COMPARISON BETWEEN RENDERING 3D-CT AND TRANSPARENT 3D-CT IN ACL TUNNEL POSITIONING.

Area of Science:

• Orthopedic Surgery
• Radiology
• Biomedical Imaging

Background:

• Anatomic anterior cruciate ligament (ACL) reconstruction relies on accurate femoral tunnel placement.
• Conventional 3D-CT image-rendering protocols may have limitations in precise tunnel assessment.
• Novel imaging techniques are needed to improve the accuracy of evaluating ACL reconstruction outcomes.

Purpose of the Study:

• To compare the accuracy of a transparent 3D computed tomography (CT) protocol versus a conventional 3D-CT rendering protocol.
• To evaluate femoral tunnel positioning in anatomic ACL reconstructions.
• To determine if the transparent 3D-CT method offers advantages in assessing tunnel height and length.

Main Methods:

• Eight cadaveric knee CT scans were analyzed using both 3D-CT image rendering (Rhinoceros software) and transparent 3D-CT (OsiriX software) protocols.
• Femoral tunnel central points were identified using sagittal, coronal, and axial planes.
• Tunnel positions were compared using the Bernard and Hertel grid system, focusing on height and length parameters.

Main Results:

• A significant difference was found in tunnel height measurements between the image rendering (23.8 ± 7.9mm) and transparent 3D-CT (33.0 ± 5.0mm) protocols (p=0.017).
• No significant difference was observed in tunnel length measurements between the two protocols (18.6 ± 4.2mm vs. 18.3 ± 4.5mm; p=0.560).

Conclusions:

• The transparent 3D-CT protocol yields different height measurements compared to the 3D-CT rendering protocol for femoral tunnels in ACL reconstructions.
• Tunnel length measurements were consistent between both CT protocols when using the Bernard and Hertel method.
• Further investigation may be warranted to understand the clinical implications of height discrepancies in transparent 3D-CT measurements.