1. Abstract Article
Larissa Durán Becerra

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Steven A. Claes, MD, Pellenberg, Belgium
Stijn Bartholomeeusen, MD, Malle, Belgium
Evie E. Vereecke, PhD, Kortrijk, Belgium
Jan M. Victor, MD, GENT, Belgium
Peter Verdonk, MD, PhD, Ghent, Belgium
Johan Bellemans, MD, Langdorp, Belgium
OASIS Magazine.

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McCormick Place, Academy Hall B
Wednesday, Mar 20, 2013, 7:00 AM - 6:00 PM

4. In 1879 Dr.Segond described the existence of a “pearly,
fibrous band” at the anterolateral aspect of the human
knee attached to the eponymous fracture. To date, the
enigma surrounding this anatomical structure is reflected
in confusing names like “(mid-third) lateral capsular
ligament” “capsulo-osseous layer of the ITB”, or
“anterolateral ligament”, and no clear function has yet
been attributed to it.
 Therefore, the goal of this study was to provide a precise
anatomic description of this anterolateral ligament (ALL),
describe its biomechanics in computer-navigated
sequential cutting experiments, characterize the ALL on
knee MRIs and delineate the Segond fracture as a bony
avulsion of the ALL.
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The ALL was investigated in 35 human cadaveric knees its
dimensions and relation with anatomical landmarks were
recorded.
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Navigated knee kinematics were obtained from 10 freshfrozen cadavers in the native knee, after sequential cutting
of the two bundles of the ACL and the ALL respectively.
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The aspect of the ALL was studied on MRI images of 350
ACL injured subjects.
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Segond fracture characteristics were studied on MR
images of 26 subjects and compared with the anatomical
findings.

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The ALL was found in all knees; it invariably originated on the lateral femoral
epicondyle, in close relation to the lateral collateral ligament. The ALL
showed an oblique course to the tibia (posterior and proximal to Gerdy’s
tubercle), firmly attached to the lateral meniscus.
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The ALL was found to be an important internal rotatory stabilizer of the knee,
especially in flexion angles between 30° and 60° and this in both the ACLintact and deficient knee. With regard to the pivot-shift, cutting of the ALL
increased the pivot-shift with a least one grade, regardless of the condition
the ACL. All knees with both ALL and ACL cut, resulted in a gross, grade III
pivot-shift, while removal of both ACL bundles alone did never, the latter only
delivering a grade I pivot-shift in 40% of the knees.
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The ALL was found on MRI in 95,3% of the ACL-injured subjects. Lesions of
the ALL were noted in 79,2% of these patients, mostly distal. The Segond
fracture was delineated as a bony avulsion of the ALL.

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Previously undescribed, the ALL was found to be a distinct anatomical structure
of the human knee with definite biomechanical properties. Although the classic
concept of anterolateral rotatory knee instability developed by Hughston,
already implied a combination of injuries to both the ACL and the “anterolateral
stabilizing structures”, this interesting notion has seemingly become obsolete
under the boom of arthroscopic surgery.
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However, the high incidence of ALL lesions on MR images of ACL-injured subjects
and its causative relationship with a high-grade pivot-shift, yield exciting new
insights related to the interaction between ALL and ACL, and stimulate further
research in this common field of knee instability. For illustration, a multi-media
presentation of Segond refixation and ALL reconstruction procedures will be
displayed.
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In conlusion, the ALL is a distinct anatomical structure with definite
biomechanical properties.Its recognition yields new insights for the diagnosis and
treatment of common knee instability patterns, previously attributed to isolated
injuries of the ACL or one of its bundles.