2015 ISAKOS Biennial Congress ePoster #1252

Are Standard Post-Operative Anteroposterior and Lateral Knee Radiographs Predictive of Anatomic Femoral Tunnel Placement in ACL Reconstruction?

Randy Mascarenhas, MD, FRCSC, Houston, TX UNITED STATES
Marc Scott Haro, MD, MSPT, Oak Park, IL UNITED STATES
Jonathan Riboh, MD, Chicago, IL UNITED STATES
Jason J. Shin, MD, Moose Jaw, SK CANADA
Amanda Ross, BS, Chicago, IL UNITED STATES
Nikhil N. Verma, MD, Chicago, IL UNITED STATES
Brian Forsythe, MD, Chicago, IL UNITED STATES
Bernard R. Bach, Jr., MD, Chicago, IL UNITED STATES

Rush University Medical Center / Midwest Orthopaedics at Rush, Chicago, IL, USA

FDA Status Not Applicable

Summary: Coronal femoral tunnel angle on anteroposterior radiographs is predictive of tunnel accuracy in a cadaveric model.




The primary objective of this study was to determine whether anteroposterior (AP) and lateral knee radiographs were predictive of anatomic femoral tunnel placement in ACL reconstruction. The secondary objective was to compare femoral tunnel characteristics between transtibial (TT) and anteromedial (AM) drilling techniques.


Twelve matched cadaveric knees underwent ACL tunnel drilling using either TT or AM technique. ImageJ software was used to define % coverage (percent of the ACL footprint covered by the femoral tunnel) and % accuracy (percent of the femoral tunnel that fell into the ACL footprint). Coronal femoral tunnel angles were measured on AP radiographs, and tunnel placement on the lateral radiograph was defined as anatomic or non-anatomic based on a 4x4 grid. Continuous variables were compared using two-tailed student’s T-tests and correlations were estimated with the Pearson correlation and univariate regression coefficients.


% coverage did not differ between TT (45.5% +/- 8.1) and AM groups (51.9% +/- 19.7), p = 0.48. Similarly, % accuracy did not differ between TT (62.1% +/- 8.9) and AM groups (80% +/- 24.9), p = 0.13. Tunnel location on lateral radiographs was not predictive of % accuracy or % coverage. However, there was a strong negative correlation between coronal femoral tunnel angle and % accuracy (Pearson’s R = - 0.547, univariate regression p = 0.06). There was a negligible relationship between coronal femoral tunnel angle and % coverage (Pearson’s R = -0.055, univariate regression p = 0.86).


In a cadaver model, coronal femoral tunnel angle showed a strong negative correlation with % accuracy. TT vs. AM drilling had no significant effect on % coverage or % accuracy.

Clinical Relevance:

The coronal angle of an ACL femoral tunnel, as measured on AP radiographs, is a useful predictor of the anatomic accuracy of that tunnel.