Rheumatoid arthritis is a chronic systemic auto-immune inflammatory disease which may affect all parts of the body but predominantly afflicts the limb joints. Despite progress in medical therapy, a high number of patients still face the destructive and deforming sequelae of the disease, in part because of a late, inadequate, or refused early pharmacological treatment. Flexible prostheses, like the Swanson, rely on the elastic properties of their material, for their performance. Surface replacement prostheses are partially able to reproduce the physiological sliding of the bony segments but require the capsulo-ligamentous structure of the joint to be in a suitably good condition. Hinged prostheses rely on their coupling mechanism to provide stability in a given range of motion, but inherent weakness of the recipient bone and incompleteness of the capsulo-ligamentous structures may cause their failure. Flexible prostheses are the option but, strictly speaking, they cannot be defined as true prosthetic devices because their design does not enable the restoration of an adequate range of motion and strength.