COMPARISON OF RENDERING 3D-CT WITH TRANSPARENT 3D-CT FOR ACL TUNNEL POSITION

ABSTRACT Objective: To compare the transparent 3D computed tomography (CT) image protocol against conventional 3D-CT image-rendering protocol for assessment of femoral tunnel position in anatomic anterior cruciate ligament (ACL) reconstructions. Methods: 8 knee CT scans, from cadavers, were analized by image rendering 3D-CT protocol, using Rhinoceros® software. Central point of the ACL tunnel was set using the sagittal plane. The same CT scans were analized using transparent 3D-CT measurement protocol with OsiriX® software. Central point of the ACL tunnel was set using sagittal, coronal and axial planes. The grid system described by Bernard and Hertel was used to compare tunnel positions between protocols, using height and length parameters. Results: There was a significant difference between measurements using image rendering 3D-CT and transparent 3D-CT protocol for height (23.8 +/- 7.9 and 33.0 +/- 5.0, respectively; P = 0.017) and no differences for length (18.6 +/- 4.2 and 18.3 +/- 4.5, respectively; P = 0.560). Conclusion: Height in transparent CT protocol was different and length was equal when comparing to 3D-CT rendering protocol in Bernard and Hertel method for tunnel measurements. Level of Evidence II, Descriptive Laboratory Study. Keywords: Anterior cruciate ligament reconstruction. Imaging, three-dimensional. Image processing computer-assisted.