Transtibial Versus Anteromedial Portal Drilling for Anterior Cruciate Ligament Reconstruction: A Cadaveric Study of Femoral Tunnel Length and Obliquity

doi:10.1016/j.arthro.2009.12.006

Arthroscopy: The Journal of Arthroscopic & Related Surgery

Volume 26, Issue 3, March 2010, Pages 342-350

https://doi.org/10.1016/j.arthro.2009.12.006 Get rights and content

Purpose

To compare the obliquity and length of femoral tunnels prepared with transtibial versus anteromedial portal drilling for anterior cruciate ligament (ACL) reconstruction and identify potential risks associated with the anteromedial portal reaming technique.

Methods

We used 18 human cadaveric knees (9 matched pairs) without ACL injury or pre-existing arthritis for the study. Femoral tunnels for ACL reconstruction were prepared by either a transtibial (n = 6) or anteromedial portal (n = 12) technique. For the anteromedial portal technique, a guidewire was advanced through the medial portal in varying degrees of knee flexion (100° [n = 4], 110° [n = 4], or 120° [n = 4]) as measured with a goniometer. By use of a 6-mm femoral offset guide, two 6-mm femoral tunnels were reamed with the guide placed (1) as far posterior and lateral in the notch as possible and (2) as far medial and vertical in the notch as possible to define the range of maximal and minimal achievable coronal obliquity for each technique. All knees were imaged with high-resolution, 3-dimensional fluoroscopy to define (1) coronal tunnel obliquity relative to the lateral tibial plateau, (2) sagittal tunnel obliquity relative to the long axis of the femur, (3) intraosseous tunnel length, and (4) the presence of posterior cortical wall blowout. Data analysis was performed with a paired t-test and repeated-measures analysis of variance, with P < .05 defined as significant.

Results

Preparation of a vertical tunnel was possible with both transtibial and anteromedial portal drilling. The maximal achievable coronal obliquity, however, was significantly better with an anteromedial portal compared with transtibial drilling. However, 7 of 36 tunnels (19.4%) showed violation of the posterior tunnel wall, and all of these cases occurred with the anteromedial portal drilling technique. In addition, 1 of 6 oblique femoral tunnels (16.7%) drilled with the transtibial technique and 5 of 12 oblique femoral tunnels (41.7%) drilled with the anteromedial portal had an intraosseous length less than 25 mm. Increasing knee flexion with anteromedial portal drilling was associated with a significant reduction in tunnel length, increase in coronal obliquity, increase in sagittal obliquity, and increased risk of posterior wall blowout (P < .05).

Conclusions

The anteromedial portal technique allows for slightly greater femoral tunnel obliquity compared with transtibial drilling. However, there is a substantially increased risk of critically short tunnels (<25 mm) and posterior tunnel wall blowout when a conventional offset guide is used. Increasing knee flexion with anteromedial portal drilling allows for greater coronal obliquity of the femoral tunnel but is accompanied by a greater risk of critically short tunnels and posterior wall compromise.

Clinical Relevance

Our findings provide insight into the potential risks and advantages of a transtibial versus an anteromedial femoral tunnel drilling technique in ACL reconstruction.

Section snippets

Methods

After institutional review board approval was obtained, 18 human cadaveric knees (9 matched pairs) without ACL injury or pre-existing arthritis were obtained for the study. Each femur was secured in a custom jig allowing free flexion of the knee. A 30° 3.5-mm arthroscope (Stryker, Warsaw, IN) was introduced into the knee through a standard anterolateral portal. Through an AM portal placed approximately 4 mm medial to the border of the patellar tendon, the ACL was arthroscopically resected and a

Results

Vertical femoral tunnels could be prepared with transtibial and AM portal drilling techniques (79.55° ± 9.32° and 77.88° ± 7.90°, respectively). The maximal achievable coronal obliquity, however, was significantly greater with an AM portal compared with transtibial drilling (46.85° ± 6.89° v 54.08° ± 7.17°, P < .05). In contrast, sagittal tunnel orientation was not significantly different between groups (Table 1).

Of 36 tunnels, 7 (19.4%) showed compromise of the posterior tunnel wall on axial

Discussion

The purpose of this study was to compare the obliquity, length, and wall compromise of femoral tunnels prepared with transtibial versus AM portal drilling for ACL reconstruction. Using CT analysis of tunnel position, we found that the AM portal technique allows for slightly greater femoral tunnel obliquity compared with transtibial drilling, but this is accompanied by an increased risk of critically short tunnels (<25 mm) and posterior tunnel wall blowout when using a conventional offset guide.

Conclusions

The AM portal technique allows for slightly greater femoral tunnel obliquity compared with transtibial drilling. However, there is a substantially increased risk of critically short tunnels (<25 mm) and posterior tunnel wall blowout with AM portal compared with transtibial drilling when a conventional offset guide is used. Increasing knee flexion with AM portal drilling allows for greater coronal obliquity of the femoral tunnel at the expense of a greater risk of critically short tunnels and

References (20)

M.C. Lee et al.
Vertical femoral tunnel placement results in rotational knee laxity after anterior cruciate ligament reconstruction
Arthroscopy
(2007)
J.M. Scopp et al.
The effect of oblique femoral tunnel placement on rotational constraint of the knee reconstructed using patellar tendon autografts
Arthroscopy
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A. Chhabra et al.
Recreating an acceptable angle of the tibial tunnel in the coronal plane in anterior cruciate ligament reconstruction using external landmarks
Arthroscopy
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S.R. Golish et al.
The effect of femoral tunnel starting position on tunnel length in anterior cruciate ligament reconstruction: A cadaveric study
Arthroscopy
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F. Giron et al.
Double-bundle “anatomic” anterior cruciate ligament reconstruction: A cadaveric study of tunnel positioning with a transtibial technique
Arthroscopy
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Arthroscopic double-bundle anterior cruciate ligament reconstruction: An anatomic approach
Arthroscopy
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C.D. Harner et al.
Anteromedial portal technique for creating the anterior cruciate ligament femoral tunnel
Arthroscopy
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J.C. Loh et al.
Knee stability and graft function following anterior cruciate ligament reconstruction: Comparison between 11 o'clock and 10 o'clock femoral tunnel placement
2002 Richard O'Connor Award paper. Arthroscopy
(2003)
K. Yasuda et al.
Anatomic reconstruction of the anteromedial and posterolateral bundles of the anterior cruciate ligament using hamstring tendon grafts
Arthroscopy
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S.M. Howell et al.
The relationship between the angle of the tibial tunnel in the coronal plane and loss of flexion and anterior laxity after anterior cruciate ligament reconstruction
Am J Sports Med
(2001)

There are more references available in the full text version of this article.

Cited by (183)

Posterior wall blowout on computed tomography after anterior cruciate ligament reconstruction
2023, Journal of Orthopaedic Science
During anterior cruciate ligament (ACL) reconstruction, even when a posterior wall of the femoral bone tunnel is identified, computed tomography (CT) occasionally demonstrates a breach of the posterior femoral cortex of the femoral bone tunnel, i.e., posterior wall blowout, after ACL reconstruction (posterior wall blowout-like phenomenon). This study aimed to investigate the influence of the posterior wall blowout-like phenomenon on clinical outcomes after ACL reconstruction using hamstring tendon.
A total of 105 patients who underwent CT examination two weeks after ACL reconstruction were enrolled. A cortical suspension device was used for femoral side fixation in all cases. Posterior wall was identified in all cases during the surgery. The side-to-side difference in anterior knee laxity, pivot shift test, Lysholm knee score, the International Knee Documentation Committee (IKDC) subjective form, and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were evaluated one year after the surgery. A second CT examination was performed 6–12 months after the surgery, if a posterior wall blowout-like phenomenon was identified in the first CT examination.
Two weeks after the surgery, 16 of the 105 patients showed a posterior wall blowout-like phenomenon. Twelve of the 16 cases demonstrated a regenerated posterior femoral cortex of the femoral bone tunnel on their second CT images. There were no significant differences between the posterior wall blowout-like phenomenon group and the normal posterior wall group in terms of a side-to-side difference in anterior knee laxity (0.4 ± 1.5 mm and 0.1 ± 1.6 mm, respectively), pivot shift test, Lysholm knee score, IKDC score, and KOOS at one year after surgery. The length and diameter of the femoral bone tunnel were not significantly different between the two groups.
Posterior wall blowout-like phenomenon after ACL reconstruction using a cortical suspension device did not negatively influence clinical outcomes.
III – retrospective comparative clinical study.
Six Percent Incidence of Graft-Tunnel Mismatch in Anatomic Anterior Cruciate Ligament Reconstruction Using Bone-Patella Tendon-Bone Autograft and Anteromedial Portal Drilling
2022, Arthroscopy, Sports Medicine, and Rehabilitation
The purpose of this study was to determine the incidence of graft-tunnel mismatch (GTM) when performing anatomic anterior cruciate ligament reconstruction (ACLR) using bone-patella tendon-bone (BPTB) grafts and anteromedial portal drilling.
Beginning in November 2018, 100 consecutive patients who underwent ACLR by two sports fellowship-trained, orthopedic surgeons using BPTB autograft and anteromedial portal drilling were prospectively identified. The BPTB graft dimensions and the femoral tunnel distance, tibial tunnel distance, intra-articular distance, and total distance were measured. Surgeons determined the depth and angle of tunnels based on the patella tendon graft length dimensions in each case. After passage of the graft, the distance from the distal graft tip to the tibial cortex aperture was measured. GTM was defined as the need for additional measures to obtain satisfactory tibial graft fixation (<15–20 mm of bone fixation).
The incidence of mismatch was 6/100 (6%). Five cases involved the graft being too long, with the tibial bone plug protruding excessively from the tibial tunnel—4/5 had a patella tendon length ≥ 50 mm. Three cases were managed with femoral tunnel recession, and two were treated with a free bone plug technique. One patient with a patella tendon length of 35 mm had a graft that was too short, with the tibial bone plug recessed in the tibial tunnel. Of patients whose tibial tunnel distance was within 5 mm of the patella tendon length, only 1/46 (2%) patients had mismatch, whereas 5/54 (9%) of patients who had >5 mm difference had mismatch.
The incidence of graft-tunnel mismatch after anatomic ACLR using BTPB and anteromedial portal drilling in this study is 6%. To limit the occurrence of GTM where the graft is too long, surgeons should drill tibial tunnel distances within 5 mm of the patella tendon length.
The results of this study provide surgeons with a technique of limiting graft tunnel mismatch when performing ACLR using BPTB and anteromedial portal drilling.
Freehand Anatomic Transtibial Single-Bundle Anterior Cruciate Ligament Reconstruction
2022, Arthroscopy Techniques
Creation of the femoral tunnel for single-bundle anterior cruciate ligament (ACL) reconstruction has a high rate of nonanatomic placement with the transtibial (TT) technique but yields better restoration with the anteromedial portal technique and close restoration of the anatomic femoral footprint with the outside-in technique. Modifications of the traditional (TT) technique have been described to restore the native femoral ACL footprint and to simulate double-bundle reconstruction. Modified TT techniques try to capture the anatomic femoral footprint through an anatomic tibial tunnel. In the technique described in this article, the anatomic femoral footprint is drilled first by the use of a 2.5-mm Kirschner wire through the parapatellar anteromedial portal, making an angle 30° to the sagittal plane and 20° to the horizontal plane. The wire is drilled while the knee is hyperflexed and then withdrawn from outside until its distal end reaches the intercondylar notch. The wire is then advanced in an antegrade manner while the knee is flexed 90° until it reaches the center of the marked tibial footprint. The angle of knee flexion may be slightly increased or decreased around 90° with or without slight internal rotation to capture the anatomic tibial footprint. The procedure is completed as a TT single-bundle ACL reconstruction.
Patellar tendon autograft for anterior cruciate ligament reconstruction
2022, Surgical Techniques of the Shoulder, Elbow, and Knee in Sports Medicine, Third Edition
Patellar tendon autograft is the most commonly used graft in collegiate and professional athletes due to ready accessibility, mechanical strength, and rapid osseous tunnel integration. Long-term clinical results have been excellent, which has resulted in patellar tendon being the “Gold Standard” of grafts. In this chapter we discuss surgical technique pearls and pitfalls for anatomic anterior cruciate ligament (ACL) reconstruction using patellar tendon autograft, including incision and portal placement and strategy, graft harvest and tunnel placement, graft passing as well as fixation, with a focus on anatomic transtibial as well as medial portal femoral independent drilling techniques. While both techniques are outlined, the authors prefer a modified transtibial technique when possible as it allows for placement of the tibial and femoral tunnels in the native or near anatomic footprints and has been demonstrated to have a lower revision rate as compared to femoral independent drilling techniques. We recommend that surgeons be familiar with both drilling techniques however, as individual anatomy may vary and multiple options should be available and familiar to the surgeon for optimal reconstruction. Outcomes and return to play following ACL reconstruction with patellar tendon autograft have generally been very good to excellent, with similar outcomes, return to play and decreased revision rates as compared to autograft hamstrings, quadriceps, and allograft.
The Ideal Cortical Button Location on the Lateral Femur for Anterior Cruciate Ligament Suspensory Fixation is 30 mm Proximal to the Lateral Epicondyle
2021, Arthroscopy, Sports Medicine, and Rehabilitation
To determine the ideal location for anterior cruciate ligament (ACL) suspensory cortical button placement on the lateral femur with the highest failure load and to establish the relationship of tunnel diameter and cortical thickness on load to failure.
Computed tomography (CT) data were obtained from 45 cadaveric distal femurs. A Cartesian coordinate system was established along the lateral femur with the lateral epicondyle (LE) as a reference point. Locations 0, 20 and 30 mm from the LE along lines 0°, 25°, 50°, and 75° posterioproximal from the axial plane were created. Tunnels connecting from each location to the center of the ACL footprint were simulated. Cortical thickness and long axis diameter of the oval cortical holes were determined for each location. Based on the CT data, custom drill guides were created and used to drill 4.5 mm tunnels at each lateral femur location to the ACL footprint on the cadaver femurs. Cortical buttons were placed at each location and pulled using a servohydraulic testing system. The correlation of tunnel diameter and cortical thickness to button failure load were analyzed using a regression analysis.
Significant differences were found for failure load (P<.0001) and cortical thickness between the locations tested (P<.0001). The location 30 mm proximal from the LE and 75⁰ from the axial plane had the highest failure load of 573 N. A regression analysis (R² = .15) indicated that the cortical thickness was significantly correlated with load to failure (P <.0001), whereas the long-axis diameter was not (P = .33).
The ideal cortical button location on the lateral femur for ACL suspensory fixation was located 30 mm proximal from the lateral epicondyle, based on this area’s high failure load. Oblique tunnel drilling of this proximal location may cause a larger long-axis diameter cortical hole, but the cortex is also thicker, which is more closely correlated with failure load.
Different ACL suspensory cortical button locations on the lateral femur have different failure loads based on the cortical thickness of the bone supporting the button. It is important for surgeons to understand which drilling techniques place the button in a proximal and posterior location, especially if the bone quality of the patient is of concern.
Femoral Tunnel Widening After Double-Bundle Anterior Cruciate Ligament Reconstruction With Hamstring Autograft Produces a Small Shift of the Tunnel Position in the Anterior and Distal Direction: Computed Tomography–Based Retrospective Cohort Analysis
2021, Arthroscopy - Journal of Arthroscopic and Related Surgery
To determine whether the femoral tunnel position remains in an anatomical footprint after tunnel widening and shifting.
Patients who underwent unilateral double-bundle anterior cruciate ligament reconstruction with hamstring autograft and performed computed tomography scan evaluation at the time of 5 days and 1 year postoperatively were included in this retrospective cohort study. Three-dimensional models of the femur and femoral tunnels were reconstructed from computed tomography scan data. The location of the tunnel center and tunnel margins in the anatomical coordinate system, and the mean shifting distance of tunnel center and margin were measured with image analysis software during the period. The change of tunnel center location in Bernard quadrant was confirmed if the tunnel center remained within the boundaries of anatomical position after tunnel widening.
A total of 56 patients satisfied the inclusion criteria. The mean shifting distance of AM and PL tunnel centers were 1.7 ± 0.9 mm and 1.6 ± 0.6 mm. The Tunnel margin of the anteromedial (AM) and posteromedial (PL) tunnels were shifted to 2.5 ± 1.3 mm and 2.6 ± 1.4 mm in the anterior direction, and 1.4 ± 0.9 mm and 1.0 ± 0.7 mm in the distal direction, respectively. Among the anatomical located tunnel, 97% (32/33) and 87.1% (27/31) of AM and PL tunnel centers remained in a range of anatomical footprint. The tunnel center was shifted from the anatomical position into a nonanatomical position in 3% (1/33) of the AM tunnel and 12.9% (4/31) of PL tunnel after tunnel widening. The tunnel location which shifted nonanatomically were relatively anterior and distal position.
Tunnel widening shifts the tunnel position to the anterior and distal direction, which could change the initial tunnel position. Nevertheless, the majority of tunnel positions remained in the anatomical position after tunnel widening and shifting.
Level III, retrospective cohort study.

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: Supported by the Institute for Sports Medicine Research, Hospital for Special Surgery. The authors report no conflict of interest.

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Arthroscopy: The Journal of Arthroscopic & Related Surgery

Purpose

Methods

Results

Conclusions

Clinical Relevance

Section snippets

Methods

Results

Discussion

Conclusions

References (20)

Vertical femoral tunnel placement results in rotational knee laxity after anterior cruciate ligament reconstruction

Arthroscopy

The effect of oblique femoral tunnel placement on rotational constraint of the knee reconstructed using patellar tendon autografts

Arthroscopy

Recreating an acceptable angle of the tibial tunnel in the coronal plane in anterior cruciate ligament reconstruction using external landmarks

Arthroscopy

The effect of femoral tunnel starting position on tunnel length in anterior cruciate ligament reconstruction: A cadaveric study

Arthroscopy

Double-bundle “anatomic” anterior cruciate ligament reconstruction: A cadaveric study of tunnel positioning with a transtibial technique

Arthroscopy

Arthroscopic double-bundle anterior cruciate ligament reconstruction: An anatomic approach

Arthroscopy

Anteromedial portal technique for creating the anterior cruciate ligament femoral tunnel

Arthroscopy

Knee stability and graft function following anterior cruciate ligament reconstruction: Comparison between 11 o'clock and 10 o'clock femoral tunnel placement

2002 Richard O'Connor Award paper. Arthroscopy

Anatomic reconstruction of the anteromedial and posterolateral bundles of the anterior cruciate ligament using hamstring tendon grafts

Arthroscopy

The relationship between the angle of the tibial tunnel in the coronal plane and loss of flexion and anterior laxity after anterior cruciate ligament reconstruction

Am J Sports Med

Cited by (183)

Posterior wall blowout on computed tomography after anterior cruciate ligament reconstruction

Six Percent Incidence of Graft-Tunnel Mismatch in Anatomic Anterior Cruciate Ligament Reconstruction Using Bone-Patella Tendon-Bone Autograft and Anteromedial Portal Drilling

Freehand Anatomic Transtibial Single-Bundle Anterior Cruciate Ligament Reconstruction

Patellar tendon autograft for anterior cruciate ligament reconstruction

The Ideal Cortical Button Location on the Lateral Femur for Anterior Cruciate Ligament Suspensory Fixation is 30 mm Proximal to the Lateral Epicondyle

Femoral Tunnel Widening After Double-Bundle Anterior Cruciate Ligament Reconstruction With Hamstring Autograft Produces a Small Shift of the Tunnel Position in the Anterior and Distal Direction: Computed Tomography–Based Retrospective Cohort Analysis

Original ArticleTranstibial Versus Anteromedial Portal Drilling for Anterior Cruciate Ligament Reconstruction: A Cadaveric Study of Femoral Tunnel Length and Obliquity

Purpose

Methods

Results

Conclusions

Clinical Relevance

Section snippets

Methods

Results

Discussion

Conclusions

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

2002 Richard O'Connor Award paper. Arthroscopy

Arthroscopy

The relationship between the angle of the tibial tunnel in the coronal plane and loss of flexion and anterior laxity after anterior cruciate ligament reconstruction

Am J Sports Med

Original Article
Transtibial Versus Anteromedial Portal Drilling for Anterior Cruciate Ligament Reconstruction: A Cadaveric Study of Femoral Tunnel Length and Obliquity