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

Background: The pivot-shift test is commonly used for assessing dynamic instability in anterior cruciate ligament–insufficient knees, which is related to subjective knee function, unlike static load-displacement measurement. Conventional measurements of 3-dimensional position displacement cannot a...

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Bibliographic Details
Published in:The American journal of sports medicine 2007-07, Vol.35 (7), p.1098
Main Authors: Yuichi Hoshino, Ryosuke Kuroda, Kouki Nagamune, Masayoshi Yagi, Kiyonori Mizuno, Motoi Yamaguchi, Hirotsugu Muratsu, Shinichi Yoshiya, Masahiro Kurosaka
Format: Article
Language:English
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Summary:Background: The pivot-shift test is commonly used for assessing dynamic instability in anterior cruciate ligament–insufficient knees, which is related to subjective knee function, unlike static load-displacement measurement. Conventional measurements of 3-dimensional position displacement cannot assess such dynamic instability in vivo and produce comparable parameters. Not only 3-dimensional position displacement but also its 3-dimensional acceleration should be measured for quantitative evaluation of the pivot-shift test. Hypothesis: Knees with a positive pivot-shift test result have increased tibial anterior translation and acceleration of its subsequent posterior translation, and they are correlated with clinical grading. Study Design: Controlled laboratory study. Materials and Methods: Thirty patients with isolated anterior cruciate ligament injury were included. Pivot-shift tests were evaluated under anesthesia manually and experimentally using an electromagnetic knee 6 degrees of freedom measurement system. From 60 Hz of 6 degrees of freedom data, coupled tibial anterior translation was calculated, and acceleration of posterior translation was computed by secondary derivative. Results: All anterior cruciate ligament–deficient knees demonstrated a positive pivot-shift test result. The coupled tibial anterior translation was 7.7 and 15.6 mm in anterior cruciate ligament–intact and –deficient knees, respectively. The acceleration of posterior translation was −797 and −2001 mm/s 2 , respectively. These differences were significant ( P < .01). The coupled tibial anterior translation and acceleration of posterior translation in the anterior cruciate ligament–deficient knee were larger in correlation with clinical grading ( P = .03 and P < .01, respectively). Conclusion: The increase of tibial anterior translation and acceleration of subsequent posterior translation could be detected in knees with a positive pivot-shift result, and this increase was correlated to clinical grading. Clinical Relevance: These measurements can be used for quantified evaluation of dynamic instability demonstrated by the pivot-shift test. Keywords: pivot-shift test dynamic instability electromagnetic device ACL injury
ISSN:0363-5465
1552-3365
DOI:10.1177/0363546507299447