Use of magnetic resonance imaging to diagnose the cause of proximal metacarpal pain in a standardbred trotter.

This research uses a magnetic resonance imaging (MRI) technique to diagnose the cause of proximal metacarpal pain in a standardbred trotter horse. The study further delves into how MRI can provide essential information beyond the conventional diagnostic methods, contributing to the effective diagnosis of musculoskeletal afflictions in horses.

Background

• Proximal palmar metacarpal pain is a significant contributor to forelimb lameness in athletic horses, commonly diagnosed using clinical findings, perineural analgesia, and different types of diagnostic imaging such as ultrasonography, radiography, and nuclear scintigraphy.
• Magnetic resonance imaging (MRI) is known for its accuracy and sensitivity in detecting musculoskeletal injuries, with an ability to provide critical insights into evaluating the proximal suspensory ligament (PsL), a ligament in the horse’s leg.

Case Study

• The research presents a case study focused on a four-year-old Italian standardbred trotter suffering from right forelimb lameness, improved by analgesia treatment of the middle carpal joint.
• Despite resting for over two months, the horse’s lameness didn’t show improvement. Furthermore, diagnostic arthroscopy of the carpal joints failed to reveal any significant abnormality.
• Through examination and testing, the horse was graded as 1/5 lame (with 0 being sound and 5 being non-weight bearing lame), and a digital flexion test of the right forelimb showed mild positive results.
• Marked bone remodeling in the proximomedial metacarpal area and the second to third intercarpal joint was observed through radiographic examination.

Conducting MRI

• A thorough MRI of the right proximal metacarpus and carpus was performed while the horse was under general anesthesia. This procedure included a low field strength magnet and a surface coil implementation.
• The MRI images collected spanned from the middle carpal joint to the proximal third of the metacarpus.

Findings

• Detailed MRI scans revealed mild enlargement and hypoechogenicity (reduced echo on ultrasound) of the deep part of the medial lobe of the PSL.
• Bone remodeling of the intermetacarpal syndesmosis, a fibrous joint between the second and third metacarpal bones, was also distinctly identified.
• These definitive findings underscore the use of MRI in providing essential diagnostic information on horse lameness, going beyond traditional methods.