title: Revision surgery for patellofemoral problems: should we always resurface?
abstract: BACKGROUND
  Routine patellar resurfacing performed at the time of knee arthroplasty is controversial, with some evidence of utility in both TKA (tricompartmental) and bicompartmental knee arthroplasty. However, whether one approach results in better implant survival remains unclear.
  
  
  OBJECTIVE
  We asked whether (1) routine patellar resurfacing in TKAs resulted in lower cumulative revision rates compared to bicompartmental knee arthroplasties, (2) patella-friendly implants resulted in lower cumulative revision rates than earlier designs, and (3) bicompartmental knee arthroplasties revised to TKAs had higher cumulative revision rates than primary TKAs.
  
  
  METHODS
  From a community-based joint registry, we identified 8135 patients treated with 9530 cemented, all-polyethylene patella TKAs and 627 bicompartmental knee arthroplasties without patellar resurfacing. We compared age, gender, year of index procedure, diagnosis, cruciate status, revision, and revision reason.
  
  
  RESULTS
  TKAs had a lower cumulative revision rate for patella-only revision than bicompartmental knee arthroplasties (0.8% versus 4.8%). Adjusting for age, bicompartmental knee arthroplasties were 6.9 times more likely to undergo patellar revision than TKAs. There was no difference in the cumulative revision rate for patella-only revisions between patella-friendly and earlier designs. The cumulative revision rate for any second revision after a patella-only revision was 12.7% for bicompartmental knee arthroplasties while that for primary TKAs was 6.3%.
  
  
  CONCLUSIONS
  Bicompartmental knee arthroplasties had higher revision rates than TKAs. Femoral component design did not influence the cumulative revision rate. Secondary patella resurfacing in a bicompartmental knee arthroplasty carried an increased revision risk compared to resurfacing at the time of index TKA. To reduce the probability of reoperation for patellofemoral problems, our data suggest the patella should be resurfaced at the time of index surgery.
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota Medical School, Minneapolis VAMC Section 112E, 1 Veterans Drive, Minneapolis, MN 55417, USA.
authors.forename: Todd C
authors.initials: TC
authors.lastname: Johnson
authors.forename: Penny J
authors.initials: PJ
authors.lastname: Tatman
authors.forename: Susan
authors.initials: S
authors.lastname: Mehle
authors.forename: Terence J
authors.initials: TJ
authors.lastname: Gioe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D057071:Patellofemoral Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D020959:Polyethylene / Q000009:adverse effects / Q000737:chemistry; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D012042:Registries; D012086:Reoperation; D018570:Risk Assessment; D016896:Treatment Outcome
chemical_list: D020959:Polyethylene