Comparison of conventional and alternative arthroscopic approaches to the palmar/plantar pouch of the equine distal interphalangeal joint.

This study explored an alternative method for arthroscopic procedures on horse joints (particularly the the distal interphalangeal joint, or DIPJ), finding that this method significantly reduces the risk of accidental penetration of nearby tendon and bursa, which can be particularly harmful in the case of infected joints.

Study Objective and Methods

The research aimed to compare two arthroscopic procedures (a type of minimally invasive surgery) on horse joints: the conventional approach and a novel lateral/medial approach. The focus was on the distal interphalangeal joint (DIPJ), which connects the bones in the horse’s hoof and lower leg.

• The conventional way sometimes inadvertently punctures the digital flexor tendon sheath (DFTS) and the navicular bursa (NB), which can result in complications, especially when the joint is infected.
• The alternative lateral/medial approach was hypothesized to have a lower risk of puncturing the DFTS and NB while still allowing for adequate examination of the joint.
• The study was conducted on cadaveric horse limbs (30 for each method). The researchers injected India ink into the dorsal pouch of the DIPJ, and then examined the DFTS and NB for the presence or absence of ink, which would indicate whether these structures were inadvertently punctured.
• The study also recorded the number of attempts it took to access the joint, any evidence of unintentional intra-articular trauma (damage inside the joint), and any instances of incomplete visualization of the joint pouch.

Study Results and Conclusion

• The study found that the risk of DFTS and NB penetration was significantly less with the lateral/medial approach. With the conventional method, DFTS penetration occurred in 60% of the limbs, compared to just 3.3% with the alternative approach. For the NB, 50% of limbs were penetrated with the old method, compared to zero with the new approach.
• The lateral/medial method did not require significantly more attempts to access the joint than the conventional method. Additionally, there was no significant difference between the techniques in terms of evidence of intra-articular trauma or instances of incomplete joint visualization.
• The study concluded that the alternative lateral/medial approach to arthroscopy of the DIPJ is more effective, as it significantly decreases the risk of injuring the DFTS and NB. This is particularly advantageous when the joint is infected and needs to be flushed out (a procedure called arthroscopic lavage).

In summary, this research supports a shift towards the lateral/medial arthroscopic approach to the DIPJ in horses, particularly in situations where the DIPJ is infected.