title: Good survivorship of all-polyethylene tibial component UKA at long-term follow-up.
abstract: OBJECTIVE
  To determine the long-term survival rate of an all-polyethylene tibial unicompartmental knee arthroplasty (UKA) in a large series of consecutive patients and to investigate the possible factors that could influence the outcome.
  
  
  METHODS
  A retrospective evaluation of 273 patients at 6-13 years of follow-up was performed. Clinical evaluation was based on KSS and WOMAC scores. Subjective evaluation was based on a visual analogue scale for pain self-assessment. Radiographic evaluation was performed to assess femoral-tibial angle (FTA), posterior tibial slope (PTS) and tibial plateau angle (TPA). A Kaplan-Meier survival analysis was performed assuming revision for any reason as primary endpoint.
  
  
  RESULTS
  The 10-year implant survivorship was 87.6%. Twenty-five revisions (9.2%) were performed, and aseptic loosening of the tibial component was the most common failure mode (11 cases, 4%). The comparison of survival rate according to age at surgery did not show significant difference. Age at surgery, FTA, TPA and PTS were not related to higher risk of revision. No correlations were found between BMI, age at surgery and clinical scores. Finally, no statistical differences of radiographic measurements were found between revisions and non-revisions.
  
  
  CONCLUSIONS
  The present study has demonstrated on a large series of patients that UKA with an all-polyethylene tibial component, with an accurate technique and a proper patient selection, can provide a satisfactory clinical and functional outcome and a good overall survivorship of the implant at long-term follow-up. These advantages could be achieved at a lower cost.
  
  
  METHODS
  Retrospective Therapeutic Study, Level IV.
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. d.bruni@biomec.ior.it.
authors.forename: Danilo
authors.initials: D
authors.lastname: Bruni
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. Michele.ts88@live.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Gagliardi
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. Ibrahim.akkawi@studio.unibo.it.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Akkawi
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. Giov.ras@hotmail.it.
authors.forename: Giovanni Francesco
authors.initials: GF
authors.lastname: Raspugli
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. s.bignozzi@biomec.ior.it.
authors.forename: Simone
authors.initials: S
authors.lastname: Bignozzi
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. tedi.marko@studio.unibo.it.
authors.forename: Tedi
authors.initials: T
authors.lastname: Marko
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. l.bragonzoni@biomec.ior.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Bragonzoni
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. alberto.grassi3@studio.unibo.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Grassi
authors.affiliation: Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna, Italy. m.marcacci@biomec.ior.it.
authors.forename: Maurilio
authors.initials: M
authors.lastname: Marcacci
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D001672:Biocompatible Materials; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010020:Osteonecrosis / Q000601:surgery*; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D012189:Retrospective Studies; D013977:Tibia / Q000601:surgery
chemical_list: D001672:Biocompatible Materials; D020959:Polyethylene
keywords: All-polyethylene tibial component; Failure mechanism; Fixed-bearing; Implant survivorship; Unicompartmental knee replacement