Clinical and radiologic outcomes of total knee arthroplasty using the Advance Medial Pivot prosthesis. A mean 7 years follow-up.

Background: Medial Pivot total knee prosthesis has been designed according to studies on normal knee kinematics aiming to replicate physiological knee movement. The purpose of this study was to evaluate clinical and radiologic results of the Advance Medial Pivot Total Knee Arthroplasty, at a mean follow-up of seven years.

Methods: One hundred seventy two Medial Pivot total knee arthroplasties in 160 consecutive patients have been evaluated using the American Knee Society Score and the Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. Statistical analysis was performed using the Student's t-test and the Wilcoxon matched-pairs signed-rank (Mann-Whitney) test in order to evaluate the significance of differences within the groups of patients. Patients compliance was 93.75% thus only six patients (3.75%) lost to follow-up and four patients (2.5%) died for reasons unrelated to the surgery.

Results: The mean Knee Society score and range of motion was improved from 77.6 points and 97.7° to 152.8 points and 112.5° respectively (p<.001). In total 85.8% and 82.4% of the knees had an excellent (≥ 80) or good (70-79) functional and knee scores respectively. Relief of pain was satisfactory in 88.9% of the patients, while 96% of the patients return to age-related daily life activities. Stability and comfort during walking was subjectively judged by the patients as satisfactory in about 90%. Anterior knee pain was observed in eight patients (5.4%). The Kaplan-Meier survivorship analysis showed a cumulative success rate of 98.6%.

Conclusions: The results are encouraging but longer follow-up of this cohort is necessary in the study of this specific design. Level of evidence IV.