Superior Bone Microarchitecture in Anatomic Versus Nonanatomic Fibular Drill Tunnels for Reconstruction of the Posterolateral Corner of the Knee

Abstract

Background: Several fibula-based reconstruction techniques have been introduced to address ligamentous injuries of the posterolateral corner of the knee. These techniques involve a drill tunnel with auto- or allograft placement through the proximal fibula. Purpose: To determine the skeletal microarchitecture of the proximal fibula and its association with age and to compare the microarchitecture within the regions of different drill tunnel techniques for reconstruction of the posterolateral corner. Study Design: Descriptive laboratory study. Methods: A total of 30 human fibulae were analyzed in this cadaveric imaging study. High-resolution peripheral quantitative computed tomography measurements were performed in a 4.5 cm–long volume of interest at the proximal fibula. Three-dimensional microarchitectural data sets of cortical and trabecular compartments were evaluated using customized scripts. The quadrants representing the entry and exit drill tunnel positions corresponding to anatomic techniques (LaPrade/Arciero) and the Larson technique were analyzed. Linear regression models and group comparisons were applied. Results: Trabecular microarchitecture parameters declined significantly with age in women but not men. Analysis of subregions with respect to height revealed stable cortical and decreasing trabecular values from proximal to distal in both sexes. Along with a structural variability in axial slices, superior values were found for the densitometric and microarchitectural parameters corresponding to the fibular drill tunnels in the anatomic versus Larson technique (mean ± SD; bone volume to tissue volume at the entry position, 0.273 ± 0.079 vs 0.175 ± 0.063; P < .0001; cortical thickness at the entry position, 0.501 ± 0.138 vs 0.353 ± 0.081 mm; P < .0001). Conclusion: Age represented a relevant risk factor for impaired skeletal microarchitecture in the proximal fibula in women but not men. The region of drill tunnels according to anatomic techniques showed superior bone microarchitecture versus that according to the Larson technique.