Computational analysis of the clinical presentation of a ligamentous Lisfranc injury

Abstract

Lisfranc injuries in the midfoot disrupt key arches of the foot which, if left untreated, can progress to pain, dysfunction, and arthritis. A clinical challenge is that 30-40% of Lisfranc injuries are missed in initial evaluations. The objective of this study was to explore different conditions of limb loading that could influence the biomechanics of the Lisfranc joint in a validated computational model. A computational model was created using SolidWorks software to represent the bones and soft tissues of the lower leg and foot. The model was compared to a cadaveric study of healthy and injured Lisfranc joints. The model was then used to simulate weight-bearing radiographs and evaluate how muscle activity and foot position impacted the diastasis of the Lisfranc joint, a key indicator used to diagnose Lisfranc injuries. The computational model was within one standard deviation of the cadaveric study in all measurements for the healthy and injured foot. When simulating weight-bearing radiographs, the presence of muscle activity or inversion/eversion resulted in less joint separation for the model with ligamentous Lisfranc injuries. While previous research has noted that weight-bearing radiographs provide better conditions to assess Lisfranc injuries than nonweightbearing, this study suggests that in weight-bearing radiographs both altering the position of the foot, possibly due to pain, and the active contraction of the extrinsic flexor muscles can obfuscate indications of a Lisfranc injury.

Computational analysis of Lisfranc surgical repairs

“…Motion in the joints was determined solely by the 3D articular surfaces of the bones and the ligament/muscle forces. The model predictions of joint diastasis was confirmed to be within the standard deviation of the previous cadaveric study 23 . Results from the previous validation work for healthy and injured models were used as a point of comparison for the four different surgical procedures.…”

“…The diastasis of the Lisfranc joint could be compared across all four surgeries and with a healthy and injured foot from previous work (Figure 4). 23 ORIF with screws and arthrodesis did not replicate the small amount of motion in the healthy joint; however, the little to no diastasis these procedures showed throughout the depth of the joint was the closest in returning the injured joint to diastasis values comparable to a healthy state. ORIF with endobutton had larger diastasis on both the dorsal and plantar sides while the dorsal plate minimized diastasis on the dorsal side but had increased levels interior to the joint as well as on the plantar side.…”

“…The model predictions of joint diastasis was confirmed to be within the standard deviation of the previous cadaveric study. 23 Results from the previous validation work for healthy and injured models were used as a point of comparison for the four different surgical procedures. The previously developed rigid body model and new finite element models in this study were used to investigate the kinematics and other clinical indicators that could be observed in postoperative radiographs for the surgical procedures.…”

“…Five screws used to fuse the three cuneiforms and first two metatarsals as per clinical practice [Color figure can be viewed at wileyonlinelibrary.com] Rigid body kinematic simulations Once the hardware was incorporated into the rigid body model, the first round of simulations was performed. These simulations applied a 50% weight bearing steady-state compressive load and tensile muscle loads, the same loading as the model validation work for a postinjury joint 23. The rigid body model allowed for ligament and joint contact forces to be captured for the postoperative foot.…”