This article aims at determining the differences in resources needed for the treatment of patients with rheumatoid arthritis as opposed to osteoarthritis. Data on ten patients for each of these diagnoses, all of whom had been subject to the implantation of a knee arthroplasty,were compared. We looked at parameters such as the duration of surgery, further diagnoses, costs of radiological measures and medical treatment, simultaneous operations, need of nursing care,physical and occupational therapy and complications. Patients presenting with rheumatoid arthritis in many respects required substantially more clinical and/or financial resources than osteoarthritis patients. This statement holds true at least for the period of hospital care during which the knee-prosthesis was implanted.