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EXAMINING THE RELIABILITY OF CERVICAL VERTEBRAL RADIOGRAPHY FOR THE ASSESSMENT OF EQUINE CERVICAL ARTICULAR PROCESS JOINT OSTEOARTHRITIS
V. Unt, E. Eliashar, R.J. Piercy
Department of Veterinary Clinical Sciences, The Royal Veterinary College, Hertfordshire, United Kingdom
Purpose: Lateral radiographs of the cervical vertebrae are frequently acquired when evaluating horses presenting with ataxia, lameness or neck pain and in these cases the severity of degenerative joint disease (DJD in the articular process joints (APJs)) is generally assessed. This study aimed to determine whether the subjective radiographic appearance of DJD in APJs of equine cervical vertebrae is correlated with the gross post mortem appearance of the same joints, and to examine and compare pathology on each side of the neck and at different levels.
Methods: APJs between C3 and C7 of 9 cadaveric necks, of horses (older than 15 years) were evaluated. Lateral radiographs of the cervical region and digital photography of the articular cartilage surfaces before and after staining with Indian ink were acquired. Two blinded independent observers scored both the radiographs and articular cartilage surfaces for DJD and osteochondrosis (OC)-related changes for each APJ between C3 and C7 twice.
Results: Intra- and inter- observer agreements were moderate-good. From radiographs, caudal joints were assigned significantly higher DJD scores than cranial joints (p= 0.04), however there was no significant difference between gross post mortem scores for DJD or OC at different intervertebral levels. There was no significant association between the radiographic and post mortem appearance for DJD or OC scores. A significant association was observed between the left and right APJs at each vertebral level for both DJD (rho = 0.47; P = 0.01) and OC scores (rho = 0.60; p = 0.001). There was no association between gross DJD scores and the OC scores.
Conclusions: This study suggests that radiographic assessment of equine cervical vertebral articular process joints should be interpreted with caution, as radiographic appearance is not an accurate predictor of severity of apparent DJD as assessed at gross post mortem. Without additional information, it appears prudent to medicate articular process joints bilaterally when attempting to treat cervical vertebral pathology since severity of DJD was correlated between left and right sides. Further studies are required to determine whether these results apply also to younger animals.
BVetMed Final Year Elective Project presented by Victoria Unt at the American College of Veterinary Radiology meeting in Chicago in November. This project won the RVC's best equine elective project prize.
