title: Does patellectomy jeopardize function after TKA?
abstract: BACKGROUND
  The patella provides important mechanical leverage to the knee extensor mechanism. Patellectomy does not exclude the development of tibiofemoral arthrosis.
  
  
  OBJECTIVE
  We asked whether (1) TKA provides improvements in clinical outcome scores in patellectomized knees and (2) the scores of TKA in patellectomized knees are comparable to those in knees with intact patellae.
  
  
  METHODS
  We evaluated 50 patients (52 primary TKAs) with patellectomized knees and a control group of 52 patients (52 primary TKAs) with intact patellae matched for age, sex, implant, and surgical year between 1984 and 2009. We compared the preoperative and latest postoperative SF-12, WOMAC, and Knee Society score (KSS). Minimum followup was 24 months (mean, 69 months; range, 24-204 months).
  
  
  RESULTS
  The mean WOMAC score in the control group improved from 41.8 (range, 7.5-72.4) preoperatively to 69.1 (range, 17.0-100.0) postoperatively, while that in the patellectomized group improved from 35.8 (range, 5.2-62.2) to 61.3 (range, 17.5-96.2). The mean KSS improved from 80.4 (range, 4.0-143.0) preoperatively to 161.4 (range, 69.0-200.0) postoperatively in the control group and from 76.9 (range, 5-134) to 136.8 (range, 7-199) in the patellectomized group. Mean postoperative WOMAC scores were comparable between the two groups, while the mean KSS was lower in the patellectomized group. The mean SF-12 scores were not different after TKA or between groups.
  
  
  CONCLUSIONS
  Despite the mechanical disadvantage to the knee extensor mechanism rendered by a previous patellectomy, TKA for tibiofemoral arthrosis in these patients relieved pain and restored function, but function was on average lower than that in patients with intact patellae.
  
  
  METHODS
  Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Division of Orthopaedic Surgery, University of Western Ontario & London Health Sciences Centre, University Campus, 339 Windermere Road, London, ON, N6A 5A5, Canada.
authors.forename: Reina
authors.initials: R
authors.lastname: Yao
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Lyons
authors.forename: James L
authors.initials: JL
authors.lastname: Howard
authors.forename: James P
authors.initials: JP
authors.lastname: McAuley
mesh_terms: D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery*; D010146:Pain / Q000503:physiopathology / Q000601:surgery*; D010147:Pain Measurement; D010329:Patella / Q000503:physiopathology / Q000601:surgery*; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D016896:Treatment Outcome