2015 ISAKOS Biennial Congress ePoster #1324

Reliability and Reproducibility of Several Methods of Arthroscopic Assessment of Femoral Tunnel Position During Anteriror Cruciate Ligament Reconstruction

Omer A. Ilahi, MD, Houston, TX UNITED STATES
David Mansfield, MD, El Paso, TX UNITED STATES
Luis Urrea, II, MD, El Paso, TX UNITED STATES
Ali Qadeer, BS, Houston, TX UNITED STATES

Texas Arthroscopy & Sports Medicine Institute, Houston, Texas, USA

FDA Status Not Applicable

Summary: A linear method of arthroscopically estimating femoral tunnel position during single-bundle ACL reconstruction had greater interobserver agreement than the clock face analogy unless a visual template was used, which greatly increased the reliability of the clock face analogy.




To assess interobserver and intraobserver agreement of estimating anterior cruciate ligament (ACL) femoral tunnel positioning arthroscopically using circular and linear (non-circular) estimation methods and to see if overlay template visual aids improve agreement.


Standardized intraoperative pictures of femoral tunnel pilot holes (taken with a 30° arthroscope through an anterolateral portal at 90° of knee flexion with horizontal being parallel to the tibial surface) in 27 patients undergoing single bundle ACL reconstruction were presented to 3 fellowship-trained arthroscopists on 2 separate occasions. On both viewings, each surgeon estimated femoral tunnel pilot hole location to the nearest half hour mark using a whole clock face and half clock face; to the nearest 15° using a whole compass and half compass; in the top or bottom half of a linear quadrant; in the top or bottom half of a linear trisector. Evaluations were performed first without and then with an overlay template of each estimation method.


The average difference among reviewers was quite similar for all 4 circular methods with the use of visual aids. Without overlay template visual aids, pairwise kappa statistic values for interobserver agreement ranged from -0.14 to 0.56 for the whole clock face and from 0.16 to 0.42 for the half clock face. With overlay visual guides, interobserver agreement ranged from 0.29 to 0.63 for the whole clock face and from 0.17 to 0.66 for the half clock face. The quadrant method’s intrerobserver agreement ranged from 0.22 to 0.60 and that of the trisection method ranged from 0.17 to 0.57. Neither linear estimation method’s reliability uniformly improved with use of overlay templates. Intraobserver agreement without overlay templates ranged from 0.17 to 0.49 for the whole clock face, 0.11 to 0.47 for the half clock face, 0.01 to 0.66 for the quadrant method, and 0.20 to 0.57 for the trisection method. Use of overlay templates did not uniformly improve intraobserver agreement for any estimation method.


There does not appear to be any advantage of using a half clock face or compass in estimating femoral tunnel position compared to a whole clock face analogy. Visual reference aids appear to improve interobserver agreement (reliability) of circular analogies. The linear quadrant appears to be the most reliable method (fair to moderate agreement) for estimating femoral tunnel position without a visual aid for reference, but even better reliability, ranging from fair to good agreement, may be obtained by using the whole clock face analogy with a visual aid.