Irish horse female intact 11 years of age. Presented after trauma hind left limb, probably was stuck in a fence. Extensive soft tissue injury, radiographs of the region were taken. Radiographic examination Dorsoplantar and lateromedial view (with close up) of the distal hind left limb Dorsolateral-plantaromedial oblique projection (left) and dorsomedial-plantarolateral oblique projection (right) of the distal left hind limb. Radiographic findings
- There is extensive severe soft tissue swelling mainly plantar of the distal MT bone in the region of the flexor tendons with irregular borders and extending further distally up to the level of the PIP joint. The radio-opacity of the soft tissue is heterogenous, with multiple gas inclusions partially linear, partially visible as collection of gas bubbles (arrows). Similar lucencies are also present in the soft tissue dorsal to the MT bone. An additional, well defined, semicircular radio lucency is visible proximal to the sesamoid bones and axially (arrowheads).
- There is a very well and smooth defined separate bone opacity dorsal to the proximal border of the medial sesamoid bone with a corresponding identation in the border of the bone (empty arrow).
- An additional separate mineral opacity dorsal to the proximal periarticular border of P2 is visible (empty arrowhead) together with new bone proliferation.
- The DIP joint is widened dorsally with a secondary malalignment of the digital axis (short arrow).
Lateromedial and close up of the dorsolateral- plantaromedial view of the distal hind left limb. Radiographic diagnosis The radiographic diagnosis is:
- Hind left limb: Extensive soft tissue trauma with skin defect and involvement of the tendon sheat of the flexor tendons, compatible with septic tenosynovitis.
- DIP joint subluxation
- Mild OA PIP joint with chip
- Chronic bone fragment in the medial sesamoid bone DD avulsion from the insertion of the medial branch of the suspensory ligament, old focal sesamoiditis.
Comments
- Gas lucencies may be present in the soft tissue structures of equine limbs as a result of traumatic lacerations, puncture wounds, needle centesis or gas producing bacterial infections. Gas can be localized radiographically to subcutanous tissue, muscle fascial planes, intramuscular tissues, intraarticular or peritendinous.
- In this case, the multiple gas inclusions in the soft tissues of the plantar region have different shape and localisations, which can yield information about the structures involved in the trauma. Gas bubbles are visible within all the soft tissue. Linear radiolucencies are visible along the tendon sheat of the flexor tendon. The semicircular gas lucency (with gas-fluid interface) is pathognomonic for gas inclusions in a ‚cavity‘ where the gas is trapped and migrates to the highest regions. The anatomic location of the described gas inclusion is the proximal pouch of the digital sheath (compatible with septic tenosynovitis). Much less likely differential diagnosis would be abscess formation.
- The luxation of the DIP joint seems acute because there is no evidence of accompanying new bone remodelling or other degenerative changes. Considering the evidence of soft tissue trauma also plantar in the distal limb, at the level of the PIP joint, an involvement of the further distal ligaments or tendons is possible.
- The lesions in the PIP joint and in the sesamoid bone appear to be chronic and not directly related to the acute trauma.
- Considering the poor prognosis the horse was euthanized.
