McConnell taping shifts the patella inferiorly in patients with patellofemoral pain: a dynamic magnetic resonance imaging study

Abstract

Background: Patellar taping is widely used clinically to treat patients with patellofemoral pain syndrome (PFPS). Although patellar taping has been demonstrated to reduce patellofemoral pain in patients with PFPS, the kinematic source for this pain reduction has not been identified.

Objective: The purpose of this study was to quantify the changes in the 6-degrees-of-freedom patellofemoral kinematics due to taping in patients with PFPS.

Design: A within-subject design and a sample of convenience were used.

Participants: Fourteen volunteers (19 knees) who were diagnosed with patellofemoral pain that was present for a year or longer were included. Each knee had to meet at least 1 of the following inclusion criteria: Q-angle of > or =15 degrees, a positive apprehension test, patellar lateral hypermobility (> or =10 mm), or a positive "J sign."

Methods: Each knee underwent 2 randomly ordered testing conditions (untaped and taped). A full fast-phase contrast (PC) magnetic resonance image set was acquired for each condition while the participants volitionally extended and flexed their knee. Three-dimensional displacements and rotations were calculated through integration of the fast-PC velocity data. Statistical comparisons between baseline patellofemoral kinematics and the change in kinematics due to taping were performed using a 2-tailed paired Student t test. Correlations between baseline patellofemoral kinematics and the change in kinematics due to taping also were quantified.

Results: Patellar taping resulted in a significant patellofemoral inferior shift. The strongest correlation existed between the change in lateral-medial displacement with taping and baseline (r=-.60).

Conclusions: The inferior shift in patellar displacement with taping partially explains the previously documented decrease in pain due to increases in contact area. The lack of alteration in 5 of the 6 kinematic variables with taping may have been due to the fact that post-taping kinematic alterations are sensitive to the baseline kinematic values.

Figure 1.

Patellofemoral kinematics in the untaped and taped conditions: Each variable is plotted relative to knee extension, with full extension being equal to zero (participant movement is read from left to right). Data were interpolated to 1-degree knee angle increments, but symbols are provided at every 5 degrees for clarity. One standard deviation bars are provided. The dotted line represents a knee extension angle of 8 degrees. The top row contains displacements (medial, superior, and anterior are the positive directions, respectively), and the bottom row contains the rotations (flexion, medial tilt, and varus rotation are the positive directions, respectively). Δdisp=changed in displacement.

Figure 2.

Change in kinematics with taping (taped and untaped conditions) versus baseline. The 3 variables with significant correlations between the change with taping and the baseline value are shown (top row: lateral to medial displacement and lateral to medial tilt; bottom row: valgus to varus rotation and legend to symbols). The x-axis indicates the untaped value of each variable (positive values indicate medial displacement, medial tilt, and varus rotation). The y-axis indicates the change in each variable with taping (positive values indicate medial displacement, medial tilt, and varus rotation with taping, shown by gray shading). The regression lines are shown for each variable set using a thick black line. Based on previous work, the average value for an asymptomatic cohort (untaped, n=34) for each of the 3 variables is shown using a vertical dashed line (medial displacement=−0.11 mm, medial tilt=14.7, varus rotation=0.52°). All graphs represent kinematics at 10 degrees of knee extension. Participants who were laterally translated, laterally tilted, and in valgus rotation (relative to the asymptomatic population) are shown in blue. This distinction is independent for each graph. Thus, a single participant who demonstrated medial displacement and lateral tilt at baseline would be designated by 2 different colors in each of the respective graphs.