Development of an ultrasound-guided proximo-medial approach for injection of the carpal flexor tendon sheath in horses and comparison with the conventional proximo-lateral ´blind` technique.
Authors: Dörner C A, Vargas V, Castellón C H
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Ultrasound-Guided Injection of the Carpal Flexor Tendon Sheath Injection of the carpal flexor tendon sheath remains a common therapeutic intervention in equine practice, yet the conventional proximo-lateral "blind" technique carries significant risk of off-target placement. Dörner and colleagues developed and validated a novel ultrasound-guided proximo-medial approach by first establishing anatomical landmarks on ten cadaveric limbs using contrast medium, then testing the technique in ten clinical cases against the traditional blind method. The new ultrasound-guided approach achieved perfect intrasynovial accuracy (100%; 95% CI 69–100%), compared with only 70% success for the blind technique (95% CI 35–93%), which was complicated by inadvertent injection into the dorsopalmar pouch of the radiocarpal joint, surrounding soft tissues, and vascular structures. For practitioners managing horses with carpal flexor tendon sheath pathology—particularly those presenting without obvious effusion where anatomical landmarks are unclear—this medial ultrasound-guided approach offers a more reliable method of ensuring therapeutic agents reach the intended target whilst minimising iatrogenic complications. The straightforward technical execution suggests this technique warrants serious consideration as a standard of care rather than an alternative approach.
Read the full abstract on PubMed
Practical Takeaways
- •If you perform carpal sheath injections, switching from blind proximo-lateral to ultrasound-guided proximo-medial approach will improve your first-attempt success rate from 70% to 100%, reducing treatment time and repeated needle insertions for your horse
- •The ultrasound-guided technique is described as straightforward, meaning it should be learnable and implementable in practice without requiring specialized equipment beyond standard ultrasound
- •This approach is particularly valuable for horses with non-distended sheaths where landmark-based 'blind' techniques are most unreliable
Key Findings
- •Ultrasound-guided proximo-medial approach achieved 100% accuracy (10/10) for intrasynovial contrast delivery to the carpal sheath
- •Conventional proximo-lateral 'blind' technique achieved only 70% accuracy (7/10) with common complications including inadvertent injection into the radiocarpal joint dorso-palmar pouch, surrounding soft tissue, and intravenous injection
- •The ultrasound-guided technique was technically straightforward and reliable after initial cadaveric development and validation on live horses
- •Ultrasound-guided approach should be considered as the preferred method for carpal sheath synoviocentesis, particularly in horses without evident effusion