34th Annual Scientific Meeting proceedings

Objectives:

Diagnosing sacroiliac joint (SIJ) disease is challenging. Transrectal ultrasonongraphy (US) evaluates the caudal SIJ part and computer tomography (CT) the complete joint. The study objective was to describe, quantify and associate US-, CT-, and histological SIJ findings of clinically asymptomatic Warmblood cadavers.

Methods:

Twenty-five SIJs underwent post-mortem US and CT. Osteophytes/enthesiophytes, effusion, sacrum/ilium modelling, and ventral sacroiliac ligament changes were evaluated ultrasonographically. Osteophytes/enthesiophytes, sclerosis, subchondral bone lesions and sacrum/ilium modelling were assessed by CT. CT- and US-findings were scored (maximum 15 points for US, CT of the caudal third, and CT of the complete SIJ). Frequencies of US- and CT-findings were calculated and correlated. 13 SIJs were assessed histologically. SIJ findings were correlated between imaging modalities. Histological findings were described.

Results:

All SIJs had abnormal CT-findings, 92% had abnormal US-findings. The most prevalent US-findings were osteophytes (92%), effusion (76%) and sacrum/ilium modelling (76%). The most prevalent CT-findings in the SIJ caudal third and complete SIJ were osteophytes (92% and 100%), sclerosis (72% and 88%), subchondral bone lesions (60% and 88), and enthesiophytes (60% and 68%). The most severe CT-changes were in the SIJ caudal third (44%). No significant correlation was found between the mean US-grade and complete SIJ CT-grade (p=0.087), or with the SIJ caudal third CT-grade (p=0.159). Histology revealed degenerative joint changes.

Conclusions:

Mild to moderate SIJ findings are common in asymptomatic Warmblood horses, their clinical relevance is unknown. SIJ US is not representative of the CT-changes, and vice versa. Modalities should be used in a complimentary fashion.