A NEW TOOL TO OBJECTIVE ASSESSMENT OF ROTATIONAL INSTABILITY AND ACL/PCL DEFICIENT KNEES INSIDE MAGNETIC RESONANCE IMAGING OR CT SCAN.
Porto Knee Testing Device

THE PKTD®, A KNEE LAXITY TESTING DEVICE FOR MEASUREMENT OF ANTEROPOSTERIOR, POSTEROANTERIOR TIBIAL TRANSLATION AND INTERNAL/EXTERNAL ROTATION DURING THE MRI/CT-SCAN EXAMINATION.

This device is made of a plastic polyurethane allowing it to be used during MRI/CT-scan, in positions in which the knee is placed under stress caused by plungers and its supporting pieces that force the leg with a standardized pressure applied in its proximal third, in the anterior or posterior direction (fig. 2, A&B) and lateral and medial side of the foot.

Porto Knee Testing Device Protocol

FIG. 1


Although the device can now be adjusted to different degrees of knee flexion, and different degrees of external/internal rotation inflected by the footplate, all exams herein described were performed at 20° to 30° of flexion. The foot rests in the plantigrade position and initial “neutral” rotation; foot position is determined in each case by dorsiflexion of the ankle (locking effect of talus in ankle mortise); then other images are acquired with internal or external pressure application.

The measurements are determined using two sets of MRI (closed or open MRI) images with 1mm spacing, one without (at rest) and another with the application of pressure and 3D reconstructions. Both injured and healthy knees can be evaluated.

 

Porto Knee Testing Device Protocol

FIG. 2-A

 

Porto Knee Testing Device

FIG. 2-B