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Tissue engineered devices for ligament
repair, replacement and regeneration
Joseph W. Freeman
School of
Biomedical Engineering and Sciences, Virginia Tech,
Blacksburg, VA, USA, 24060. E-mail:
jwfreeman@vt.edu. Tel:
(540) 231-5686. Fax: (540) 231-0970.
Accepted 10 November, 2008 |
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The
anterior cruciate ligament (ACL) is one of five ligaments in
the knee that are important for stability and kinematics. It
is also the most commonly injured ligament of the knee and
due to its poor healing potential, severe damage warrants
surgical intervention including complete replacement.
Ligaments are longitudinally arranged, complex tissues; the
mechanical properties of ligaments are a direct result of
their components and the arrangement of these components in
the tissue. It is these mechanics that have made ligaments
so difficult to replace. Past ACL replacements have had many
limitations that prevented their extensive use. These
limitations range from mechanical fatigue over time to
fraying of the device after implantation. In light of these
problems, investigators have begun to pursue a host of new
techniques to create a range of viable options for the
repair, replacement, and/or regeneration of the ACL. These
options include tissue engineered scaffolds with novel
designs and specially treated transplanted tissues. In this
article, the composition, arrangement, and mechanics of the
ACL will be discussed in order to elucidate important
aspects of ACL repair and past replacements will be
described. Afterwards, novel replacement options that look
to solve problems faced by older replacement options will be
presented. These devices use a wide variety of materials and
designs to replicate ligament mechanics and allow for new
tissue regeneration.
Key words:
Anterior cruciate ligament (ACL), tissue engineering, cells,
tensile, stress relaxation, polymer, allograft, xenograft. |
