A Randomized Controlled Trial Comparing Poly-Ether-Ether-Ketone and Cobalt-Chromium-Molybdenum Total Knee Arthroplasties: A Mean Follow-Up of Three Years.

BACKGROUND

Previously, we reported 1-year outcomes of a randomized controlled trial comparing poly-ether-ether-ketone (PEEK) prostheses to cobalt chromium molybdenum (CoCrMo). In this study, we present the mean 3-year follow-up results (range, 2.8 to 3.3) from the same trial.

METHODS

The original cohort comprised 48 total knee arthroplasties (TKAs), randomly assigned to either the PEEK group (n = 24) or the CoCrMo group (n = 24), performed between June 2021 and December 2021. A total of 46 patients were followed up. Survivorship, Knee Society Score, Visual Analog Scale for pain, and patient satisfaction were evaluated. In addition, records of revisions, reoperations, and complications were documented.

RESULTS

Both groups demonstrated excellent mean 3-year prosthesis survivorships (100%). Significant and sustained improvements in clinical outcomes were observed from baseline to 1-year follow-up; however, there was a slight decline in these measures at the 3-year follow-up. Notably, the functional score in the PEEK group was significantly higher than that in the CoCrMo group at the 3-year follow-up (P = 0.04). Despite this, no other statistically significant differences were observed between the PEEK and CoCrMo groups regarding the knee score (P = 0.08) or the Visual Analog Scale score (P = 0.06). Although not statistically significant, the PEEK group reported higher satisfaction levels from six weeks postoperatively to the latest follow-up. Complications were noted, with four patients experiencing knee stiffness and 12 reporting contralateral knee pain. In addition, one patient in the CoCrMo group developed radiolucent lines on the medial tibial plateau at the 3-year follow-up with no sign of loosening or failure associated with this finding.

CONCLUSIONS

The results of TKA using PEEK demonstrate excellent outcomes at three years, comparable to those of CoCrMo prostheses, and PEEK TKA is associated with superior patient-reported outcomes and higher patient satisfaction.