Abstract
Introduction
Ceramic total knee arthroplasty (TKA) was introduced as a new-generation of knee prostheses in clinical practice, and are expected to reduce polyethylene wear due to its resistance to abrasion and lubrication. In 1992, we developed a cruciate retaining LFA-I total knee prosthesis (KYOCERA Medical Co., Japan), which comprises an alumina ceramic femoral component and a titanium-alloy tibial component with a polyethylene insert. The purpose of this study was to evaluate clinical results in rheumatoid patients who were treated with the alumina-ceramic LFA-I prosthesis with a minimum 15-year follow-up period.
Methods
A total of 70 primary TKAs were performed in 51 patients between 1993 and 1996 using the cemented alumina-ceramic LFA-I prosthesis. Sixteen of these patients (20 knees) had died by the time of this study, of causes unrelated to the index arthroplasty, and 11 patients (16 knees) were lost to the follow-up. The remaining 34 knees were clinically and radiographically evaluated in the present study. The average follow-up time was 16.7 years. The average age of the patients was 58.2 years at the time of the operation. The clinical assessment was conducted with the Hospital for Special Surgery Knee rating score and the Knee Society scoring system. The component alignment and bone-implant interface were evaluated according to the Knee Society Roentgenographic Evaluation System.
Results
The cumulative survival rate for revision for any reason at 15 years was 94.1%. The mean postoperative range of motion was 115.3 degrees at the time of the most recent follow-up. The mean postoperative knee score was 90.1 and 84.7 using the Knee Society and the Hospital for Special Surgery rating systems, respectively. Reoperations had been required on two knees due to loosening and on one knee due to infection. Periprosthetic radiolucencies or osteolysis were present in six knees. All lesions occurred around the prosthetic rim; 3 lesions at the anterior femoral flange, 5 lesions at the medial tibia, 2 lesions at the lateral tibia, and 1 lesion at the anterior tibia. These implants did not migrate, subside, or have circumferential radiolucencies that would indicate radiographic loosening.
Discussion
In this series of patients with rheumatoid arthritis, the alumina-ceramic LFA-I prosthesis has performed well for the average 16.7 years of follow-up. It is not possible to draw any conclusions regarding the superiority of the ceramic prosthesis with respect to wear and survivability, however, the lack of a ceramic breakage with this anatomical design has encouraged us to continue to use this ceramic prostheses.
