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

Reasons for performing the study: The conventional arthroscopic approach to the palmar/plantar aspect of the distal interphalangeal joint (DIPJ) may result in the inadvertent penetration of the digital flexor tendon sheath (DFTS) and the navicular bursa (NB). This iatrogenic communication would be undesirable subsequent to arthroscopic lavage of a septic DIPJ. Hypothesis: A lateral/medial approach to the palmar/plantar aspect of the DIPJ will result in a significantly lower rate of inadvertent penetration of the DFTS and NB, whilst still providing adequate intra‐articular evaluation. Methods: The conventional palmar/plantar approach or a novel lateral/medial approach to the DIPJ was performed on cadaver fore‐ and hindlimbs (30 limbs/approach). Subsequently, India ink was injected into the dorsal pouch of the DIPJ, and the DFTS (n = 60) and NB (n = 20) were examined for the presence/absence of ink. In addition, observations of the number of attempts made to access the joint, evidence of iatrogenic intra‐articular trauma and occurrence of incomplete visualisation of the palmar/plantar pouch were recorded. Results: With the conventional approach, DFTS penetration was noted in 18/30 (60%) of the limbs, compared to 1/30 (3.3%) with the lateral/medial approach (P≤0.001). NB penetration was seen in 5/10 limbs with the palmar/plantar approach compared to 0/10 with the lateral/medial approach (P = 0.01). No significant differences were found between the approaches in the number of attempts made to access the joint, the incidence of iatrogenic intra‐articular trauma, or the occurrence of incomplete visibility of the palmar/plantar pouch. Conclusions: The novel lateral/medial approach to the DIPJ significantly decreases the risk of inadvertent penetration of the DFTS and NB. Potential relevance: The novel lateral/medial approach to the DIPJ is an effective technique to gain access to the palmar/plantar pouches, and is particularly advantageous for arthroscopic lavage of a septic DIPJ.