Osteoarthritis: with emphasis on primary osteoarthritis of the shoulder

Fifty-three shoulders in 35 patients were found to have osteoarthritis (OA) of the shoulder using radiographic criteria to establish the diagnosis. Thirty of these shoulders did not exhibit any predetermined signs of secondary OA and were labeled primary OA. The average age of the patients was 79 years. This article discusses OA, with special emphasis on primary OA of the shoulder. Primary OA of the shoulder appears to occur in older individuals and may not be as rare as many observers have stated.