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, 7 (12), 2325967119885882
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Do Rotation and Measurement Methods Affect Reliability of Anterior Cruciate Ligament Tunnel Position on 3D Reconstructed Computed Tomography?

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Do Rotation and Measurement Methods Affect Reliability of Anterior Cruciate Ligament Tunnel Position on 3D Reconstructed Computed Tomography?

Hyun-Soo Moon et al. Orthop J Sports Med.

Abstract

Background: The literature has seldom investigated the anterior cruciate ligament (ACL) tunnel position while considering the effect of rotation of 3-dimensional computed tomography (3D-CT) images during measurements.

Hypothesis: We hypothesized that (1) measurement of the ACL tunnel position in the femur and tibia through use of 3D-CT is considerably influenced by rotation of the 3D model and (2) there exists a reliable measurement method for ACL tunnel position least affected by rotation.

Study design: Controlled laboratory study.

Methods: The 3D-CT images of 30 randomly selected patients who underwent single-bundle ACL reconstruction were retrospectively reviewed. For femoral tunnel assessments, rectangular reference frames were used that involved the highest point of the intercondylar notch and outer margins of the lateral femoral condyle (method 1), the highest point of the intercondylar notch and outer margins of the lateral wall of the intercondylar notch (method 2), and the lowest point of the intercondylar notch and outer margins of the lateral femoral condyle (method 3). For tibial tunnel assessments, rectangular reference frames with the cortical outline at the articular surface of the tibia (method A) and the cortical outline of the proximal tibia (method B) were used. For both femoral and tibial assessments, the tunnel positions at 5°, 10°, and 15° of rotation of the 3D model were compared with that at a neutral position.

Results: The values measured by methods 1 and 3 showed significant differences at greater than 5° of rotation compared with the value at the neutral position, whereas method 2 showed relatively consistent results. However, the values measured with both methods A and B showed significant differences at greater than 5° of rotation compared with the value at the neutral position.

Conclusion: The tunnel position on 3D-CT images was significantly influenced by rotation during measurements. For femoral tunnel position, measurement with a reference frame using the lateral wall of the intercondylar notch (method 2) was the least affected by rotation, with relatively consistent results.

Clinical relevance: This study demonstrates that measurement using the lateral wall of the intercondylar notch might be a consistent and reliable method for evaluating the ACL femoral tunnel position considering the effect of 3D-CT image rotation during measurements. However, both methods to measure tibial tunnel position described in this study were similarly affected by rotation.

Keywords: 3-dimensional CT analysis; ACL reconstruction; ACL tunnel position measurement; rotation.

Conflict of interest statement

The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Figures

Figure 1.
Figure 1.
Flowchart of patient selection in the study. ACL, anterior cruciate ligament.
Figure 2.
Figure 2.
The process of 3-dimensional model preparation with specified coordinates for accurate realignment.
Figure 3.
Figure 3.
(A) The 3-dimensional (3D) femoral model of the patient was simulated to rotate according to specified coordinates. On the basis of (B) the neutral position of the femur at the strict lateral position, the 3D model was rotated spatially for (C) varus, valgus, internal rotation (IR), and external rotation (ER), each at 5°, 10°, and 15°.
Figure 4.
Figure 4.
(A) The 3-dimensional (3D) tibial model of the patient was simulated to rotate according to specified coordinates. On the basis of (B) the neutral position of the tibia with the posterior articular margin of both tibial condyles aligned at the same horizontal plane, the 3D model was rotated spatially for (B) varus, valgus, flexion, and extension, each at 5°, 10°, and 15° . Ext, extension; Flx, flexion.
Figure 5.
Figure 5.
The 3 measurement methods for femoral tunnel height and depth, with different reference frames. The height of the femoral tunnel was expressed as a percentage in each method: vertical distance from the superior border of the reference frame to the center of the tunnel (dashed blue line) ÷ total height of the reference frame (solid blue line) × 100. Likewise, depth was expressed as a percentage in each method: horizontal distance from the deepest border of the reference frame to the center of the tunnel (dashed red line) ÷ total depth of the reference frame (solid red line) × 100.
Figure 6.
Figure 6.
The 2 measurement methods for tibial tunnel width and depth, with different reference frames. The depth of the tibial tunnel was expressed as a percentage in each method: vertical distance from the anterior border of the reference frame to the center of the tunnel (dashed blue line) ÷ total depth of the frame (solid blue line) × 100. Likewise, width was expressed as a percentage in each method: horizontal distance from the deepest border of the reference frame to the center of the tunnel (dashed red line) ÷ total width of the reference frame (solid red line) × 100.
Figure 7.
Figure 7.
Measurements of the height and depth of the femoral tunnel in the neutral position and the measurements at 5° to 15° of rotation for varus, valgus, internal rotation (IR), and external rotation (ER) according to the 3 methods used to assess femoral tunnel position. Ref, reference value. *P < .05. **P < .001.
Figure 8.
Figure 8.
Measurements of the width and depth of the tibial tunnel in the neutral position and the measurements at 5° to 15° of rotation for varus, valgus, flexion (Flx), and extension (Ext) according to the 2 methods used to assess tibial tunnel position. Ref, reference value. *P < .05. **P < .001.

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References

    1. Amis AA, Jakob RP. Anterior cruciate ligament graft positioning, tensioning and twisting. Knee Surg Sports Traumatol Arthrosc. 1998;6(suppl 1):S2–S12. - PubMed
    1. Anderson AF, Lipscomb AB, Liudahl KJ, Addlestone RB. Analysis of the intercondylar notch by computed tomography. Am J Sports Med. 1987;15(6):547–552. - PubMed
    1. Bedi A, Musahl V, Steuber V, et al. Transtibial versus anteromedial portal reaming in anterior cruciate ligament reconstruction: an anatomic and biomechanical evaluation of surgical technique. Arthroscopy. 2011;27(3):380–390. - PubMed
    1. Bernard M, Hertel P, Hornung H, Cierpinski T. Femoral insertion of the ACL: radiographic quadrant method. Am J Knee Surg. 1997;10(1):14–21. - PubMed
    1. Bird JH, Carmont MR, Dhillon M, et al. Validation of a new technique to determine midbundle femoral tunnel position in anterior cruciate ligament reconstruction using 3-dimensional computed tomography analysis. Arthroscopy. 2011;27(9):1259–1267. - PubMed

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