Surgical fixation for rheumatoid arthritis of the feet. Coloured lateral X-ray of screws and pins used in surgical fixation of the foot joints of a 52-year-old woman with rheumatoid arthritis. Rheumatoid arthritis is a degenerative autoimmune disease that mainly affects the capsule (synovium) around the synovial (flexible) joints, causing chronic inflammation. It can be a debilitating and painful condition and can lead to deformities and loss of functioning and mobility. Here, surgical fixation has been used to restore some function.