The femoral posterior fan-like extension of the ACL insertion increases the failure load
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To examine the role of the posterior fan-like extension of the ACL’s femoral footprint on the ACL failure load.
Sixteen (n = 16) fresh frozen, mature porcine knees were used in this study and randomized into two groups (n = 8): intact femoral ACL insertion (ACL intact group) and cut posterior fan-like extension of the ACL (ACL cut group). In the ACL cut group, flexing the knees to 90°, created a folded border between the posterior fan-like extension and the midsubstance insertion of the femoral ACL footprint and the posterior fan-like extension was dissected and both areas were measured. Specimens were placed in a testing machine at 30° of flexion and subjected to anterior tibial loading (60 mm/min) until ACL failure.
The intact ACL group had a femoral insertion area of 182.1 ± 17.1 mm2. In the ACL cut group, the midsubstance insertion area was 113.3 ± 16.6 mm2, and the cut posterior fan-like extension portion area was 67.1 ± 8.3 mm2. The failure load of the ACL intact group was 3599 ± 457 N and was significantly higher (p < 0.001) than the failure load of the ACL cut group 392 ± 83 N.
Transection of the posterior fan-like extension of the ACL femoral footprint has a significant effect on the failure load of the ligament during anterior loading at full extension. Regarding clinical relevance, this study suggests the importance of the posterior fan-like extension of the ACL footprint which potentially may be retained with remnant preservation during ACL reconstruction. Femoral insertion remnant preservation may allow incorporation of the fan-like structure into the graft increasing graft strength.
KeywordsACL Midsubstance Posterior fan-like extension Femoral footprint Failure load Morphology
This study was funded by the Department of Orthopaedic Surgery at the University of Pittsburgh.
Compliance with ethical standards
Conflict of interest
Authors have no conflicts to disclose.
No ethical approval was required from IACUC.
Not applicable to this study.
- 8.Li F, Qin L, Gong X, Huang Z, Wang T, Liu Z, Sandiford S, Yang J, Zhu S, Liang X, Huang W, Hu N (2019) The Chinese ACL injury population has a higher proportion of small ACL tibial insertion sizes than Western patients. Knee Surg Sports Traumatol Arthrosc. https://doi.org/10.1007/s00167-019-05541-z CrossRefPubMedGoogle Scholar
- 10.Mochizuki T, Fujishiro H, Nimura A, Mahakkanukrauh P, Yasuda K, Muneta T, Akita K (2014) Anatomic and histologic analysis of the mid-substance and fan-like extension fibres of the anterior cruciate ligament during knee motion, with special reference to the femoral attachment. Knee Surg Sports Traumatol Arthrosc 22:336–344CrossRefGoogle Scholar
- 15.Smigielski R, Zdanowicz U, Drwiega M, Ciszek B, Ciszkowska-Lyson B, Siebold R (2015) Ribbon like appearance of the midsubstance fibres of the anterior cruciate ligament close to its femoral insertion site: a cadaveric study including 111 knees. Knee Surg Sports Traumatol Arthrosc 23:3143–3150CrossRefGoogle Scholar