Equine Sports Medicine and Rehabilitation Resident University of Pennsylvania, New Bolton Center West Chester, Pennsylvania
Interobserver Agreement in the Interpretation of Cervical Facet Radiography and Computed Tomography of the Caudal Cervical Articular Process Joints of the Horse. Brown KA, Davidson EJ, Johnson AL, Stefanovski D, Wulster KB, Ortved K. University of Pennsylvania, New Bolton Center, Department of Clinical Studies, Kennett Square, PA.
Cervical articular process joint osteoarthritis (CAPJ OA) can lead to career altering clinical signs in the athletic horse. Oblique radiographs and standing cone beam computed tomography (CBCT) facilitate assessment of this area, however, the variability of interpretation of these images between imaging modalities and clinicians is unknown. This study aimed to investigate interobserver agreement between grades of CAPJ OA on lateral and oblique radiographs and standing CBCT between clinicians and agreement between modalities in grades of CAPJ OA. We hypothesized that agreement between clinicians’ grades of CAPJ OA would be lowest for oblique radiographs and highest for standing CBCT, and that agreement between mean grades of CAPJ OA would be low for all modalities. Horses underwent lateral and oblique radiographs and standing CBCT of the CAPJs of C5–6 and C6–7. Radiographic images and transverse CBCT images were graded retrospectively by four blinded clinicians using a three-point grading scheme. Agreement between clinicians’ grades of CAPJ OA was moderate for lateral radiographs, and fair for oblique radiographs and standing CBCT. For all modalities, agreement was only fair between clinicians for joints with grade 1 (normal) or 2 (mild) CAPJ OA. Agreement between modalities was superior for standing CBCT and oblique radiographs. Limitations include the use of an unvalidated grading scheme for evaluation of CAPJ OA on oblique radiographs and standing CBCT, and lack of other CBCT plane images for evaluation. This study provides important information regarding the inconsistency of interpretation of mild CAPJ OA on radiographs and standing CBCT amongst clinicians.