The Anterolateral Structure of the Knee Does Not Affect Anterior and Dynamic Rotatory Stability in Anterior Cruciate Ligament Injury: Quantitative Evaluation With the Electromagnetic Measurement System

Background: The biomechanical function of the anterolateral structure (ALS), which includes the anterolateral joint capsule and anterolateral ligament (ALL), remains a topic of debate. Hypothesis: The ALS contributes to knee joint stability during the Lachman test and the pivot-shift test in anterior cruciate ligament (ACL)–deficient knees. Study Design: Controlled laboratory study. Methods: Fourteen fresh-frozen hemipelvis lower limbs were used. For 7 specimens, the anterior one-third of the ALS and the residual ALS were cut intra-articularly with a radiofrequency device. Subsequently, the ACL was cut arthroscopically. For the other 7 specimens, the ACL was cut first, followed by the anterior one-third of the ALS and the residual ALS intra-articularly. During the procedures, the iliotibial band (ITB) was kept intact. At each condition, the anterior tibial translation (ATT) during the manual Lachman test and the acceleration of posterior tibial translation (APT) and the posterior tibial translation (PTT) during the manual pivot-shift test were measured quantitatively with an electromagnetic measurement system. The mean values of those parameters were compared among 6 groups (ACL intact, one-third ALS cut, all ALS cut, ACL cut, ACL/one-third ALS cut, and ACL/all ALS cut). Results: The mean ATTs during the Lachman test and the mean APTs and PTTs in the ACL-cut conditions (ACL cut, ACL/one-third ALS cut, and ACL/all ALS cut) were significantly larger than those under the ACL-intact conditions (ACL intact, one-third ALS cut, all ALS cut) ( P < .01). However, no statistically significant differences were observed among the intact, one-third ALS–cut, and all ALS–cut conditions, within the ACL-intact or ACL-cut conditions. Conclusion: Intra-articular dissection of the ALS did not increase the ATT during the Lachman test or the APT and PTT during the pivot-shift test under the intact condition of the ITB, regardless of the integrity of the ACL. When the ITB is intact, the ALS does not have a significant role in either anterior or dynamic rotatory knee stability, while the ACL does. Clinical Relevance: Recent growing interest about ALL reconstruction or ALS augmentation may not have a large role in controlling either anterior or dynamic rotatory knee instability in isolated ACL-deficient knees.

Magnetic properties of ferromagnetic steels under different stress by the alternating current magnetization

The alternating current magnetic characteristics of the ferromagnetic materials act a significant factor to reflect their stress states. To reveal the relationship between the stress and the magnetic properties of the ferrimagnetic steels, we deduce the relation of alternating current permeability and the detected voltage of the nine-feet probe by using the basic laws in magnetism and law of electromagnetic reaction, and then we use the nine-feet probe to design and build the electromagnetic measurement system. Next some corresponding experiments were carried out to test the induction voltage of the two kinds Q-steel samples under the different stress. The results were shown that there was a similar variation tendency of the detected voltage in the two kinds the Q-steel samples, the max different values of the detected voltage can be reach 150 mV in the Q215 sample and 280 mV in the Q275 sample, respectively. Therefore, with the help of the difference detected voltage we can check the stress state of the ferrimagnetic steels conveniently in the engineering.

Design and Optimization of Annular Flow Electromagnetic Measurement System for Drilling Engineering

Using the downhole annular flow measurement system to get real-time information of downhole annular flow is the core and foundation of downhole microflux control drilling technology. The research work of electromagnetic flowmeter in recent years creates a challenge to the design of downhole annular flow measurement. This paper proposes a design and optimization of annular flow electromagnetic measurement system for drilling engineering based on the finite element method. Firstly, the annular flow measuring and optimization principle are described. Secondly, a simulation model of an annular flow electromagnetic measurement system with two pairs of coil is built based on the fundamental equation of electromagnetic flowmeter by COMSOL. Thirdly, simulations of the structure of excitation system of the measurement system are carried out, and simulations of the size of the electrode’s radius are also carried out based on the optimized structure, and then all the simulation results are analyzed to evaluate the optimization effect based on the evaluation indexes. The simulation results show that optimized shapes of the excitation system and electrode size can yield a better performance in the annular flow measurement.