Osteochondral fragments within the dorsal pouch or dorsal joint capsule of the proximal intertarsal joint of the horse.

The study examines the anatomy of a particular joint in the horse’s leg, specifically the interaction between the tarsocrural and proximal intertarsal joints, and investigates the cases of osteochondral fragments found within these areas. The fragments were categorized based on their location and impact on horse’s health and performance was analyzed post-surgery.

Anatomy of Proximal Intertarsal Joint and Tarsocrural Joint

• The researchers dissected 15 pairs of horse hocks to study the anatomy of the proximal intertarsal joint (PIJ) and the tarsocrural joint (TCJ), specifically their communication through a fenestration.
• The PIJ and TCJ fenestration ranged in mediolateral length from 14 to 29 mm.
• The possible volume of the dorsal pouch of the PIJ was between 3 to 5 ml and a recess extended from 10 to 28 mm medially to the medial commissure of the TCJ-PIJ fenestration.

Observation of Osteochondral Fragments

• In a related clinical study, the researchers identified osteochondral fragments within the dorsal pouch or dorsal joint capsule of the PIJ in 17 horses.
• The fragments were categorized into two groups. Category 1 fragments located in the dorsal pouch and Category 2 fragments were found within the joint capsule itself.

Impact and Outcome of Arthroscopic Surgery

• Six horses with category 1 lesions had their osteochondral fragments freely floating within the dorsal pouch. These were surgically removed. Five other horses with category 1 fragments could not have them located. All 11 horses were reported sound after surgery by their owners.
• For seven horses with category 2 lesions, a minimally displaced fragment was identified at the distal aspect of the medial trochlear ridge, within the synovium separating the TCJ and PIJ. Five of these fragments were surgically removed.
• Out of the seven horses with category 2 lesions, four were in active training or racing, two were unsound, and one was still recuperating at the time of the follow-up.