title: [Patellofemoral arthroplasty: indication, technique and results].
abstract: BACKGROUND
  Although patellofemoral arthroplasty has been used for more than 30 years, it is still a challenging subject in orthopedics. The reason for this are the complex kinematics of the patellofemoral joint which are influenced by dynamic and static factors. New implant concepts that incorporate multiple coronal and sagittal curvatures and surface controlled inlay implantation show a positive direction in modern patellofemoral arthroplasty.
  
  
  OBJECTIVE
  The purpose of this work is the review of the literature on patellofemoral arthroplasty and the presentation of our own experience.
  
  
  METHODS
  We present indications and surgical techniques of patellofemoral arthroplasty as well as the most important aspects of preoperative evaluation. The patellofemoral joint can be reconstructed using either an inlay or an onlay prosthesis. Both arthroplasty concepts are discussed. Additional pathologies like chronic patellofemoral instabilities due to dysplasia, valgus/varus or rotational malalignment, and soft-tissue alterations are addressed with concomitant procedures.
  
  
  RESULTS
  Both inlay and onlay arthroplasty have demonstrated good functional outcome scores in patients with patellofemoral osteoarthritis. Patients with patellofemoral instability and/or trochlear dysplasia may benefit more from patellofemoral arthroplasty than patients with primary osteoarthritis because not only pain but also secondary pathologies are addressed.
  
  
  CONCLUSIONS
  Patellofemoral arthroplasty is an effective and safe procedure if the indication criteria are respected and the specific surgical technique is used. However, comparative results on current inlay and onlay prostheses have not been published in the literature to date.
authors.affiliation: Abteilung für Sportorthopädie, Klinikum Rechts der Isar, TU München, Ismaninger Straße 22, 81675, München, Deutschland.
authors.forename: M
authors.initials: M
authors.lastname: Cotic
authors.forename: A B
authors.initials: AB
authors.lastname: Imhoff
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000601:surgery*; D057071:Patellofemoral Joint / Q000601:surgery*; D011300:Preoperative Care / Q000379:methods; D011474:Prosthesis Design; D020127:Recovery of Function; D016896:Treatment Outcome