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Evaluation and Comparison of Femoral Tunnel Placement During Anterior Cruciate Ligament Reconstruction Using 3-Dimensional Computed Tomography: Effect of Notchplasty on Transtibial and Medial Portal Drilling.

Dugas JR, Pace JL, Bolt B, Wear SA, Beason DP, Cain EL - Orthop J Sports Med (2014)

Bottom Line: Advocates of medial portal drilling claim that the transtibial technique results in a more vertical positioning of the graft, which could lead to subsequent failure and/or a residual pivot shift on postoperative examination.However, advocates of transtibial drilling state that with appropriate placement and adequate notchplasty, their technique places the graft in a more anatomically correct position on the wall, negating the resultant potential for pivot shift and early postoperative failure.Both drilling techniques place the graft in an anatomically correct position.

View Article: PubMed Central - PubMed

Affiliation: American Sports Medicine Institute, Birmingham, Alabama, USA.

ABSTRACT

Background: Advocates of medial portal drilling claim that the transtibial technique results in a more vertical positioning of the graft, which could lead to subsequent failure and/or a residual pivot shift on postoperative examination. However, advocates of transtibial drilling state that with appropriate placement and adequate notchplasty, their technique places the graft in a more anatomically correct position on the wall, negating the resultant potential for pivot shift and early postoperative failure.

Hypothesis: Transtibial femoral drilling can adequately reproduce the femoral origin of the anterior cruciate ligament (ACL) and place the graft in an anatomical position equivalent to medial portal drilling.

Study design: Controlled laboratory study.

Methods: Ten matched-pair cadaveric knees (N = 20) were scanned using computed tomography (CT), and 3-dimensional images of the native ACL origin were reconstructed. The matched pairs were then randomized into transtibial and medial portal groups. The femoral tunnel was drilled in each knee according to group. A bamboo skewer was placed in the femoral tunnel, and the knees underwent a second CT scan. Arthroscopic notchplasty was performed, and the femoral tunnels were redrilled. Radiographs confirmed placement, and the post-notchplasty tunnel was reamed with a 4-mm reamer. The knees underwent a third CT scan. CT scans compared femoral tunnel placement with the native ACL footprint before and after notchplasty.

Results: The post-notchplasty transtibial group revealed an average of 68.3% coverage of the native ACL femoral origin. The medial portal group revealed an average of 60.8% coverage, with 1 instance of perforation of the posterior cortex. There were no instances of perforation in the transtibial group.

Conclusion: Both drilling techniques place the graft in an anatomically correct position.

Clinical relevance: Transtibial drilling of the femur can adequately place the entry tunnel at the origin of the ACL's native footprint.

No MeSH data available.


Related in: MedlinePlus

(A) Sagittal 3-dimensional computed tomography (CT) reconstruction of a right femur along its long axis. Looking at the medial aspect of the lateral femoral condyle, the native anterior cruciate ligament (ACL) origin is depicted in green. The red oval shows the entrance tunnel a 10-mm reamer would make via the transtibial technique before notchplasty. The blue oval corresponds to the entrance tunnel post-notchplasty using a 10-mm reamer. (B) Coronal 2-dimensional CT through the notch showing length of tunnel (purple), which may have led to posterior cortical compromise. (C) Three-dimensional CT reconstruction of the contralateral knee shown in (A). Because of the short tunnel length, the posterior cortex was compromised and the tunnels were not placed in the anatomic position of the origin of the ACL (green).
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fig3-2325967114525572: (A) Sagittal 3-dimensional computed tomography (CT) reconstruction of a right femur along its long axis. Looking at the medial aspect of the lateral femoral condyle, the native anterior cruciate ligament (ACL) origin is depicted in green. The red oval shows the entrance tunnel a 10-mm reamer would make via the transtibial technique before notchplasty. The blue oval corresponds to the entrance tunnel post-notchplasty using a 10-mm reamer. (B) Coronal 2-dimensional CT through the notch showing length of tunnel (purple), which may have led to posterior cortical compromise. (C) Three-dimensional CT reconstruction of the contralateral knee shown in (A). Because of the short tunnel length, the posterior cortex was compromised and the tunnels were not placed in the anatomic position of the origin of the ACL (green).

Mentions: Once 3-dimensional reconstructions were created, these images were evaluated to determine the anatomic location of the ACL origin. The values were mapped out (Figure 3A) according to prior values stated in the literature.16 Using a mathematic ratio, the size of the tunnel after reaming (4.5 mm) was extrapolated to resemble the oval, which would be produced by a 10-mm reamer used intraoperatively. The percentage contact of the entrance oval along the native ACL was determined before and after notchplasty. Also, the tunnel length for each specimen was calculated (Figure 3, B and C). Paired t tests with an alpha level of .05 were used to determine if there were any statistical differences between the 2 techniques.


Evaluation and Comparison of Femoral Tunnel Placement During Anterior Cruciate Ligament Reconstruction Using 3-Dimensional Computed Tomography: Effect of Notchplasty on Transtibial and Medial Portal Drilling.

Dugas JR, Pace JL, Bolt B, Wear SA, Beason DP, Cain EL - Orthop J Sports Med (2014)

(A) Sagittal 3-dimensional computed tomography (CT) reconstruction of a right femur along its long axis. Looking at the medial aspect of the lateral femoral condyle, the native anterior cruciate ligament (ACL) origin is depicted in green. The red oval shows the entrance tunnel a 10-mm reamer would make via the transtibial technique before notchplasty. The blue oval corresponds to the entrance tunnel post-notchplasty using a 10-mm reamer. (B) Coronal 2-dimensional CT through the notch showing length of tunnel (purple), which may have led to posterior cortical compromise. (C) Three-dimensional CT reconstruction of the contralateral knee shown in (A). Because of the short tunnel length, the posterior cortex was compromised and the tunnels were not placed in the anatomic position of the origin of the ACL (green).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2 - License 3
Show All Figures
getmorefigures.php?uid=PMC4555567&req=5

fig3-2325967114525572: (A) Sagittal 3-dimensional computed tomography (CT) reconstruction of a right femur along its long axis. Looking at the medial aspect of the lateral femoral condyle, the native anterior cruciate ligament (ACL) origin is depicted in green. The red oval shows the entrance tunnel a 10-mm reamer would make via the transtibial technique before notchplasty. The blue oval corresponds to the entrance tunnel post-notchplasty using a 10-mm reamer. (B) Coronal 2-dimensional CT through the notch showing length of tunnel (purple), which may have led to posterior cortical compromise. (C) Three-dimensional CT reconstruction of the contralateral knee shown in (A). Because of the short tunnel length, the posterior cortex was compromised and the tunnels were not placed in the anatomic position of the origin of the ACL (green).
Mentions: Once 3-dimensional reconstructions were created, these images were evaluated to determine the anatomic location of the ACL origin. The values were mapped out (Figure 3A) according to prior values stated in the literature.16 Using a mathematic ratio, the size of the tunnel after reaming (4.5 mm) was extrapolated to resemble the oval, which would be produced by a 10-mm reamer used intraoperatively. The percentage contact of the entrance oval along the native ACL was determined before and after notchplasty. Also, the tunnel length for each specimen was calculated (Figure 3, B and C). Paired t tests with an alpha level of .05 were used to determine if there were any statistical differences between the 2 techniques.

Bottom Line: Advocates of medial portal drilling claim that the transtibial technique results in a more vertical positioning of the graft, which could lead to subsequent failure and/or a residual pivot shift on postoperative examination.However, advocates of transtibial drilling state that with appropriate placement and adequate notchplasty, their technique places the graft in a more anatomically correct position on the wall, negating the resultant potential for pivot shift and early postoperative failure.Both drilling techniques place the graft in an anatomically correct position.

View Article: PubMed Central - PubMed

Affiliation: American Sports Medicine Institute, Birmingham, Alabama, USA.

ABSTRACT

Background: Advocates of medial portal drilling claim that the transtibial technique results in a more vertical positioning of the graft, which could lead to subsequent failure and/or a residual pivot shift on postoperative examination. However, advocates of transtibial drilling state that with appropriate placement and adequate notchplasty, their technique places the graft in a more anatomically correct position on the wall, negating the resultant potential for pivot shift and early postoperative failure.

Hypothesis: Transtibial femoral drilling can adequately reproduce the femoral origin of the anterior cruciate ligament (ACL) and place the graft in an anatomical position equivalent to medial portal drilling.

Study design: Controlled laboratory study.

Methods: Ten matched-pair cadaveric knees (N = 20) were scanned using computed tomography (CT), and 3-dimensional images of the native ACL origin were reconstructed. The matched pairs were then randomized into transtibial and medial portal groups. The femoral tunnel was drilled in each knee according to group. A bamboo skewer was placed in the femoral tunnel, and the knees underwent a second CT scan. Arthroscopic notchplasty was performed, and the femoral tunnels were redrilled. Radiographs confirmed placement, and the post-notchplasty tunnel was reamed with a 4-mm reamer. The knees underwent a third CT scan. CT scans compared femoral tunnel placement with the native ACL footprint before and after notchplasty.

Results: The post-notchplasty transtibial group revealed an average of 68.3% coverage of the native ACL femoral origin. The medial portal group revealed an average of 60.8% coverage, with 1 instance of perforation of the posterior cortex. There were no instances of perforation in the transtibial group.

Conclusion: Both drilling techniques place the graft in an anatomically correct position.

Clinical relevance: Transtibial drilling of the femur can adequately place the entry tunnel at the origin of the ACL's native footprint.

No MeSH data available.


Related in: MedlinePlus