Clinical Orthopaedics and Related Research®

, Volume 471, Issue 8, pp 2641–2648

Association Between Measures of Patella Height, Morphologic Features of the Trochlea, and Patellofemoral Joint Alignment: The MOST Study

  • Joshua J. Stefanik
  • Ann C. Zumwalt
  • Neil A. Segal
  • John A. Lynch
  • Christopher M. Powers
Clinical Research

DOI: 10.1007/s11999-013-2942-6

Cite this article as:
Stefanik, J.J., Zumwalt, A.C., Segal, N.A. et al. Clin Orthop Relat Res (2013) 471: 2641. doi:10.1007/s11999-013-2942-6



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.


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.


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.


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.


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.

Level of Evidence

Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Copyright information

© The Association of Bone and Joint Surgeons® 2013

Authors and Affiliations

  • Joshua J. Stefanik
    • 1
  • Ann C. Zumwalt
    • 5
  • Neil A. Segal
    • 2
  • John A. Lynch
    • 3
  • Christopher M. Powers
    • 4
  1. 1.Clinical Epidemiology Research and Training UnitBoston University School of MedicineBostonUSA
  2. 2.University of IowaIowa CityUSA
  3. 3.University of CaliforniaSan FranciscoUSA
  4. 4.University of Southern CaliforniaLos AngelesUSA
  5. 5.Department of Anatomy and NeurobiologyBoston University School of MedicineBostonUSA