Anatomical variations of the equine femur and tibia using statistical shape modeling.
Authors: He Hongjia, Banks Scott A, Biedrzycki Adam H
Journal: PloS one
Summary
# Editorial Summary Anatomical variations within equine populations have long been suspected to influence stifle biomechanics and predispose certain individuals to joint disease, yet quantifying this morphological diversity has remained challenging. He, Banks and Biedrzycki used statistical shape modeling on 15 femora and 14 tibiae to characterise natural variation in these critical bones, finding that six modes of femoral variation and three modes of tibial variation could account for approximately 95% of population diversity. Beyond simple size differences, the most significant variations included femoral mechanical-anatomical angle and neck angle (femoral mode 2), femoral version angle and trochlear tubercle orientation (modes 3–4), and notably asymmetrical tibial plateau slopes, with lateral caudal slopes significantly steeper than medial counterparts. These quantified anatomical parameters provide an evidence-based reference framework that could underpin future investigations into how morphological deviations contribute to stifle pathology and biomechanical dysfunction. Clinically, the shape models enable patient-specific surgical planning through radiographic matching and support the production of bespoke 3D-printed models for pre-surgical rehearsal—offering farriers, veterinarians and physiotherapists more individualized approaches to managing conformational risk factors and designing targeted rehabilitative strategies.
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Practical Takeaways
- •Understanding normal anatomical variation in stifle structure provides a baseline for identifying abnormal morphology that may predispose to joint disease
- •The quantified biometric parameters (femoral version angle, tibial slopes) can help clinicians assess whether an individual horse's anatomy may contribute to stifle problems
- •3D printed patient-specific models could revolutionize pre-surgical planning and allow surgeons to rehearse procedures before operating on valuable horses
Key Findings
- •Statistical shape modeling of 15 equine femora and 14 tibiae identified 6 and 3 primary modes of variation respectively, accounting for ~95% of population shape variation
- •Femur variation primarily involves scaling (mode 1), followed by mechanical-anatomical angle and femoral neck angle (mode 2), trochlear tubercle orientation (mode 3), and femoral version angle (mode 4)
- •Tibia variation includes scaling (mode 1), coronal plateau angle (mode 2), and tibial slopes (mode 3), with lateral caudal slope significantly larger than medial
- •Patient-specific 3D models generated from radiographs could enable surgical planning and pre-operative practice on printed models