title: Association between measures of patella height, morphologic features of the trochlea, and patellofemoral joint alignment: the MOST study.
abstract: BACKGROUND
  Patellofemoral joint (PFJ) malalignment (lateral patella displacement and tilt) has been proposed as a cause of patellofemoral pain. Patella height and/or the morphologic features of the femoral trochlea may predispose one to patella malalignment.
  
  
  OBJECTIVE
  The purposes of our study were to assess the associations among patella height, morphologic features of the trochlea, and measures of PFJ alignment and to determine which measures of patella height and morphologic features of the trochlea were the best predictors of PFJ alignment.
  
  
  METHODS
  Measures of patella height (Insall-Salvati ratio and modified Insall-Salvati ratio), morphologic features of the trochlea (sulcus angle, trochlear angle, lateral trochlear inclination, medial trochlear inclination), and PFJ alignment (bisect offset and patella tilt angle) were assessed in 566 knees from the Multicenter Osteoarthritis Study.
  
  
  RESULTS
  Bisect offset was correlated with the Insall-Salvati ratio (r = 0.25) and lateral trochlear inclination (r = -0.38). Patella tilt angle correlated with the trochlear angle (-0.27) and lateral trochlear inclination (-0.32). Linear regression models including the Insall-Salvati ratio and lateral trochlear inclination explained 20% and 11% of the variance in bisect offset and patella tilt angle, respectively.
  
  
  CONCLUSIONS
  Of the variables measured in the current study, the Insall-Salvati ratio and lateral trochlear inclination were the best predictors of lateral patella displacement and lateral tilt. This knowledge will aid clinicians in the identification of anatomic risk factors for PFJ malalignment and/or PFJ dysfunction.
authors.affiliation: Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, 650 Albany Street, Suite 200, Boston, MA 02118, USA. stefanik@bu.edu
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Stefanik
authors.forename: Ann C
authors.initials: AC
authors.lastname: Zumwalt
authors.forename: Neil A
authors.initials: NA
authors.lastname: Segal
authors.forename: John A
authors.initials: JA
authors.lastname: Lynch
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Powers
mesh_terms: D000407:Alabama; D059925:Anatomic Landmarks; D018771:Arthralgia / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D007484:Iowa; D007593:Joint Instability / Q000175:diagnosis* / Q000503:physiopathology; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000503:physiopathology; D010329:Patella / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D057071:Patellofemoral Joint / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D012307:Risk Factors
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