Does metal backing improve fixation of tibial component in unicondylar knee arthroplasty? A randomized radiostereometric analysis.
In a prospective, randomized study, patients with medial gonarthrosis stage I to III according to Ahlbäck were allocated to a unicondylar knee arthroplasty (Miller-Galante, Zimmer, Inc., Warsaw, IN) with an all-polyethylene tibial component or metal-backed tibial component of the same design. The purpose of the study was to evaluate if metal backing enhanced tibial component fixation. A total of 45 knees (42 patients; 23 metal-backed components and 22 all-polyethylene components) were examined. We used radiostereometric analysis to measure micromotion of the tibial component over a period of 2 years after surgery. Hospital for Special Surgery score was used for clinical evaluation. We found no statistically significant differences in clinical results or migration of the tibial component over a 2-year follow-up period. These findings do not support better fixation of metal-backed tibial components. Because of these findings, we advocate all-polyethylene tibial components in unicondylar knee arthroplasties because of optimal biomechanical strength at a given height of tibial component, avoiding potential problems of modularity and minimizing the amount of interfaces, at a lower cost.
Department of Orthopaedics, St Görans Hospital, S-11281 Stockholm, Sweden.
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Hyldahl
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Regnér
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Carlsson
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Kärrholm
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Weidenhielm
D000368:Aged; D000369:Aged, 80 and over; D000497:Alloys; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000601:surgery*; D011095:Polyethylenes; D011446:Prospective Studies; D011474:Prosthesis Design; D011859:Radiography; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery; D016896:Treatment Outcome
D000497:Alloys; D011095:Polyethylenes