Cup arthroplasty of the rheumatoid shoulder.

Hemiarthroplasty of the humeral head, using a stainless steel cup, was performed in 26 shoulders of patients with rheumatoid arthritis who had severe pain and loss of function. All the shoulders were Larsen's radiographic Grade 4 or 5. After 2 (1-5) years, all the shoulders were painless and had satisfactory function. Partial radiolucent zones exceeding 1 mm were seen in three shoulders.