🔍 Key Findings
- Quadriceps muscle length/femoral length ratio (QML/FL) was significantly lower in dogs with grade IV MPL than grades I–III (p ≤ .002).
- Shortened QML was associated with increased femoral torsion angle (FTA) and increased aLDFA, indicating correlation with femoral deformity.
- QML/FL increased with age, possibly due to muscular development or reduced deformity in older dogs (p = .004).
- Grade IV MPL dogs had QML/FL < 0.87, the lower normal limit based on healthy beagles, suggesting clinically significant muscle shortening.
- PLL/PL ratio (used to diagnose patella alta) was not associated with QML/FL or MPL severity in small breeds.
- QML/FL can help preoperatively identify candidates for femoral shortening ostectomy, improving femoropatellar alignment.
- Multivariate regression model confirmed QML/FL is independently influenced by age, FTA, and aLDFA (R² = 0.45).
- CT-based 3D measurements enabled objective, noninvasive quantification of femoral and muscle alignment parameters.

