Immediate effects of an elastic patellar brace on pain, neuromuscular activity and knee kinematics in subjects with patellofemoral pain.

INTRODUCTION

The aim of this randomized controlled trial was to investigate immediate effects of a patellar brace on pain, neuromuscular activity, and knee kinematics in subjects with patellofemoral pain syndrome.

MATERIALS AND METHODS

Fifty subjects with a diagnosis of patellofemoral pain syndrome completed 6 activities each with and without a patellar brace in a randomized order. The subjects were asked to rate their perceived pain on a Visual Analog Scale after each activity. During the activities, neuromuscular activity of vastus medialis and vastus lateralis, as well as knee angles were measured.

RESULTS

Subjects showed a statistically significant pain reduction of 33-56% on the Visual Analog Scale during all activities while wearing the brace. Two groups with different onset patterns for vastus medialis and vastus lateralis were identified: one group who activated vastus medialis prior to vastus lateralis, and one who activated vastus medialis after vastus lateralis. In the subgroup of subjects activating vastus lateralis prior to vastus medialis, bracing resulted in a significantly (p = 0.048) earlier onset of vastus medialis by 56 ms. In all but one activity, the vastus medialis/vastus lateralis ratio without the patellar brace was < 1.0 and inverted with the patellar brace > 1.0. Knee angles in the sagittal plane increased significantly with the patellar brace in two activities.

CONCLUSION

Patellofemoral bracing results in an immediate decrease of pain, an earlier onset of vastus medialis and inverted vastus medialis/vastus lateralis ratio and altered knee kinematics.