Routine Surveillance of Modular PFC TKA Shows Increasing Failures after 10 Years

Background/rationale A 10-year survivorship of 100% was reported for patients with PFC cruciate-retaining prostheses. Beyond 10 years, we observed additional polyethylene wear likely related to thin liners gamma-irradiated in air and were concerned this wear might predispose to implant construct failure.

Questions/purposes We therefore determined (1) the functional scores at a minimum of 15 years followup, (2) rates of radiographic failure, (3) overall revision rates, and (4) mode of failure after 10 years and the fate of the revised implants.

Methods We retrospectively reviewed 75 patients with 101 press-fit condylar posterior cruciate-retaining prostheses. At a minimum followup of 15 years, 35 patients (47 knees) were living and evaluated clinically. No patients were lost to followup.

Results There were no revisions during the first 11 years and six reoperations subsequently were performed in five patients (6% overall rate of revision but 12.8% in patients who survived more than 15 years). Three of six revisions had concerning liner wear at 10 years and all six were revised for polyethylene wear. Polyethylene exchange was performed in four of the five patients who underwent revisions, all of whom were doing well at an average of 7.2 years (range, 4.7-9.1 years) after the revision procedure.

Conclusions At long-term followup, the overall revision rate remained low (6%). For patients surviving 15 years or more, the rate of revision was 12.8% and all revisions were secondary to aseptic sequelae of polyethylene wear. All revisions occurred more than 10 years after the initial procedures.

Level of Evidence Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.