Endoscopic examination of the tarsal sheath of the lateral digital flexor tendon in horses.

This research focused on developing a reliable method for examining the tarsal sheath of the lateral digital flexor tendon in horses using endoscopy. The technique was performed and analyzed using cadavers initially and further applied to horses affected with tarsal sheath tenosynovitis for examination and treatment purposes. The results showed promising efficacy with horses not indicating any loss of function in future follow-ups.

Research Objective and Methodology

• The purpose of the researchers was to create a reliable procedure for carrying out an endoscopic examination of the tarsal sheath of the lateral digital flexor tendon in horses. This involved studying the anatomy of the tendon sheath and the associated structures within deceased horses (cadavers).
• The examination started with identification of portals for insertion of an arthroscope into the sheath, which was followed by approaches into the sheath via the proximal pouch and a flexor retinaculum undertaken and compared in cadavers.

Findings from the Study

• The examination showed that the proximal pouch portal allowed visualization of only the proximal half of the sheath, while the approach through the retinaculum provided a complete view of the entire sheath. The endoscopic appearance of the normal tarsal sheath was also studied during this procedure.
• The developed endoscopic technique was thereafter employed to examine and treat five horses suffering from tarsal sheath tenosynovitis, which included two cases of chronic traumatic tenosynovitis and three instances of subacute septic tenosynovitis.
• Within the examined horses, four had indications of fragmentation of the sustentaculum tali. The study observed that fragments dorsal to the medioplantar edge of the sustentaculum tali could not be seen endoscopically and needed wound< widening for removal.
• Able to resolve the issue, the procedure facilitated adequate examination of the sheath, and the debridement of adhesions and lesions within the sheath’s lumen.

Outcome and Follow-up

• All the five treated horses survived. In follow-up findings (spanning 8-31 months), the horses were reported to be sound, with four out of five returning to their previous level of activity while one was used for hacking.
• The two horses with chronic tenosynovitis exhibited residual sheath distension but with no associated loss of function.
• The research was further being carried on via a prospective study, encompassing extended follow-up.