Naturally occurring osteoarthritis in the metacarpophalangeal joints of wild horses.

The research investigates signs of osteoarthritis in the metacarpophalangeal joints of wild horses in New Zealand. The findings reveal increased changes consistent with osteoarthritis in the mentioned area as horses age, suggesting a relationship between overlying cartilage degeneration and aging, and hypothesise that racing and training could speed up this aging process.

Research Study Overview

The scientific paper focusses on the nature, occurrence, and severity of osteoarthritis in the metacarpophalangeal joints of wild New Zealand horses. The researchers indicate various changes that align with osteoarthritis, such as articular cartilage damage, subchondral bone sclerosis, and creation of marginal osteophytes.

Methodology

• The team used Indian ink staining techniques and histology to identify articular cartilage lesions.
• The lesions were commonly found on the proximodorsal aspect of the first phalanx (P1) and displayed more severity on the medial eminence compared to the lateral.
• The study leveraged conventional radiography and dual energy absorptiometry to assess the bone mineral density of the subchondral bone beneath the cartilage lesions.

Findings

• The research ascertained that the severity of lesions and bone mineral density increased with the age of the horses.
• Greater subchondral bone sclerosis was observed in horses with severe cartilage damage, as revealed by subjective cabinet radiographic assessments.
• Ossicles, characterized by a distinct trabecular bone pattern, were found at the proximo-dorsal margin of P1 in several specimens from the older age groups (over 5 years old).

Conclusions and Hypothesis

• The findings demonstrate age-related changes in horses, which are consistent with osteoarthritis, particularly in the metacarpophalangeal joints.
• The research also points to a significant correlation between subchondral bone sclerosis and overlying cartilage degeneration in the proximodorsal aspect of P1.
• Lastly, the study proposes a hypothesis: the stresses stemming from racing and training may speed up the observed ageing process, consequently elevating the risk and impact of osteoarthritis in horses.