Jolt Test / Nakajima N-Test | Anterior Cruciate Ligament Tear
Around the time that the Pivot Shift test of Macintosh for the ACL was proposed, Nakajima et al. (1972) observed a similar jolt of the ACL-deficient knee during examination using their “n-test”. However, this procedure has not undergone diagnostic accuracy assessment and the clinical value thus remains questionable.
To conduct the test, the patient is in supine lying position. We are going to describe the procedure for the right knee.
The patient’s knee is flexed to 90°. Using your right hand, pick up the patient’s leg by grasping the lateral side of the ankle and applying internal rotation.
Your left hand rests on the lateral aspect of the patient’s knee and applies a valgus force. At the same time, place your thumb on the posterior aspect of the head of the fibula.
The knee is then gradually extended.
The test is positive if the tibial plateau suddenly subluxates anteriorly and medially with a palpable jolt that usually occurs at around 40-20 degrees of extension. The patient may also report that sensation as the “giving-way” feeling they experience during activities.
21 OF THE MOST USEFUL ORTHOPAEDIC TESTS IN CLINICAL PRACTICE
Other common tests to assess for an ACL tear are:
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