July 2012, Large animal case

Large Animals Case of the Month

Islandic horse, female, 3 years of age. Presented 10 weeks before for acute lameness front left. Mild improvement with rest, never sound. At the clincal examination there was axial limb deformity with varus deviation. Radiographs of the left carpus were taken. Radiographic examination of the left carpus: From left to right, dorsopalmar, lateromedial, dorsomedial-palmarolateral oblique and dorsolateral-palmaromedial oblique view. Radiographic changes

  • There is moderate soft tissue swelling centred on the carpal joint (arrow).
  • There are multiple, well defined and rounded mineral dense opacities in the area of the Os carpale II (open arrow).
  • There is subluxation of the carpal metacarpal joint in the area of the Os carpale II.
  • What to do next?
  • Two sky-line radiographs with flexion were also taken

Dorsoproximal-dorsodistal oblique view of the proximal (left) and distal (right row of carpal bones. The multiple bone fragments (open arrow) are visible in the area of the second carpal bone. The dorsal surface of the third carpal bone (arrow) is intact. The radiographic diagnosis was: comminuted fracture of the Os carpi II left, chronic with accompanying soft tissue swelling and subluxation. Before surgery and for a better evaluation of the fracture, the horse underwent to a CT study. Bone algorithm, transverse (left) and dorsal (right) MPR of the CT scan. A small fragment from the medial border of the third carpal bone is visible (arrow). A surgical terapy was recommended. Radiographic examination of the left carpus post OP: From left to right, dorsopalmar, lateromedial, dorsomedial-palmarolateral oblique and dorsolateral-palmaromedial oblique view. Comments

  • Intraarticular fractures of the carpus are classified as chip, slab (extending from one articular surface to another in proximal to distal direaction), comminuted and oblique fractures, from highes to lowest frequency of occurence.
  • Fractures of the second or fourth carpal bones are often comminuted. These fractures often involve the proximal aspect of the  second or fourth carpal bone.
  • This will result in marked lateromedial instability of the carpometacarpal joint.
  • In the presented case the shape of the bony fragments, rounded and smooth, suggest a subacute or chronic process, with an ongoing remodelling.