Unicompartmental arthroplastyversus total knee arthroplasty：stress analysis of prosthetic contact surface / 中国组织工程研究

ABSTRACT

BACKGROUND:Compared with total knee arthroplasty, unicompartmental arthroplasty has the advantage of minimal invasion. Regarding the gold standard of total knee arthroplasty, the survival rate of unicompartmental arthroplasty remains controversial. OBJECTIVE:To establish three-dimensional finite element model of unicompartmental arthroplasty and total knee arthroplasty, and comparatively analyze the changes in stress on the prosthetic contact surface. METHODS:One case underwent unicompartmental arthroplasty on one side, and received total knee arthroplasty on the opposite side. Knees were scanned by 3D CT before operation. Knee models were established by three-dimensional software. The matched prosthesis was designed by parameterization software. Three-dimensional models for unicompartmental arthroplasty and total knee arthroplasty were established. By finite element analysis software, maximal equivalent stress was simulated when knee flexion was 0°, 10°, 30° and 60° in standing and walking cases, and results were compared and analyzed. RESULTS AND CONCLUSION: No significant difference in maximal equivalent stress was detected when knee flexion was 0° and 10° in unicompartmental arthroplasty prosthesis and total knee arthroplasty prosthesis in standing case (P > 0.05). At knee flexion of 30° and 60° in standing case, the maximal equivalent stress was significantly greater in unicompartmental arthroplasty prosthesis than in the total knee arthroplasty prosthesis (15.01%, 6.08%;P < 0.05). When knee flexion was 0°, 10° 30° and 60° in standing case, the maximal equivalent stress was higher in unicompartmental arthroplasty prosthesis than in the total knee arthroplasty prosthesis (5.45%, 6.65%, 6.67%, 9.01%;P < 0.05). These findings verified that in the case of standing, there was no practical significance in wearing of polyethylene insert between unicompartmental arthroplasty prosthesis and total knee arthroplasty prosthesis. In the case of walking, the wearing of unicompartmental arthroplasty may be higher than that of total knee arthroplasty prosthesis, which provides guidance for the clinical practice.