Trakehner horse 7 Years of age. Female intact presented for a very mild lameness front right, she fell on the carpi some days before, now there was a mild soft tissue swelling distal to the right carpus. Radiographs of the right carpus were taken. Radiographic examination Lateromedial, dorsopalmar, dorsolater-palmaromedial and dorsomedial-plantarolateral view of the right carpus. Radiographic findings
- There is a well defined, round, approximately 1.2cm in size lucent area in the Os carpi radiale, centrally located. The lucency is surrounded by a thin sclerotic rim (arrow).
- From this structure, there is a lucent canal running proximally up to the proximal border of the Os carpi radiale (arrow head).
- There is mild periarticular new bone proliferation around the carpometacarpal joint, mainly dorsomedially (empty arrow).
Radiographic findings Close up of the dorsopalmar and dorsomedial-palmarolateral view of the right tarsus
- The diagnosis was subchondral cyst like lesion in the carpal radial bone right with likely connection to the radiocarpal joint.
- Mild degenerative changes in the carpometacarpal joint right.
Radiographic diagnosis For a better evaluation and before undergoing surgical therapy, the horse underwent CT examination. Multiplanar reconstruction, bone window of the CT scan, dorsal (left) and sagittal (right) plane. The cyst like lesion with the connection to the radiocarpal joint is visible. A surgical approach was elected and post OP radiographs were taken Lateromedial, dorsopalmar, dorsomedial-palmarolateral and dorsolateral-palmaromedial view of the right carpus. Comments
- Subchondral or osseous cystlike lesions have been reported in the carpal bones, the proximal aspect of the 2nd and 4th metacarpal bones and distal aspect of the radius with the most commonly reported site at the ulnar carpal bone.
- These lesions are frequently noted as incidental findings but some are associated with lameness.
- The lesions associated with articular margins and subchondral cyst like lesions in the distal medial aspect of the radius are more likely to be clinically significant.
- The use of other diagnostic methods like scintigraphy can show osteoblastic activity at the site.
- Osseous cyst like lesions are generally considered developmental abnormalities, but trauma to the articular cartilage and subchondral bone can potentially lead to formation of these cyst like lesions.
