title: Clinical and technical factors influencing outcomes of unicompartmental knee arthroplasty: Retrospective multicentre study of 944 knees.
abstract: BACKGROUND
  Unicompartmental knee arthroplasty (UKA) is reserved for osteoarthritis confined to a single femoro-tibial compartment with an intact anterior cruciate ligament. UKA remains controversial. The objective of this retrospective multicentre study in a large sample was to assess the influence of age, sex, body mass index (BMI), patellofemoral involvement, and implant design on functional outcomes and prosthesis survival rates.
  
  
  METHODS
  Nine hundred and forty-four patients who underwent UKA at centres located in western France between 1988 and 2008 were re-evaluated. The IKS scores and KOOS were determined. Prosthesis survival according to various factors was assessed using the Kaplan-Meier method.
  
  
  RESULTS
  A clinical evaluation was performed in 720 cases after a mean follow-up of 62 months. The IKS function score improved by 23.6 points in men and 17.3 points in women (P=0.007). Ten-year prosthesis survival was 83.7% overall; 79% in women versus 87% in men (P<0.01); and 76.7% in patients younger than 70 years versus 88.3% in those 70 years or over (P<0.01). BMI had no significant influence on prosthesis survival. No significant differences between clinical outcomes or prosthesis survival were found across implant design categories.
  
  
  CONCLUSIONS
  The retrospective design and large number of centres and surgeons mandate caution when interpreting our results. Subgroup sizes were too small for an analysis of factors such as anterior cruciate ligament deficiency, BMI>40 kg/m(2), or cementless implant.
  
  
  METHODS
  Level IV, retrospective study.
authors.affiliation: Département de chirurgie orthopédique, CHU de Caen, avenue de la Côte-de-Nacre, Caen, France. Sebilo-a@chu-caen.fr
authors.forename: A
authors.initials: A
authors.lastname: Sébilo
authors.forename: C
authors.initials: C
authors.lastname: Casin
authors.forename: B
authors.initials: B
authors.lastname: Lebel
authors.forename: J-L
authors.initials: JL
authors.lastname: Rouvillain
authors.forename: S
authors.initials: S
authors.lastname: Chapuis
authors.forename: P
authors.initials: P
authors.lastname: Bonnevialle
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000295:instrumentation; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000209:etiology*; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D016896:Treatment Outcome