17

Caudal Cruciate Ligament

Rupture

Peter Muir

Introduction

Rupture of the caudal cruciate ligament (CaCL)
is less common than rupture of the cranial cru-
ciate ligament (CrCL). Isolated disruption of the
CaCL is found in less than 2% of stifle surgery
patients (Harari 1993). Experimentally, transec-
tion of the CaCL does not cause an obvious
lameness, and only leads to mild internal rota-
tion of the tibia relative to the femur (Harari
et al. 1987). Although caudal drawer motion was
detectable during a six-month study period,
minimal degeneration of the articular cartilage
with very little osteophyte formation was found
experimentally (Pournaset al. 1983; Harariet al.
1987). Meniscal damage was not found after
experimental transection of the CaCL (Pournas
et al. 1983; Harariet al. 1987). Therefore, whether
naturally occurring isolated disruption of the
CaCL causes lameness clinically in the dog is
unclear.
Rupture of the CaCL often involves avulsion
fracture of an attachment site. Affected dogs are
usually immature or adolescent patients with
history of trauma and often additional injuries
(Johnson & Olmstead 1987). Complete rupture
of the CaCL is also seen in dogs with stifle luxa-
tion, in combination with rupture of the CrCL
and the medial collateral ligament, secondary

to stifle trauma (Hulse & Shires 1986; Aron

1988). Mild damage to the CaCL is underap-

preciated clinically (Sumneret al. 2010). Super-

ficial fraying, splits in the ligament matrix and

fiber rupture of the CaCL are often found in

dogs with degenerative cruciate ligament rup-

ture (CR) in both partial and complete CR cases.

Some degree of damage to both cruciate liga-

ments is often found in dogs with a stable sti-

fle during arthroscopic examination of the stifle

(Figures 17.1 and 17.2).

Clinical presentation

Mid-substance tears

Dogs with isolated mid-substance tears usually

have a history and clinical signs that are similar

to dogs affected with the typical CR condition.

A history of trauma may be described by the

owner in some patients. Although stifle insta-

bility is often appreciated on physical examina-

tion, caudal drawer motion is difficult to recog-

nize specifically (Mightet al. 2013), and may be

misinterpreted as cranial drawer motion. Con-

sequently, it is easy to fail to diagnose CaCL

rupture clinically during patient examination.

Radiographic signs are also similar to dogs

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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