Tearing of the Palmar Aspect of the Intersesamoidean Ligament as Primary Pathology of the Digital Tendon Sheath: An Endoscopic Diagnosis in Two Horses

Introduction: Imaging techniques frequently fail to diagnose digital tendon sheath (DTS) pathology, thus diagnostic endoscopy is often employed. Ultrasonographic detection of proximal scutum pathology has been reported, but there are no published reports of endoscopic abnormalities. The aim of this case report is to describe palmar intersesamoidean ligament (IL) pathology, to raise awareness of this as a differential diagnosis.

Case 1: 11 yo TB eventer gelding with RF lameness localized to foot and DTS, which failed to respond to medical management. Ultrasound and standing MRI showed only mild PAL thickening. DTS endoscopic examination revealed horizontal tearing of palmar aspect of the IL, distal–to-distal margin of manica flexoria. This was debrided using synovial resectors. No other pathology was evident. The PAL was transected. After 8 months, field rest the horse resumed work and has competed successfully for two seasons with no lameness.

Case 2: A 13yo TBX eventer gelding with RF lameness, localized to foot and DTS, which failed to respond to medical management. Ultrasound showed mild PAL desmitis. There were negative findings on a positive contrast DTS study. Endoscopic examination, findings, and treatment were as in Case 1. The horse is in early stages of rehabilitation.

Discussion: The two cases are remarkably similar with concurrent foot pathology and mild PAL findings. Foot problems are common, so may be coincidence. There is possibly an association between PAL and IL pathology. The long-term soundness of Case 1 is prognostically encouraging for this condition.

Acknowledgment: There was no proprietary interest or funding provided for this project

No conflict of interest has been declared by the author(s).