Potential Risks of Femoral Tunnel Drilling Through the Far Anteromedial Portal: A Cadaveric Study

doi:10.1016/j.arthro.2008.11.010

Arthroscopy: The Journal of Arthroscopic & Related Surgery

Volume 25, Issue 5, May 2009, Pages 481-487

https://doi.org/10.1016/j.arthro.2008.11.010 Get rights and content

Purpose

The purpose of this study was to estimate the potential risks when drilling femoral tunnels through the far anteromedial portal in double-bundle anterior cruciate ligament reconstruction in cadaveric knees.

Methods

Ten cadaveric knees were used. We drilled the anteromedial bundle (AMB) and posterolateral bundle (PLB) through the far anteromedial portal at 3 different knee flexion angles: 70°, 90°, and 110°. We measured the shortest distance to the common peroneal nerve and the posterior articular cartilage of the lateral femoral condyle and the femoral tunnel length.

Results

At 70°, the distance to the nerve was less than 10 mm in 7 AMB cases and in 9 PLB cases, and the distance to the cartilage was less than 10 mm in all the AMB and PLB cases. At 90°, the distance to the nerve was less than 10 mm in 1 AMB and 5 PLBs, and the distance to the cartilage was less than 10 mm in 2 AMBs and all the PLBs. On the other hand, at 110°, the distance to the nerve was greater than 10 mm in all the AMBs and PLBs, and the distance to the cartilage did not exceed 10 mm in just 2 of the PLBs.

Conclusions

In our cadaveric study we found that the low knee flexion angles when drilling femoral tunnels through the far anteromedial portal might have the potential risks of damage to the common peroneal nerve and the posterior articular cartilage, and the risks would be decreased at higher degrees of knee flexion. However, we found there was a 20% risk of damage to the cartilage while drilling the PLB at 110°.

Clinical Relevance

High knee flexion angles are recommended to avoid damage to the nerve and the cartilage when drilling femoral tunnels through the far anteromedial portal in double-bundle anterior cruciate ligament reconstruction.

Section snippets

Methods

We used 10 cadaveric knees, consisting of 5 cadavers (2 male and 3 female cadavers from the 2007 gross anatomy course at Hiroshima University School of Medicine) embalmed and fixed with formalin, ethanol, isopropanol, phenol, and glycerin, excluding malalignment of legs with the varus deformity or flexion contracture of the knee. The mean age of the subjects at the time of death was 72.6 years (range, 66 to 80 years). The subjects' mean height was 161.6 cm. We performed the arthrotomy of the

Results

Results from the measurements of 10 cadaveric knees (5 cadavers) when drilling the AMB and PLB at 3 different knee flexion angles are shown in Table 1.

The mean shortest distances to the common peroneal nerve when drilling the AMB were 10.5 mm (range, 7 to 15 mm; SD, 2.3 mm) at a knee flexion angle of 70°, 16.0 mm (range, 10 to 20 mm; SD, 3.0 mm) at 90°, and 23.6 mm (range, 18 to 30 mm; SD, 4.0 mm) at 110°. The mean shortest distances when drilling the PLB were 6.3 mm (range, 0 to 12 mm; SD, 3.4

Discussion

Recently, some studies to estimate the risks of damage to the lateral femoral condyle or the surrounding structures when drilling femoral tunnels through the medial portals in double-bundle ACL reconstruction were reported.18, 19, 20 Even if the femoral tunnel placements were correct, the improper portal placements or knee flexion angles when drilling the AMB and PLB have the potential risks to cause iatrogenic damage to the normal structures around the lateral femoral condyle. Zantop et al.¹⁸

Conclusions

In our cadaveric study we found that the low knee flexion angles when drilling femoral tunnels through the far anteromedial portal might have the potential risks of damage to the common peroneal nerve and the posterior articular cartilage, and the risks would be decreased at higher degrees of knee flexion. However, we found that there was 20% risk of damage to the cartilage while drilling the PLB at 110°.

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Cited by (82)

Posteromedial Portal Technique With Bone–Patellar Tendon–Bone Graft for Inside-Out Revision of Anterior Cruciate Ligament Reconstruction
2023, Arthroscopy Techniques
Bone–patellar tendon–bone (BTB) is a graft material used in anterior cruciate ligament (ACL) reconstruction. We describe creating a femoral tunnel using an inside-out posteromedial (PM) portal technique during anatomic double-bundle ACL reconstruction with a hamstring graft. We hypothesized that applying this femoral tunnel creation method to the revision ACL reconstruction using BTB would enable reconstruction in 1 stage. In this technique, an anteromedial, an anterolateral, and a PM portal are created to confirm the original ACL footprint and location and direction of the bone tunnel during primary reconstruction. The surgeon then drills from the PM portal, so that the femoral tunnel opening touches the posterior proximal articular cartilage margin in the ACL footprint. Even if the opening partially overlaps with the primary tunnel, it is possible to create a new tunnel with a different direction. Finally, the BTB graft is guided from the tibial tunnel to the femoral tunnel and fixed with interference screws. Intraoperative PM arthroscopic views can confirm that the femoral tunnel has been created, avoiding overlap, and that the revision ACL has been reconstructed. This procedure may be useful for 1-stage revision ACL reconstruction for reinjury after primary ACL reconstruction by other conventional procedures.
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 length has no correlation with graft rupture: A retrospective cohort study
2021, Knee
Literature is controversial on femoral tunnel length as a risk factor for graft injury if the graft length in the tunnel is kept constant at ≥15 mm.
A total of 1079 sportspersons, meeting our inclusion criteria, were assessed for graft rupture. Patients with femoral tunnel length (FTL) ≤30 mm were labeled as Group 1, while those with FTL > 30 mm were labeled as Group 2. Both groups were compared for potential risk factors for graft injury keeping graft length in the tunnel at ≥15 mm and statistical analysis was performed to study whether the femoral tunnel length acted as an additional risk factor.
Of 1079 sportspersons, 37 suffered from graft rupture. Patients with FTL > 30 mm were included in Group 1(n = 22) and patients with FTL ≤ 30 mm (n = 15) were included in Group 2. Both groups were comparable for risk factors for ACL injury: age (P = 0.37), gender (P = 0.53), mode of re-injury (P = 0.38), graft diameter (P = 0.71), level of sports activity (P = not significant), duration from injury to index surgery (P = 0.74), duration from index surgery to re-injury (P = 0.52), timing of return to sports after index surgery (P = 0.30), duration of sporting activity before second injury (P = 0.31), Tegner’s level (P = not siginificant), Notch width index (P = 0.12) posterior slope (P = 0.77) and height (P = 0.41).
Because the graft length in the tunnel was kept at optimum and the risk factors for ACL injury were comparable in both groups at a follow up period, we suggest that femoral tunnel length is not a risk factor for graft failure.
Comparison of three approaches for femoral tunnel during double-bundle anterior cruciate ligament reconstruction: A case controlled study
2019, Journal of Orthopaedic Science
It is still controversial whether which femoral tunnel creation technique is best during anterior cruciate ligament reconstruction (ACLR). We aimed to clarify the features of three different techniques based on the femoral tunnel position created with the same tunnel-creating concept and the measurement data.
The femoral tunnel of double-bundle (DB) ACLR was created using the behind-remnant approach in a remnant preserved manner following the policy of our institute. The trans-tibial approach (TT) was applied for all primary ACL injured cases until December 2012. The trans-portal approach (TP) was applied from January to September 2013, and the outside-in approach (OI) was indicated from October 2013 to March 2014. We compared the femoral tunnel aperture positions with the postoperative three-dimensional computed tomography (3D-CT). Additionally, the femoral tunnel length and the septum distance of each anteromedial (AM) and posterolateral (PL) tunnel were analyzed.
The AM tunnel aperture position of TT was significantly higher and shallower than that of TP in knee flexion position. The femoral tunnel length of TP was significantly shorter than that of TT and OI. The septum between each tunnel of OI trended wider than that of TT and TP.
The AM tunnel aperture position of TT runs the risk of a high and shallow position. TP runs the risk of insufficiently short tunnel length. It is important to apply each method flexibly to each case because no single best approach was found.
Comparison of Modified Transtibial and Outside-In Techniques in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction
2018, Arthroscopy - Journal of Arthroscopic and Related Surgery
To compare the bending angle of anterior cruciate ligament (ACL) graft at femoral tunnel, graft maturation, and tunnel positions and the clinical outcomes of the modified transtibial (mTT) and outside-in (OI) techniques.
Patients who met the inclusion criteria were divided into the mTT group (n = 50) and the OI group (n = 50). Using 3-dimensional computed tomography (3-D CT), tunnel placement and femoral tunnel bending angle were analyzed. The 3.0-T magnetic resonance imaging (MRI) was used to assess the graft signal intensity (indicative of maturation) with signal/noise quotient (SNQ). Graft tension and synovialization were evaluated with second-look arthroscopy in all cases. Clinical and functional tests were completed at 36 months of follow-up.
When tunnel placements were analyzed using the quadrant method, no significant differences were found between the mTT group and the OI group. The femoral graft bending angle was reduced in the mTT group, and the total mean of SNQ values and mean SNQ values at the femoral intraosseous and proximal graft of the mTT group were significantly lower than in the OI group (P < .001), respectively. The femoral graft bending angle on the coronal and axial planes showed moderate-to-strong correlation with the SNQ values at the femoral intraosseous and proximal graft. Second-look arthroscopy revealed better synovialization in the mTT group than in the OI group (P = .040), with no significant difference in graft tension between the 2 groups (P = .328).
Anatomic tunnel placements did not vary between the mTT group and the OI group. However, the mTT group had more benefits in femoral graft bending angle and showed higher graft maturity and better synovial coverage than the OI group, although there were no significant differences in clinical outcomes. The acute femoral graft bending angle might negatively affect the maturation of proximal graft.
Level III, retrospective comparative study.
Compression Aperture Fixation of Soft-Tissue Anterior Cruciate Ligament Reconstructions
2018, The Anterior Cruciate Ligament: Reconstruction and Basic Science: Second Edition

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: The authors report no conflict of interest.

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Original ArticlePotential Risks of Femoral Tunnel Drilling Through the Far Anteromedial Portal: A Cadaveric Study

Purpose

Methods

Results

Conclusions

Clinical Relevance

Section snippets

Methods

Results

Discussion

Conclusions

J Orthop Res

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

Arthroscopy

Functional anatomy of the anterior cruciate ligament: Fiber bundle actions related to ligament replacements and injuries

J Bone Joint Surg Br

Original Article
Potential Risks of Femoral Tunnel Drilling Through the Far Anteromedial Portal: A Cadaveric Study