In Vivo Measurement of the Pivot-Shift Test in the Anterior Cruciate Ligament—Deficient Knee Using an Electromagnetic Device

Abstract

These measurements can be used for quantified evaluation of dynamic instability demonstrated by the pivot-shift test.

Electromagnetic tracking of the pivot-shift

“…The maximum differences between invasive and non-invasive results were 0.85 mm in anterior translation, 1.92°in rotation, and 0.62°in abduction [18]. Considering that the increase of the tibial translation and rotation due to ACL resection is more than 5 mm and 2°according to a report using the robotic system [32], the non-invasive application of the electromagnetic tracking system had an acceptable measurement accuracy to communicate the abnormal knee kinematics in ACL-deficient knees.…”

“…Non-invasive usage of the electromagnetic tracking system was then attempted to broaden its application in our clinical practice [17,18]. An electromagnetic tracking device with a high sampling rate, i.e., 60 or 240 Hz (FASTRAK or LIBERTY, respectively, Polhemus, Colchester, VT, USA), was utilized [17, 18, 25•, 26••, 27].…”

“…The pivot-shift test provides a rough four-grade evaluation, such as none (−), glide (+), clunk (++), and gross (+++), according to the magnitude of the pivot-shift phenomenon, and the clinical grading is determined in a highly subjective way based on the examiner's feeling [13][14][15][16]. In order to achieve more objective evaluation of the pivot-shift test, various measurement systems have been developed, such as an electromagnetic tracking system, a navigation system, an image analysis, and an accelerometer [17][18][19][20][21][22][23][24].…”

Basic biomechanic principles of knee instability

“…This has established the need for continued development and validation of new technologies to detect and quantify the pivot shift with ease of use for patients and clinicians alike. New technologies utilizing simple image analysis of anterior tibial translation and the measurement of lateral compartment acceleration during the tibial reduction have been utilized, and their output was shown to correlate with the clinical grade of pivot shift [26][27][28][29]. The most recent studies concerning the emerging techniques for objective quantification of the pivot shift and their clinical significance will be described within this chapter.…”

Kinematic outcomes following ACL reconstruction

“…Another approach to quantify the pivot shift exam aims for measuring the acceleration during the tibial reduction, as acceleration of posteriorly directed translation has been shown to be significantly higher in ACL deficient knees and may correlate with the clinical grading of the pivot shift [129]. For this purpose, commercial inertial sensors, consisting of a 3D accelerometer and three perpendicularly arranged gyroscopes, are attached to the lateral aspect of the proximal tibia, close to Gerdy's tubercle.…”