Ultrasonographic and histologic evaluation of medial and middle patellar ligaments in exercised horses following injection with ethanolamine oleate and 2% iodine in almond oil.
OBJECTIVE
To describe the ultrasonographic and quantitative histologic effect of injecting 2% iodine in almond oil (IAO) and ethanolamine oleate (EO) in the medial and middle patellar ligaments of horses and to determine whether a difference in response exists between IAO and EO treatment.


METHODS
10 healthy horses.


METHODS
In 5 horses, the medial and middle patellar ligaments of 1 limb were injected with EO, whereas IAO was injected in the medial and middle patellar ligaments of another 5 horses. Ultrasonographic evaluation was performed on the experimental and control limb before injection of IAO and EO and prior to euthanasia to determine cross-sectional area and evaluate fiber pattern. The patellar ligaments were harvested 2 weeks after injection and examined histologically to evaluate the inflammatory response, fibroplasia, and chondroid metaplasia.


RESULTS
Injection of the patellar ligaments with IAO resulted in a greater increase in cross-sectional area on ultrasonography than EO. Both agents caused a decrease in echogenicity of the ligament. Histologically, significantly greater infiltration of inflammatory cells and fibroplasia developed after injection with IAO, compared with EO. Both agents resulted in significantly greater fibroplasia relative to control specimens.


CONCLUSIONS
Injection of the medial and middle patellar ligaments with IAO induces more severe inflammation and fibroplasia than EO. Maturation of the inflammatory and fibrous response may contribute to resolution or attenuation of upward fixation of the patella by subsequent stiffening of the ligaments.
Van Hoogmoed
Linda M
LM
Department of Surgical & Radiological Sciences, School of Veterinary Medicine, University of California, Davis 95616, USA.
Agnew
Dalen W
DW
Whitcomb
Marybeth
M
Hyde
Dallas W
DW
MacDonald
Melinda H
MH
Snyder
Jack R
JR
D000818:Animals; D006736:Horses / Q000033:anatomy & histology*; D007455:Iodine / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D009829:Oleic Acids / Q000009:adverse effects / Q000627:therapeutic use*; D017847:Patellar Ligament / Q000166:cytology* / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D011897:Random Allocation; D012597:Sclerosing Solutions / Q000009:adverse effects / Q000627:therapeutic use*; D014463:Ultrasonography
D009829:Oleic Acids; D012597:Sclerosing Solutions; D007455:Iodine; C033343:ethanolamine oleate