title: [Patellofemoral arthroplasty].
abstract: OBJECTIVE
  Isolated resurfacing of the trochlea using an inlay prosthesis without changing the complex kinematics of the patellofemoral joint.
  
  
  METHODS
  Symptomatic, isolated patellofemoral osteoarthritis or isolated osteochondral lesions, failed conservative and cartilage regeneration procedures. No or concurrently corrected ligament instability, tibiofemoral and patellofemoral malalignment.
  
  
  METHODS
  Symptomatic patellofemoral osteoarthritis, inflammatory joint disease, chondrocalcinosis, chronic pain syndromes, active infections or knee ankylosis.
  
  
  METHODS
  Following a medial arthrotomy, coronal and sagittal curvatures of the trochlea are measured. Based on these measurements, corresponding surface reamers create an implant bed by removing damaged cartilage of the trochlea. A central fixation screw is placed to the desired depth and the inlay prosthesis is tapped carefully onto it. Final placement of the prosthesis is targeted slightly recessed to the surrounding joint surface.
  
  
  METHODS
  Free passive range of motion exercises of the knee joint are recommended starting on postoperative day 1. Depending on symptoms (e.g., pain and joint effusion), partial weight-bearing of 20 kg is allowed during postoperative weeks 1 and 2, which is increased by 20 kg/week thereafter.
  
  
  RESULTS
  In a prospective study of 29 patients (mean age: 42 years) treated with inlay arthroplasty, 2‑year follow-up results showed significant improvements (p < 0.05) in WOMAC, IKDC and VAS (pain) scores when compared to baseline. Compared to onlay PF arthroplasty modern inlay prosthetic placement showed a better preservation of the tibiofemoral joint without progression of tibiofemoral degeneration. This may be due to possible avoidance of patellofemoral overstuffing using a more physiological placement of the inlay prosthesis.
authors.affiliation: Abteilung für Sportorthopädie, Klinikum Rechts der Isar, TU München, Ismaninger Str. 22, 81675, München, Deutschland.
authors.forename: M
authors.initials: M
authors.lastname: Cotic
authors.affiliation: Abteilung für Sportorthopädie, Klinikum Rechts der Isar, TU München, Ismaninger Str. 22, 81675, München, Deutschland.
authors.forename: P
authors.initials: P
authors.lastname: Forkel
authors.affiliation: Abteilung für Sportorthopädie, Klinikum Rechts der Isar, TU München, Ismaninger Str. 22, 81675, München, Deutschland. Imhoff@tum.de.
authors.forename: A B
authors.initials: AB
authors.lastname: Imhoff
mesh_terms: D000328:Adult; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation / Q000379:methods* / Q000534:rehabilitation*; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000601:surgery*; D057071:Patellofemoral Joint / Q000601:surgery*; D011474:Prosthesis Design; D016896:Treatment Outcome
keywords: Arthroplasty, knee replacement; Bone malalignment; Osteoarthritis, knee; Patellofemoral joint; Prostheses and implants