Desmotomy of the accessory ligament of the superficial digital flexor tendon in the horse with use of a tenoscopic approach to the carpal sheath.

The research explores a tenoscopic surgical technique for the desmotomy of the accessory ligament of the superficial digital flexor tendon in horses, and its potential as an alternative to the medial incisional approach.

Procedure and Methodology

• The study initially developed the surgical method using normal forelimbs from horse cadavers and then on experimental horses.
• Overall, a total of 12 horse cadaveric forelimbs, 4 forelimbs from 2 horses anesthetized for terminal surgical laboratories, and 10 forelimbs from five experimental horses were used.
• The positioning of the limbs involved placing them lateral side upwards with the carpus slightly flexed.
• The carpal sheath was distended, subsequently an arthroscope insertion was made at a portal approximately 2 cm proximal to the distal radial physis. Additionally, an instrument portal was made about 0.2 cm proximal to the distal radial physis.
• Following the flexion of the limb to 90 degrees, the superficial digital flexor tendon’s accessory ligament was palpated and desmotomy was performed.
• Cadaveric limbs were dissected post-surgery to confirm the complete desmotomy. The experimental horses were closely monitored for short-term (perioperative) and long-term (4 weeks) postoperative complications.

Results

• The tenoscopic surgery offered enough surgical access to perform desmotomy on the accessory ligament of the superficial digital flexor tendon.
• It was observed that most parts of the accessory ligament of the superficial digital flexor tendon were clearly visible within the sheath apart from the proximal 2 cm, which could be readily palpated and then transected.
• Critical technical considerations included punctual and accurate location of the arthroscope portal, enough sheath distention, limb flexion to 90 degrees, and the precise location for desmotomy.
• Another point raised was beneficial, but not necessary, was to avoid the proximal perforating vessel.
• Post-surgery, a few of the horses experienced swelling, however, they were not lame and maintained a normal range of motion of the carpus.

Conclusion

• The research concludes that desmotomy of the accessory ligament of the superficial digital flexor tendon can be performed using a lateral tenoscopic approach to the carpal sheath.
• The technique proposed presents itself as a viable alternative to the traditional medial incisional approach.