Mid-term results and factors affecting outcome of a metal-backed unicompartmental knee design: a case series.

Published online

Journal Article

BACKGROUND: Controversies exist regarding the indications for unicompartmental knee arthroplasty. The objective of this study is to report the mid-term results and examine predictors of failure in a metal-backed unicompartmental knee arthroplasty design. METHODS: At a mean follow-up of 60 months, 80 medial unicompartmental knee arthroplasties (68 patients) were evaluated. Implant survivorship was analyzed using Kaplan-Meier method. The Knee Society objective and functional scores and radiographic characteristics were compared before surgery and at final follow-up. A Cox proportional hazard model was used to examine the association of patient's age, gender, obesity (body mass index > 30 kg/m2), diagnosis, Knee Society scores and patella arthrosis with failure. RESULTS: There were 9 failures during the follow up. The mean Knee Society objective and functional scores were respectively 49 and 48 points preoperatively and 95 and 92 points postoperatively. The survival rate was 92% at 5 years and 84% at 10 years. The mean age was younger in the failure group than the non-failure group (p < 0.01). However, none of the factors assessed was independently associated with failure based on the results from the Cox proportional hazard model. CONCLUSION: Gender, pre-operative diagnosis, preoperative objective and functional scores and patellar osteophytes were not independent predictors of failure of unicompartmental knee implants, although high body mass index trended toward significance. The findings suggest that the standard criteria for UKA may be expanded without compromising the outcomes, although caution may be warranted in patients with very high body mass index pending additional data to confirm our results. LEVEL OF EVIDENCE: IV.

Full Text

Duke Authors

Cited Authors

  • Seyler, TM; Mont, MA; Lai, LP; Xie, J; Marker, DR; Zywiel, MG; Bonutti, PM

Published Date

  • October 26, 2009

Published In

Volume / Issue

  • 4 /

Start / End Page

  • 39 -

PubMed ID

  • 19857264

Pubmed Central ID

  • 19857264

Electronic International Standard Serial Number (EISSN)

  • 1749-799X

Digital Object Identifier (DOI)

  • 10.1186/1749-799X-4-39


  • eng

Conference Location

  • England