The Journal of Bone and Joint Surgery (American). 2009;91:1587-1594.
doi:10.2106/JBJS.G.01427
© 2009 The Journal of Bone and Joint Surgery, Inc.
All-Polyethylene Compared with Metal-Backed Tibial Components in Total Knee Arthroplasty at Ten YearsA Prospective, Randomized Controlled Trial
Karen A. Bettinson, MSc, RN1,
Ian M. Pinder, FRCS2,
Chris G. Moran, MD, FRCS(Ed)3,
David J. Weir, FRCS(Orth)1 and
Elizabeth A. Lingard, BPhty, MPhil, MPH1
1 Department of Orthopaedics, Freeman Hospital, Level 1, Room 22a, Newcastle upon Tyne NE7 7DN, United Kingdom. E-mail address for K.A. Bettinson: karen.bettinson{at}nuth.nhs.uk
2 126 Darras Road, Darras Hill, Ponteland, Newcastle upon Tyne NE20 9PG, United Kingdom
3 Department of Orthopaedics, Queens Medical Centre, Nottingham University Hospital, Nottingham NG7 2UTH, United Kingdom
Investigation performed at the Department of Orthopaedics, Freeman Hospital, Newcastle upon Tyne, United Kingdom
Disclosure: In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants in excess of $10,000 from Stryker Howmedica (Newbury, United Kingdom). Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. A commercial entity (Stryker Howmedica) paid or directed in any one year, or agreed to pay or direct, benefits in excess of $10,000 to a research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which one or more of the authors, or a member of his or her immediate family, is affiliated or associated.
Background: Several studies have described equivalent performance on radiostereometric analysis at two years for metal-backed compared with all-polyethylene stemmed tibial implants. The purpose of this study was to determine the ten-year survivorship results of these two designs from a large randomized controlled trial.
Methods: Patients who were fifty years old or more, with no history of infection, and were undergoing primary total knee arthroplasty were randomized at the time of surgery to receive either an all-polyethylene or a metal-backed tibial component. Patients were assessed preoperatively and at one, three, five, eight, and ten years postoperatively. All assessments included a clinical history, a physical examination, and a radiographic evaluation. A total of 510 consecutive patients (566 knees) were recruited from August 1993 to January 1997. The mean age of the patients at the time of the index arthroplasty was 69.3 years, and 299 (59%) were women. The primary diagnosis was osteoarthritis for 458 knees (80.9%) and rheumatoid arthritis for 108 knees (19.1%).
Results: Two hundred and ninety-three patients returned for the ten-year follow-up evaluation. A total of twenty-eight knees had been revised. Ten-year survivorship, with revision for any reason (or the time at which patients were documented as requiring revision but were unfit for surgery) as the end point, was 94.5% (95% confidence interval, 90.4% to 96.8%) for the all-polyethylene design and 96% (95% confidence interval, 92.6% to 97.8%) for the metal-backed design. Ten-year survivorship, with aseptic failure as the end point, was 97% (95% confidence interval, 93.3% to 98.7%) for the all-polyethylene design and 96.8% (95% confidence interval, 93.6% to 98.4%) for the metal-backed design. On the basis of the numbers available at ten years, there was no significant difference in survivorship between the two designs (p > 0.05).
Conclusions: The long-term results demonstrate excellent survivorship, with revision as the end point, for both the metal-backed and the all-polyethylene tibial component designs with no differences noted between the two.
Level of Evidence: Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

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