A case of implantation of hip prosthesis and knee joints in a patient with juvenile idiopathic arthritis in the Rheumoorthopaedic Department of the Institute of Rheumatology in Warsaw is described. Because of the greatly advanced destructive changes in the hip and knee, arthroplasty was necessary in those joints. The patient underwent two hip arthroplasties, two revision operations of these joints, and two knee arthroplasties. One of the primary operations of the knee intraoperatively required withdrawal from the implantation of the femoral stem and was complicated by early periprosthetic fracture of the femur. The fracture required revision knee replacement using a „custom made” prosthesis. Despite the complications of surgical procedures the final result of multi-stage treatment was very satisfactory.