Dynamic simulation of tibial tuberosity realignment: model evaluation

Abstract

This study was performed to evaluate a dynamic multibody model developed to characterize the influence of tibial tuberosity realignment procedures on patellofemoral motion and loading. Computational models were created to represent four knees previously tested at 40°, 60°, and 80° of flexion with the tibial tuberosity in a lateral, medial and anteromedial positions. The experimentally loaded muscles, major ligaments of the knee, and patellar tendon were represented. A repeated measures ANOVA with post-hoc testing was performed at each flexion angle to compare data between the three positions of the tibial tuberosity. Significant experimental trends for decreased patella flexion due to tuberosity anteriorization and a decrease in the lateral contact force due to tuberosity medialization were reproduced computationally. The dynamic multibody modeling technique will allow simulation of function for symptomatic knees to identify optimal surgical treatment methods based on parameters related to knee pathology and pre-operative kinematics.

Keywords: biomechanics; dynamic model; kinematics; knee; patellofemoral joint; tuberosity realignment.

Figures

Figure 1

(A) Computational representation of a knee on the testing frame, including representation of the ostetomized tibial tuberosity and simulated quadriceps and hamstrings forces. (B) Frontal and back views of the knee joint with ligamentous structures.

Figure 2

Average (+ standard deviation) patellar flexion from computational simulation and the in vitro experimental study. Significant differences at a flexion angle due to altering the position of the tibial tuberosity are marked with different small letters (a > b). A significant difference between the experimental and computational data at 80° of flexion is also marked (A > B).

Figure 3

Average (+ standard deviation) patellar lateral shift from computational simulation and the in vitro experimental study. Significant differences at a flexion angle due to altering the position of the tibial tuberosity are marked with different letters (a > b).

Figure 4

Average (+ standard deviation) patellar lateral tilt from computational simulation and the in vitro experimental study. No significant differences were identified due to altering the position of the tibial tuberosity.

Figure 5

Average (+ standard deviation) tibial external rotation from computational simulation and the in vitro experimental study. Significant differences at a flexion angle due to altering the position of the tibial tuberosity are marked with different letters (a > b).

Figure 6

Average (+ standard deviation) lateral force percentage from computational simulation and the in vitro experimental study. Significant differences at a flexion angle due to altering the position of the tibial tuberosity are marked with different letters (a > b).