Ultrasonography of the medial palmar intercarpal ligament in the Thoroughbred: technique and normal appearance

Abstract

Summary Reasons for performing study: Tearing of the medial palmar intercarpal ligament (MPICL) has been recognised as a cause of lameness in the Thoroughbred, but diagnosis is difficult due to the nonspecific clinical signs, and can be achieved only by performing arthroscopy on the mid carpal joint (MCJ). It would be beneficial to be able to image the MPICL using ultrasonography to determine whether pathology is present in the ligament in order to aid diagnosis and prognosis. Objectives: To determine whether the MPICL could be imaged using ultrasound from the dorsal aspect of the MCJ, and to describe the technique and normal ultrasonographic appearance of the ligament. Methods: A pilot study was performed using 2 cadaver carpi. Each carpus in turn had the MPICL imaged simultaneously using arthroscopy and ultrasound, with a metallic probe positioned on the dorsal aspect of the ligament to highlight the position of the MPICL. Six further pairs of carpi had the MPICL imaged ultrasonographically followed by dissection of the carpus to evaluate the ligament and relate its anatomy to the ultrasound images. Finally, 15 Thoroughbreds with no history of lameness isolated to the carpus had their MPICLs assessed and measured ultrasonographically. Results: The MPICL could be imaged via the dorsal aspect of the MCJ using standard ultrasound equipment. The body and division into medial and lateral branches could be seen as a distinct, moderately dense granular echogenic structure in the palmar aspect of the joint, with clearly defined margins. Conclusions: The normal MPICL can be imaged reliably using ultrasound in the Thoroughbred from the dorsal aspect of the MCJ. There is a wide range in the normal width of the lateral aspect of the MPICL, but there is good symmetry between contralateral limbs. Potential relevance: This report of the normal ultrasonographic appearance of the ligament will be beneficial in acting as a reference for the detection of pathology using ultrasound.

Computed Tomographic Arthrography of the Intercarpal Ligaments of the Equine Carpus

“…To our knowledge, this is one of the first studies describing CT arthroscopic anatomy and characteristics of intercarpal ligaments in horses. Previously, traditional imaging modalities have not been successful at visualizing entire ligamentous structures . Results of this study indicate that the entire medial palmar intercarpal ligament, lateral palmar intercarpal ligament as well as the radiocarpal ligament, transverse intercarpal ligaments, and palmar carpal ligament were easily identifiable by this method.…”

“…Antemortem diagnosis of intercarpal ligament pathology remains difficult due to the lack of specific clinical signs complexity of the carpal anatomy and limitations with routine diagnostic imaging modalities. Radiography and ultrasound have a low sensitivity for the identification or diagnosis of pathology of medial palmar intercarpal ligament and lateral palmar intercarpal ligament . Radiographic signs are limited to abnormalities at the ligament entheses and variation exists in the carpal bone margins that may or may not be associated with ligament damage .…”

Diagnostic techniques for the carpal and fetlock joints in horses with arthritis

“…In the carpus, the intra-articular ligaments and most of the articular surfaces cannot be imaged. The technique can, however, be used to evaluate soft tissues associated with the joint, including the collateral ligaments, joint capsule, other associated ligaments, and the menisci (11). In the present study, joint effusion was demonstrated in cases of arthritis.…”

Intra‐articular soft tissue injuries in the carpus

“…The normal ultrasonographic appearance of the palmar intercarpal ligaments has been described (Driver et al . ), but lesions diagnosed by ultrasonography have not been documented. These ligaments can be visualised by MRI (Nagy and Dyson ) and computed tomography (Gray et al .…”