title: Mechanical tensile properties of the anterolateral ligament.
abstract: BACKGROUND
  In a noticeable percentage of patients anterolateral rotational instabilities (ALRI) remain after an isolated ACL reconstruction. Those instabilities may occur due to an insufficiently directed damage of anterolateral structures that is often associated with ACL ruptures. Recent publications describe an anatomical structure, termed the anterolateral ligament (ALL), and suggest that this ligament plays a significant role in the pathogenesis of ALRI of the knee joint. However, only limited knowledge about the biomechanical characteristics and tensile properties of the anterolateral ligament exists.
  
  
  METHODS
  The anterolateral ligament was dissected in four fresh-frozen human cadaveric specimens and all surrounding tissue removed. The initial length of the anterolateral ligament was measured using a digital caliper. Tensile tests with load to failure were performed using a materials testing machine. The explanted anterolateral ligaments were histologically examined to measure the cross-sectional area.
  
  
  RESULTS
  The mean ultimate load to failure of the anterolateral ligament was 49.90 N (± 14.62 N) and the mean ultimate strain was 35.96% (± 4.47%). The mean length of the ligament was 33.08 mm (± 2.24) and the mean cross-sectional area was 1.54 m m (2) (± 0.48 m m (2)). Including the areal measurements the maximum tension was calculated to be 32.78 [Formula: see text] (± 4.04 [Formula: see text]).
  
  
  CONCLUSIONS
  The anterolateral ligament is an anatomical structure with tensile properties that are considerably weaker compared to other peripheral structures of the knee. Knowledge of the anterolateral ligament's tensile strengths may help to better understand its function and with graft choices for reconstruction procedures.
authors.affiliation: Albert-Ludwigs-University Freiburg, Department of Microsystems Engineering (IMTEK), Design of Microsystems, Georges-Koehler-Allee 102, Freiburg i. Brsg., 79110, Germany. martin.zens@imtek.uni-freiburg.de.|University Medical Center Freiburg, Department of Orthopaedics and Trauma Surgery, Hugstetter Str. 55, Freiburg i. Brsg., 79106, Germany. martin.zens@imtek.uni-freiburg.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Zens
authors.affiliation: University Medical Center Freiburg, Department of Orthopaedics and Trauma Surgery, Hugstetter Str. 55, Freiburg i. Brsg., 79106, Germany. matthias.feucht@uniklinik-freiburg.de.
authors.forename: Matthias J
authors.initials: MJ
authors.lastname: Feucht
authors.affiliation: Albert-Ludwigs-University Freiburg, Department of Microsystems Engineering (IMTEK), Design of Microsystems, Georges-Koehler-Allee 102, Freiburg i. Brsg., 79110, Germany. johannes.ruhhammer@imtek.uni-freiburg.de.
authors.forename: Johannes
authors.initials: J
authors.lastname: Ruhhammer
authors.affiliation: University Medical Center Freiburg, Department of Orthopaedics and Trauma Surgery, Hugstetter Str. 55, Freiburg i. Brsg., 79106, Germany. anke.bernstein@uniklinik-freiburg.de.
authors.forename: Anke
authors.initials: A
authors.lastname: Bernstein
authors.affiliation: University Medical Center Freiburg, Department of Orthopaedics and Trauma Surgery, Hugstetter Str. 55, Freiburg i. Brsg., 79106, Germany. hermann.mayr@uniklinik-freiburg.de.
authors.forename: Hermann O
authors.initials: HO
authors.lastname: Mayr
authors.affiliation: University Medical Center Freiburg, Department of Orthopaedics and Trauma Surgery, Hugstetter Str. 55, Freiburg i. Brsg., 79106, Germany. norbert.suedkamp@uniklinik-freiburg.de.
authors.forename: Norbert P
authors.initials: NP
authors.lastname: Südkamp
authors.affiliation: Albert-Ludwigs-University Freiburg, Department of Microsystems Engineering (IMTEK), Design of Microsystems, Georges-Koehler-Allee 102, Freiburg i. Brsg., 79110, Germany. woias@imtek.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Woias
authors.affiliation: University Medical Center Freiburg, Department of Orthopaedics and Trauma Surgery, Hugstetter Str. 55, Freiburg i. Brsg., 79106, Germany. philipp.niemeyer@uniklinik-freiburg.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Niemeyer
keywords: ALL; Anterolateral ligament; Biomechanics; Histology; Load to failure; Mechanical properties; Tensile testing