title: A randomised trial of all-polyethylene and metal-backed tibial components in unicompartmental arthroplasty of the knee.
abstract: This randomised trial evaluated the outcome of a single design of unicompartmental arthroplasty of the knee (UKA) with either a cemented all-polyethylene or a metal-backed modular tibial component. A total of 63 knees in 45 patients (17 male, 28 female) were included, 27 in the all-polyethylene group and 36 in the metal-backed group. The mean age was 57.9 years (39.6 to 76.9). At a mean follow-up of 6.4 years (5 to 9.9), 11 all-polyethylene components (41%) were revised (at a mean of 5.8 years; 1.4 to 8.0) post-operatively and two metal-backed components were revised (at one and five years). One revision in both groups was for unexplained pain, one in the metal-backed group was for progression of osteoarthritis. The others in the all-polyethylene group were for aseptic loosening. The survivorship at seven years calculated by the Kaplan-Meier method for the all-polyethylene group was 56.5% (95% CI 31.9 to 75.2, number at risk 7) and for the metal-backed group was 93.8% (95% CI 77.3 to 98.4, number at risk 16) This difference was statistically significant (p < 0.001). At the most recent follow-up, significantly better mean Western Ontario and McMaster Universities Arthritis Index Scores were found in the all-polyethylene group (13.4 vs 23.0, p = 0.03) but there was no difference in the mean Knee injury and Osteoarthritis Outcome scores (68.8; 41.4 to 99.0 vs 62.6; 24.0 to 100.0), p = 0.36). There were no significant differences for range of movement (p = 0.36) or satisfaction (p = 0.23). This randomised study demonstrates that all-polyethylene components in this design of fixed bearing UKA had unsatisfactory results with significantly higher rates of failure before ten years compared with the metal-back components.
authors.affiliation: Hôpital Maisonneuve-Rosemont, 5415 Boul. L'Assomption Montréal, QC H1T 2M4, Canada.
authors.forename: J R B
authors.initials: JR
authors.lastname: Hutt
authors.affiliation: Hôpital Maisonneuve-Rosemont, 5415 Boul. L'Assomption Montréal, QC H1T 2M4, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Farhadnia
authors.affiliation: Hôpital Maisonneuve-Rosemont, 5415 Boul. L'Assomption Montréal, QC H1T 2M4, Canada.
authors.forename: V
authors.initials: V
authors.lastname: Massé
authors.affiliation: Hôpital Maisonneuve-Rosemont, 5415 Boul. L'Assomption Montréal, QC H1T 2M4, Canada.
authors.forename: M
authors.initials: M
authors.lastname: LaVigne
authors.affiliation: Hôpital Maisonneuve-Rosemont, 5415 Boul. L'Assomption Montréal, QC H1T 2M4, Canada.
authors.forename: P-A
authors.initials: PA
authors.lastname: Vendittoli
mesh_terms: D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D018450:Disease Progression; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D020959:Polyethylene; D011474:Prosthesis Design
chemical_list: D020959:Polyethylene
keywords: All Polyethylene; Fixed Bearing; Knee; Randomised; Unicompartmental