Rheumatoid arthritis in Singapore: carpal predominance and lower incidence of erosive changes

Radiographs of the hand and wrists in 33 patients with a diagnosis of classic or definite rheumatoid arthritis were reviewed. The mean duration of disease was about five years. A scoring system for quantitative analysis was used to assess the presence and severity of erosions, joint space narrowing and deviation of joint alignment. No radiological abnormality was seen in 30% of patients while in another 30%, only minor radiological changes were seen. Moderate to severe radiological abnormality was seen in only 40% and in this group of patients all showed more severe disease in the wrists than in the finger joints. Erosions in the fingers were only seen in 21% of patients and erosions in the wrists were present in 57%. Previous reports have indicated that disease in the wrists can be more severe than the hands in up to 60% while the incidence of erosions can be expected to range from 40% at 3 months to 95% at 10 years. Although the sample size in this study is small, the findings suggest that the radiological pattern of rheumatoid in the hands in Singapore is quite different from that classically described in temperate countries as the incidence of erosions appears lower while disease in the wrists can be expected to be more severe than in the fingers in almost all cases. The usual radiological criteria used to aid diagnosis of the disease may not be applicable.