title: Partial lateral facetectomy plus Insall's procedure for the treatment of isolated patellofemoral osteoarthritis: survival analysis.
abstract: OBJECTIVE
  The purpose of this study was to report the survival analysis of partial lateral facetectomy and Insall's procedure in patients with isolated patellofemoral osteoarthritis, and to assess the risk and protective factors for failure of this procedure.
  
  
  METHODS
  From 1992 to 2004, all subjects with isolated patellofemoral osteoarthritis who met the inclusion criteria and underwent this procedure were enrolled. Risk and protective factors for failure (failure considered as the need for total knee arthroplasty) were assessed by comparing obtained baseline data between failed and non-failed cases. Eighty-seven cases (mean (SD) age 61.8 (7.7) years, mean (SD) follow-up 9.6 (3.2) years) were included.
  
  
  RESULTS
  Twenty-three failed cases were found. Mean (SD) survival time was 13.6 (0.5) years. At 13 years (last failure case), the cumulative survival was 59.3 %. Baseline medial tibiofemoral pain, genu flexum, and worst grade of tibiofemoral osteoarthritis were significant risk factors for failure (p < 0.0001, p = 0.02, p < 0.0001, respectively). In contrast, higher anatomical (p = 0.02) and total (p = 0.03) knee society score (KSS) scores, absence of knee effusion (p = 0.03), higher value of the Caton-Deschamps index (p = 0.03), and lateral position of the patella (p = 0.01) were all protective factors against failure.
  
  
  CONCLUSIONS
  The treatment for isolated patellofemoral osteoarthritis through partial lateral facetectomy and Insall's procedure demonstrated good long-term survival. The presence of preoperative medial tibiofemoral pain, genu flexum, and incipient tibiofemoral osteoarthritis increased the risk of failure of this procedure. In contrast, higher anatomical and total KSS scores, absence of knee effusion, higher value of the Caton-Deschamps index, and lateral position of the patella were found to protect against failure.
authors.affiliation: Department of Orthopaedic Surgery, Hospital de l'Esperança - Parc de Salut Mar, Parc de Salut Mar. Av. Sant Josep de la Muntanya, 12 6th floor, 08024, Barcelona, Spain, drfmontserrat@pulso.com.
authors.forename: Ferran
authors.initials: F
authors.lastname: Montserrat
authors.forename: Eduard
authors.initials: E
authors.lastname: Alentorn-Geli
authors.forename: Vicente
authors.initials: V
authors.lastname: León
authors.forename: Alberto
authors.initials: A
authors.lastname: Ginés-Cespedosa
authors.forename: Pau
authors.initials: P
authors.lastname: Rigol
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010329:Patella / Q000601:surgery*; D057071:Patellofemoral Joint / Q000601:surgery; D012307:Risk Factors; D016019:Survival Analysis; D017211:Treatment Failure