TY - JOUR
T1 - Randomized clinical trial of rotating-platform and fixed-bearing total knee arthroplasty
T2 - No clinically detectable differences at five years
AU - Kalisvaart, Michael M.
AU - Pagnano, Mark W.
AU - Trousdale, Robert T.
AU - Stuart, Michael J.
AU - Hanssen, Arlen D.
PY - 2012/3/21
Y1 - 2012/3/21
N2 - Background: For some surgeons, rotating-platform total knee designs are an intellectually appealing option to use for total knee arthroplasty because of the contention that they can self-align and accommodate small mismatches in the rotational position of the tibial and femoral components. We carried out a randomized clinical trial to determine if a posterior-stabilized, rotating-platform knee design provided better maximum knee flexion, better function, or better durability at five years of follow-up when compared with a fixed-bearing design. Methods: This randomized clinical trial of 240 primary total knee arthroplasties involved a single type of distal femoral implant (posterior-stabilized) and three different types of tibial implant (all-polyethylene fixed-bearing, modular-metalbacked fixed-bearing, and rotating-platform). The three tibial implant groups were balanced dynamically with a computerized randomization process that accounted for patient age, sex, and body mass index; surgeon; and implant type. Patients returned for examination and radiographs at three months, one year, two years, and five years postoperatively. Results: Knee range of motion was not significantly different among the all-polyethylene, modular-metal-backed, and rotating-platform tibial component groups at two years (mean, 111°, 111°, and 110°, respectively) or five years (mean, 110°, 109°, and 109°, respectively). Function, as measured with Knee Society scores, was not significantly different among the all-polyethylene, modular-metal-backed, and rotating-platform groups at two years (mean, 90, 91, and 91 points, respectively) or five years (mean, 88, 89, and 88 points, respectively). Stair-climbing scores were not significantly different among the three groups at two years (mean, 39, 40, and 39 points, respectively) or five years (mean, 37, 40, and 36 points, respectively). There were four revisions: one in the all-polyethylene group (patellar fracture), two in the modular metal-backed group (aseptic loosening), and one in the rotating-platform group (deep infection). Conclusions: In this randomized clinical trial, the rotating-platform total knee design was reliable and durable but did not provide better maximum knee flexion, better function, or better durability at five years postoperatively when compared with a posterior-stabilized, fixed-bearing design incorporating either an all-polyethylene or a modular-metal-backed tibial component. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
AB - Background: For some surgeons, rotating-platform total knee designs are an intellectually appealing option to use for total knee arthroplasty because of the contention that they can self-align and accommodate small mismatches in the rotational position of the tibial and femoral components. We carried out a randomized clinical trial to determine if a posterior-stabilized, rotating-platform knee design provided better maximum knee flexion, better function, or better durability at five years of follow-up when compared with a fixed-bearing design. Methods: This randomized clinical trial of 240 primary total knee arthroplasties involved a single type of distal femoral implant (posterior-stabilized) and three different types of tibial implant (all-polyethylene fixed-bearing, modular-metalbacked fixed-bearing, and rotating-platform). The three tibial implant groups were balanced dynamically with a computerized randomization process that accounted for patient age, sex, and body mass index; surgeon; and implant type. Patients returned for examination and radiographs at three months, one year, two years, and five years postoperatively. Results: Knee range of motion was not significantly different among the all-polyethylene, modular-metal-backed, and rotating-platform tibial component groups at two years (mean, 111°, 111°, and 110°, respectively) or five years (mean, 110°, 109°, and 109°, respectively). Function, as measured with Knee Society scores, was not significantly different among the all-polyethylene, modular-metal-backed, and rotating-platform groups at two years (mean, 90, 91, and 91 points, respectively) or five years (mean, 88, 89, and 88 points, respectively). Stair-climbing scores were not significantly different among the three groups at two years (mean, 39, 40, and 39 points, respectively) or five years (mean, 37, 40, and 36 points, respectively). There were four revisions: one in the all-polyethylene group (patellar fracture), two in the modular metal-backed group (aseptic loosening), and one in the rotating-platform group (deep infection). Conclusions: In this randomized clinical trial, the rotating-platform total knee design was reliable and durable but did not provide better maximum knee flexion, better function, or better durability at five years postoperatively when compared with a posterior-stabilized, fixed-bearing design incorporating either an all-polyethylene or a modular-metal-backed tibial component. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
UR - http://www.scopus.com/inward/record.url?scp=84860619867&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84860619867&partnerID=8YFLogxK
U2 - 10.2106/JBJS.K.00315
DO - 10.2106/JBJS.K.00315
M3 - Article
C2 - 22437996
AN - SCOPUS:84860619867
SN - 0021-9355
VL - 94
SP - 481
EP - 489
JO - Journal of Bone and Joint Surgery
JF - Journal of Bone and Joint Surgery
IS - 6
ER -