Anterior Cruciate Ligament Graft Isometry Is Affected by the Orientation of the Femoral Tunnel

Ebersole, Gregg M.; Eckerle, Paul; Farrow, Lutul D.; Cutuk, Adnan; Bledsoe, Gary; Kaar, Scott G.

doi:10.1055/s-0035-1554926

Cited by 11 publications

(17 citation statements)

References 18 publications

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“…It is possible the small differences in deep-shallow femoral aperture position and/or femoral tunnel obliquity between these 2 techniques may have explained some of the differences, as other authors have suggested. 12 We also feel it is possible that factors unrelated to either technique played a role in the anisometry data. One potential explanation for the difference in graft-length change between HTT and AM portal knees is that grafts may have tended to occupy slightly different locations within the respective tunnels for these 2 techniques.…”

Section: Discussionmentioning

confidence: 99%

“…It is not yet clear that the degree of graft-tunnel angulation seen with AM portal reconstructions has any implications for graft survival in a clinical setting, although the effect of femoral tunnel orientation has recently been recognized as significant biomechanically. Ebersole et al 12 demonstrated in a cadaveric model that, with the same anatomic femoral tunnel aperture, the increased femoral tunnel angulation associated with an all-epiphyseal technique tripled graft strain relative to TT and AM constructs. Further study is needed to determine if lesser degrees of femoral tunnel obliquity affect graft survival and/or performance.…”

Section: Discussionmentioning

confidence: 99%

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Transtibial Versus Anteromedial Portal ACL Reconstruction: Is a Hybrid Approach the Best?

Jennings¹,

Leas

Fleischli

et al. 2017

Orthopaedic Journal of Sports Medicine

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Background:Improved biomechanical and clinical outcomes are seen when the femoral tunnels of the anterior cruciate ligament (ACL) are placed in the center of the femoral insertion. The transtibial (TT) technique has been shown to be less capable of this than an anteromedial (AM) portal approach but is more familiar to surgeons and less technically challenging. A hybrid transtibial (HTT) technique using medial portal guidance of a transtibial guide wire without knee hyperflexion may offer anatomic tunnel placement while maintaining the relative ease of a TT technique.Purpose:To evaluate the anatomic and biomechanical performance of the HTT technique compared with TT and AM approaches.Study Design:Controlled laboratory study.Methods:Thirty-six paired, fresh-frozen human knees were used. Twenty-four knees (12 pairs) underwent all 3 techniques (TT, AM, HTT) for femoral tunnel placement, with direct measurement of femoral insertional overlap and femoral tunnel length. The remaining 12 knees (6 pairs) underwent completed reconstructions to evaluate graft anisometry and tunnel orientation, with each technique performed in 4 specimens and tested using motion sensors with a quad-load induced model. Graft length changes and graft/femoral tunnel angle were measured at varying degrees of flexion.Results:Percentage overlap of the femoral insertion averaged 37.0% ± 28.6% for TT, 93.9% ± 5.6% for HTT, and 79.7% ± 7.7% for AM, with HTT significantly greater than both TT (P = .007) and AM (P = .001) approaches. Graft length change during knee flexion (anisometry) was 30.1% for HTT, 12.8% for AM, and 8.5% for TT. When compared with the TT approach, HTT constructs exhibited comparable graft–femoral tunnel angulation (TT, 150° ± 3° vs HTT, 142° ± 2.3°; P < .001) and length (TT, 42.6 ± 2.8 mm vs HTT, 38.5 ± 2.0 mm; P = .12), while AM portal tunnels were significantly shorter (31.6 ± 1.6 mm; P = .001) and more angulated (121° ± 6.5°; P < .001).Conclusion:The HTT technique avoids hyperflexion and maintains femoral tunnel orientation and length, similar to the TT technique, but simultaneously achieves anatomic graft positioning.Clinical Relevance:The HTT technique offers an anatomic alternative to an AM portal approach while maintaining the technical advantages of a traditional TT reconstruction.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Transtibial Versus Anteromedial Portal ACL Reconstruction: Is a Hybrid Approach the Best?

Jennings¹,

Leas

Fleischli

et al. 2017

Orthopaedic Journal of Sports Medicine

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“…It has been previously shown that the magnitude of the graft bending angle seen with AM portal tunnels results in a 2- to 3-fold increase in graft strain at the femoral tunnel aperture, producing increased graft signaling on postoperative magnetic resonance imaging. 12,21,34,35…”

Section: Discussionmentioning

confidence: 99%

“…This makes graft passage more tedious, increases graft forces at the tunnel aperture, and may negatively affect graft healing. 5,12,34,35…”

mentioning

confidence: 99%

“…This makes graft passage more tedious, increases graft forces at the tunnel aperture, and may negatively affect graft healing. 5,12,34,35 The juxtaposition of these 2 opposing techniques has left surgeons with a difficult choice: accept a less anatomic aperture position but with an otherwise ideal and easily prepared tunnel (TT) versus achieving an anatomic aperture position but creating greater technical difficulty and an otherwise suboptimal tunnel (AM portal). Furthermore, there are conflicting clinical data regarding which technique results in superior patient outcomes.…”

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confidence: 99%

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A Hybrid Transtibial Technique Combines the Advantages of Anteromedial Portal and Transtibial Approaches: A Prospective Randomized Controlled Trial

et al. 2020

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Background: The anteromedial (AM) portal and transtibial (TT) approaches are 2 common anterior cruciate ligament (ACL) femoral tunnel drilling techniques, each with unique benefits and disadvantages. A hybrid TT (HTT) technique using medial portal guidance of a flexible TT guide wire has recently been described that may combine the strengths of both the AM portal and the TT approaches. Hypothesis: The HTT technique will achieve anatomic femoral tunnel apertures similar to the AM portal technique, with improved femoral tunnel length and orientation. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: A total of 30 consecutive patients with primary ACL tears were randomized to undergo the TT, AM portal, or HTT technique for femoral tunnel positioning at the time of reconstruction. All patients underwent 3-dimensional computed tomography of the operative knee at 6 weeks postoperatively. Femoral and tibial tunnel aperture positions and tunnel lengths, as well as graft bending angles in the sagittal and coronal planes, were measured. Results: Tibial tunnel lengths and aperture positions were identical between the 3 groups. The AM portal and HTT techniques achieved identical femoral aperture positions in regard to both height ( P = .629) and depth ( P = .582). By contrast, compared with the AM portal and HTT techniques, femoral apertures created with the TT technique were significantly higher ( P < .001 and P < .001, respectively) and shallower ( P = .014 and P = .022, respectively) in the notch. The mean femoral tunnel length varied significantly between the groups, measuring 35.2, 41.6, and 54.1 mm for the AM portal, HTT, and TT groups, respectively ( P < .001). Last, there was no difference between the mean coronal ( P = .190) and sagittal ( P = .358) graft bending angles between the TT and HTT groups. By contrast, compared with the TT and HTT techniques, femoral tunnels created with the AM portal technique were significantly more angulated in the coronal plane (17.7° [ P < .001] and 12.5° [ P = .006], respectively) and sagittal plane (13.5° [ P < .001] and 10.5° [ P = .013], respectively). Conclusion: This prospective randomized controlled trial found that the HTT technique achieved femoral aperture positions equally as anatomic as the AM portal technique but produced longer, less angulated femoral tunnels, which may help reduce graft strain and mismatch. As such, this hybrid approach may represent a beneficial combination of both the TT and the AM portal techniques. Registration: NCT02795247 (ClinicalTrials.gov identifier)

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Implant preloading in extension reduces spring length change in dynamic intraligamentary stabilization: a biomechanical study on passive kinematics of the knee

Häberli

Voumard

Kösters

et al. 2018

Knee Surg Sports Traumatol Arthrosc

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During passive flexion/extension, the highest spring shortening was consistently measured in full extension with a continuous decrease towards flexion. If preloading of the spring is performed in extension, the spring can be downsized to incorporate a maximum length change of 5 mm resulting in a smaller implant with less bone sacrifice and, therefore, improved conditions in case of revision surgery.

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Anterior Cruciate Ligament Graft Isometry Is Affected by the Orientation of the Femoral Tunnel

Abstract: ACL graft length and tension change throughout knee range of motion and also depend on femoral tunnel orientation and fixation type. The use of an all-epiphyseal tunnel with suspensory fixation should be studied further for evidence of graft elongation.

Cited by 11 publications

References 18 publications

Transtibial Versus Anteromedial Portal ACL Reconstruction: Is a Hybrid Approach the Best?

Transtibial Versus Anteromedial Portal ACL Reconstruction: Is a Hybrid Approach the Best?

A Hybrid Transtibial Technique Combines the Advantages of Anteromedial Portal and Transtibial Approaches: A Prospective Randomized Controlled Trial

Implant preloading in extension reduces spring length change in dynamic intraligamentary stabilization: a biomechanical study on passive kinematics of the knee

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