## 3 Results  
In a basic population of 75 horses, 20 horses showed hind limb lameness. Only twenty horses showed clinical signs of hind limb lameness, with AAEP scores ranging from two and four (nine horses scored two, eight horses scored three, and two horses scored four). These horses were pre-selected for further consideration. The study population comprised eleven mares and nine geldings, ranging in age from 15 to 35 years (mean age 25.7 \(\pm\) 5.4 years), representing various breeds: thirteen Polish half-bred horses (PHHs), two French trotter horses (FTHs), three Silesian horses (SHs), and two mixed-breed warm-blood (MBW) horses. None of the horses had participated in competitive sports or professional races. However, all had been ridden for at least 10 years. Thus, horses' under-saddle work was considered leisure work. Radiological signs of OA were observed in 17 out of the 40 examined tarsal joints. The predominant radiological signs included narrowed and irregular joint spaces, the presence of multiple osteophytes, subchondral bone sclerosis, and intra-articular mineralization. Based on the OA scoring system used, twenty-three tarsal joints were classified as healthy (group 0), six with mild OA (group 1), six with moderate OA (group 2), and five with severe OA (group 3). The specific demographics of the included horses, including separate lameness/OA scores for the left and right hind limb/tarsal joint, are summarized in Table 4. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**No** & **Sex** & **Breed** & **Lameness Score * & **Age** & **Training Background** & **OA Severity Scores** \\ \hline
1 & M & FTH & Left 2; Right 2 & 34 years & Leisure work for 18 years & Left 0; Right 0 \\
2 & M & SH & Left 3; Right 3 & 35 years & Leisure work for 13 years & Left 0; Right 0 \\
3 & M & MBW & Left 4; Right 4 & 28 years & Leisure work for 14 years & Left 0; Right 3 \\
4 & M & PHH & Left 2; Right 2 & 28 years & Leisure work for 15 years & Left 2; Right 0 \\
5 & M & SH & Left 3; Right 3 & 33 years & Leisure work for 14 years & Left 0; Right 0 \\
6 & M & PHH & Left 2; Right 2 & 19 years & Leisure work for 12 years & Left 0; Right 2 \\ \hline \end{tabular}
\end{table} 
Table 4: Specific demographics of the included horses (sex, breed, age, lameness score of the hind limbs, training background, and osteoarthritis (OA) severity). The BMD characteristics of the horses in each group are summarized in Figure 3. In group 0, representing normal tarsal joints, the %color pixels gradually increased from S1 to S9, with no differences observed between S1, S2, S3, and S4, as well as between S3, S4, S5, and S10. Additionally, no differences were found between S6, S7, and S10, as well as between S7 and S8 and S8 and S9 (Figure 3A). In group 1, representing mild tarsal joint OA, the %color pixels similarly gradually increased from S1 to S9, however, with no differences observed between S1, S2, S3, S5, S6, S7, and S10. Moreover, no differences were found between S8 and S9 (Figure 3B). In group 2, representing moderate tarsal joint OA, the %color pixels similarly gradually increased from S1 to S9, however, with no differences observed between S1, S2, S3, S4, S5, and S10. No differences were also found between S2, S3, S4, S5, S6, and S10 as well as between S6, S7, and S10. Additionally, none were found between S7 and S8 as well as between S8 and S9 (Figure 3C). In group 3, representing moderate tarsal joint OA, the %color pixels gradually increased from S3 to S9. No differences were found between S1, S2, S3, S4, and S5, as well as between S1, S2, S4, S5, S6, and S7. Moreover, no differences were found between S6, S7, and S10. However, S8 and S9 differed from the %color pixels for other steps and from each other (Figure 3D). The visualizations of the BMD characteristics in each group are displayed in Figure 4. One may observe that the pixels in a range of different grayscale masked with subsequent colors corresponding to different tissue densities are visible in each sub-image.