Osteochondrosis Can Lead to Formation of Pseudocysts and True Cysts in the Subchondral Bone of Horses.

The study explores how a condition known as osteochondrosis – a disruption of blood supply to growth cartilage – can lead to the formation of pseudocysts and true cysts in the subchondral bone of horses. The researchers examined a variety of equine subjects, uncovering key information about the development and location of these pseudocystic and cystic lesions.

Research Methodology

• The research subjects were horses with identified lesions believed to be precursors to or existing pseudocysts or true cysts in the epiphyseal bone. There were 17 such cases, involving horses of different ages and breeds.
• The sample included a spectrum of horse breeds, including 3 Warmbloods, 3 Standardbreds, a Quarter Horse, an Arabian, and 2 Fjord ponies, which had experimentally induced lesions. The age of the horses ranged from 48 days to 5 years old.

Findings

• Out of the 17 lesions, seven were areas of ischemic chondronecrosis – tissue death due to inadequate blood supply – and were deemed compatible with pseudocysts. These pseudocystic lesions were found in varied sites, including the metaphyseal growth plate and the ossification front.
• Ten of the cases revealed lesions that contained dilated blood vessels, which are regarded as consistent with the characteristics of true cysts. Two of these were found within the lumina of failed cartilage canals, whilst the remaining eight were associated with granulation tissue in the subjacent bone.

Conclusion

• The research concluded that disruptions of blood supply, leading to ischemic chondronecrosis, can cause the formation of pseudocysts or true cysts in the epiphyseal bone of horses.
• The granulation tissue associated with ischemic chondronecrosis contained dilated vessels also located within the lumina of failed cartilage canals, contributing to the formation of true cysts.

This study provides valuable insight into the pathogenesis of subchondral bone cysts in horses, potentially guiding future treatment and prevention strategies for osteochondrosis and its associated complications.