The three-dimensional orientation of trabeculae is a key factor in determining the load carrying capabilities of cancellous bone. Previous biomechanical studies have shown that proximal tibias resected parallel to the articulating surface are stronger and stiffer than the contralateral tibias resected perpendicular to the long axis of the bone. However, morphologic evidence was not provided to help explain the mechanical differences.
To determine the orientation of the trabeculae in the medial condyle for both parallel cut and perpendicular cut specimens, a scanning electron microscope and stereoscopic techniques were used. Data showed that tibias cut parallel to the articular surface had trabeculae oriented nearly vertical with a mean angle of 4.5° ± 14.7° (range, 0° to 56.3°). The contralateral tibias cut perpendicular to the long axis of the tibia had trabeculae oriented at a mean angle of 36.0° ± 12.2° (range, 16.1° to 67.4 °) from vertical. The differences between the two resection techniques were shown to be significant (p s. 0.01) using an Analysis of Variance.
This study provided morphologic evidence to explain why previous specimens cut parallel to the articular surface had stronger and stiffer cancellous bone than the contralateral specimens cut perpendicular to the long axis of the tibia. This information is important in understanding the load carrying capabilities of cancellous bone and how it may be applied to improving the clinical results of primary total knee arthroplasty.
Bachus, K. N.; Harman, M. K.; and Bloebaum, R. D.
"Stereoscopic Analysis of Trabecular Bone Orientation in Proximal Human Tibias,"
Cells and Materials: Vol. 2
, Article 2.
Available at: http://digitalcommons.usu.edu/cellsandmaterials/vol2/iss1/2