Retrospective analysis of distal limb conformation and lameness in mature horses after desmotomy of the accessory ligament of the deep digital flexor tendon for management of a flexural deformity

Ex-vivo evaluation of a percutaneous looped thread desmotomy of the accessory ligament of the deep digital flexor tendon in horses

OBJECTIVE

To determine the ability to completely transect the equine accessory ligament of the deep digital flexor tendon (AL-DDFT) via an ultrasonographically-guided, percutaneous looped thread desmotomy using FiberWire suture as a cutting device.

STUDY DESIGN

Ex-vivo study.

SAMPLE POPULATION

A total of 24 normal equine distal forelimb specimens.

METHODS

Under ultrasonographic guidance, a Jamshidi needle was placed between the suspensory ligament and the AL-DDFT, and between the AL-DDFT and the deep digital flexor tendon, through two stab incisions. FiberWire suture was fed through the needle and looped around the AL-DDFT. Using a sawing motion, the ligament was transected, and the suture exited through the lateral incision. Surgical sites were dissected and assessed for completeness of transection, iatrogenic injuries, and suture remnants. Descriptive statistics were reported.

RESULTS

The procedure met the successful criteria in 18/24 (75%) of the limbs. The median surgical time was 11 min (range 7-25). No suture failure or suture remnants were noted in any of the specimens. Complications included iatrogenic injury to the medial and lateral neurovascular bundles in 4/24 and 1/24 specimens, respectively.

CONCLUSION

Complete transection of the AL-DDFT was achieved in 22/24 (92%) of the specimens; however, the neurovascular bundles were injured in 5/24 (21%) of the specimens.

CLINICAL SIGNIFICANCE

A percutaneous looped thread desmotomy of the AL-DDFT can be studied as an alternative technique for use in equine models prior to its clinical use in patients. Additional studies are required to evaluate efficacy and safety in anesthetized or standing horses.

Long-term athletic performance in sport horses after desmotomy of the accessory ligament of the deep digital flexor tendon

BACKGROUND

Outcome after desmotomy of the accessory ligament of the deep digital flexor tendon (AL-DDFT) to treat flexural deformity of the distal interphalangeal joint has been reported to be excellent. However, no studies have compared long-term athletic performance of sport horses exposed to desmotomy of the AL-DDFT to that of matched controls.

OBJECTIVES

The objective of this study is to compare long-term athletic performance in sports horses subjected to desmotomy of the AL-DDFT with the performance of matched controls.

STUDY DESIGN

This is an observational multicentre retrospective matched cohort study.

METHODS

Records from horses undergoing desmotomy of the AL-DDFT between 2004 and 2015 were reviewed. Various databases were used to identify age-matched siblings as unexposed controls and data on the horses' athletic careers.

RESULTS

Seventy-four exposed and 194 matched unexposed horses were included. Although not significantly different, the proportion of exposed horses entering competition (28%, 95% CI 16%-38%) had a substantial risk difference compared with the proportion of unexposed horses entering competition (38%, 95% CI 26%-44%) (P = .2). Career longevity was significantly better for unexposed (15.6 competitions [95% CI 10.7-22.5] over a median of 570 days [IQR 210-1340]) than for exposed horses (9.7 competitions [95% CI 6.4-14.6] over a median of 219 days [IQR 2-1159] for horses operated in one limb and 6.1 competitions [95% CI 3.6-9.9] over a median of 446 days [IQR 23-603 days] for horses operated in two limbs, P < .001). Age at surgery and whether the condition was unilateral or bilateral did not affect chance of competing.

MAIN LIMITATIONS

Small sample size, varying quality of medical records, stage of contraction not noted in many records and missing information on reasons for not entering into competition.

CONCLUSIONS

Desmotomy of the AL-DDFT is associated with decreased long-term athletic performance in sport horses compared with matched unexposed horses.