Direct versus indirect ACL femoral attachment fibres and their implications on ACL graft placement

Abstract

Purpose

To further elucidate the direct and indirect fibre insertion morphology within the human ACL femoral attachment using scanning electron microscopy and determine where in the footprint each fibre type predominates. The hypothesis was that direct fibre attachment would be found centrally in the insertion site, while indirect fibre attachment would be found posteriorly adjacent to the posterior articular cartilage.

Methods

Ten cadaveric knees were dissected to preserve and isolate the entirety of the femoral insertion of the ACL. Specimens were then prepared and evaluated with scanning electron microscopy to determine insertional fibre morphology and location.

Results

The entirety of the fan-like projection of the ACL attachment site lay posterior to the lateral intercondylar ridge. In all specimens, a four-phase architecture, consistent with previous descriptions of direct fibres, was found in the centre of the femoral attachment site. The posterior margin of the ACL attachment attached directly adjacent to the posterior articular cartilage with some fibres coursing into it. The posterior portion of the ACL insertion had a two-phase insertion, consistent with previous descriptions of indirect fibres. The transition from the ligament fibres to bone had less interdigitations, and the interdigitations were significantly smaller (p < 0.001) compared to the transition in the direct fibre area. The interdigitations of the direct fibres were 387 ± 81 μm (range 282–515 μm) wide, while the interdigitations of indirect fibres measured 228 ± 75 μm (range 89–331 μm).

Conclusions

The centre of the ACL femoral attachment consisted of a direct fibre structure, while the posterior portion had an indirect fibre structure. These results support previous animal studies reporting that the centre of the ACL femoral insertion was comprised of the strongest reported fibre type. Clinically, the femoral ACL reconstruction tunnel should be oriented to cover the entirety of the central direct ACL fibres and may need to be customized based on graft type and the fixation device used during surgery.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8

References

  1. 1.

    Dave LY, Nyland J, Caborn DN (2012) Knee flexion angle is more important than guidewire type in preventing posterior femoral cortex blowout: a cadaveric study. Arthroscopy 28(10):1381–1387

    Article  PubMed  Google Scholar 

  2. 2.

    Fernandes TL, Fregni F, Weaver K, Pedrinelli A, Camanho GL, Hernandez AJ (2014) The influence of femoral tunnel position in single-bundle ACL reconstruction on functional outcomes and return to sports. Knee Surg Sports Traumatol Arthrosc 22(1):97–103

    Article  PubMed  Google Scholar 

  3. 3.

    Gao J, Messner K (1996) Quantitative comparison of soft tissue-bone interface at chondral ligament insertions in the rabbit knee joint. J Anat 188(Pt 2):367–373

    PubMed  PubMed Central  Google Scholar 

  4. 4.

    Iwahashi T, Shino K, Nakata K, Otsubo H, Suzuki T, Amano H, Nakamura N (2010) Direct anterior cruciate ligament insertion to the femur assessed by histology and 3-dimensional volume-rendered computed tomography. Arthroscopy 26(9 Suppl):S13–S20

    Article  PubMed  Google Scholar 

  5. 5.

    Kawaguchi Y, Kondo E, Takeda R, Akita K, Yasuda K, Amis AA (2015) The role of fibers in the femoral attachment of the anterior cruciate ligament in resisting tibial displacement. Arthroscopy 31(3):435–444

    Article  PubMed  PubMed Central  Google Scholar 

  6. 6.

    Kopf S, Pombo MW, Szczodry M, Irrgang JJ, Fu FH (2011) Size variability of the human anterior cruciate ligament insertion sites. Am J Sports Med 39(1):108–113

    Article  PubMed  Google Scholar 

  7. 7.

    Musahl V, Plakseychuk A, VanScyoc A, Sasaki T, Debski RE, McMahon PJ, Fu FH (2005) Varying femoral tunnels between the anatomical footprint and isometric positions: effect on kinematics of the anterior cruciate ligament-reconstructed knee. Am J Sports Med 33(5):712–718

    Article  PubMed  Google Scholar 

  8. 8.

    Noh JH, Roh YH, Yang BG, Yi SR, Lee SY (2013) Femoral tunnel position on conventional magnetic resonance imaging after anterior cruciate ligament reconstruction in young men: transtibial technique versus anteromedial portal technique. Arthroscopy 29(5):882–890

    Article  PubMed  Google Scholar 

  9. 9.

    Pathare NP, Nicholas SJ, Colbrunn R, McHugh MP (2014) Kinematic analysis of the indirect femoral insertion of the anterior cruciate ligament: implications for anatomic femoral tunnel placement. Arthroscopy 30(11):1430–1438

    Article  PubMed  Google Scholar 

  10. 10.

    Robert HE, Bouguennec N, Vogeli D, Berton E, Bowen M (2013) Coverage of the anterior cruciate ligament femoral footprint using 3 different approaches in single-bundle reconstruction: a cadaveric study analyzed by 3-dimensional computed tomography. Am J Sports Med 41(10):2375–2383

    Article  PubMed  Google Scholar 

  11. 11.

    Robin BN, Jani SS, Marvil SC, Reid JB, Schillhammer CK, Lubowitz JH (2015) Advantages and disadvantages of transtibial, anteromedial portal, and outside-in femoral tunnel drilling in single-bundle anterior cruciate ligament reconstruction: a systematic review. Arthroscopy 31(7):1412–1417

    Article  PubMed  Google Scholar 

  12. 12.

    Sasaki N, Ishibashi Y, Tsuda E, Yamamoto Y, Maeda S, Mizukami H, Toh S, Yagihashi S, Tonosaki Y (2012) The femoral insertion of the anterior cruciate ligament: discrepancy between macroscopic and histological observations. Arthroscopy 28(8):1135–1146

    Article  PubMed  Google Scholar 

  13. 13.

    Siebold R (2011) The concept of complete footprint restoration with guidelines for single- and double-bundle ACL reconstruction. Knee Surg Sports Traumatol Arthrosc 19(5):699–706

    Article  PubMed  Google Scholar 

  14. 14.

    van der List JP, Zuiderbaan HA, Nawabi DH, Pearle AD (2015) Impingement following anterior cruciate ligament reconstruction: comparing the direct versus indirect femoral tunnel position. Knee Surg Sports Traumatol Arthrosc. doi:10.1007/s00167-015-3897-9

    Google Scholar 

  15. 15.

    Villegas DF, Haut Donahue TL (2010) Collagen morphology in human meniscal attachments: a SEM study. Connect Tissue Res 51(5):327–336

    Article  PubMed  Google Scholar 

  16. 16.

    Zantop T, Diermann N, Schumacher T, Schanz S, Fu FH, Petersen W (2008) Anatomical and nonanatomical double-bundle anterior cruciate ligament reconstruction: importance of femoral tunnel location on knee kinematics. Am J Sports Med 36(4):678–685

    Article  PubMed  Google Scholar 

  17. 17.

    Zhao L, Thambyah A, Broom ND (2014) A multi-scale structural study of the porcine anterior cruciate ligament tibial enthesis. J Anat 224(6):624–633

    Article  PubMed  PubMed Central  Google Scholar 

  18. 18.

    Ziegler CG, Pietrini SD, Westerhaus BD, Anderson CJ, Wijdicks CA, Johansen S, Engebretsen L, LaPrade RF (2011) Arthroscopically pertinent landmarks for tunnel positioning in single-bundle and double-bundle anterior cruciate ligament reconstructions. Am J Sports Med 39(4):743–752

    Article  PubMed  Google Scholar 

Download references

Acknowledgments

This work was sponsored by Steadman Philippon Research Institute, Vail, Colorado.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Robert F. LaPrade.

Additional information

Investigation performed at the Department of Biomedical Engineering, Steadman Philippon Research Institute, Vail, Colorado, and the Soft Tissue Mechanics Laboratory, Colorado State University, Fort Collins, Colorado.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Moulton, S.G., Steineman, B.D., Haut Donahue, T.L. et al. Direct versus indirect ACL femoral attachment fibres and their implications on ACL graft placement. Knee Surg Sports Traumatol Arthrosc 25, 165–171 (2017). https://doi.org/10.1007/s00167-016-4188-9

Download citation

Keywords

  • Anterior cruciate ligament
  • Scanning electron microscopy
  • Lateral intercondylar ridge
  • Direct fibres
  • Indirect fibres