title: Comparison of Outcome and Survival After Unicompartmental Knee Arthroplasty Between Navigation and Conventional Techniques With an Average 9-Year Follow-Up.
abstract: BACKGROUND
  Unicompartmental knee arthroplasty(UKA) has become a treatment of choice for many patients with isolated unicomparmental arthritis due to its specific advantages over total knee arthroplasty, but few studies have compared conventional and navigational UKA with similar instrumentation on mid- to long-term results. We investigated whether the use of imageless navigation can improve implant positioning and clinical outcomes of UKA at a long-term follow-up compared to the conventional technique.
  
  
  METHODS
  We prospectively studied clinical and radiological results in 68 patients with an average age of 64.0 years (range, 50 to 81 years) who received UKA between January 2003 and December 2005 using the conventional or navigational technique. Clinical evaluations were performed preoperatively and the last follow-up included knee range of motion, Hospital for Special Surgery (HSS) scores, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and Visual Analogue Scale (VAS) pain score. For radiologic evaluation, the mechanical alignment of the lower limb was measured using mechanical femoro-tibial angle (mFTA) and Kennedy protocol.
  
  
  RESULTS
  After an average 9-year follow-up (range, 7.4 to 10.8 years), the navigation group showed better coronal alignments of the components, fewer radiological outliers and better clinical scores, but similar estimated 10-year prosthesis survival rates.
  
  
  CONCLUSIONS
  This study indicates that the use of navigation significantly contributes to the desired mechanical axis and improved component placement as compared to the conventional technique.
  
  
  METHODS
  Prospective comparative study, Level III.
authors.affiliation: Department of Orthopedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Republic of Korea.
authors.forename: Eun Kyoo
authors.initials: EK
authors.lastname: Song
authors.affiliation: Department of Orthopedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Republic of Korea.
authors.forename: Mohite
authors.initials: M
authors.lastname: N
authors.affiliation: Department of Orthopedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Republic of Korea.
authors.forename: Seung-Hun
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Republic of Korea.
authors.forename: Bo-Ram
authors.initials: BR
authors.lastname: Na
authors.affiliation: Department of Orthopedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Republic of Korea.
authors.forename: Jong-Keun
authors.initials: JK
authors.lastname: Seon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001168:Arthritis / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013238:Stereotaxic Techniques; D016896:Treatment Outcome
keywords: arthroplasty; conventional; knee; navigation; unicompartmental