The dynamic response of human lungs due to underwater shock wave exposure.

Since the 19th century, underwater explosions have posed a significant threat to service members. While there have been attempts to establish injury criteria for the most vulnerable organs, namely the lungs, existing criteria are highly variable due to insufficient human data and the corresponding inability to understand the underlying injury mechanisms. This study presents an experimental characterization of isolated human lung dynamics during simulated exposure to underwater shock waves.

Whole Body PMHS Response in Injurious Experimental Accelerative Loading Events.

Previous studies involving whole-body post-mortem human surrogates (PHMS) have generated biomechanical response specifications for physically simulated accelerative loading intended to reproduce seat and floor velocity histories occurring in under-body blast (UBB) events (e.g.,.

Dynamic Response of the Thoracolumbar and Sacral Spine to Simulated Underbody Blast Loading in Whole Body Post Mortem Human Subject Tests.

Fourteen simulated underbody blast impact sled tests were performed using a horizontal deceleration sled with the aim of evaluating the dynamic response of the spine in under various conditions. Conditions were characterized by input (peak velocity and time-to-peak velocity for the seat and floor), seat type (rigid or padded) and the presence of personnel protective equipment (PPE). A 50% (T12) and 30% (T8) reduction in the thoracic spine response for the specimens outfitted with PPE was observed.

Mechanisms and timing of injury to the thoracic, lumbar and sacral spine in simulated underbody blast PMHS impact tests.

During an underbody blast (UBB) event, mounted occupants are exposed to high rate loading of the spine via the pelvis. The objective of this study was to simulate UBB loading conditions and examine mechanisms of injury in the thoracic, lumbar and sacral spine. Fourteen instrumented, whole-body, postmortem human subject (PMHS) experiments were performed using the WSU-decelerative horizontal sled system.

Evaluation of the Whole Body Spine Response to Sub-Injurious Vertical Loading.

It is critical to understand the relationship between under-body blast (UBB) loading and occupant response to provide optimal protection to the warfighter from serious injuries, many of which affect the spine. Previous studies have examined component and whole body response to accelerative based UBB loading. While these studies both informed injury prediction efforts and examined the shortcomings of traditional anthropomorphic test devices in the evaluation of human injury, few studies provide response data against which future models could be compared and evaluated.

Kinematic and Biomechanical Response of Post-Mortem Human Subjects Under Various Pre-Impact Postures to High-Rate Vertical Loading Conditions.

Limited data exist on the injury tolerance and biomechanical response of humans to high-rate, under-body blast (UBB) loading conditions that are commonly seen in current military operations, and there are no data examining the influence of occupant posture on response. Additionally, no anthropomorphic test device (ATD) currently exists that can properly assess the response of humans to high-rate UBB loading. Therefore, the purpose of this research was to examine the response of post-mortem human surrogates (PMHS) in various seated postures to high-rate, vertical loading representative of those conditions seen in theater.

Anatomically-based skeletal coordinate systems for use with impact biomechanics data intended for anthropomorphic test device development.

Post-mortem human subjects (PMHS) are frequently used to characterize biomechanical response and injury tolerance of humans to various types of loading by means of instrumentation installed directly on the skeleton. Data extracted from such tests are often used to develop and validate anthropomorphic test devices (ATDs), which function as human surrogates in tests for injury assessment. Given that the location and orientation of installed instrumentation differs between subjects, nominally similar measurements made on different PMHS must be transformed to standardized, skeletal-based local coordinate systems (LCS) before appropriate data comparisons can be made.

Evaluation of WIAMan Technology Demonstrator Biofidelity Relative to Sub-Injurious PMHS Response in Simulated Under-body Blast Events.

Three laboratory simulated sub-injurious under-body blast (UBB) test conditions were conducted with whole-body Post Mortem Human Surrogates (PMHS) and the Warrior Assessment Injury Manikin (WIAMan) Technology Demonstrator (TD) to establish and assess UBB biofidelity of the WIAMan TD. Test conditions included a rigid floor and rigid seat with independently varied pulses. On the floor, peak velocities of 4 m/s and 6 m/s were applied with a 5 ms time to peak (TTP).

Strain Response of the Anterior Cruciate Ligament to Uniplanar and Multiplanar Loads During Simulated Landings: Implications for Injury Mechanism.

Background: Despite basic characterization of the loading factors that strain the anterior cruciate ligament (ACL), the interrelationship(s) and additive nature of these loads that occur during noncontact ACL injuries remain incompletely characterized.

Hypothesis: In the presence of an impulsive axial compression, simulating vertical ground-reaction force during landing (1) both knee abduction and internal tibial rotation moments would result in increased peak ACL strain, and (2) a combined multiplanar loading condition, including both knee abduction and internal tibial rotation moments, would increase the peak ACL strain to levels greater than those under uniplanar loading modes alone.

Study Design: Controlled laboratory study.

Uni-directional coupling between tibiofemoral frontal and axial plane rotation supports valgus collapse mechanism of ACL injury.

Despite general agreement on the effects of knee valgus and internal tibial rotation on anterior cruciate ligament (ACL) loading, compelling debate persists on the interrelationship between these rotations and how they contribute to the multi-planar ACL injury mechanism. This study investigates coupling between knee valgus and internal tibial rotation and their effects on ACL strain as a quantifiable measure of injury risk. Nineteen instrumented cadaveric legs were imaged and tested under a range of knee valgus and internal tibial torques.

The Effect of Ligament Modeling Technique on Knee Joint Kinematics: A Finite Element Study.

Finite element (FE) analysis has become an increasingly popular technique in the study of human joint biomechanics, as it allows for detailed analysis of the joint/tissue behavior under complex, clinically relevant loading conditions. A wide variety of modeling techniques have been utilized to model knee joint ligaments. However, the effect of a selected constitutive model to simulate the ligaments on knee kinematics remains unclear.

Finite element model of the knee for investigation of injury mechanisms: development and validation.

Multiple computational models have been developed to study knee biomechanics. However, the majority of these models are mainly validated against a limited range of loading conditions and/or do not include sufficient details of the critical anatomical structures within the joint. Due to the multifactorial dynamic nature of knee injuries, anatomic finite element (FE) models validated against multiple factors under a broad range of loading conditions are necessary.

Diagnostic value of knee arthrometry in the prediction of anterior cruciate ligament strain during landing.

Background: Previous studies have indicated that higher knee joint laxity may be indicative of an increased risk of anterior cruciate ligament (ACL) injuries. Despite the frequent clinical use of knee arthrometry in the evaluation of knee laxity, little data exist to correlate instrumented laxity measures and ACL strain during dynamic high-risk activities. Purpose/

Hypotheses: The purpose of this study was to evaluate the relationships between ACL strain and anterior knee laxity measurements using arthrometry during both a drawer test and simulated bipedal landing (as an identified high-risk injurious task).

Timing sequence of multi-planar knee kinematics revealed by physiologic cadaveric simulation of landing: implications for ACL injury mechanism.

Background: Challenges in accurate, in vivo quantification of multi-planar knee kinematics and relevant timing sequence during high-risk injurious tasks pose challenges in understanding the relative contributions of joint loads in non-contact injury mechanisms. Biomechanical testing on human cadaveric tissue, if properly designed, offers a practical means to evaluate joint biomechanics and injury mechanisms. This study seeks to investigate the detailed interactions between tibiofemoral joint multi-planar kinematics and anterior cruciate ligament strain in a cadaveric model of landing using a validated physiologic drop-stand apparatus.

Preferential loading of the ACL compared with the MCL during landing: a novel in sim approach yields the multiplanar mechanism of dynamic valgus during ACL injuries.

Background: Strong biomechanical and epidemiological evidence associates knee valgus collapse with isolated, noncontact anterior cruciate ligament (ACL) injuries. However, a concomitant injury to the medial collateral ligament (MCL) would be expected under valgus collapse, based on the MCL's anatomic orientation and biomechanical role in knee stability. Purpose/

Hypothesis: The purpose of this study was to investigate the relative ACL to MCL strain patterns during physiological simulations of a wide range of high-risk dynamic landing scenarios.

Clinically relevant injury patterns after an anterior cruciate ligament injury provide insight into injury mechanisms.

Background: The functional disability and high costs of treating anterior cruciate ligament (ACL) injuries have generated a great deal of interest in understanding the mechanism of noncontact ACL injuries. Secondary bone bruises have been reported in over 80% of partial and complete ACL ruptures.

Purpose: The objectives of this study were (1) to quantify ACL strain under a range of physiologically relevant loading conditions and (2) to evaluate soft tissue and bony injury patterns associated with applied loading conditions thought to be responsible for many noncontact ACL injuries.

Suture capsulorrhaphy versus capsulolabral advancement for shoulder instability.

Purpose: The purpose of this study was to test the strength of a suture capsulorrhaphy repair versus a capsulolabral repair with knotless suture anchors in a cadaveric model with anteroinferior shoulder instability.

Methods: Fourteen cadaveric shoulders were tested with either a suture capsulorrhaphy to the intact labrum or a capsulolabral advancement using a knotless suture anchor into the glenoid. Specimens were translated with the shoulder in an abducted, externally rotated position to failure.

Instant axis of rotation of L4-5 motion segment--a biomechanical study on cadaver lumbar spine.

The instant axis of rotation (IAR) is an important kinematic property to characterise of lumbar spine motion. The goal of this biomechanical study on cadaver lumbar spine was to determine the excursion of the IAR for flexion (FE), lateral bending (LB) and axial rotation (AR) motion at L4-5 segment. Ten cadaver lumbar spine specimens were tested in a 6 degrees-of-freedom spine tester with continuous clyclical loading using pure moment and follower pre-load, to produce physiological motion.

Cartilage pressure distributions provide a footprint to define female anterior cruciate ligament injury mechanisms.

Background: Bone bruises located on the lateral femoral condyle and posterolateral tibia are commonly associated with anterior cruciate ligament (ACL) injuries and may contribute to the high risk for knee osteoarthritis after ACL injury. The resultant footprint (location) of a bone bruise after ACL injury provides evidence of the inciting injury mechanism. Purpose/

Hypothesis: (1) To analyze tibial and femoral articular cartilage pressure distributions during normal landing and injury simulations, and (2) to evaluate ACL strains for conditions that lead to articular cartilage pressure distributions similar to bone bruise patterns associated with ACL injury.

Distractive force relative to initial graft compression in an in vivo anterior cervical discectomy and fusion model.

Study Design: An in vivo biomechanical anterior cervical discectomy and instrumented fusion (ACDFI) model employing a calibrated distractor and a subminiature load cell used to intraoperatively measure distractive force across the discectomy site and subsequent compressive force across the interbody load cell following distractor removal.

Objective: To determine the relationship between the distractive force and resultant initial graft compression in an in vivo ACDFI model.

Summary Of Background Data: The relationship between the distractive force and subsequent graft compression following distractor removal has not been studied in an in vivo ACDFI model.

Biomechanical evaluation of the kinematics of the cadaver lumbar spine following disc replacement with the ProDisc-L prosthesis.

Study Design: Biomechanical study of the ProDisc-L in a cadaveric model under pure moment loading. OBJECTIVE.: To determine the kinematic properties of a lumbar spine motion segment and the adjacent level following ProDisc-L disc replacement in the cadaveric spine.

Effects of zone-specific superior labral detachment on biceps anchor stability.

Purpose: This study aimed to elucidate the degree of biceps anchor displacement that occurs when specific zones of the superior labrum are detached from the glenoid.

Study Design: Descriptive laboratory study.

Methods: Twelve cadaveric scapulae with intact labrums were prepared by removing the surrounding musculature with the labrum, biceps anchor, and biceps tendon carefully preserved.

Failure of coracoclavicular artificial graft reconstructions from repetitive rotation.

Purpose: To assess how suture type and suture construct in an augmented Weaver-Dunn reconstruction affect coracoclavicular sling failure and rotary stability.

Methods: Fifteen cadaveric shoulders were tested in rotation about the long axis of the clavicle with 10 lb of simulated arm weight. The clavicle was rotated 50 degrees about its long axis, and the applied torque was recorded.