Journal Published Online: 07 October 2011
Volume 9, Issue 1

In-Vitro Wear and Radiographic Analyses of High Flexion Posterior Stabilized Mobile- and Fixed-Bearing Knee Implants

CODEN: JAIOAD

Abstract

In vitro wear tests results and 2-year follow up radiographic analyses of implanted fixed- and mobile-bearing LPS Flex knees are compared. The two knee designs use gamma-sterilized GUR 1050 ultra high molecular weight polyethylene (UHMWPE) patellae and tibial inserts, and the same CoCrMo alloy (ASTM F 75) femoral components. The in vitro wear tests were performed on six fixed- and six mobile-bearing knee implants using modified ISO 14243-3 load and kinematic waveforms. Tests were conducted at a frequency of 1 Hz for 5 × 106 cycles (Mc) in bovine serum lubricant. Two year follow up radiographic analyses were performed on 341 patients implanted with 173 mobile- and 168 fixed-bearing implants. Average accumulative in vitro polyethylene wear rates of the mobile- and fixed-bearing knees were 19.9 ± 5.1 mg/Mc and 14.2 ± 2.1 mg/Mc, respectively. There is no statistically significant difference in the wear rates of both devices (p > 0.05, Mann–Whitney test). Overall survivorship at two years with revision for any reason as the endpoint was 99.3 % for the mobile group and 100 % in the fixed group. There was no evidence of tibial, femoral, or patella bone loss at the two year follow up. The mean active range of motion increased from 110.8° to 127.0° in the mobile- bearing group and from 110.7° to 127.2° in the fixed-bearing one. Overall, radiographic evaluation showed similar performance of both devices.

Author Information

Popoola, Oludele
Zimmer Research Laboratory, US
Yu, Ning
Zimmer Research Laboratory, US
Scuderi, Giles
Insall Scott Kelly Institute, US
Pages: 9
Price: $25.00
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Stock #: JAI103907
ISSN: 1546-962X
DOI: 10.1520/JAI103907