Kim Sung-Jae, Song Si Young, Kim Tae Soung, Kim Yoon Sang, Jang Seong-Wook, Seo Young-Jin
Department of Orthopaedic Surgery, Hallym University, Dongtan Sacred Heart Hospital, Hwaseong, Gyeonggi-do, Republic of Korea.
BioComputing Lab, School of Computer Science and Engineering, Korea University of Technology and Education (KOREATECH), Cheonan, Republic of Korea.
Orthop J Sports Med. 2021 Apr 29;9(4):23259671211001802. doi: 10.1177/23259671211001802. eCollection 2021 Apr.
It remains unclear whether an anteromedial (AM) footprint or a central footprint anterior cruciate ligament (ACL) graft exhibits less contact stress with the femoral tunnel aperture. This contact stress can generate graft attrition forces, which can lead to potential graft failure.
PURPOSE/HYPOTHESIS: The purpose of this study was to compare the difference in contact stress patterns of the graft around a femoral tunnel that is created at the anatomic AM footprint versus the central footprint. It was hypothesized that the difference in femoral tunnel positions would influence the contact stress at the interface between the reconstructed graft and the femoral tunnel orifice.
Controlled laboratory study.
A total of 24 patients who underwent anatomic single-bundle ACL reconstruction were included in this study. In 12 patients, the femoral tunnels were created at the center of the native AM footprint (AM group), and in the remaining 12 patients the center of the femoral tunnel was placed in the anatomic central footprint (central group). Three-dimensional knee models were created and manipulated using several modeling programs, and the graft-tunnel angle (GTA) was determined using a special software program. The peak contact stresses generated on the virtual ACL graft around the femoral tunnel orifice were calculated using a finite element method.
The mean GTA was significantly more obtuse in the AM group than in the central group (124.2° ± 5.9° vs 112.6° ± 7.9°; = .001). In general, both groups showed high stress distribution on the anterior surface of the graft, which came in contact with the anterior aspect of the femoral tunnel aperture. The degree of stress in the central group (5.3 ± 2.6 MPa) was significantly higher than that in the AM group (1.2 ± 1.1 MPa) ( < .001).
Compared with the AM footprint ACL graft, the central footprint ACL graft developed significantly higher contact stress in the extended position, especially around the anterior aspect of the femoral tunnel orifice.
The contact stress of the ACL graft at the extended position of the knee may be minimized by creating the femoral tunnel at the AM-oriented footprint.
目前尚不清楚前内侧（AM）足迹或中央足迹的前交叉韧带（ACL）移植物与股骨隧道开口处的接触应力是否更小。这种接触应力会产生移植物磨损力，这可能导致潜在的移植物失效。
目的/假设：本研究的目的是比较在解剖学AM足迹处创建的股骨隧道与中央足迹处创建的股骨隧道周围移植物的接触应力模式差异。假设股骨隧道位置的差异会影响重建移植物与股骨隧道口之间界面处的接触应力。
对照实验室研究。
本研究共纳入24例行解剖单束ACL重建的患者。12例患者的股骨隧道在天然AM足迹的中心创建（AM组），其余12例患者的股骨隧道中心置于解剖学中央足迹处（中央组）。使用多个建模程序创建并操作三维膝关节模型，并使用特殊软件程序确定移植物-隧道角度（GTA）。使用有限元方法计算股骨隧道口周围虚拟ACL移植物上产生的峰值接触应力。
AM组的平均GTA明显比中央组更钝（124.2°±5.9°对112.6°±7.9°；P = 0.001）。一般来说，两组在移植物前表面与股骨隧道口前侧接触处均显示出高应力分布。中央组的应力程度（5.3±2.6MPa）明显高于AM组（1.2±1.1MPa）（P<0.001）。
与AM足迹ACL移植物相比，中央足迹ACL移植物在伸展位时产生的接触应力明显更高，尤其是在股骨隧道口前侧周围。
通过在AM方向的足迹处创建股骨隧道，可使膝关节伸展位时ACL移植物的接触应力最小化。
