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Cranial Cruciate Ligament

Debridement

David E. Spreng

Introduction

Historically, total debridement of the torn
ends of the cranial cruciate ligament (CrCL)
was considered necessary to decrease inflam-
matory responses during the postoperative
period. Some investigators also advocated that
partially ruptured ligaments should be com-
pletely removed, again to decrease postoper-
ative inflammation. Meanwhile, current infor-
mation published on the function of the CrCL
has led to new developments in the approach
to ligament debridement.
The CrCL has a primarily mechanical func-
tion. It is the main restraint mechanism for cra-
nial tibial translation throughout complete stifle
range of motion. It is also responsible for limita-
tion of the internal rotation of the tibia (Vasseur
2002). Most surgeons consider ligaments only
to be passive stabilizers of the joint. However,
there is good evidence that the CrCL plays an
important role in proprioception and neuro-
muscular function, and it has been shown that
the residual portion of the CrCL maintains its
blood flow (Brayet al. 2002), providing potential
support for the healing process after joint stabi-
lization.
Mechanoreceptors within the CrCL might be
responsible for signaling muscle stiffness of the

pelvic limb and contribute to the proprioceptive

function of the stifle (Adachiet al. 2002). Many

human patients who have had an injury of

the lower extremity describe vague symptoms

such as unsteadiness (giving-way) of the joint

(Noyeset al. 1989). It seems likely that at least

some aspects of these symptoms are related to

mechanoreceptors. However, this is difficult to

document due to the lack of sufficiently sen-

sitive, yet measurable, parameters. A tear or

removal of the anterior cruciate ligament (ACL)

in humans has been associated with neuromus-

cular changes such as loss of proprioception,

alterations in muscle reflexes initiated by the

ligament, alterations in muscle stiffness, deficits

in quadriceps strength and changes in gait and

electromyographic measurements (DeFranco &

Bach 2009). It is not clear whether these changes

are caused by the loss of mechanoreceptors in

the ruptured ligament or by an altered stimula-

tion of the remaining receptors in other articular

tissue such as the joint capsule.

Mechanoreceptors have been identified

within the canine CrCL. The receptors are

pressure-sensitive corpuscles and include

Ruffini and Pacini receptors, as well as free

nerve endings which are responsible for pain

perception and autonomic nervous system

regulation of blood flow (Coleet al. 1996).

Advances in the Canine Cranial Cruciate Ligament, Second Edition. Edited by Peter Muir. © 2018 ACVS Foundation.
This Work is a co-publication between the American College of Veterinary Surgeons Foundation and Wiley-Blackwell.

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