The prevalence and characteristics of sacroiliac (SI) joint region pain and its relationship to lameness in horses has been investigated by research conducted by the Animal Health Trust (AHT).
The research, conducted by head of clinical orthopaedics Sue Dyson and previous AHT intern Amy Barstow, built on previous AHT research that recognised SI joint region pain as a contributor to poor performance and/or hindlimb lameness.
Notable results include the observation that clinical signs of SI joint region pain are worse when horses are ridden, such as bucking in canter and spontaneously breaking from canter. This highlights the importance of vets examining horses under saddle wherever possible to observe the true severity and breadth of the clinical signs, the research suggests.
Clinical signs of SI joint region pain can be dramatically reduced following diagnostic analgesia – a safe, but non-specific, block. Signs suggestive of SI joint region pain included canter quality that is worse than trot, and bucking and kicking out – especially in canter. Other signs include bunny hopping-type canter, being on the forehand and croup high or a stiff, stilted canter, changing legs behind, spontaneously breaking from canter to trot and being reluctant to canter, as well as the tendency to come above the bit.
For horses showing the above signs, blocking the SI joint in a diagnostic investigation could provide crucial answers. The majority of horses in the study had SI joint region pain and hindlimb lameness. Although clear improvement in lameness in hand was seen in some horses after removing the source of pain in the lame limb, ridden exercise highlighted the persistence of another source of pain, which was sometimes worse after abolishing the lameness. This emphasised the crucial importance of ridden exercise in both trot and canter when assessing lameness and poor performance, the researchers said.
Dr Dyson said: “Assessing the effect of treatment of the SI joints is not an effective method of diagnosis; the use of nerve blocks is much more reliable.”