COMPARISON OF MOBILE VERSUS FIXED BEARING IN HIGH-FLEX TOTAL KNEE ARTHROPLASTY

Abstract

The purpose of this study was to compare the clinical and radiological results of the PFC flex mobile bearing design with those of the LPS flex fixed bearing design in high-flex total knee arthroplasty.

Between January 2005 and November 2006, forty-six patients who received PFC flex mobile bearing prosthesis in one knee and LPS flex fixed bearing prosthesis in the contralateral knee followed up for a minimum 2 years were evaluated. Clinical results were assessed using the ROM, HSS score, the Knee rating systems of the knee society, WOMAC score and SF-36. Radiological results were evaluated tibio-femoral angle and loosening or osteolysis of components. We subdivided preoperative less 90 degree and more 90 degree in each group.

Mean ROM range of last follow up was increased to 131.1 degree in LPS group and 130.1 degree in PFC group. But there was no significant difference between the two groups. HSS score, knee pain and function score, WOMAC score, SF-36 score didn’t differ significantly between two groups. But descending stairs, rising from sitting, bending to the floor more improved significantly in LPS group. T-F angle was changed from preoperative 8.2 degree varus to a postoperative 4.8 degree valgus. No knee had aseptic loosening or osteolysis.

Postoperative ROM was increase significantly in both groups. We found no significant differences between the two groups with regard to clinical and radiological parameters excepts descending stairs, rising from sitting, bending to the floor in WOMAC score. There was no aseptic loosening or osteolysis but needed long term observation about these concerns.