Tibiofemoral kinematics in the transverse and frontal planes influence the location and magnitude of peak patella cartilage stress: An investigation of runners with and without patellofemoral pain.

Abstract

To determine whether the location and magnitude of peak patella cartilage stress varies among runners with and without patellofemoral pain. To determine whether tibiofemoral kinematics in the frontal and transverse planes predict peak lateral and medial patella cartilage stress. Twelve recreational runners with patellofemoral pain and 10 pain-free controls participated. Peak patella cartilage stress was quantified using finite element models that incorporated subject-specific kinematic and kinetic data obtained during running. Chi-square analysis was used to determine whether the location of peak patella cartilage stress (medial or lateral) varied between groups. Student's t-tests were used to determine whether the magnitude of peak medial and lateral patella cartilage stress varied between groups. In addition, stepwise regression analysis was performed to determine if tibiofemoral kinematics were predictive of peak medial and lateral cartilage stress. Among all subjects, 64% exhibited peak cartilage stress on the lateral patella facet. No group differences were found for the location and magnitude of peak cartilage stress on the medial or lateral facets. Tibiofemoral rotation in the transverse plane was the best predictor of peak lateral stress (45% of the variance, r = 0.67). Tibiofemoral rotation in the transverse plane was the best predictor of peak medial stress (44% of the variance, r = -0.67), followed by tibiofemoral rotation in the frontal plane (26% of the variance, r = 0.57). The location and magnitude of peak patella cartilage stress was similar among runners with and without patellofemoral pain. Tibiofemoral kinematics in the frontal and transverse planes are predictive of cartilage stress on the medial and lateral patella facets.