Lateral approach for arthrocentesis of the distal interphalangeal joint in horses.

OBJECTIVE: To determine anatomic landmarks for a lateral approach for arthrocentesis of the proximopalmarolateral aspect of the distal interphalangeal (DIP) joint in horses and the likelihood of entering synovial structures other than the DIP joint through this approach. DESIGN: Prospective study. SAMPLE POPULATION: Paired forelimbs of 8 cadavers and 12 horses. PROCEDURE: Anatomic preparations were used to determine anatomic landmarks. Positive-contrast arthrography was used to determine which structures were entered. RESULTS: Landmarks for the lateral approach included a depression in the proximal border of the lateral ungular cartilage and the palmar border of the middle phalanx. Use of the lateral approach for arthrography resulted in deposition of contrast material exclusively in the DIP joint in only 13 of 20 limbs, whereas use of the dorsal approach resulted in deposition of contrast material exclusively in the DIP joint in 20 of 20 limbs. CLINICAL IMPLICATIONS: The lateral approach is an alternative to the conventional dorsal approach to the DIP joint in horses, however, inadvertent entry into adjacent synovial structures is a possible complication. The lateral approach provides an additional portal for through-and-through lavage and arthroscopic access to the palmar aspect of the DIP joint.