Prevalence and Associated Factors for Primary Osteoarthritis of the Scaphotrapeziotrapezoid, Radiocarpal, and Distal Radioulnar Joints in the Japanese General Elderly Population.

Purpose: The incidence and etiology of primary osteoarthritis (OA) of the scaphotrapeziotrapezoid joint (STTJ), radiocarpal joint (RCJ), and distal radioulnar joint (DRUJ) remains unknown. The purpose of this study was to evaluate the prevalence and factors associated with primary wrist OA in a cross-sectional study of a basic resident registry.

Methods: A total of 1,297 residents between the ages of 50 and 89 years were randomly sampled from the registry of a Japanese town. A questionnaire was administered to all subjects, and each of them underwent radiographs of the bilateral hands, wrists, and elbows. STTJ, RCJ, and DRUJ radiographic osteoarthritis (ROA) were evaluated according to a previously described method. Associated factors for STTJ and DRUJ ROA were recorded. Associations between the incidence of ROA of the DRUJ, ulnar variance, and severity of elbow ROA were investigated.

Results: A total of 676 wrists (162 men and 176 women; mean age of 69.0 years) were investigated. The prevalence of STTJ, RCJ, and DRUJ ROA was 5.3%, 1.5%, and 21.2%, respectively. Factors associated with STTJ ROA were thumb carpometacarpal joint ROA, female sex, and increasing age. Factors associated with DRUJ ROA were elbow ROA, use of vibrating tools, increasing age, and positive ulnar variance. Prevalence of DRUJ ROA was 54.4% in wrists with severe-grade elbow ROA. Ulnar variance of the wrist in severe-grade elbow ROA was significantly larger than that in mild-grade or nonelbow ROA.

Conclusions: The prevalence of ROA was highest in the DRUJ, followed by the STTJ, and lowest in the RCJ. The occurrence of ROA of the STTJ and DRUJ was affected by the presence of ROA of the adjacent joint.

Clinical relevance: Primary DRUJ ROA occurs at a moderate frequency, similar to primary ROA of other extremity joints; however, primary STTJ and RCJ ROA is rare.