Mapping of Contributions From Collateral Ligaments to Overall Knee Joint Constraint: An Experimental Cadaveric Study

Abstract

Understanding the contribution of the soft-tissues to total joint constraint (TJC) is important for predicting joint kinematics, developing surgical procedures, and increasing accuracy of computational models. Previous studies on the collateral ligaments have focused on quantifying strain and tension properties under discrete loads or kinematic paths; however, there has been little work to quantify collateral ligament contribution over a broad range of applied loads and range of motion (ROM) in passive constraint. To accomplish this, passive envelopes were collected from nine cadaveric knees instrumented with implantable pressure transducers (IPT) in the collateral ligaments. The contributions from medial and lateral collateral ligaments (LCL) were quantified by the relative contribution of each structure at various flexion angles (0-120 deg) and compound external loads (±10 N m valgus, ±8 N m external, and ±40 N anterior). Average medial collateral ligament (MCL) contributions were highest under external and valgus torques from 60 deg to 120 deg flexion. The MCL showed significant contributions to TJC under external torques throughout the flexion range. Average LCL contributions were highest from 0 deg to 60 deg flexion under external and varus torques, as well as internal torques from 60 deg to 110 deg flexion. Similarly, these regions were found to have statistically significant LCL contributions. Anterior and posterior loads generally reduced collateral contribution to TJC; however, posterior loads further reduced MCL contribution, while anterior loads further reduced LCL contribution. These results provide insight to the functional role of the collaterals over a broad range of passive constraint. Developing a map of collateral ligament contribution to TJC may be used to identify the effects of injury or surgical intervention on soft-tissue, and how collateral ligament contributions to constraint correlate with activities of daily living.

Mid-flexion laxity could be identified with continuous flexion-arc gap assessment in patients with a large preoperative convergence angle

“…Previous studies have suggested the possibility of mid‐flexion laxity even after flexion–extension and medial–lateral gap balancing in TKA due to the following mechanism [6, 7]. Although collateral ligaments are tightest at extension, as the knee starts to flex, the distance between the attachment sites of the collateral ligaments becomes smaller, reducing the force applied by these ligaments on the knee joint [7]. In addition, reduction in not only the collateral ligament load, but also the posterior capsular tension and home screw effect, can cause knee laxity to increase up to 30° of flexion [6].…”

Comparison between kinetic and kinetic-kinematic driven knee joint finite element models

“…For varus-valgus rotation, all models behaved almost identically. This was due to the fact that all models had the same ligament prestrain and stiffness, and ligaments have been suggested to have a significant role in varus-valgus rotation 64 – 66 .…”

A Combined Experimental and Computational Approach to Subject-Specific Analysis of Knee Joint Laxity

“…Specifically, the MCL was a major resistor against valgus rotation and was also actively engaged during external rotation [13,15,16,30,32,33]. The MCL also engaged to a lesser degree during internal rotation [30].…”

“…An effective method for measuring the timing and extent of ligament recruitment during knee motion in various degrees-offreedom (DOF) is with experimental tests of knee laxity. Quantitative knee laxity (i.e., knee envelope) tests can provide important information about ligament engagement and overall contributions to knee stability [12][13][14][15][16]. When developing a computational model, knee laxity tests in multiple DOF can be used to calibrate simulated ligament material properties and ensure accurate prediction of ligament-constrained knee motion and loading.…”