title: Secondary patellar resurfacing in the treatment of patellofemoral pain after total knee arthroplasty.
abstract: OBJECTIVE
  This paper reports a prospective review of patients who, between 2004 and 2007, underwent secondary patellar resurfacing (SPR) due to anterior knee pain after a primary total knee arthroplasty (TKA). The aim was to evaluate the clinical outcomes obtained with the SPR and to compare them with radiological findings.
  
  
  METHODS
  A total of twenty-seven consecutive patients met the inclusion criteria. There were twenty-three (85%) women and four (15%) men with a median age of 70 years. The patients were evaluated before and after the surgery with the same functional scores and radiological parameters. Bone scintigraphy was also used in the assessment, and a CT-scan was performed in order to evaluate the femoral component rotation. The median time between TKA and SPR was 18 months.
  
  
  RESULTS
  With a median follow-up of 23 months, seventeen patients (63%) reported a clear subjective improvement after SPR, and patellofemoral scores (primary outcome measure), KSS and WOMAC (secondary outcome measures) showed a statistically significant improvement following the procedure. There were no significant changes after SPR in the Insall-Salvati ratio, the lateral patellar displacement or the lateral patellar tilt. The mean time between TKA and SPR had no statistically significant effect on outcome. The bone scintigraphy revealed increased patellar uptake in seven cases, but this was not related to subsequent improvement after SPR. Rotational computed tomography showed a median internal rotation of the femoral component of 1º. The complications observed were a patellar component loosening and an acute post-infection.
  
  
  CONCLUSIONS
  No clinical or radiological parameter was found to be related to the final outcome after SPR. There was a discrepancy between functional scale scores and the patient's subjective satisfaction.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Unit of Knee, Hospital Clínic of Barcelona, University of Barcelona, C/Villarroel 170, 08036 Barcelona, Spain. e.munoz.mahamud@gmail.com
authors.forename: E
authors.initials: E
authors.lastname: Muñoz-Mahamud
authors.forename: D
authors.initials: D
authors.lastname: Popescu
authors.forename: E
authors.initials: E
authors.lastname: Nuñez
authors.forename: L M
authors.initials: LM
authors.lastname: Lozano
authors.forename: M
authors.initials: M
authors.lastname: Nuñez
authors.forename: S
authors.initials: S
authors.lastname: Sastre
authors.forename: P
authors.initials: P
authors.lastname: Torner
authors.forename: J M
authors.initials: JM
authors.lastname: Segur
authors.forename: F
authors.initials: F
authors.lastname: Maculé
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D010149:Postoperative Pain / Q000175:diagnosis / Q000601:surgery*; D046788:Patellofemoral Pain Syndrome / Q000209:etiology* / Q000601:surgery*; D017060:Patient Satisfaction; D011446:Prospective Studies; D011859:Radiography; D020127:Recovery of Function; D012086:Reoperation / Q000379:methods; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D016896:Treatment Outcome