Radiographic analysis in Thoroughbreds reveals morphological changes in healthy maturing stifle joints and possible association between subchondral lesions and femoral condyle width.

The study examines morphological changes in the stifle joints of Thoroughbred foals as they mature and investigates a potential link between subchondral bone lesion presence and femoral condyle width.

Methods

• The researchers divided their investigation into three independent but related radiographic studies.
• In the first study, they retrospectively examined radiographs of foals, measuring femoral-tibial morphological parameters both in instances with subchondral radiolucencies (SR+) and without (SR-).
• The second study involved a qualitative comparison of drawings of the intercondylar notch shape derived from postmortem radiographs of SR- foals.
• The third study prospectively assessed femoral-tibial parameters in foals at one month of age (SR-).

Measurements

• In studies 1 and 3, the researchers measured 13 specific morphological parameters.
• They particularly looked at limb directional symmetry in two age brackets: foals under seven months and those seven months or older.

Findings

• In SR- foals, researchers observed an increase in femoral measurements as foals matured, with the exception of the distal femoral intercondylar notch width (FINwal), which decreased.
• However, in SR+ stifles, three femoral parameters (medial femoral condyle width [MFCwpf], MFC height, or FINwal) demonstrated no changes.
• The tibial plateau width increased with maturation in both SR- and SR+ foals.
• Also, it was found that the left SR- stifles in foals aged seven months or older had larger femoral bicondylar width and FINw, while right SR+ stifles in foals of similar age had a broader MFCw.

Conclusions

• The researchers concluded that in SR+ stifles, the distal femur showcased divergent maturation, indicating a broader MFC in the right stifle in older foals.
• This study proposes that since SR lesions are more common on the right, there could be a potential association between MFC morphology and SR lesions.