"Inching closer to native anatomy: A CT scan based morphometric analysis of tunnels in all-inside ACL reconstruction"
Imroz Jindal1, Kamparsh Thakur2, Chander Mohan Singh1
1Department of Orthopaedics, AFMC (Pune), 411040, India.
Background:
Placement of ACL tunnels closer to native ACL footprint is of utmost importance. Thus, study was designed to analyze radiomorphometric parameters of tunnels in All-inside technique (AI) and compare them to Antero-medial portal with full Tibial tunnel technique (AMP).
Methods:
Observational study was conducted from January 2019 to December 2021. Participants were divided into two groups for single bundle ACL reconstruction: AI and AMP. Radiomorphometric analysis of tunnels was done on CT-scan. Paired t-test was used for comparison, with p < 0.05 considered to be significant.
Results:
60 patients were included in the study, with one female and 29 males, with no significant differences in demographic parameters (p = 0.0554). For femoral tunnels, t% was 22.27 ± 3.677 and 22.506 ± 2.481; h% was 29.92 ± 3.255 and 27.654 ± 2.938 for AMP and AI respectively, with no significant differences. For tibial tunnels, ap% was 45.658 ± 3.33 and 46.008 ± 3.448; ml% was 51.247 ± 1.91 and 52.035 ± 2.533 for AMP and AI, respectively. There was no significant differences for t% (p = 0.84), h% (p = 0.0551), ap% (p = 0.7794), and ml% (p = 0.3443). Mean diameter of femoral tunnels was 9.43 ± 0.75 mm and 9.16 ± 0.58 mm, and tibial tunnels were 9.43 ± 0.70 mm and 9.06 ± 0.70 mm for AMP and AI, respectively, with no statistical difference. The length of femoral tunnels was 20.146 ± 3.256 mm and 21.64 ± 2.011 mm, and tibial tunnels were 39.16 ± 5.447 mm and 20.72 ± 3.68 mm for AMP and AI respectively, showing a significant difference in tibial tunnel length (p < 0.00001). No significant difference was noted in sagittal orientation in two techniques. However, a significant difference was noted in coronal alignment for femoral tunnels (p < 0.0001).
Conclusion:
There is no significant differences in femoral and tibial tunnel placement, length, diameter, and sagittal orientation. However, significant difference was noted in femoral tunnels' coronal orientation and tibial tunnels' length. Drilling femoral tunnel at 90° enhances ease of placement for femoral-jig but does not affect tunnel placement.
