Review of the clinical diagnosis of sacroiliac dysfunction in horses - Challenges and limitations.

ABSTRACT

Sacroiliac dysfunction (SID) is a condition seen in horses associated with poor performance that affects hind limb gait and impulsion. The condition comprises pain and dysfunction but there lacks clarity around the aetiopathogenesis and whether SID encompasses abnormal joint pathology, abnormal joint movement, abnormal regional biomechanical function, joint laxity and pain, or various combinations of these that may vary over time. Clinical assessment remains challenging for equine clinicians due to the deep location of the sacroiliac joint (SIJ) and surrounding structures which limits access for palpation, diagnostic imaging and joint-specific injection. There is no recognised single reference standard diagnostic test for SID. Clinical diagnosis has been based on ruling out other causes of hind limb lameness, along with combinations of ultrasonography, scintigraphy and periarticular anaesthesia of the SIJ. Recent studies have highlighted the lack of specificity of injections targeting the SIJ, with significant dispersal of injectate into surrounding structures including around the lumbosacral joint (LSJ). Advanced imaging modalities such as computed tomography offers promise for assessment of the structure and pathology of the SIJ and surrounding bony structures. However, there is a need to improve the understanding of the significance of anatomic variation of the sacroiliac region structures, with recent studies reporting detailed anatomic variation in groups of horses with and without SID. There are also limitations around functional assessment of the joint which is still largely reliant on a thorough clinical examination. This review aims to present an update on clinical approaches to the diagnosis of horses with SID, and to consider the challenges and limitations.