Comparison of graft bending angle during knee motion after outside-in, trans-portal and trans-tibial anterior cruciate ligament reconstruction

Tashiro, Yasutaka; Irarrázaval, Sebastián; Osaki, Koichi; Iwamoto, Yukihide; Fu, Freddie H.

doi:10.1007/s00167-016-4191-1

Cited by 26 publications

(42 citation statements)

References 62 publications

(130 reference statements)

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“…Secondly, the range of motion examined in the dynamic activity was limited and knee flexion over 90° was not examined. Previous studies on GBA during knee motion have shown lower bending angle of reconstructed grafts in over 90° knee flexion than in 0° to 30° flexion 32,64 , therefore assessment of motion at these lower flexion angles should be clinically relevant. Thirdly, we didn’t have a trans-tibial control group, which might have lower GBA at 0° knee flexion 33,64 .…”

Section: Discussionmentioning

confidence: 98%

“…Previous studies on GBA during knee motion have shown lower bending angle of reconstructed grafts in over 90° knee flexion than in 0° to 30° flexion 32,64 , therefore assessment of motion at these lower flexion angles should be clinically relevant. Thirdly, we didn’t have a trans-tibial control group, which might have lower GBA at 0° knee flexion 33,64 . However, in clinical practice, we didn’t use the trans-tibial technique during this period because it could sometimes lead to non-anatomical tunnel positions 8-12 .…”

Section: Discussionmentioning

confidence: 98%

“…These results are consistent with a previous study that reported higher GBA and more anterior location of femoral exits with an outside-in drilling technique, compared to lower GBA with trans-portal drilling (which resulted in femoral exits at approximately the level of the lateral epicondyle) 40 . A study using computer simulation also concluded that more proximal location of femoral exits could reduce graft bending angles without changing the anatomic femoral and tibial aperture position 64 . Another previous study, however, reported apparently contradictory results, with lower GBA with flexible (as opposed to rigid) drills 39 .…”

Section: Discussionmentioning

confidence: 99%

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In Vivo Analysis of Dynamic Graft Bending Angle in Anterior Cruciate Ligament–Reconstructed Knees During Downward Running and Level Walking: Comparison of Flexible and Rigid Drills for Transportal Technique

Tashiro

Sundaram

Thorhauer

et al. 2017

Arthroscopy: The Journal of Arthroscopic & Related Surgery

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Purpose To determine in vivo dynamic graft bending angle (GBA) in anterior cruciate ligament (ACL) reconstructed knees, correlate the angle to tunnel positions and tunnel widening, and evaluate the effects of two femoral tunnel drilling techniques on GBA. Methods Patients with an isolated ACL injury undergoing reconstruction were included from 2011 to 2012. Trans-portal techniques were used to create femoral tunnels. Tunnel locations were determined using 3D-CT. Tibio-femoral kinematics during treadmill walking and running were assessed using dynamic stereo X-ray analysis 6 months and 2 years postoperatively. The GBA was calculated from the 3D angle between the graft and femoral tunnel vectors at each motion frame. Cross-sectional area of femoral tunnels were measured at 6 months and compared to initial size to assess tunnel widening. Results A total of 54 patients were included. Use of flexible drills resulted in significantly higher GBA during walking (80.6° ± 7.8°; p<0.001) and running (80.5° ± 9.0°; p=0.025) than rigid drills (walking: 67.5° ± 9.3°, running: 74.1° ± 9.6°). It led to greater tunnel widening of 113.9±17.6 %, compared with rigid drills of 97.7±17.5 % (p=0.003). Femoral and tibial apertures were located in similar anatomic positions in both groups, but femoral tunnel exits were located more anteriorly (p<0.001) in the flexible drill group. Higher GBA was highly correlated with anterior location of femoral exits (r=0.63, p<0.001) and moderately correlated with greater tunnel widening (r=0.48, p<0.001). Conclusions High GBA was identified during dynamic activities after anatomic ACL reconstruction using a trans-portal femoral tunnel drilling technique. The GBA was greater when flexible drills were used. The high bending angle resulted from more anterior location of femoral tunnel exits, and correlated with early bone tunnel widening at 6 months. These results suggest that high GBA may increase stress on the bone-graft interface and contribute to greater tunnel widening after anatomic ACL reconstruction, although clinical impact should be further investigated. Level of Evidence Level III, retrospective comparative study

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

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In Vivo Analysis of Dynamic Graft Bending Angle in Anterior Cruciate Ligament–Reconstructed Knees During Downward Running and Level Walking: Comparison of Flexible and Rigid Drills for Transportal Technique

Tashiro

Sundaram

Thorhauer

et al. 2017

Arthroscopy: The Journal of Arthroscopic & Related Surgery

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“…Although the clinical relevance of this finding has yet to be determined, in theory an acute GBA will cause higher stress at the proximal bone-graft interface and negatively affect graft healing and remodeling. 33…”

Section: Discussionmentioning

confidence: 99%

Graft Size and Orientation Within the Femoral Notch Affect Graft Healing at 1 Year After Anterior Cruciate Ligament Reconstruction

et al. 2019

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Background: The combined influence of anatomic and operative factors affecting graft healing after anterior cruciate ligament (ACL) reconstruction within the femoral notch is not well understood. Purpose: To determine the influence of graft size and orientation in relation to femoral notch anatomy, with the signal/noise quotient (SNQ) of the graft used as a measure of graft healing after primary single-bundle ACL reconstruction. Study Design: Case series; Level of evidence, 4. Methods: A total of 98 patients with a minimum 2-year follow-up after primary single-bundle ACL reconstruction with hamstring tendon autografts were included. Graft healing was evaluated at 1 year on magnetic resonance imaging (MRI) scan as the mean SNQ measured from 3 regions situated at sites at the proximal, middle, and distal graft. Patient characteristics, chondropenia severity score, tunnel sizes, tunnel locations, graft bending angle (GBA), graft sagittal angle, posterior tibial slope (PTS), graft length, graft volume, femoral notch volume, and graft-notch volume ratio (measured using postoperative 3-T high-resolution MRI) were evaluated to determine any association with 1-year graft healing. The correlation between 1-year graft healing and clinical outcome at minimum 2 years was also assessed. Results: There was no significant difference in mean SNQ between male and female patients ( P > .05). Univariate regression analysis showed that a low femoral tunnel ( P = .005), lateral tibial tunnel ( P = .009), large femoral tunnel ( P = .011), large tibial tunnel ( P < .001), steep lateral PTS ( P = .010), steep medial PTS ( P = .004), acute graft sagittal angle ( P < .001), acute GBA ( P < .001), large graft volume ( P = .003), and high graft-notch volume ratio ( P < .001) were all associated with higher graft SNQ values. A multivariate regression analysis showed 2 significant factors: a large graft-notch volume ratio ( P = .001) and an acute GBA ( P = .004). The 1-year SNQ had a weak correlation with 2-year Tegner Activity Scale score ( r = 0.227; P = .026) but no other clinical findings, such as International Knee Documentation Committee subjective and Lysholm scores and anterior tibial translation side-to-side difference. Conclusion: The 1-year SNQ value had a significant positive association with graft-notch volume ratio and GBA. Both graft size and graft orientation appeared to have a significant influence on graft healing as assessed on 1-year high-resolution MRI scan.

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“…T he article "In vivo analysis of graft bending angle in anterior cruciate ligament reconstructed knees during downward running and level walking: Comparison of flexible and rigid drills for trans-portal technique" 1 by Tashiro, Sundaram, Thorhauer, Gale, Anderst, Irrgang, Fu, and Tashman attempts to add to the understanding of this concept and shed light on the potential clinical impact. Many other publications [2][3][4][5][6][7][8][9] have evaluated graft bending angle (GBA) and the effect that drilling technique has. These reviews include the effects of variations within anatomic anterior cruciate ligament drilling such as type of drill, where we are drilling from, and where the drill exits.…”

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confidence: 99%

Editorial Commentary: Angle Versus Anatomy: Sacrificing Graft Bending Angle for Anatomic Anterior Cruciate Ligament Reconstruction

Pula¹

2017

Arthroscopy: The Journal of Arthroscopic & Related Surgery

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Graft bending angle (GBA) is the angle created by the intra-articular anterior cruciate ligament (ACL) graft and the femoral tunnel. By definition then, it is affected by the angle at which the surgeon drills the femoral tunnel. In an attempt to create a more anatomic ACL, different techniques have been described to put the femoral tunnel in the anatomic footprint. If you can get past each author's unique description of GBA, whether they are referring to the graft, the tunnel angle, or using adjectives such as acute or higher GBA, you see that attempting to create more anatomic ACL reconstructions has resulted in a sharper turn for our grafts. The million-dollar question is: what does that mean? For now, the answer is unknown.

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Comparison of graft bending angle during knee motion after outside-in, trans-portal and trans-tibial anterior cruciate ligament reconstruction

Abstract: Therapeutic study (prospective comparative study), Level II.

Cited by 26 publications

References 62 publications

In Vivo Analysis of Dynamic Graft Bending Angle in Anterior Cruciate Ligament–Reconstructed Knees During Downward Running and Level Walking: Comparison of Flexible and Rigid Drills for Transportal Technique

In Vivo Analysis of Dynamic Graft Bending Angle in Anterior Cruciate Ligament–Reconstructed Knees During Downward Running and Level Walking: Comparison of Flexible and Rigid Drills for Transportal Technique

Graft Size and Orientation Within the Femoral Notch Affect Graft Healing at 1 Year After Anterior Cruciate Ligament Reconstruction

Editorial Commentary: Angle Versus Anatomy: Sacrificing Graft Bending Angle for Anatomic Anterior Cruciate Ligament Reconstruction

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