, in 42 patients with active RA. Films were scored blindly using both scoring methods. Patients were under treatment with methotrexate (intramuscular injections).

Results: Radiographic evidence of progression or amelioration was detected in 25 patients by Larsen's method and in 35 patients by Sharp's method. The relative sensitivity to change over time was greater for Sharp's method (0.01 less than P less than 0.025).

Conclusion: Sharp's radiographic scoring method seems to be more sensitive to change over time than is Larsen's method. The clinical importance of the change needs to be definitively established.