The Self-Aligning knee prosthesis: clinical and radiological outcome and survival analysis at 5-year follow up

The purpose of this study is to evaluate the clinical and radiological results and the survival of the SAL II mobile bearing knee prosthesis at 5-year follow up. Between February 1995 and March 1998 a total of 246 SAL II total knee arthroplasties were performed in 232 patients. The mean follow up was 5.0 years. Thirteen revisions had been carried out (5%). The mean total Knee Society Score increased from 88 preoperatively to 153 and 155 at 1 and 5 years follow up, respectively. The mean flexion angles were 106° and 107° pre- and postoperatively. None of the prostheses showed radiological loosening. No dislocations or subluxations of inserts were seen. The Kaplan–Meier cumulative survival is 95% for revision for any reason at 5.0 years, with a worst case scenario of 91%. The survival for aseptic loosening is 99%. The results of SAL II after a minimum follow up of 5 years are favourable and comparable with fixed bearing and other mobile bearing designs in terms of Knee Society Score and survival. Noteworthy are the good radiological results of this device which showed a good fixation of the prosthesis at 5 years.