Abstract
We present a simple seated dial test that can be used by a single examiner in the acute or chronic situation to diagnose posterolateral corner knee injury.
In the acute setting a traditional prone dial test can be cumbersome and painful for patients. Therefore a supine technique can be utilised, however this requires an assistant in order to hold the knees together with the tibia in a reduced position. We therefore utilise a seated technique in which the patient sits with their knees flexed over the edge of the examination couch. The patient is then able to hold their knees together, negating the need for an assistant. The sensitivity of a dial test is improved if the knee is reduced and so with this technique the tibia will be held in the anatomical position by the examination couch.
The patients' feet are grasped with both medial malleoli together and then an external rotation moment is exerted at 30 and 90 degrees of flexion measuring the thigh-foot angle or visualising the tibial tuberosities. A positive test being 10 degrees or more of increased external rotation in the affected knee.
This test is similar to the Spin test however it relies on the tactile sensation of posterolateral tibial rotation. This can be difficult to elicit in the acute situation due to haemarthrosis. Simultaneous side-to-side comparison is also not possible. A further disadvantage of the Spin test is that it can only be performed at 90 degrees of flexion and so only applies in combined PCL and posterolateral corner repair.
In conclusion we believe that this modification of the standard dial test is a simple to perform accurate method for assessing posterolateral corner knee injury in the acute and chronic setting.
