Assessment of Magnetic Resonance Imaging, Musculoskeletal Ultrasound, and Arthroscopy in the Diagnosis of Medial Shoulder Syndrome in Canines

Introduction: Medial shoulder syndrome (MSS) is an important cause of forelimb lameness in dogs. Following relevant physical exam findings, advanced imaging modalities aid in diagnosis. The aim of the current study was to evaluate the efficacy of MRI for diagnosis or MSS, using arthroscopy as the gold standard.

Materials and Methods: Medical records of dogs that had an MRI of the affected shoulder(s) from 2008–2018 were evaluated for correlation of MRI findings to arthroscopy, as well as musculoskeletal ultrasound findings to arthroscopy (where applicable), in relation to a diagnosis of MSS.

Results: Arthroscopy confirmed MSS in 15/15 shoulders that were included. Musculoskeletal ultrasound was performed in 13/15 (86%) shoulders, and correlated with intra-articular shoulder pathology (inclusively, MSS) in 12/13 (92%). MRI was performed in 15/15 shoulders, and confirmed MSS in 1/15 (7%).

Discussion/Conclusion: The present study indicates that MRI is not a sensitive diagnostic modality for the diagnosis of MSS, in contrast to previous reports. In addition, musculoskeletal ultrasound offers several advantages over MRI, including the ability to perform the test without general anesthesia, less expense, easy evaluation of both shoulders, and dynamic evaluation of relevant structures. The incidence of bilateral MSS has been reported as high as 24%, making bilateral evaluation crucial. Limitations of this study include its retrospective design and natural variation in interpretation between ultrasonographers, radiologists, and surgeons. In addition, this study population represents some of the most diagnostically challenging cases.

Acknowledgment: There was no proprietary interest of funding for this study.