Prevalence of osseous pathology in the articular process articulations in the equine cervical and cranial thoracic vertebrae

Reasons for performing study:

Osteoarthritis (OA) of the articular processes (APs) is recognised as a clinical condition in the equine cervical spine, but there is little information on the prevalence and distribution of OA in the APs of the cervical and cranial thoracic vertebrae.

Objectives:

To determine the prevalence and distribution of OA in the APs of the equine cervical and cranial thoracic vertebrae in relation to vertebral level, age and size of the horse and side of the neck.

Study design:

A post mortem longitudinal randomised study of 53 horses.

Hypotheses:

OA is more prevalent and more severe in the APs of the cervicothoracic junction, the prevalence and severity of OA increases with horse age and size, and OA is equally distributed on left and right sides.

Methods:

The cervical (C1–C7) and cranial thoracic (T1–T7) vertebrae of 53 horses were removed at necropsy and boiled out. Based on the size (percentage) of the joint margin that was affected, OA of the 4 APs of each vertebra was graded on a scale of 0 (no osseous lesions) to 3 (severe osseous lesions). Based on these grades, a 3-factor ANOVA was used to test the random effects of horse, age (young, old) and size (small, large), and the fixed factors of side (left, right) and vertebral level (C1 to T7).

Results:

OA lesions were most severe in the mid-cervical vertebrae (C3–C4) followed by the cervicothoracic curvature (C5–T1). Severity of OA increased with age and size of the horse but there was no difference between left and right sides.

Conclusions:

OA is symmetrically present with higher severity in the mid-cervical and cervicothoracic regions and with higher prevalence in older and larger horses. These factors support bilateral injections in specific APs for clinical treatment of OA in the equine cervical spine