Revisiting the role of isolated polyethylene exchange for aseptic failures in total knee arthroplasty.

Abstract

Controversy continues to exist regarding the advisability of isolated polyethylene exchange (IPE) following total knee arthroplasty (TKA) for aseptic indications. We sought to compare the difference in the cumulative incidence of reoperation after IPE specifically for aseptic failure and to evaluate risk factors for failure. We performed a retrospective cohort study of 122 knees revised for aseptic failure. Reasons for IPE in aseptic knees included: instability, polyethylene wear, arthrofibrosis, patella fracture, patellar resurfacing, patellar maltracking, extensor mechanism failure, patellectomy, and a custom polyethylene for correction of valgus deformity. The relatively high rate of mortality warranted a competing risk model to evaluate the cumulative incidence reoperation. Follow-up time was defined by years from IPE to date of reoperation or last follow-up. Generalized estimating equations were used for comparisons. Our analysis demonstrated an 87% (95% CI, 78-92%) survivorship free of reoperation at five years. Re-revision was secondary to aseptic failure, infection, and patellar malalignment. IPE for polyethylene wear was found to be protective and less likely to require reoperation (SHR 0.121 95% CI: 0.016-0.896, p = 0.039). The current study suggests that when done for carefully selected indications, IPE may be an acceptable procedure and helpful alternative for aseptic TKA revisions, particularly when the pre-operative diagnosis is polyethylene wear. This is in contrast to prior reports and may represent a need to re-visit the role of isolated polyethylene exchange.