Ultrasonographic and histologic evaluation of medial and middle patellar ligaments in exercised horses following injection with ethanolamine oleate and 2% iodine in almond oil.

The study looks at the effect of injections of 2% iodine in almond oil (IAO) and ethanolamine oleate (EO) on the patellar ligaments in horses. The research found that both substances caused changes, but IAO resulted in a greater increase in the size and inflammation of the ligaments than EO.

Objective of the Research

• The research aimed to explore the impact of injecting two different solutions, 2% iodine in almond oil (IAO) and ethanolamine oleate (EO), into the medial and middle patellar (knee) ligaments of horses.
• The study also aimed to determine whether the bodily responses differ between the two solutions, in an attempt to further understand the upward fixation of the patella.

Methods and Process

• The research was conducted on 10 healthy horses. In five horses, the knee ligaments of one limb were treated with EO, whereas IAO was administered in the knee ligaments of the other five horses.
• Ultrasonographic evaluation was conducted before the injections and also prior to euthanasia, to examine the cross-sectional area and fiber pattern of the ligaments.
• Two weeks after administering the injections, the patellar ligaments were analyzed histologically to determine the degree of inflammation, fibroplasia (an increase in fibrous tissue), and chondroid metaplasia (a transformation of normal tissue into cartilaginous tissue).

Findings

• The ultrasonographic evaluation showed that IAO treatment caused a more significant increase in the cross-sectional area of the ligaments, compared to EO.
• Both IAO and EO treatments resulted in a decrease in the echogenicity of the ligaments, implying that the tissues absorbed more sound and hence appeared darker on the ultrasonograph.
• As per the histological examination, IAO caused a significantly higher infiltration of inflammatory cells and increased fibroplasia, in comparison to the EO group. However, both treatments led to considerably more fibroplasia compared to the control group.

Conclusions

• The study concludes that injecting medial and middle patellar ligaments with IAO causes a more severe inflammatory and fibrous response than EO.
• The increase in fibroplasia and inflammation may help resolve or lessen the upward fixation of the patella, as the subsequent stiffening of the ligaments caused by these responses might contribute towards this outcome.