Differences of morphological attributes between 62 proximal and distal subchondral cystic lesions of the proximal phalanx as determined by radiography and computed tomography.

The research article focuses on comparing the morphological differences of subchondral cystic lesions (SCLs) in the proximal phalanx (PP) of adult horses, found either near the joint or in the distal PP. The findings indicated different characteristics based on their position, suggesting chronic stress and trauma causing proximal SCLs, while developmental bone cysts caused by ossification failure lead to distal SCLs.

Research Methodology

• The study involved scientific scans (Radiographs and/or CT scans) of the proximal phalanx (PP) from 46 horses.
• To be included in the study, the horses need to have a subchondral cystic lesion (SCL) in the PP, which is confirmed either through radiography or computed tomography.
• Other data such as history, signalment, and orthopedic examination were collected retrospectively for every case.

Research Findings

• The findings covered a total of 62 SCls characterized in 46 qualified horses.
• The majority of the SCLs, 70.5% (43 SCLs), were found in the proximal PP and were largely associated with short, incomplete fractures. 69.7% of the SCLs were found mid sagittal, indicating a middle split position.
• Proximal SCLs mostly appeared to have an irregular, blurred shape and were long, wide, but of shallow depth.
• On the other hand, 29.5% of the SCLs (18 in total) located in the distal PP, near the proximal interphalangeal joint, were distinctly larger and well outlined, often circular or oval in shape.
• Group A (proximal PP SCLs) had significantly older horses with a mean age of 11.47 years than Group B (distal PP SCLs) with an average age of 6.72 years.

Conclusions

• The distribution and morphological attributes of the SCLs in proximal PP suggest that such lesions may have developed more recently due to chronic stress factors, such as continuous trauma to the cartilage and subchondral bone.
• Conversely, the characteristics and distribution of distal SCLs are consistent with characteristics of developmental bone cysts, which are likely to originate from a failure of endochondral ossification, a crucial process in the formation and development of bone.