34th Annual Scientific Meeting proceedings

Objectives:

Arthroscopy is the gold standard for treating dorsal tarsocrural osteochondritis dissecans (OCD) but few surgeons routinely inspect the plantar joint pouch. This study aims to standardise joint evaluation by developing a wear-line scoring (WLS) system, to assess the accuracy of dorsal evaluations in representing total cartilage damage, and to explore associations among WLS and various parameters.

Methods:

Data were collected from horses undergoing arthroscopy for tarsocrural OCD treatment. Parameters included age, sex, breed, pre-operative joint effusion grade (0-3), inflammation grade (0-4), fragment size and location, and the presence of detached fragments or concurrent OC lesions. A WLS (0-3) was assigned to dorsal flexed (DF), dorsal extended (DE), and plantar (PL) lateral and medial talus ridges, together representing the total WLS. Statistical analyses included Spearman’s rank correlation and Wilcoxon signed-rank tests to compare different WLS. Regression models were used to explore associations between parameters.

Results:

A total of 225 joints were included. The PL WLS showed a strong correlation with total WLS (r=0.916; P<0.001) and was significantly higher than DF WLS and mean DF+DE WLS (P<0.001). Horses with inflammation grades >0 had increased odds of elevated effusion grade (P<0.001) and elevated WLS (P<0.05). OC lesions increased the likelihood of elevated WLS (P=0.027). Higher inflammation grades were linked to larger fragment sizes (P<0.001) and detached fragments (P=0.026).

Conclusions:

Routine arthroscopic assessment of the plantar tarsocrural pouch is recommend when treating dorsal lesions, as this provides a more accurate assessment of total joint wear. Future research should focus on clinical follow-up and prognosis.