Original Article
Validation of a New Technique to Determine Midbundle Femoral Tunnel Position in Anterior Cruciate Ligament Reconstruction Using 3-Dimensional Computed Tomography Analysis

https://doi.org/10.1016/j.arthro.2011.03.077Get rights and content

Purpose

The purpose of this study was to investigate and report on a new intraoperative measuring technique to place the anterior cruciate ligament (ACL) femoral tunnel in the center of the native ACL femoral insertion site.

Methods

We investigated a novel measuring technique based on identifying the proximal border of the articular cartilage and using a specific ruler parallel to the femoral axis to locate the origin of the ACL. The accuracy of this technique was validated by measuring tunnel position on postoperative 3-dimensional computed tomography scans. Bony tunnels created by the ruler technique were compared with tunnels drilled by a traditional technique referenced from the back wall of the notch.

Results

Fifty ACL reconstructions were performed by the novel measuring technique, with placement of the femoral tunnel at the center of the femoral insertion. The mean position for the center of the femoral tunnel measured by the ruler technique was 0.9 mm from the theoretic optimal center position but was a very distinct 5 mm from the mean position in the traditional tunnels.

Conclusions

The ruler technique produced femoral tunnels comparable to published radiographic criteria used for tunnel placement and is reproducible and accurate. We recommend placement of the femoral tunnel at the midpoint of the lateral femoral condyle when using the anatomic single-bundle technique.

Level of Evidence

Level IV, case series.

Section snippets

Methods

Fifty-five consecutive, functionally unstable, ACL-deficient patients underwent ACL reconstruction by use of a femoral tunnel in the anatomic position on the medial wall of the lateral femoral condyle with the described technique. CT scans were performed postoperatively, and reconstructive images were used to measure the tunnel position as referenced from the posterior aspect of the lateral femoral condyle and the roof of the intercondylar notch. The precise details of the anatomic technique

Results

There were 55 patients in the anatomic group operated on between September 2009 and April 2010. Five patients in this group did not attend their CT scan appointments and so were excluded. This left a total of 50 patients. Sixteen patients undergoing ACL reconstruction by the traditional technique were also evaluated. The mean patient age at surgery was 30 years (range, 16 to 66 years) in the anatomic group and 33 years (range, 21 to 62 years) in the traditional group. There were 38 male and 12

Discussion

We have described a new technique to reliably position the femoral tunnel in the midbundle position of the ACL insertion on the lateral wall of the intercondylar notch. An arthroscopic ruler is used to measure the depth of the lateral wall, and the tunnel is drilled at the midpoint of this line. Quantification of the center of the resulting tunnel on specific 3D CT scan reconstructions has shown that the technique reproducibly places the tunnel close to the anatomic center of the insertion as

Conclusions

The ruler technique produced femoral tunnels comparable to published radiographic criteria used for tunnel placement and is reproducible and accurate. We recommend placement of the femoral tunnel at the midpoint of the lateral femoral condyle when using the anatomic single-bundle technique.

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    The authors report no conflict of interest.

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