Abstract Swanson silastic arthroplasty, introduced by Alfred Swanson in the late sixties, has long been the treatment of choice for metacarpophalangeal (MCP) arthroplasty in cases of rheumatoid arthritis. Silastic implant arthroplasty has a significant role in the reconstruction of eroded MCP joints, but the method does not recreate a normal MCP joint. The Sutter implant has been designed to improve the function of the MCP joint, and especially to reduce the extension deficit. There are numerous studies concerning the Swanson implant, but limited number of previous articles on the use of the Sutter implant. The aim of this thesis was to determine the outcome of MCP arthroplasty with the Sutter implant in patients with inflammatory joint disease. This thesis is based on two studies concerning Sutter implant arthroplasty in patients with advanced rheumatoid arthritis. One of these was a prospective study performed at Oulu University Hospital in which patients were randomised into Swanson and Sutter implant groups representing 49 hands and 174 implants, with a mean follow up time of 4.8 years, and the other was a prospective study performed at the Rheumatism Foundation Hospital in Heinola in which Sutter implant arthroplasty was carried out on 117 hands employing 350 implants, with a mean follow-up time of 5.3 years. The main results were that arthroplasty yields similar results with both of these implants with respect to clinical parameters such as range of motion, ulnar deviation, grip strength and pain. Furthermore, the revision rate in our Sutter follow-up study was high, and survival, with revision surgery as the end point, was poor. We created a new radiographic grading system for bone resorption, i.e. osteolysis, in MCP arthroplasty and found this to be more severe after Sutter than Swanson implant arthroplasty, for some unknown reason. Moreover, we found that osteolysis was symptom-free but related to implant fractures. As a conclusion silicone implant arthroplasty should be used only with rheumatoid patients with advanced destruction. High implant fracture rates and high amounts of osteolytic changes in radiographs are not favourable for the use of the Sutter implant. If continuous development of new prostheses achieves implant with as good clinical outcome and reasonable costs as Swanson implant, the use of the silicone implants will be questionable.