ULTRASOUND-GUIDED INJECTIONS IN HORSES WITH CRANIOVENTRAL DISTENSION OF THE COXOFEMORAL JOINT CAPSULE: FEASIBILITY FOR A CRANIOVENTRAL APPROACH.

Intrasynovial access to the equine coxofemoral joint (CFJ) is inherently challenging. Blind injection techniques rely upon inconsistently palpable landmarks, and ultrasound guidance requires expertise for needle placement into the coxofemoral articulation. Aspiration is recommended to confirm intrasynovial placement and avoid sciatic nerve anesthesia. The aim of this observational, descriptive, retrospective study was to evaluate the feasibility for an alternative ultrasound-guided approach in horses with cranioventral distention of the CFJ identified during pelvic ultrasound. Thirteen horses with cranioventral CFJ distention, including 12 with severe pathology, were recruited from 2009 to 2014. Seven were excluded as they were not injected or underwent ultrasound-guided injection using a dorsal approach. The remaining six horses underwent a total of nine injections into the cranioventral recess. With the exception of one foal, all were aged horses (15-29 years) of varying breeds and uses, with prominent lameness due to subluxation (three), luxation (two), and severe osteoarthritis (one). The cranioventral recess was imaged adjacent to the proximal femur using a low-frequency curvilinear transducer placed ventral to the cranial joint margins. Using aseptic technique, spinal needles were placed cranial to the transducer and advanced caudomedially into the distended cranioventral recess. Synovial fluid was retrieved in all cases with one needle placement. Findings indicated that, when distended, ultrasound-guided access to the cranioventral CFJ recess is a feasible alternative approach and may reduce the potential for extra-synovial placement. Distention in this sample of horses was accompanied by severe pathology, also supporting the use of this approach for therapeutic interventions.