Knee Joint Model for Anterior Cruciate Ligament Reconstruction - Computational Biomechanics of the Musculoskeletal System - page 75

6 Knee Joint Model for

Anterior Cruciate Ligament
Reconstruction

Jie Yao, Ming Zhang, and Yubo Fan

ContentS
Summary .......................................................................................................................................... 75
6.1 Introduction ............................................................................................................................. 76
6.2 Development of a Comprehensive Knee Model ..................................................................... 76
6.2.1 Geometry Acquisition ................................................................................................. 76
6.2.2 Finite Element Discretization ..................................................................................... 77
6.2.3 Model Validation ......................................................................................................... 77
6.3 Application of the Finite Element Model ................................................................................ 78
6.3.1 Model of ACL Reconstruction .................................................................................... 78
6.3.2 Change of SED Distribution after ACL Reconstruction ............................................. 78
6.3.3 Change of Stress Direction after ACL Reconstruction ............................................... 80
6.3.4 Effect of Screw Material on SED Distribution ........................................................... 80
6.3.5 Distribution of SED in Interference Screw ................................................................. 80
Acknowledgments ............................................................................................................................ 81
References ........................................................................................................................................ 82

Summary
Tearing of the anterior cruciate ligament (ACL) is a common knee injury, and is frequently treated
through ACL reconstruction. However, sequelae such as tunnel enlargement and tibia fracture have
been reported. The creation of bone tunnels or implantation of interference devices may inter-
rupt the normal loading transmission and potentially contribute to long-term sequelae. This chapter
aims to (1) develop a three-dimensional finite element (FE) model of the human knee joint with
ACL reconstructions; (2) quantify the change of strain energy density (SED) distribution induced
by the tunnel creation and interference screw; and (3) investigate the influence of screw material
on the SED changes in the tibia. The bone SED distribution was derived from the validated FE
model under compressive loading. The numerical results confirmed that the bone SED distribution
and stress orientation changed after surgery. These changes occurred around the bone tunnel, and
could produce abnormal bone remodeling. The consequential bone resorption and micro-damage
may serve as a predisposing factor for tunnel enlargement and osteoarthritis. The material property
of the screw could also influence the postoperative SED distribution in the tibia. On the premise
of achieving sufficient fixation strength, using a screw with a modulus similar to the bone could
decrease the risk of stress shielding. These findings together with histology factors could help us to
understand the pathomechanism of the sequelae, and help to improve surgical techniques.

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