Ultrasound-guided intralesional tendon and ligament injections in the horse.

Abstract

OBJECTIVE: To describe principles of ultrasound-guided injection techniques for intralesional delivery of regenerative orthobiologics into equine tendon and ligament core lesions. ANIMALS: A university-owned horse and equine cadaver forelimbs. METHODS: A reproducible protocol for ultrasound-guided injection is demonstrated with the superficial digital flexor tendon used as an example. Following diagnosis of the lesion, the horse should be sedated and the affected limb desensitized with perineural anesthesia. The lesion is identified ultrasonographically in transverse and longitudinal planes, marked externally, and aseptically prepared. Under sterile conditions, the needle is placed through the skin, viewed on ultrasound, advanced to the lesion's hypoechoic core or region of fiber disruption, and stabilized during attachment of the syringe and subsequent injection. Injectate volume is governed by product type and lesion size, with platelet-rich plasma (PRP), bone marrow aspirate concentration (BMAC), mesenchymal stem cells (MSCs), and autologous conditioned serum or protein solution (ACS/APS) representing the most commonly used equine orthobiologics. Ultrasound monitoring throughout the injection confirms intralesional placement and dispersion of the injectate. RESULTS: Ultrasound guidance enables precise intralesional placement and real-time observation of injectate dispersion. Current clinical opinion suggests injecting tendon/ligament injuries during the sub-acute phase or within a few weeks of injury. The technique minimizes iatrogenic trauma and improves delivery accuracy for regenerative treatments. CLINICAL RELEVANCE: Ultrasound-guided intralesional injection is an accessible and effective method to enhance the precision, safety, and therapeutic success of orthobiologic delivery in equine tendon and ligament injuries.