ABSTRACTS FROM THEAMERICAN ASSOCIATION OF

HIP AND KNEE SURGEONSEIGHTEENTH ANNUAL MEETING

November 7-9, 2008Dallas, Texas

entations\Paper #1Fixed vs. Mobile Bearing Total Knee Arthroplasty Does It really Matter? – A ProspectiveRandomized Study

Melvyn Harrington, MD, William J. Hopkinson, MD, Patricia Hsu, MD, Leslie Manion, RN

Introduction: The purpose of this prospective, randomized study was to compare the early clinical andfunctional results of primary total knee arthroplasty using a fixed bearing and a rotating platform prosthesis.

Methods: Surgery was performed using an identical technique. Patients were randomized intraoperatively toreceive either a fixed-bearing or a rotating platform (RP) total knee. Randomization occurred after femoral andinitial tibial preparation and the knees were ligamentously balanced to accept either type of device.Postoperative management was identical for both groups. Outcomes measured included range of motion(ROM), Knee Society Score (KSS), WOMAC score and SF-36.Radiographic analysis was also performed toevaluate component alignment and radiolucencies. These outcomes were measured preoperatively andpostoperatively at 6 weeks, 3 months, 6 months, 1 year, and 2 years.

Results: There were 66 fixed bearing and 66 rotating platform knees in the two groups. The only significantdifference in the outcomes measured were a greater range of motion for the RP group at 6 weeks and 1 year.ROM was greater for the RP group at 6 weeks (102.1° + 1.7° vs. 96.5° + 2.1° for the fixed-bearing group, p =0.039) and at 1 year post-op (119.8° + 1.6° vs. 114.5° + 1.9° for the fixed-bearing group, p = 0.038). However,this difference was not statistically significant at 2 years post-op (p = .0261) There were no differences in theROM at any other time period. There were no significant differences in KSS or WOMAC scores measured atany time period. For the radiographic analysis the alignment was slightly better for the rotating-platform groupin regard to femoral-tibial angle.

Conclusion: The use of a fixed or mobile bearing design did not affect the early functional outcomes after totalknee arthroplasty.

The Journal of Arthroplasty Vol. No. 2009

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