Evaluation of anterior cruciate ligament surgical reconstruction through finite element analysis

Abstract

Anterior cruciate ligament (ACL) tear is one of the most common knee injuries. The ACL reconstruction surgery aims to restore healthy knee function by replacing the injured ligament with a graft. Proper selection of the optimal surgery parameters is a complex task. To this end, we developed an automated modeling framework that accepts subject-specific geometries and produces finite element knee models incorporating different surgical techniques. Initially, we developed a reference model of the intact knee, validated with data provided by the Open Knee(s) project. This helped us evaluate the effectiveness of estimating ligament stiffness directly from MRI. Next, we performed a plethora of “what-if” simulations, comparing responses with the reference model. We found that (a) increasing graft pretension and radius reduces relative knee displacement, (b) the correlation of graft radius and tension should not be neglected, (c) graft fixation angle of 20$$^{\circ }$$ ∘ can reduce knee laxity, and (d) single-versus double-bundle techniques demonstrate comparable performance in restraining knee translation. In most cases, these findings confirm reported values from comparative clinical studies. The numerical models are made publicly available, allowing for experimental reuse and lowering the barriers for meta-studies. The modeling approach proposed here can complement orthopedic surgeons in their decision-making.

Can lateral tenodesis improve the rotational stability of the ACL reconstruction? A finite element analysis

“…In this section, we will describe the developed “Surgery Modeling” tool that can be used to create ACLR knee models, suitable for FE analysis, similar to our previous work [30]. The tool accepts as inputs the segmented and reconstructed bone geometries and various user-defined parameters related to ACLR surgery.…”

“…In the scope of this study, we adjusted a validated FE model used in our previous work [30]. The bones geometries were acquired directly from the Openknee (s) database in the case of the healthy and injured knee joint FE model.…”

“…This in situ strain is evident in biological tissues in vivo and contributes to joint stability [64]. The Posterior Cruciate Ligament (PCL) ligament was modeled as nonlinear tension-only springs with a force - displacement curve that was calibrated and validated in our previous study [30].…”

“…The material properties assigned to these geometries are usually adopted from cadaver studies. The graft models are adjusted to represent various harvesting areas [30–32, 36, 37, 40, 41]. The menisci and cartilages are usually modeled as 3D meshes with suitable material properties [24, 25, 42–44].…”

“…Furthermore, knee joint kinematics are modeled by imposing suitable rigid body constraints that are adjusted based on in vivo or in vitro experiments where the knee joint is mechanically tested [27–29, 45, 46]. These validated models also serve as reference points for subsequent researches [30, 31, 33, 34, 36].…”