Abstract
Introduction
Polyethylene wear and osteolysis remain a concern with the use of modular, fixed bearing total knee arthroplasty (TKA). A variety of highly cross-linked polyethylenes (XLPs) have been introduced to address this problem, but there are few data on the results and complications of this polyethylene in posterior-stabilized knee prosthesis. We have previously reported an interim analysis of a study comparing polyethylene tibial liners.
Methods
This is a prospective randomized study of one modular posterior-stabilized total knee arthroplasty by a single surgeon. 265 patients (329 knees) were randomized to receive a standard compression molded liner (SP) or a highly cross-linked (6.5 CGy electron-beam irradiated and remelted) polyethylene liner (XLP). Patients were evaluated clinically using the classic Knee Society scores, LEAS score, presence of a knee effusion, and by standard radiographs for radiolucent lines and osteolytic lesions. The analysis was performed at a mean of 6 years (range, 2–11 years).
Results
There were no clinical differences between 122 knees with SP and 123 knees with XLP in Knee Society total score; change in total score; knee function score; change in function score; LEAS score; and change in LEAS score. There was a difference in the presence of effusion (one of 123 XLP, and 10 of 122 SP; p=0.02). There was no difference in the frequency of radiolucent lines (21 knees with SP and 22 with XLP). Osteolysis was present in 4 knees (3.3%) with SP, and no knees with XLP (p=0.06). There was no difference in frequency of reoperation between the two groups (3 infection in 123 knees allocated to XLP group and six (3 infection, 1 femoral loosening, 1 instability, 1 fracture plating) in 122 knees allocated to SP group. There were no complications related to the XLP liner.
Conclusion
At this length of follow-up time, with the numbers available, there were no complications, but no advantages, related to the use of this XLP tibial liner. The presence of effusion and small osteolytic lesions are more frequent with SP than XLP, but of unknown clinical importance.
