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ACLAUGMENTATION AND
ITS POTENTIALADVANTAGE
Anterior cruciate ligament (ACL) rupture is
one of the most frequent orthopaedic sports-
related injuries, and ACL reconstruction has
become a common surgical treatment in the
field of orthopaedic sports medicine. It is
important to continue to develop new
approaches to reconstruct the normal ACL
from the biomechanical and biological point of
view. Anatomic ACL reconstruction has
attracted much attention because of its greater
potential to restore knee kinematics. Over the
past few years, an emerging body of evidence
has shown the importance of anatomic ACL
reconstruction. Restoration of normal bio
mechanical function is one of the essential
factors for successful ACL reconstruction.
However, early biological healing of the
grafted tendon is also vital to obtaining
satisfactory clinical results. Accelerated graft
remodeling, ligamentization, and reinnervation
of the grafted tendon are necessary in order to
restore sufficient function and mechanical
strength to the reconstructed ACL [1].
Arthroscopic examination for ACL re
construction occasionally demonstrates a
relatively thick and abundant ACL remnant,
maintaining a bridge between the tibia and the
intercondylar notch. The femoral attachment of
the ACL remnant is positioned abnormally in
many cases. This represents a complete rupture
of the ACL. However, a partial rupture of the
ACL can be observed sometimes. In cases of
partial ACL rupture, although complete rupture
of the anteromedial (AM) or posterolateral
(PL) bundle can be seen, the other bundle is
preserved, if not normally, with an attachment
of anatomical femoral origin. In standard
single- or double-bundle ACL reconstruction,
the ACL remnant is totally debrided. However,
the ACL remnant has synovial tissue which
contains many capillary blood vessels. An
experimental animal study showed greater
cellularity and angiogenesis in augmented
grafts than in conventionally reconstructed
grafts [2]. In addition, it is known that the ACL
has an important proprioceptive function for
the knee. Several studies have shown that
human ACL remnants contain some types of
mechanoreceptors [3]. Moreover, several
studies have shown that the ACL remnant can
contribute to biomechanical stability of the
knee to some extent [4]. Therefore, ACL
augmentation (remnant-preserving ACL re
construction) might have several advantages:
• Preservation of the ACL remnant may
accelerate cellular proliferation, revascula
rization, and ligamentization of the grafted
tendon;
• With respect to the proprioceptive function of
the knee, the preserved mechanoreceptors in
ANTERIOR CRUCIATE LIGAMENT
AUGMENTATION
M. OCHI, A. NAKAMAE, N. ADACHI