Transthecal Arthroscopy of the Palmar Distal Interphalangeal Joint in the Horse: A Cadaver Study.

This research study compares a new technique, referred to as the transthecal approach, to the conventional blind approach for visualizing the palmar pouch of the distal interphalangeal joint (DIPJ) in horses. The study concludes that the transthecal approach provides improved visualization compared to the conventional method with no significant difference in terms of damage to surrounding structures.

Study Methodology

• The research was an ex vivo study, meaning it was conducted with horse cadaver forelimbs rather than live horses.
• 26 pairs of these forelimbs were used, with each limb from a pair randomly assigned to either the transthecal arthroscopic approach or the conventional arthroscopic approach.
• The conventional approach was performed as per standard procedures already set out in the literature.
• The transthecal approach involved sharp dissection of the distal reflection of the digital flexor tendon sheath (DFTS) to access the DIPJ.

Measurement and Analysis

• The researchers estimated the proportions of certain areas that could be visualized by each approach. These areas included the navicular bone, the palmar aspect of the second phalanx, the collateral sesamoidean ligaments, and the palmar synovial pouches of the DIPJ.
• After the arthroscopic procedures, the limbs were dissected and examined for any iatrogenic (caused by the procedure itself) damage to the relevant structures.
• A statistical method known as the Nondirectional Mann-Whitney U-test was used to compare the two groups. The level at which the differences between the groups were considered significant was set at a P-value of less than 0.05.

Results and Conclusions

• The transthecal approach performed better than the conventional approach in terms of visualization of the navicular bone, palmar aspect of the second phalanx, and the palmar synovial pouches of the DIPJ.
• There was no significant difference between the two approaches with regard to iatrogenic damage.
• The researchers concluded that while the transthecal approach provides improved visualization of the palmar aspect of the DIPJ compared to the conventional blind approach, it might not be suitable for cases where synovial sepsis of the DIPJ is suspected, as this approach involves the creation of communication with the DFTS that could spread the infection.