Abnormal Biomechanics Research Articles

Transfemoral Amputation Adductor Myodesis Using FiberTape and Knotless Anchors.

Level V, expert opinion.

A MECHANISM FOR LIGAMENTUM TERES INJURIES IN FEMOROACETABULAR IMPINGEMENT: AN ANATOMICAL STUDY

Femoroacetabular impingement can produce abnormal biomechanics that lead to compensatory injuries around the hip and pelvis. Ligamentum teres pathologies are commonly associated with these bony deformities but a mechanism for injury has not been described in the literature. The purpose of this study was to describe a potential mechanism behind ligamentum teres injury and impingement between the femoral neck and acetabulum. Laboratory controlled cadaveric study. Twenty-six hips from 15 embalmed cadavers (8 male; 7 female) with lifespans between 55-93 years were skeletonized. The hip was placed in 90 ° flexion and 0 ° abduction/adduction and internally rotated until the femoral head neck contacted the acetabulum. This position of impingement with respect to internal rotation was recorded with a goniometer. The hip was then further internally rotated until end range of motion was achieved and again the position of internal rotation recorded with a goniometer. The positions of internal rotation at which impingement occurred (mean 9 °; SD 4.2; Range -2 ° to 15 °) when compared to end range (mean 21 °; SD 5.7; Range 5 ° to 27 °) were significantly different (p<0.005; t = 14.8). In all the hips, after impingement occurred the site of bony contact between the femoral neck and acetabulum acted as a pivot point. The femoral head was levered inferiorly with a loss of the rotational center within the acetabulum, as internal rotation continued. This movement of the femoral head caused the ligamentum teres to tighten and restricted further movement. Movement into internal rotation beyond this end position caused rupture of the ligamentum teres. Internal rotation range of motion can occur beyond the position of impingement and resulted in abnormal inferior movement of the femoral head and tightening of the ligament teres. This study provides cadaveric evidence for the mechanism of ligamentum teres injury in those with who engage in activities that required motion beyond the point of impingement.

Defining the Role of Solid Stress and Matrix Stiffness in Cancer Cell Proliferation and Metastasis.

Solid tumors are characterized by an abnormal stroma that contributes to the development of biomechanical abnormalities in the tumor microenvironment. In particular, these abnormalities include an increase in matrix stiffness and an accumulation of solid stress in the tumor interior. So far, it is not clearly defined whether matrix stiffness and solid stress are strongly related to each other or they have distinct roles in tumor progression. Moreover, while the effects of stiffness on tumor progression are extensively studied compared to the contribution of solid stress, it is important to ascertain the biological outcomes of both abnormalities in tumorigenesis and metastasis. In this review, we discuss how each of these parameters is evolved during tumor growth and how these parameters are influenced by each other. We further review the effects of matrix stiffness and solid stress on the proliferative and metastatic potential of cancer and stromal cells and summarize the in vitro experimental setups that have been designed to study the individual contribution of these parameters.

REDUCTION IN LEFT VENTRICULAR OUTFLOW TRACT GRADIENT WITH MAVACAMTEN (MYK-461) IN SYMPTOMATIC OBSTRUCTIVE HYPERTROPHIC CARDIOMYOPATHY PATIENTS (PIONEER-HCM)

In obstructive hypertrophic cardiomyopathy (oHCM) LV hypertrophy, reduced compliance, and hyperdynamic function result in dyspnea, fatigue, and limited exercise capacity. Mavacamten is an oral, allosteric modulator of cardiac myosin that targets an underlying biomechanical abnormality in HCM and was

Canine hip dysplasia: A natural animal model for human developmental dysplasia of the hip.

Developmental dysplasia of the hip (DDH) in humans is a common condition that is associated with hip pain, functional limitations, and secondary osteoarthritis (OA). Surgical treatment of DDH has improved in the last decade, allowing excellent outcomes at short- and mid-term follow-up. Still, the etiology, mechanobiology, and pathology underlying this disease are not well understood. A pre-clinical animal model of DDH could help advance the field with a deeper understanding of specific pathways that initiate hip joint degeneration secondary to abnormal biomechanics. An animal model would also facilitate different interventional treatments that could be tested in a rigorous and controlled environment. The dog model exhibits several important characteristics that make it valuable as a pre-clinical animal model for human DDH. Dogs are naturally prone to develop canine hip dysplasia (CHD), which is treated in a similar manner as in humans. Comparable to human DDH, CHD is considered a pre-OA disease; if left untreated it will progress to OA. However, progression to OA is significantly faster in dogs than humans, with progression to OA within 1-2 years of age, associated with their shorter life span compared to humans. Animal studies could potentially reveal the underlying biochemical pathway(s), which can inform refined treatment modalities and provide opportunities for new treatment and prevention targets. Herein, we review the similarities and differences between the two species and outline the argument supporting CHD as an appropriate pre-clinical model of human DDH. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1807-1817, 2018.

Imaging Corneal Biomechanical Responses to Ocular Pulse Using High-Frequency Ultrasound.

Imaging corneal biomechanical changes or abnormalities is important for better clinical diagnosis and treatment of corneal diseases. We propose a novel ultrasound-based method, called ocular pulse elastography (OPE), to image corneal deformation during the naturally occurring ocular pulse. Experiments on animal and human donor eyes, as well as synthetic radiofrequency (RF) data, were used to evaluate the efficacy of the OPE method. Using very high-frequency ultrasound (center frequency = 55 MHz), correlation-based speckle tracking yielded an accuracy of less than 10% error for axial tissue displacements of or above. Satisfactory speckle tracking was achieved for out-of-plane displacements up to . Using synthetic RF data with or without a pre-defined uniform strain, the OPE method detected strains down to 0.0001 axially and 0.00025 laterally with an error less than 10%. Experiments in human donor eyes showed excellent repeatability with an intraclass correlation of 0.98. The measurement outcome from OPE was also shown to be highly correlated with that of standard inflation. These results suggest the feasibility of OPE as a potential clinical tool for evaluating corneal biomechanics in vivo.

Особенности кальцификации клапанов сердца и их биологических протезов: состав, структура и локализация кальцификатов

Calcification of cardiovascular tissues and biological substitutes results in abnormal biomechanics, causing stenosis or tissues ruptures. Therefore, the understanding of calcification pathways will facilitate the development of strategies for calcification risk reduction. Even though calcification pathways have been studied since the mid-80s and are widely described in the medical literature, there is no consensus on the cause-and-effect relationships in this pathological process. The current review covers the composition, structural aspects and specific localization of calcific deposits in native heart valves and blood vessels, bioprosthetic heart valves treated with glutaraldehyde. Moreover, experimental data on the composition of in vivo and in vitro calcification are presented. These characteristics of calcific deposits provide new insights in the calcification pathways. According to the results of the literature review, one may conclude that cell death, microfracture of the surrounding tissues with the overall biochemical imbalance may potentiate the calcification process. Moreover, the progression of calcification process is associated with the accumulation of mechanical stress.

Chapter 39 - Sport-related injury and pain classification

Pain is common in athletes, and pain management in sport has traditionally been equated with injury management. Although both pain and injury interfere with sport performance, they are not synonymous. Acute musculoskeletal injury commonly manifests as nociceptive pain, inflammatory pain, or both. Pain that persists beyond expected injury recovery must account for all potential contributors to pain, including ongoing biomechanical abnormalities, underlying pathophysiology, and psychosocial issues. Pain chronification involves multiple pathophysiologic and neurobehavioral processes that lead from acute injury-related pain to subacute and chronic pain, and must be distinguished from an ongoing biomechanical overuse pattern. The foundation of pain management in athletes is proper pain classification, which involves assessing for any combination of nociceptive/inflammatory pain, neuropathic pain, central sensitization, and autonomic/motor/affective manifestations of pain. Understanding this foundation is critical because there are scant evidence-based guidelines for the management of pain in sport. This chapter will explore the relationship of sport-related injury and pain, and will provide a management framework that is consistent with International Olympic Committee consensus.

Lésion de la racine méniscale postéromédiale : l’extrusion méniscale est corrélée à la durée des symptômes dans les formes à début brutal

IntroductionMedial meniscus posterior root tear (MMPRT) leads to abnormal biomechanics of the knee by inducing the medial meniscus extrusion (MME). However, a time-dependent increase of the MME is not fully elucidated in patients suffering from the acute MMPRT. The aim of this study was to investigate the relationships among disease duration of the MMPRT and severity of the MME. We hypothesized that MME measurement correlates with disease duration after a sudden onset of the minor traumatic MMPRT during the short-term follow-up period. Materials and methodsForty-six patients who had an accurate episode of the posteromedial painful popping were investigated. All the patients were diagnosed having a symptomatic MMPRT with magnetic resonance imaging (MRI) examinations. Absolute MME was measured using MRI scans within 12months after painful popping events. A correlation coefficient between duration from injury to MRI examination and absolute MME was evaluated. ResultsMean absolute MME was 4.5±1.6mm (range, 1.1−8.8mm) on MRI measurements. A good correlation was observed between MME measurement and duration from injury to MRI examination (R2=0.612). The best fit equation for predicting each value was: MME=0.014×disease duration+3.288mm. DiscussionThis study demonstrated that absolute MME increases progressively within the short duration after the onset of symptomatic MMPRT. Our results suggest that preoperative MME assessment may be important in determining disease duration and treatment strategy of the MMPRT. Level of evidenceRetrospective cohort study; level IV.

Greater trochanteric pain syndrome: a review of diagnosis and management in general practice.

Greater trochanteric pain syndrome (GTPS) is a common cause of lateral hip pain, seen more commonly in females between the ages of 40 and 60.1,2 GTPS is the cause of hip pain in 10–20% of patients presenting with hip pain to primary care, with an incidence of 1.8 patients per 1000 per year.1–3 Traditionally thought to be due to trochanteric bursitis, surgical, histological, and imaging studies have shown that GTPS is attributable to tendinopathy of the gluteus medius and/or minimus with or without coexisting bursal pathology.1,4,5 Abnormal hip biomechanics are hypothesised to predispose to the development of these gluteal tendinopathies. Compressive forces cause impingement of the gluteal tendons and bursa onto the greater trochanter by the iliotibial band (ITB) as the hip moves into adduction. Compressive forces are increased where there is weakness of the hip abductor muscles due to lateral pelvic tilt.6 Patients commonly present with lateral hip pain, localised to the greater trochanter, which is worse with weightbearing activities and side lying at night.1,4,7 There may be associated radiation down the lateral thigh to the knee. Pain may progressively worsen over time and be triggered or exacerbated by sudden unaccustomed exercise, falls, prolonged weightbearing, or sporting overuse (commonly long-distance running).4 This condition carries significant morbidity; pain on side lying and subsequent reduction in physical activity levels carry negative implications for …

Medial meniscus extrusion correlates with disease duration of the sudden symptomatic medial meniscus posterior root tear

IntroductionMedial meniscus posterior root tear (MMPRT) leads to abnormal biomechanics of the knee by inducing the medial meniscus extrusion (MME). However, a time-dependent increase of the MME is not fully elucidated in patients suffering from the acute MMPRT. The aim of this study was to investigate the relationships among disease duration of the MMPRT and severity of the MME. We hypothesized that MME measurement correlates with disease duration after a sudden onset of the minor traumatic MMPRT during the short-term follow-up period. Materials and methodsForty-six patients who had an accurate episode of the posteromedial painful popping were investigated. All the patients were diagnosed having a symptomatic MMPRT with magnetic resonance imaging (MRI) examinations. Absolute MME was measured using MRI scans within 12 months after painful popping events. A correlation coefficient between duration from injury to MRI examination and absolute MME was evaluated. ResultsMean absolute MME was 4.5±1.6mm (range, 1.1−8.8mm) on MRI measurements. A good correlation was observed between MME measurement and duration from injury to MRI examination (R2=0.612). The best-fit equation for predicting each value was: MME=0.014×disease duration+3.288mm. DiscussionThis study demonstrated that absolute MME increases progressively within the short duration after the onset of symptomatic MMPRT. Our results suggest that preoperative MME assessment may be important in determining disease duration and treatment strategy of the MMPRT. Level of evidenceRetrospective cohort study level IV.

Biomechanical differences between cases with suspected chronic exertional compartment syndrome and asymptomatic controls during running

Chronic exertional compartment syndrome (CECS) has been hypothesised, following clinical observations, to be the result of abnormal biomechanics predominantly at the ankle. Treatment of CECS through running re-education to correct these abnormalities has been reported to improve symptoms. However no primary research has been carried out to investigate the movement patterns of those with CECS. This study aimed to compare the running kinematics and muscle activity of cases with CECS and asymptomatic controls.20 men with bilateral symptoms of CECS of the anterior compartment and 20 asymptomatic controls participated. Barefoot and shod running 3D kinematics and muscle activity of the left and right legs; and anthropometry were compared.Cases displayed less anterior trunk lean and less anterior pelvic tilt throughout the whole gait cycle and a more upright shank inclination angle during late swing (peak mean difference 3.5°, 4.1° and 7.3° respectively). Cases demonstrated greater step length and stance time, although this was not consistent across analyses. There were no consistent differences in Tibialis anterior or Gastrocnemius medialis muscle activity. Cases were heavier (mean difference 7.9kg, p=0.02) than controls with no differences in height (p>0.05)These differences only partially match the clinical observations previously described. However, no consistent differences were found at the ankle joint suggesting that current running re-education interventions which focus on adjusting ankle kinematics are not modifying pathological aspects of gait. The longer step length is a continuing theme in this population and as such may be a key component in the development of CECS.

Increased Femoral Anteversion Related Biomechanical Abnormalities: Lower Extremity Functionality, Falling Frequencies and Anterior Knee and Low Back Pain

Increased femoral anteversion (IFA) is defined as forwardly rotated femoral head relative to the transcondylar knee axis which may have a potential to reduce the functional quality of adolescents. Therefore, the aim of our study was to investigate the effects of IFA on lower-extremity function, falling frequency, and fatigue onset in neurologically intact children.Does increased femoral anteversion influence lower extremity function, falling frequency and fatigue on set in healthy children?Sixty-five participants with increased femoral anteversion (IFA) and thirty-two healthy peers as control were included into the study. For the function, the lower extremity function form (LEFF) which is adapted from Lower Extremity Function Test used. Falling frequency and fatigue onset time were assessed by a Likert-type scale. In addition, the activities which cause frequently fall for the participants were questioned.Results: Lower extremity function was found deteriorated (p= 0.02) and falling frequency was higher (p = 0.00) in IFA than in controls. Fatigue onset time was not different between groups, although lower extremity function was strongly correlated with fatigue onset (rho = –0.537, p < 0.001). IFA children fall four times more during running (60%), three times more during fast walking (21.42%) than their healthy peers (14.28%, 7.14% respectively).IFA leads functional problems, especially in the form of high falling frequencies. According to the LEFF score, the most difficult functional parameters for these children were walking long distances, becoming tired, walking more than a mile, and standing on one spot. Also, shorter fatigue onset time may worsen the lower-extremity function secondarily. Because of the higher frequency of falling and functional problems, children with IFA may be more defenseless to injuries, especially in high-motor-skill activities such as running and soccer.

P19: Increased femoral anteversion related biomechanical abnormalities: Gait and hyper mobility

We consider two-player zero-sum games with infinite action spaces and bounded payoff functions. The players' strategies are finitely additive probability measures, called charges. Since a strategy profile does not always induce a unique expected payoff, we distinguish two extreme attitudes of players. A player is viewed as pessimistic if he always evaluates the range of possible expected payoffs by the worst one, and a player is viewed as optimistic if he always evaluates it by the best one. This approach results in a definition of a pessimistic and an optimistic guarantee level for each player. We provide an extensive analysis of the relation between these guarantee levels, and connect them to the classical guarantee levels, and to other known techniques to define expected payoffs, based on computation of double integrals. In addition, we also examine existence of optimal strategies with respect to these guarantee levels.

P38: Increased Femoral anteversion related biomechanical abnormalities: Hypermobility, foot posture and pressure

P38: Increased Femoral anteversion related biomechanical abnormalities: Hypermobility, foot posture and pressure

Kinematic repeatability of a multi-segment foot model for dance

The purpose of this study was to determine the intra and inter-assessor repeatability of a modified Rizzoli Foot Model for analysing the foot kinematics of ballet dancers. Six university-level ballet dancers performed the movements; parallel stance, turnout plié, turnout stance, turnout rise and flex-point-flex. The three-dimensional (3D) position of individual reflective markers and marker triads was used to model the movement of the dancers’ tibia, entire foot, hindfoot, midfoot, forefoot and hallux. Intra and inter-assessor reliability demonstrated excellent (ICC ≥ 0.75) repeatability for the first metatarsophalangeal joint in the sagittal plane. Intra-assessor reliability demonstrated excellent (ICC ≥ 0.75) repeatability during flex-point-flex across all inter-segmental angles except for the tibia-hindfoot and hindfoot-midfoot frontal planes. Inter-assessor repeatability ranged from poor to excellent (0.5 > ICC ≥ 0.75) for the 3D segment rotations. The most repeatable measure was the tibia-foot dorsiflexion/plantar flexion articulation whereas the least repeatable measure was the hindfoot-midfoot adduction/abduction articulation. The variation found in the inter-assessor results is likely due to inconsistencies in marker placement. This 3D dance specific multi-segment foot model provides insight into which kinematic measures can be reliably used to ascertain in vivo technical errors and/or biomechanical abnormalities in a dancer’s foot motion.

Increased femoral anteversion related biomechanical abnormalities: Posture and trunk symmetry

Increased femoral anteversion related biomechanical abnormalities: Posture and trunk symmetry

Effect of treatment by lymphatic osteopathy on an athlete suffering from medial tibial stress syndrome: Case Report

Medial tibial stress syndrome (MTSS) is an exercise-induced, localized pain along the distal two thirds of the posterior-medial tibia and can be a debilitating injury in runners. In studies of recreational runners, MTSS has been reported as the second most frequently diagnosed injury. It is an inflammation of the periosteum or muscle from overuse. The cause of this condition is due to many factors including training errors and biomechanical abnormalities. This case study explores the role of Lymphatic osteopathy in a runner suffering from MTSS.

Bracing of the Reconstructed and Osteoarthritic Knee during High Dynamic Load Tasks.

Lateral compartment osteoarthritis accompanied by abnormal knee biomechanics is frequently reported in individuals with knee osteoarthritis after anterior cruciate ligament reconstruction (ACLR). The aim of this study was to evaluate changes in knee biomechanics produced by an adjusted and unadjusted varus knee brace during high dynamic loading activities in individuals with lateral knee osteoarthritis after ACLR and valgus malalignment. Nineteen participants who had undergone ACLR 5 to 20 yr previously and had symptomatic and radiographic lateral knee osteoarthritis with valgus malalignment were assessed. Quantitative motion analysis experiments were conducted during hopping, stair ascent, and descent under three test conditions: (i) no brace, (ii) unadjusted brace with sagittal plane support and neutral frontal plane alignment, and (iii) adjusted brace with sagittal plane support and varus realignment (valgus to neutral). Sagittal, frontal, and transverse plane knee kinematics, external joint moment, and angular impulse data were calculated. Relative to an unbraced knee, braced conditions significantly increased knee flexion and adduction angles during hopping (P = 0.003 and P = 0.005; respectively), stair ascent (P = 0.003 and P < 0.001, respectively), and descent (P = 0.009 and P < 0.001, respectively). In addition, the brace conditions increased knee flexion (P < 0.001) and adduction (P = 0.001) angular impulses and knee stiffness (P < 0.001) during hopping, as well as increased knee adduction moments during stair ascent (P = 0.008) and flexion moments during stair descent (P = 0.006). There were no significant differences between the adjusted and the unadjusted brace conditions (P > 0.05). A knee brace, with or without varus alignment, can modulate knee kinematics and external joint moments during hopping, stairs ascent, and descent in individuals with predominant lateral knee osteoarthritis after ACLR. Longer-term use of a brace may have implications in slowing osteoarthritis progression.

The test retest reliability of gait outcomes in subjects with anterior knee pain

IntroductionAnterior knee pain (AKP) is a common condition frequently causing young, athletic patients to attend sports rehabilitation centres. Abnormal biomechanics are thought to contribute towards the development and chronicity of the condition. Gait analysis is commonly used to identify abnormal biomechanics in subjects with AKP, however the reliability of these measurements are unknown. Therefore, the aim of this study was to quantify the test retest reliability of hip, knee and ankle kinematics during gait in an AKP population so the true effects of an intervention can be established. MethodsThirty-one subjects with AKP attended the 3D Motion Analysis Laboratory at Tygerberg Medical Campus of Stellenbosch University in Cape Town, South Africa, for gait analysis. Participants returned seven days later at approximately the same time to repeat the gait analysis assessment from day one. The same assessor tested all subjects on both occasions. The intra-class correlation coefficients (ICC) and standard error of measurement (SEM) were calculated for hip, knee and ankle kinematic outcomes on the affected side and used for analysis. ResultsAll outcomes obtained were acceptable to excellent test retest reliability scores for both measures of relative reliability (ICC = 0.78–0.9) and measures of absolute reliability (SEM = 0.94–4.2°). Hip frontal plane and ankle sagittal plane outcomes were the most reliable and had the lowest measurement error. Hip transverse plane outcomes were least reliable and demonstrated the highest measurement error. ConclusionHip, knee and ankle kinematic factors that are commonly associated with AKP can be measured reliably using gait analysis. Daily and weekly variation in symptoms in an AKP population may influence the reliability of knee sagittal plane outcomes. Therefore, it is important to document factors that could influence the kinematics such as pain, activity levels and the use of pain medication.