Why Are Total Knee Arthroplasties Failing Today?

TLDR

Although knee replacement failure rates are low, over 22,000 revisions are performed annually. The study aimed to identify the current mechanisms of failure of total knee arthroplasties. A retrospective review of 212 revision surgeries on 203 patients over a 3‑year period at a single institution used preoperative evaluation, radiographs, laboratory data, and intraoperative findings to determine causes of failure, with revisions occurring from 9 days to 28 years post‑index surgery (average 3.7 years). The most common failure causes were polyethylene wear, aseptic loosening, instability, infection, arthrofibrosis, malalignment/malposition, deficient extensor mechanism, patellar avascular necrosis, periprosthetic fracture, and isolated patellar resurfacing, with over half of revisions occurring within two years and half of early revisions driven by instability, malalignment/malposition, and fixation failure.

Abstract

The incidence of failure after knee replacement is low, yet it has been reported that more than 22,000 knee replacements are revised yearly. The purpose of the current study was to determine current mechanisms of failure of total knee arthroplasties. A retrospective review was done on all patients who had revision total knee arthroplasty during a 3-year period (September 1997-October 2000) at one institution. The preoperative evaluation in conjunction with radiographs, laboratory data, and intraoperative findings were used to determine causes of failure. Two hundred twelve surgeries were done on 203 patients (nine patients had bilateral surgeries). The reasons for failure listed in order of prevalence among the patients in this study include polyethylene wear, aseptic loosening, instability, infection, arthrofibrosis, malalignment or malposition, deficient extensor mechanism, avascular necrosis in the patella, periprosthetic fracture, and isolated patellar resurfacing. The cases reviewed included patients who had revision surgery within 9 days to 28 years (average, 3.7 years) after the previous surgery. More than half of the revisions in this group of patients were done less than 2 years after the index operation. Fifty percent of early revision total knee arthroplasties in this series were related to instability, malalignment or malposition, and failure of fixation.