Quarter horse 2 Years of age Male intact Presented for lameness localised on the front right distal limb graded 3/5. Radiographs of the right distal limb were taken. Dorsoproximal-palmarodistal oblique view (on the left) and lateromedial view (on the right) of the distal right front limb. Radiographic findings
- There is an ill defined area of decreased bone opacity in the proximal and sagittal part of P3 (arrow).
- On the lateral view, there is an identation of the articular surface in the middle of P3 (open arrow).
- The diagnosis was subchondral cyst like lesion P3 front right with unclear communication to the joint.
- The contralateral limb was radiographed.
- For a better evaluation of the lesion, CT was performed of both the distal front limbs.
Radiographic findings Close up of the dorsoproximal-palmarodistal oblique and lateromedial view front right. Radiographic findings Dorsoproximal-palmarodistal oblique view of the left front limb. Similar findings to the contralateral limb, but less severe are visible (arrow). CT images, dorsal and sagittal plane, bone algorithm. The subchondral bone defect is evident, causing a focal widening of the DIP joint space. Comments
- Subchondral or osseous cystlike have been presented in some previous large animal cases.
- The phalanges are the second most common location for the occurence of osseous cyst-like lesions after the medial femoral condyle of the stifle.
- Most of the are adjacent to, if not communicating with, a joint.
- The radiographic characteristics of the ossous cyst-like lesions are dependent on the stage of development: they may first be identified as a small lucent flattening or depression in the articular surface. However, they may progress to a circular, oval or conical single or multi chambered radiolucency within the bone.
