14

Epidemiology of Cruciate

Ligament Rupture

Lauren A. Bakerand Peter Muir

Introduction

Cruciate ligament rupture (CR) is one of the
most common causes of pelvic limb lameness
in dogs (Witsbergeret al. 2008). The condition
is a chronic, progressive disease that results
in eventual rupture of the cranial cruciate lig-
ament (CrCL) (Bleedorn et al. 2011; Comer-
fordet al. 2011; Muiret al. 2011). A great deal
of time and effort has been spent characteriz-
ing the epidemiological aspects of canine CR.
Through these investigations, it has been deter-
mined that CR is a complex disease process
with multiple contributing genetic and envi-
ronmental risk factors. Furthermore, it is clear
that there is no single combination of risk fac-
tors that will invariably lead to CrCL degen-
eration and eventual ligament rupture. Every
dog should be considered an individual with a
certain amount of inborn genetic risk on which
environmental variables act to influence devel-
opment of the disease. The following para-
graphs include a summary of investigations of
risk factors known to contribute to CR. A thor-
ough understanding of these risk factors can aid
in the identification of dogs with increased sus-

ceptibility to the condition, and thereby guide

patient management.

Age

As CR is a chronic degenerative process, it fol-

lows that it is a condition of primarily middle-

aged dogs (Whitehairet al. 1993; Reif & Probst

2003; Witsbergeret al. 2008). A study examin-

ing medical records data of over one million

dogs reported that dogs aged 1–4 years were

significantly less likely than dogs in other age

groups to experience CR (Witsbergeret al. 2008).

While the peak age of onset for CR has been

reported at 7–10 years (Whitehairet al. 1993),

a more recent study of 166 Labrador Retrievers

reported a peak age of onset of approximately

4 years. Notably, only 6% of these dogs had an

age of onset over 8 years, and there were no

dogs over 10 years of age. This suggests that

older dogs are also at a decreased risk for CR

(Reif & Probst 2003). Notably, there is an inter-

action with age and other risk factors. For exam-

ple, large-breed dogs tend to present at younger

ages than small breeds (Duvalet al. 1999). 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.

109