Kinematic magnetic resonance imaging of the effect of bracing on patellar position: qualitative assessment using an extremity magnetic resonance system.

OBJECTIVE

To use an extremity magnetic resonance system to perform kinematic magnetic resonance imaging (MRI) of the patellofemoral joint to qualitatively assess the effect of bracing on patellar position.

DESIGN AND SETTING

Subjects underwent kinematic MRI of the symptomatic extremity with a 0.2-Tesla extremity magnetic resonance system. Images were obtained using a knee coil and a T1-weighted, spin echo pulse sequence.

SUBJECTS

Seven female patients with patellofemoral joint symptoms.

MEASUREMENTS

FOUR DIFFERENT AXIAL SECTIONS WERE OBTAINED FOR EACH POSITION: extension and 3 positions of flexion up to 36 degrees . An appropriate-sized patellofemoral brace was applied, and the kinematic MRI procedure was repeated.

RESULTS

Six patients had lateral displacement of the patella, and 1 patient had medial displacement of the patella. After application of the brace, 6 patients (5 with lateral displacement and 1 with medial displacement, 86%) exhibited correction (5) or improvement (1 with lateral displacement) in the abnormal patellar positions, and 1 patient had worsening of the abnormal position of the patella.

CONCLUSIONS

We used kinematic MRI to determine the presence of abnormal patellar positioning. Application of the brace counteracted the abnormal patellar positions in most of the patients studied.