title: The influence of applied internal and external rotation on the pivot shift phenomenon.
abstract: OBJECTIVE
  The pivot shift test is performed in different techniques and the rotation of the tibia seems to have a significant impact on the amount of the pivot shift phenomenon. It has been hypothesised that external rotation will increase the phenomenon due to less tension at the iliotibial band in knee extension.
  
  
  METHODS
  Twenty-four patients with unilateral anterior cruciate ligament insufficiency were included prospectively. The pivot shift test was performed bilaterally in internal and external tibial rotation under general anaesthesia. Knee motion was captured using a femoral and a tibial inertial sensor. The difference between positive and negative peak values in Euclidean norm of acceleration was calculated to evaluate the amount of the pivot shift phenomenon.
  
  
  RESULTS
  The pivot shift phenomenon was significantly increased in patients with ACL insufficiency when the test was performed in external [mean 5.2 ms- 2(95% CI 4.3-6.0)] compared to internal tibial rotation [mean 4.4 ms- 2(95% CI 3.5-5.4)] (p = 0.002). In healthy, contralateral knees did not show any difference between external [mean 4.0 ms- 2(95% CI 3.3-4.7)] and internal tibial rotation [mean 4.0 ms- 2(95% CI 3.4-4.6)] (ns).
  
  
  CONCLUSIONS
  The pivot shift phenomenon was increased with external rotation in ACL-insufficient knees, and therefore, one should perform the pivot shift test, rather, in external rotation to easily evoke the, sometimes difficult to detect, pivot shift phenomenon.
  
  
  METHODS
  I (diagnostic study).
authors.affiliation: Center for Musculoskeletal Surgery, Charité-University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany. Sebastian.kopf@charite.de.
authors.forename: Sebastian
authors.identifier: http://orcid.org/0000-0003-4373-7144
authors.initials: S
authors.lastname: Kopf
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Volker
authors.initials: V
authors.lastname: Musahl
authors.affiliation: Center for Musculoskeletal Surgery, Charité-University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Perka
authors.affiliation: Institute of Micro and Sensor Systems, Otto-von-Guericke-University, Magdeburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kauert
authors.affiliation: Center for Musculoskeletal Surgery, Charité-University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Arnd
authors.initials: A
authors.lastname: Hoburg
authors.affiliation: Department of Orthopaedic and Traumatology, Medical School Theodor Fontane, Brandenburg, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Becker
mesh_terms: D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries / Q000503:physiopathology*; D001696:Biomechanical Phenomena / Q000502:physiology; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007719:Knee Joint / Q000503:physiopathology*; D010808:Physical Examination / Q000379:methods*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology; D012399:Rotation
keywords: Anterior cruciate ligament; External and internal tibial rotation; Inertial sensor; Knee; Pivot shift