Three-Dimensional Morphometry of the Canine Pelvis: Implications for Total Hip Replacement Surgery

Area of Science:

• Veterinary Orthopedics
• Biomechanical Engineering
• Surgical Planning

Background:

• Two-dimensional measurements of acetabular geometry are standard for assessing acetabular component orientation in total hip replacement (THR).
• Three-dimensional (3D) planning using computed tomography (CT) scans offers potential for improved surgical accuracy in THR.

Purpose of the Study:

• To validate a 3D workflow for measuring canine acetabular angles of lateral opening (ALO) and version.
• To establish reference values for these angles in dogs.

Main Methods:

• Pelvic CT scans from 27 healthy adult dogs were used to create patient-specific 3D models.
• Acetabular ALO and version angles were measured, with technique validity assessed by intra-observer coefficient of variation (CV).
• Reference ranges were calculated, and left-right hemipelvis data were compared for symmetry.

Main Results:

• The 3D workflow demonstrated high repeatability, with intra-observer CVs ranging from 3.5-5.2% and inter-observer CVs from 3.3-5.2%.
• Mean ALO was 42.9° (±4.0°) and mean version angle was 27.2° (±5.3°).
• Left and right acetabular measurements were symmetrical and not significantly different.

Conclusions:

• Canine acetabular alignment values derived from the 3D workflow are broadly comparable to clinical total hip replacement guidelines.
• Significant variation in measured angles suggests a need for patient-specific planning to mitigate risks like joint luxation.