Patellar Kinematics, Part II: The Influence of the Depth of the Trochlear Groove in Subjects With and Without Patellofemoral Pain

Background and Purpose. A shallow intercondylar groove has been implicated as being contributory to abnormal patellar alignment. The purpose of this study was to assess the influence of the depth of the intercondylar groove on patellar kinematics. Subjects. Twenty-three women (mean age=26.8 years, SD=8.5, range=14–46) with a diagnosis of patellofemoral pain and 12 women (mean age=29.1 years, SD=5.0, range=24–38) without patellofemoral pain participated. Only female subjects were studied because of potential biomechanical differences between sexes. Methods. Patellar kinematics were assessed during resisted knee extension using kinematic magnetic resonance imaging. Measurements of medial and lateral patellar displacement and tilt were correlated with the depth of the trochlear groove (sulcus angle) at 45, 36, 27, 18, 9, and 0 degrees of knee flexion using regression analysis. Results. The depth of the trochlear groove was found to be correlated with patellar kinematics, with increased shallowness being predictive of lateral patellar tilt at 27, 18, 9, and 0 degrees of flexion and of lateral patellar displacement at 9 and 0 degrees of flexion (r=.51–.76). Conclusions and Discussion. The results of this study indicate that bony structure is an important determinant of patellar kinematics at end-range knee extension (0°–30°).