Acta Scientific Orthopaedics (ISSN: 2581-8635)

Research Article Volume 6 Issue 8

Does High Flexion Explain Aseptic Failure in a High Flexion Posterior Stabilized Direct Compression Molded Polyethylene Modular Total Knee?

Gireesh B Reddy1, Bradley A Lezak2 and Raymond P Robinson1

1Department of Orthopaedic Surgery, University of Miami Miller School of Medicine, Miami, Florida
2NYU Langone Orthopedics, NYU School of Medicine, New York, USA

*Corresponding Author: Raymond P Robinson, Department of Orthopaedic Surgery, University of Miami Miller School of Medicine, Miami, Florida.

Received: June 28, 2023; Published: July 19, 2023


Background: The Logic PS knee combined with the Fit tibial tray is a modular high flexion implant which became available in 2010. Early clinical results and knee range of motion reported with this prosthesis have been excellent, but some late aseptic failures have raised concerns. We are presenting our experience with this prosthesis to understand the incidence and possible explanations for aseptic failures.

Methods: A cohort of 260 primary total knees performed by the senior author with 2-to-8.7-year follow-up data were evaluated. Data pertaining to patient demographics, surgical technique, implant constraint and implant survival were collected prospectively in an IRB approved registry. Patients who could not return in person prospectively were contacted retrospectively by phone or email. Each aseptic failure was identified and assessed. Retrieved implants were examined.

Results: Average follow-up was 58 (24-104) months. Eighty-nine percent reported good or excellent Oxford knee scores and 9 of 10 satisfaction at latest follow-up. Implant survival with aseptic revision of either tibial or femoral component as an end point was 98%. Five implants (1.9%) underwent aseptic revision. One at 7 months for tibial malposition and instability and 4 at a mean 70.5 months for polyethylene wear, osteolysis, or femoral loosening.

Conclusions: A high percentage of patients in our study reported good or excellent clinical results at a mean 58 months. Four failures at 70.5 months, however, exhibited either severe damage to the posterior aspect of the tibial post, backside wear of the modular tibial junction, articular surface wear, and/or femoral loosening. These kinds of failures rarely seen in the previous PS design suggest an increase in the magnitude of the anteriorly directed force felt by the tibial post, insert, insert-baseplate junction and femoral cam in this newer high flexion design. The observations in this study cannot prove such an explanation, but hopefully will stimulate further study. There were no cases of Fit tray tibial loosening or polyethylene damage consistent with oxidation. Patient follow-up and x-ray are recommended at or before 70 months in patients receiving this implant.

Keywords: Osteolysis; PS Logic; Aseptic Loosening; Polyethylene


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Citation: Raymond P Robinson.,et al “Does High Flexion Explain Aseptic Failure in a High Flexion Posterior Stabilized Direct Compression Molded Polyethylene Modular Total Knee?”.Acta Scientific Orthopaedics 6.8 (2023): 60-67.


Copyright: © 2023 Raymond P Robinson., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


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