# Retrospective Analysis of Suspensory Ligament Branch Injuries in 70 Dressage Horses

## TL;DR

This study examines suspensory ligament branch injuries in 70 dressage horses, finding that early diagnosis and treatment improve recovery outcomes.

## Contribution

The study is the first to focus on dressage horses and investigate factors influencing the outcome of suspensory ligament branch injuries.

## Key findings

- 62.9% of horses returned to their pre-injury level of work or higher after treatment.
- Persistence of power Doppler signal was negatively associated with recovery outcomes.
- Severe injuries were more likely to result in retirement compared to mild or moderate injuries.

## Abstract

There are limited studies investigating the outcome for suspensory ligament (SL) branch injuries in sports horses, and none that focus on dressage horses. The aim was to describe the clinical and ultrasonographic features of SL branch injuries in 70 dressage horses and the response to treatment. There were 43 Warmbloods, 22 Iberian and 5 cross-breed horses, with a median age of 9 years. Geldings (64.3%) and stallions (31.4%) predominated. There were 74 limbs affected (59.5% forelimbs and 41.9% hindlimbs) and 89 branches; lateral branch injuries (75.3%) exceeded medial branch injuries (27.0%). Pain was elicited on firm palpation of 84.3% of injured branches. The most frequent lameness grade was 2/5. Most (66.3%) injuries were localised to the distal one-third of the branch. Ultrasonographic grades were mild (22.5%), moderate (48.3%) and severe (29.2%). In total, 63 percent of horses returned to the same level of work as pre-injury or higher, of which 31.3% were treated conservatively by modification of the exercise programme and serial ultrasonographic monitoring; 76.2% of these horses also received radial pressure wave therapy. Horses with severe injuries were more likely to be retired than those with mild or moderate injuries. Early diagnosis is most likely to result in a successful outcome.

There are no studies that have investigated factors influencing the outcome of dressage horses with suspensory ligament (SL) branch injuries. The aim was to determine if age, breed, work level, injury severity, anatomical localisation of injury, number of injured branches, periligamentous fibrosis, persistence of power Doppler signal or coexistent osteoarthritis of a metacarpophalangeal (MCP) or metatarsophalangeal (MTP) joint influenced the prognosis of 70 dressage horses. Outcome was defined as good (return to pre-injury level of work or higher), poor (return to a lower level of work) or retirement. Chi-squared or Fisher’s exact test and the Kruskal–Wallis test were used to identify relationships between variables of interest and follow-up outcome. Follow-up outcome was good in 44/70 horses (62.9%), poor in 13/70 (18.6.%) and 13/70 horses (19.1%) were retired due to no response to treatment. Ultrasonographic lesion grade (p = 0.07), cross-sectional area (CSA) of the SL (p = 0.96), CSA of the lesion (p = 0.28) and the lesion CSA as a percentage of the SL CSA (p = 0.40) were not associated with outcome. Power Doppler signal was present in 75.8% of injured branches at the initial examination. The severity of power Doppler signal was not associated with outcome (p = 0.20); however, persistence of power Doppler signal was negatively associated with outcome (p < 0.001). Other variables did not influence the follow-up outcome. Early recognition of SL branch injury is likely to result in a more favourable outcome with appropriate treatment and management.