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Pivot Study Group Project Update
Pivot Study Group
Yuichi Hoshino, MD, PhD, Japan 1
Additional Authors:
Volker Musahl, MD, USA2
Ryosuke Kuroda, MD, Japan1
Stefano Zaffagnini, MD, Italy3
Kristian Samuelsson, MD, PhD, MSc, Sweden4 Nicola Lopomo, PhD, MSc Eng, Italy 3
James J. Irrgang, PT, PhD, ATC, FAPTA, USA2 Chad J. Griffith, MD, USA 2
Jon Karlsson, MD, PhD, Sweden4
Freddie H. Fu, MD, USA2
1 Kobe University, Kobe, JAPAN
2 University of Pittsburgh, Pittsburgh, PA, USA
3 Bologna University, Bologna, ITALY
4 University of Gothenburg, Gothenburg, SWEDEN
ISAKOS is world renowned as an international society of expert orthopaedic surgeons, which provides and enhances the standard of medical care in sports medicine. The wide diversity of languages spoken during ISAKOS meetings is analogous to the worldwide lack of standardization in the pivot shift test. Due to its global influence, no group outside of ISAKOS could establish a globally accepted standardized language for evaluation of knee rotational laxity.
During the 8th ISAKOS congress in Rio de Janeiro, Brazil, the very first conversations were held regarding the lack of standardization in clinical evaluation for rotational laxity in the ACL injured knee. A study group was formed to establish a standard and clinically relevant objective measure of the pivot shift test.
There were numerous issues in the evaluation of rotational laxity. Several quantitative measurement tools had been developed to assess the pivot shift test, but they had not been validated. In addition, the execution of the testing maneuver was quite varied from place to place. To date, there are no measurement systems for the pivot shift test which accurately evaluate knee function and joint pathology, as well as guide surgical decision-making and predict outcomes.
The PIVOT group determined that a clinically relevant, objective, and comparable measurement should be established for the evaluation of the knee rotational laxity. As a first step, a preliminary in-vitro study was conducted in 2011 during the Panther Summit meeting in Pittsburgh, USA, to provide scientific base of the quantitative pivot shift measurement systems. As a result, some measurement tools were validated by comparing the direct bony measurement and the benefit of the standardized testing maneuver was demonstrated to reduce the measurement variability. Based on that basic study, an international multicenter clinical study was designed with funding applied for through the ISAKOS / OREF Research Grant.
In short, over 100 ACL injured patients have had their knees tested by the standardized pivot shift test (Fig. 1). The knee movement is quantitatively measured by two systems, an image based iPad system and inertial sensors in the same manner (Fig. 1).
Pre- and post-operative evaluations are collected and compared to several clinical measures, such as subjective knee function, clinical pathology, and outcome after the ACL reconstruction.
Our intermittent results of this multicenter study have been presented in previous meetings (Fig. 2). Principal preliminary results were:
1) possible relationship between quantitative measurement and clinical grading of the pivot shift test (Fig. 2),
2) successfully reduced rotational laxity by the ACL reconstruction, and
3) mutual validation between iPad and inertial sensor systems.
The ultimate goal of this study group is to establish a universal, reproducible, and clinically relevant objective measurement of the pivot shift test. The common language for addressing rotational instability will be available in near future through ISAKOS. We are always welcome to your questions and suggestions.
RESEARCH REPORT
Please feel free to contact us
Volker Musahl: musahlv@upmc.edu
Yuichi Hoshino: you.1.hoshino@gmail.com
01 Fig. 1 02 Fig. 2
Simultaneous measurement of the pivot shift test using iPad and accelerometer in four institutions.
Intermittent result of pivot shift measurements in 33
ACL deficient knees. Tibial translation measured by iPad demonstrated stepwise increase along with clinical grading (Left). Tibial acceleration measured by the accelerometer had a similar tendency without a statistical significance.
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ISAKOS NEWSLETTER 2015: VOLUME I 21