Background: The anterior-posterior-glide Low Contact Stress
mobile-bearing knee prosthesis was developed to approximate the natural
kinematics of the knee more closely than the rotating-platform Low Contact
Stress mobile-bearing knee prosthesis does. The purpose of the present study
was to compare the results associated with these two prostheses in patients
managed with simultaneous bilateral total knee replacement.
Methods: One hundred and ninety patients received an
anterior-posterior-glide Low Contact Stress mobile-bearing prosthesis in one
knee and a rotating-platform Low Contact Stress mobile-bearing prosthesis in
the contralateral knee. The mean age of the patients at the time of the index
procedure was sixty-four years. Eleven patients were men, and 179 patients
were women. The mean duration of follow-up was 6.4 years (range, five to seven
years). The patients were followed clinically and radiographically with use of
the knee-rating systems of the Knee Society and the Hospital for Special
Surgery.
Results:The mean postoperative Hospital for Special Surgery knee
score was 89.4 points for the knees treated with the anterior-posterior-glide
mobile-bearing prosthesis and 88.6 points for those treated with the
rotating-platform mobile-bearing prosthesis. Three knees in each group had a
poor result. Two knees in each group had persistent moderate pain. One knee
with an anterior-posterior-glide prosthesis had permanent tibial and deep
peroneal nerve palsies, and one knee with a rotating-platform prosthesis had a
permanent deep peroneal nerve palsy. No knee had aseptic loosening, revision,
measurable wear of the tibial or patellar polyethylene bearing, or
osteolysis.
Conclusions: After a minimum duration of follow-up of five years,
the results associated with the anterior-posterior-glide and rotating-platform
Low Contact Stress mobile-bearing total knee replacements were favorable and
comparable.
Level of Evidence: Therapeutic study, Level II-1
(prospective cohort study). See Instructions to Authors for a complete
description of levels of evidence.