Morphometric description of the feline tibia using three – dimensional computed tomography

Abstract

Background: Previous studies have described bone length and surface area of the feline tibia, however information regarding three-dimensional (3D) and internal morphometry is lacking. The objective of this study was to describe the length, external and internal bone diameter, cortical thickness, cancellous bone volume and mechanical joint angles in 8 domestic adult feline cadaver tibiae using computed tomography (CT). Measurements of the paired tibiae were performed in triplicate and the average was recorded. Results: Overall tibia length measured 111.61mm (95% CI 107.89 – 115.53mm). The proximal tibia had a mean cancellous bone volume of 12.45mm3 (95% CI 11.4 – 13.49mm3). The distal tibia had a mean cancellous bone volume of 2.09mm3 (95% CI 1.62 – 2.55mm3). The narrowest internal bone diameter mediolaterally was at 50% tibial length (4.23mm 95% CI 4.05 – 4.42mm) and craniocaudally at 75% tibial length (3.77mm 95% CI 3.57 – 3.97mm). Mean mechanical joint angles and 95% CI were: tibial plateau angle 31.42° (30.09 – 32.75°); mechanical medial proximal tibia angle 95.15° (94.63 – 95.68°); mechanical medial distal tibia angle 94.08° (93.36 – 94.79°); mechanical cranial distal tibia angle 88.69° (87.04 – 90.32°); mechanical caudal proximal tibia angle 58.53° (57.20 – 59.86°) and sagittal plane alignment 30.16° (28.47 – 31.84°). Conclusions: Use of computed tomography allowed the estimation of internal bone morphometry and joint geometry in a heterogeneous sample of feline tibias. This provided data that would be valuable in planning and developing new techniques for internal fracture fixation.