French horse - Female - 20 years of age Presented with a wound on the left tarsus After the clinical examination, which localized the lameness on the left tarsus (2 out of 5), radiographs of the region were taken. Radiographic examination Lateromedial, dorsoplantar, dorsomedial-plantarolateral oblique and dorsolateral-plantaromedial oblique view of the left tarsus Radiographic findings
- There is a very mild irregular joint surface of the dorsal part of the distal intertarsal joint with minimal periarticular new bone formation on its dorsolateral aspect. Otherwise normal bony structures.
- There is moderate soft tissue swelling, centred on the tarsus and accentuated medially.
- There are extensive gas inclusions in the soft tissues.
- The gas inclusions are for the great part arranged in lines outlining the anatomical structures of the flexor tendons palmar and distal (arrows).
- Another gas pattern is visible in the area between the tibia and the tuber calcanei: there is a well defined, semicircular radiolucency visible on the DM-PLo view, superimposed to the distal tibia and a more oval in shape gas collection between the tuber calcanei and the tibia on the lateral view (empty arrows).
LM view and its close up and close up of the DM-PLo view, showing the gas inclusions as described Radiographic diagnosis
- Extensive soft tissue swelling and trauma on the left tarsus with involvement of the flexor tendon sheath and the tibiotarsal joint left.
- Very mild osteoarthritis of the distal intertarsal joint.
- The tibiotarsal joint was tapped, the synovial fluid was opaque with a cell count of 53 000.
- Intraoperatively, also the tendon sheath was tapped and the cell count was 8000.
- A contrast study, like a fistulogram, may have been able to outline the communication from the soft tissue trauma to the tendon sheath and the joint. Injection of contrast in the tendon sheath or in the tibio tarsal joint, may have been able to show extravasation of contrast from the tibiotarsal joint and the tendon sheath to the surrounding soft tissues.
Comments
- Synovial sepsis in the horse is a serious clinical problem that can result in permanent loss of athletic function and possibly euthanasia of the animal. Bacteria can enter synovial structures by hematogenous, iatrogenic or traumatic routes.
- Traumatic is more common in adult animals while hematogenous sepsis is most common in neonates.
- Septic arthritis does not to have to be diagnosed radiographically but clinically and based upon arthrocentesis. Sometimes, by the time the radiographic changes are apparent, the disease is advanced
- Radiographic signs of infectious arthritis are:
- Intracapsular soft tissue swelling
- Periarticular soft tissue swelling
- Joint space widening (not always present, due to non-weight bearing status and increased joint capsule pressure)
- Subchondral bone lysis and erosion (in chronic cases)
- Periarticualr ostephyte formation
- Intracapsular gas secondary to penetrating wound or gas- producing organisms.
- Horses with open joints or tendon sheaths may present with minimal lameness because the synovial fluid can drain and the joint does not become tightly distended.
