title: The trochlea is medialized by total knee arthroplasty: an intraoperative assessment in 61 patients.
abstract: BACKGROUND
  A medialization of the femoral component in a total knee arthroplasty (TKA) causes abnormal patellar tracking, which could result in patellar instability, pain, wear, and failure. Previous reports defined medialization in relation to the neutral position of the femoral component, but omitted to compare it to the anatomical position of the trochlea. We assessed intraoperatively whether there is a systematic error of the position of the prosthetic groove relative to the anatomical trochlea.
  
  
  METHODS
  A special instrument was developed to measure consecutively the mediolateral position of the anatomical trochlea and the mediolateral position of the prosthetic groove. 3 experienced knee surgeons determined the mediolateral error of the prosthetic groove in primary TKAs in 61 patients.
  
  
  RESULTS
  There was a significant medial error of the prosthetic groove relative to the preoperative position of the trochlea, with a mean medial error of 2.5 mm (SD 3.3)
  
  
  CONCLUSIONS
  Our findings indicate that the trochlea is medialized by TKA. Because a conscious medialization of the femoral component in a TKA produces abnormal patellar tracking patterns, further investigations will be needed to analyze the clinical consequences of this medialization of the trochlea.
authors: Department of Orthopaedics, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
authors: Huub J
authors: HJ
authors: Meijerink
authors: Marco
authors: M
authors: Barink
authors: Corné J M
authors: CJ
authors: van Loon
authors: Paul J A
authors: PJ
authors: Schwering
authors: Roland D
authors: RD
authors: Donk
authors: Nico
authors: N
authors: Verdonschot
authors: Maarten C
authors: MC
authors: de Waal Malefijt
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects; D001696:Biomechanical Phenomena; D006801:Humans; D007720:Knee Prosthesis / Q000009:adverse effects; D015588:Observer Variation; D010329:Patella / Q000473:pathology / Q000503:physiopathology; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular