Radiographic development of osteochondral abnormalities, in the hock and stifle of Dutch Warmblood foals, from age 1 to 11 months.

The research study examines the development of osteochondral abnormalities, specifically osteochondrosis, in the hock and stifle joints of Dutch Warmblood foals from ages 1 to 11 months, observing that abnormalities could develop very early in life and were predominantly temporary.

Methodology

• The researchers conducted a longitudinal study, which involved radiographically examining the hocks and stifles of Dutch Warmblood foals from 1 to 11 months of age. Radiographs were taken at one-month intervals.
• A total of 43 foals were radiographed up until 5 months of age and 19 were radiographed up to 11 months.
• To enhance the possibility of osteochondrosis development, only offspring from diseased sires with radiographically proven osteochondrosis were utilized for the study.

Results

• The study discovered that at 1 month of age, frequent abnormalities were observed in the intermediate ridge of the distal tibia, with 67% classified under grades 1 to 3, and 1% under grade 4.
• Abnormal appearances at the distal aspect of the lateral trochlear ridge of the talus were less common, with 25% falling under grades 1 to 3, and 6% under grade 4.
• The researchers found that the midregion of the lateral ridge of the femoral trochlea was predominantly normal, with 98% at grade 0 and 2% at grade 1.

Progression of Abnormalities

• Initial abnormalities in the intermediate tibial ridge showed a strong tendency for regression, with progression being less common.
• Normal appearances rare turned abnormal, with only 18% of the hock abnormalities persisting at 11 months.
• Abnormalities in the distal aspect of the lateral trochlear ridge of the talus showed a strong tendency towards resolution without any progression, with only 3% of the hock being abnormal at 11 months.

Stability of Conditions

• Both normal and abnormal appearances in the hock became stable from 5 months onwards.
• In the stifle joint, abnormalities in the midregion of the lateral ridge of the femoral trochlea became noticeable from 3 or 4 months of age, typically followed by progression, regression, and resolution, returning to normal appearance at 8 months.
• By 5 months, 20% of the stifles were abnormal, but this percentage fell to 3% by 11 months.

Conclusion

• The researchers concluded that osteochondrosis, an osteochondral abnormality, tends to develop very early in the life of Dutch Warmblood foals.
• However, the data revealed that most of these abnormalities were temporary, with the ‘age of no return’ identified as 5 months for the hock and 8 months for the stifle joints.