Tenoscopically guided proximal digital annular ligament desmotomy for the treatment of proximal digital annular ligament desmitis.

Objective: To describe a tenoscopically guided technique for desmotomy of the proximal digital annular ligament (PDAL).

Study design: Ex vivo study and clinical case series.

Animals: A total of 10 normal cadaver equine hindlimbs and five clinical cases of PDAL desmitis.

Methods: The digital flexor tendon sheath (DFTS) was approached via a lateral basisesamoid portal and a palmar/plantar annular ligament (PAL) desmotomy was performed to improve maneuverability in the DFTS. Additional proximolateral and distal midline instrument portals were created to facilitate transection of the proximolateral attachment, the distal body and proximal body of the PDAL under tenoscopic guidance. Cadaver limbs were dissected to assess completeness of the PDAL desmotomy and iatrogenic damage. Follow up of clinical cases was obtained via telephone conversations.

Results: The proximolateral attachment and distal body of the PDAL were fully transected in each cadaver. The proximal body of the PDAL was never completely transected in cadaver limbs. Iatrogenic damage to the superficial digital flexor tendon (SDFT) occurred in four cadaver limbs. Four clinical cases were sound and returned to their previous levels of exercise following surgery. The final horse showed immediate improvement but was euthanized due to synovial sepsis 3 weeks postoperatively.

Conclusion: There are limitations of tenoscopically guided PDAL desmotomy in the cadaver model but the technique was transferrable to clinical cases of PDAL desmitis with a good prognosis for a return to soundness.

Clinical relevance: PDAL desmitis when diagnosed should be considered a significant finding and PDAL desmotomy provides a viable treatment option for these cases.