Randomized Controlled Trial of Radiographic
and Patient-Assessed Outcomes Following
Fixed Versus Rotating Platform
Total Knee Arthroplasty
Wael A. Rahman, MD, Donald S. Garbuz, MD, MHSc, FRCSC, and
Bassam A. Masri, MD, FRCSC
Abstract: This prospectively blinded randomized controlled study evaluated the difference in the
functional and radiological outcomes in patients who received a press-fit condylar Sigma cemented
cruciate-substituting total knee arthroplasty with either a rotating platform (RP) or a fixed bearing
(FB). There were 51 joints in 49 patients: 24 joints in the RP group (mean follow-up, 43 months) and
27 joints in the FB group (mean follow-up, 40 months). At baseline, there was no significant difference
in age, body mass index, preoperative diagnosis, Charnley class, range of motion, clinical and
functional scores, between the RP and FB groups.Atmid-termfollowupboththeRPandFBgive
equivalent results, but patients with the RP tended to have a higher activity level score. Keywords:
total knee arthroplasty, rotating platform, fixed bearing, randomized clinical trial.
© 2010 Published by Elsevier Inc.
Fixed-bearing (FB) total knee replacements have pro-
vided durable long-term results, but polyethylene wear
with or without periprosthetic osteolysis has been
reported [1-7].
Total knee arthroplasty (TKA) with mobile bearings
came into use in late 1979 [8]. Mobile-bearing knee
arthroplasty designs have the advantage over the FB
articulation of a potentially more accurate reproduc-
tion of knee kinematics, which can at least theoreti-
cally improve range of motion and decrease
polyethylene wear. It also allows an increased confor-
mity of the articular surface in the rotating platform
(RP) articulation, which can lead to a decrease in the
stress on the polyethylene. The rotation of the bearing
can also decrease the stress on the cement-bone
interface [9-13]. These theoretical advantages have
allowed an increase in the popularity of these designs,
particularly in younger patients [14]. Despite this,
these theoretical advantages have not been confirmed
in clinical studies [15,16].
Excellent mid and long-term clinical results have been
reported for posterior stabilized total knee arthroplasty
with either FB [11,17,18] or RP designs [19-25].
However, there are few randomized controlled studies
that have directly compared the clinical and functional
results and quality of life scores of RP and FB designs in
the same prosthesis.
The primary aim of this study was to identify any
difference in the clinical outcome (Western Ontario
and McMaster Universities Osteoarthritis Index
[WOMAC] score, Oxford-12 knee score, University
of California at Los Angeles [UCLA] activity score,
and the Short Form 12 [SF-12]) after TKA in patients
with FB and RP designs using the cemented press-fit
condylar (PFC) Sigma posterior stabilized system
(DePuy/Johnson and Johnson, Warsaw, Ind). The
secondary aim of this study was to compare the
postoperative range of motion, radiographic appear-
ance and patient satisfaction in the 2 groups of
patients at a minimum of 2 years after the surgery.
Materials and Methods
Study Design
This was a prospective randomized controlled clinical
trial with patient blinding but without surgeon blinding.
From the Division of Lower Limb Reconstruction and Oncology,
Department of Orthopaedics, University of British Columbia, Vancouver,
British Columbia, Canada.
Submitted May 19, 2009; accepted October 11, 2009.
Funding for this study was provided by DePuy Canada, Ltd.
(A Johnson & Johnson Company).
Benefits or funds were received in partial or total support of the
research material described in this article. These benefits or support
were received from the following sources: DePuy Canada, Ltd.
(A Johnson & Johnson Company).
Reprint requests: Donald S. Garbuz, MD, MHSc, Department of
Orthopaedics, University of British Columbia, Room 3114, 910 West
10th Avenue, Vancouver, British Columbia, Canada V5Z 4E3.
© 2010 Published by Elsevier Inc.
0883-5403/2508-0005$36.00/0
doi:10.1016/j.arth.2009.10.002
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The Journal of Arthroplasty Vol. 25 No. 8 2010