Displaying publications 41 - 60 of 249 in total

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  1. Fulltext Evaluation of limb load asymmetry using two new mathematical models
    Kumar SN, Omar B, Joseph LH, Htwe O, Jagannathan K, Hamdan NM, et al.
    Glob J Health Sci, 2015;7(2):1-7.
    PMID: 25716372 DOI: 10.5539/gjhs.v7n2p1
    Quantitative measurement of limb loading is important in orthopedic and neurological rehabilitation. In current practice, mathematical models such as Symmetry index (SI), Symmetry ratio (SR), and Symmetry angle (SA) are used to quantify limb loading asymmetry. Literatures have identified certain limitations with the above mathematical models. Hence this study presents two new mathematical models Modified symmetry index (MSI) and Limb loading error (LLE) that would address these limitations. Furthermore, the current mathematical models were compared against the new model with the goal of achieving a better model. This study uses hypothetical data to simulate an algorithmic preliminary computational measure to perform with all numerical possibilities of even and uneven limb loading that can occur in human legs. Descriptive statistics are used to interpret the limb loading patterns: symmetry, asymmetry and maximum asymmetry. The five mathematical models were similar in analyzing symmetry between limbs. However, for asymmetry and maximum asymmetry data, the SA and SR values do not give any meaningful interpretation, and SI gives an inflated value. The MSI and LLE are direct, easy to interpret and identify the loading patterns with the side of asymmetry. The new models are notable as they quantify the amount and side of asymmetry under different loading patterns.
    Matched MeSH terms: Biomechanical Phenomena
  2. Hybrid markerless tracking of complex articulated motion in golf swings
    Fung SK, Sundaraj K, Ahamed NU, Kiang LC, Nadarajah S, Sahayadhas A, et al.
    J Bodyw Mov Ther, 2014 Apr;18(2):220-7.
    PMID: 24725790 DOI: 10.1016/j.jbmt.2013.05.011
    Sports video tracking is a research topic that has attained increasing attention due to its high commercial potential. A number of sports, including tennis, soccer, gymnastics, running, golf, badminton and cricket have been utilised to display the novel ideas in sports motion tracking. The main challenge associated with this research concerns the extraction of a highly complex articulated motion from a video scene. Our research focuses on the development of a markerless human motion tracking system that tracks the major body parts of an athlete straight from a sports broadcast video. We proposed a hybrid tracking method, which consists of a combination of three algorithms (pyramidal Lucas-Kanade optical flow (LK), normalised correlation-based template matching and background subtraction), to track the golfer's head, body, hands, shoulders, knees and feet during a full swing. We then match, track and map the results onto a 2D articulated human stick model to represent the pose of the golfer over time. Our work was tested using two video broadcasts of a golfer, and we obtained satisfactory results. The current outcomes of this research can play an important role in enhancing the performance of a golfer, provide vital information to sports medicine practitioners by providing technically sound guidance on movements and should assist to diminish the risk of golfing injuries.
    Matched MeSH terms: Biomechanical Phenomena
  3. Intrarater test-retest reliability of static and dynamic stability indexes measurement using the Biodex Stability System during unilateral stance
    Arifin N, Abu Osman NA, Wan Abas WA
    J Appl Biomech, 2014 Apr;30(2):300-4.
    PMID: 23878204 DOI: 10.1123/jab.2013-0130
    The measurements of postural balance often involve measurement error, which affects the analysis and interpretation of the outcomes. In most of the existing clinical rehabilitation research, the ability to produce reliable measures is a prerequisite for an accurate assessment of an intervention after a period of time. Although clinical balance assessment has been performed in previous study, none has determined the intrarater test-retest reliability of static and dynamic stability indexes during dominant single stance. In this study, one rater examined 20 healthy university students (female=12, male=8) in two sessions separated by 7 day intervals. Three stability indexes--the overall stability index (OSI), anterior/posterior stability index (APSI), and medial/ lateral stability index (MLSI) in static and dynamic conditions--were measured during single dominant stance. Intraclass correlation coefficient (ICC), standard error measurement (SEM) and 95% confidence interval (95% CI) were calculated. Test-retest ICCs for OSI, APSI, and MLSI were 0.85, 0.78, and 0.84 during static condition and were 0.77, 0.77, and 0.65 during dynamic condition, respectively. We concluded that the postural stability assessment using Biodex stability system demonstrates good-to-excellent test-retest reliability over a 1 week time interval.
    Matched MeSH terms: Biomechanical Phenomena
  4. Kinetic asymmetries during running in male youth
    Rumpf MC, Cronin JB, Mohamad IN, Mohamad S, Oliver JL, Hughes MG
    Phys Ther Sport, 2014 Feb;15(1):53-7.
    PMID: 23850007 DOI: 10.1016/j.ptsp.2013.03.001
    A possible injury risk factor is limb asymmetry, which may differ across maturation given the adult growth spurt. The aim of this study is to quantify the magnitude of asymmetry in a number of kinetic variables during a running task in male youth of different maturity status.
    Matched MeSH terms: Biomechanical Phenomena
  5. The nonlinear elastic and viscoelastic passive properties of left ventricular papillary muscle of a guinea pig heart
    Hassan MA, Hamdi M, Noma A
    J Mech Behav Biomed Mater, 2012 Jan;5(1):99-109.
    PMID: 22100084 DOI: 10.1016/j.jmbbm.2011.08.011
    The mechanical behavior of the heart muscle tissues is the central problem in finite element simulation of the heart contraction, excitation propagation and development of an artificial heart. Nonlinear elastic and viscoelastic passive material properties of the left ventricular papillary muscle of a guinea pig heart were determined based on in-vitro precise uniaxial and relaxation tests. The nonlinear elastic behavior was modeled by a hypoelastic model and different hyperelastic strain energy functions such as Ogden and Mooney-Rivlin. Nonlinear least square fitting and constrained optimization were conducted under MATLAB and MSC.MARC in order to obtain the model material parameters. The experimental tensile data was used to get the nonlinear elastic mechanical behavior of the heart muscle. However, stress relaxation data was used to determine the relaxation behavior as well as viscosity of the tissues. Viscohyperelastic behavior was constructed by a multiplicative decomposition of a standard Ogden strain energy function, W, for instantaneous deformation and a relaxation function, R(t), in a Prony series form. The study reveals that hypoelastic and hyperelastic (Ogden) models fit the tissue mechanical behaviors well and can be safely used for heart mechanics simulation. Since the characteristic relaxation time (900 s) of heart muscle tissues is very large compared with the actual time of heart beating cycle (800 ms), the effect of viscosity can be reasonably ignored. The amount and type of experimental data has a strong effect on the Ogden parameters. The in vitro passive mechanical properties are good initial values to start running the biosimulation codes for heart mechanics. However, an optimization algorithm is developed, based on clinical intact heart measurements, to estimate and re-correct the material parameters in order to get the in vivo mechanical properties, needed for very accurate bio-simulation and for the development of new materials for the artificial heart.
    Matched MeSH terms: Biomechanical Phenomena
  6. Effect of pubertal developmental stages and lower limb kinetics during vertical jump task in Sepak Takraw sport
    Leonard Joseph H, Roslizawati N, Safrusahar MY, Efri NM, Das S, Baharudin O, et al.
    Clin Ter, 2009;160(5):403-7.
    PMID: 19997687
    Sepak Takraw is a sport which actively involves the lower limb. A cross sectional study was performed to investigate the lower limb kinetics (ground reaction force, flight time and contact time) involved during the vertical jumping and landing task between the early pubertal and late pubertal stages in National level Sepak Takraw athletes in Malaysia. Twenty athletes (8 pre pubertal and 12 late pubertal) with no previous history of any physical injuries were taken for the study. The kinetics data of the vertical jump task was calculated using a force platform 3-AMTI Biomechanics Force Platform. The Silicon ProCoach (Chart 5 software) was used to collect the ground reaction force signals, flight time and contact time. The results showed a non-significant decrease in peak ground reaction force in the post pubertal group as compared to the pre pubertal group (t(18)=0.659, p=0.518,CI(95)(-2.54, 4.86). Comparison of flight time between the two age groups showed a significant increase in the post pubertal group with mean and SD (0.7773 + or - 0.03) as compared to the pre pubertal group mean and SD (0.7296 + or - 0.05), which was statistically considered significant (p<0.05) (t(18)=-2.401, p<0.05,CI(95)(-0.089, -0.005). The findings from this study demonstrated that the flight time of the vertical jump task differed between the pre and post pubertal athletes with the post pubertal group having an improved ability in maintaining longer duration of flight phase.
    Matched MeSH terms: Biomechanical Phenomena
  7. Investigation on mechanical properties of contemporary metallic bone plates: towards the development of composite bone plates
    Hoque ME, Zainal NH, Syarif J
    Med J Malaysia, 2008 Jul;63 Suppl A:91-2.
    PMID: 19024999
    This study aims at investigating the mechanical properties of the contemporary metallic bone plates determining the effect of their length, width and thickness on the properties and compares with the composite bone plates. Three-points bending test was performed over the stainless steel plates of different length, width and thickness. The test results showed that different plates had different mechanical properties. However, the properties are still much higher than that of particular bones intended to be treated. Therefore, the reported findings strongly encourage developing composite bone plates with biocompatible polymers/fibers that would have modulated properties according to the requirements.
    Matched MeSH terms: Biomechanical Phenomena
  8. Anatomico-radiological study of asymmetrical articular facets on occipital condyles and its clinical implications
    Das S, Chaudhuri JD
    Kathmandu Univ Med J (KUMJ), 2008 Apr-Jun;6(2):217-9.
    PMID: 18769090
    The articular facets on the inferior aspect of the occipital condyles, articulate with the superior articular facets of the first cervical (atlas) vertebra, to form the atlanto-occipital joint. The present case, reports the asymmetrical dimensions of the facets on the occipital condyles of a human dried skull. The anatomico-radiological study of asymmetrical articular facets on the occipital condyles, may be helpful for academicians, neuro-surgeons, clinicians and radiologists in day to day clinical practice.
    Matched MeSH terms: Biomechanical Phenomena
  9. Fulltext The HUKM Spinal Instrumentation System for adolescent idiopathic scoliosis. A biomechanical comparison study using finite element analysis
    Azlan AM, Mohammad AR, Ariffin AK
    Med J Malaysia, 2005 Jul;60 Suppl C:30-4.
    PMID: 16381280 MyJurnal
    This finite element analysis is aimed at comparing relative stiffness of three different posterior instrumentation constructs: the Hospital Universiti Kebangsaan Malaysia Spinal Instrumentation System (HUKM-SIS), the Cotrell-Dubousset Instrumentation (CDI) and Harrington Instrumentation System (HIS), used in the treatment of adolescent idiopathic scoliosis (AIS). The constructs were tested under various loads using MSC Patran 2001 r2a. Under increasing flexion loads, there was a linearly corresponding increase in deflection magnitudes for all constructs on the load-deflection curve. The CDI was the stiffest construct under axial, forward flexion and extension loads, followed by the HUKM-SIS and HIS. Under lateral bending loads, the HUKM-SIS construct was the stiffest followed by CDI and HIS. The HUKM-SIS construct was stiffer than HIS under torsional loads. We conclude that multiple pedicle screws increase the stiffness of posterior instrumentation constructs under all loads and inter-segmental spinous processes wiring increase the stiffness against lateral bending.
    Matched MeSH terms: Biomechanical Phenomena
  10. Stress stabilisation behaviours in skin under small tensile loads in vitro
    Wan Abas WA
    Biomed Mater Eng, 1995;5(2):59-63.
    PMID: 7655319
    The response of human skin to "stress relaxation" tests at low loads in vitro was investigated. A number of behaviours, other than those already well established and documented, were observed. The significant behaviours are pure recovery and relaxation-recovery. Other behaviours observed are temporary stress recovery during the relaxation process, and momentary sudden non-linear drop in stress value followed by a second relaxation. The pure recovery and relaxation-recovery responses are repeatable. The latter represents the transitional response between the well-known behaviour of stress relaxation and the behaviour of stress recovery.
    Matched MeSH terms: Biomechanical Phenomena
  11. Fulltext Flex Sensor Compensator via Hammerstein-Wiener Modeling Approach for Improved Dynamic Goniometry and Constrained Control of a Bionic Hand
    Syed Mubarak Ali SAA, Ahmad NS, Goh P
    Sensors (Basel), 2019 Sep 10;19(18).
    PMID: 31509987 DOI: 10.3390/s19183896
    In this paper, a new control-centric approach is introduced to model the characteristics of flex sensors on a goniometric glove, which is designed to capture the user hand gesture that can be used to wirelessly control a bionic hand. The main technique employs the inverse dynamic model strategy along with a black-box identification for the compensator design, which is aimed to provide an approximate linear mapping between the raw sensor output and the dynamic finger goniometry. To smoothly recover the goniometry on the bionic hand's side during the wireless transmission, the compensator is restructured into a Hammerstein-Wiener model, which consists of a linear dynamic system and two static nonlinearities. A series of real-time experiments involving several hand gestures have been conducted to analyze the performance of the proposed method. The associated temporal and spatial gesture data from both the glove and the bionic hand are recorded, and the performance is evaluated in terms of the integral of absolute error between the glove's and the bionic hand's dynamic goniometry. The proposed method is also compared with the raw sensor data, which has been preliminarily calibrated with the finger goniometry, and the Wiener model, which is based on the initial inverse dynamic design strategy. Experimental results with several trials for each gesture show that a great improvement is obtained via the Hammerstein-Wiener compensator approach where the resulting average errors are significantly smaller than the other two methods. This concludes that the proposed strategy can remarkably improve the dynamic goniometry of the glove, and thus provides a smooth human-robot collaboration with the bionic hand.
    Matched MeSH terms: Biomechanical Phenomena
  12. Fulltext V-Shaped Bending Support helps in 3-Point Bending Test experiment for small mice bone
    Noor Shafini Mohamad, Mohd Hafizi Mahmud
    Jurnal Inovasi Malaysia, 2020;4(1):1-14.
    MyJurnal
    Three-point bending test is one of the main methods used in long bones to characterise bone material and determine the biomechanical properties. We have examined the mechanical competencies of the mouse bones at four-week-old by using a three-point bending jig so that the potential genotype-related deficiencies in mechanical properties of bones explored. The available bending jig was not suitable for small animal model and may cause slippage when applying the load. The tibial gross length measurements of the four-week-old mouse measured using the proximal anatomical point of the centre of the condyles to the distal anatomical significance of the medial malleolus (~16 mm). The mid tibia diameter measurement is taken at the middle tibia (~1 mm) and metaphyseal diameter (~3 mm). The bending jig was custom-made, where both ends support were cut in a v-shape to provide stability. The tibias were mechanically tested with the v-shape support under three-point bending using a Bose ElectroForce® 3200 until failure. The test revealed a significant result of flexural strength, work-to-fracture and strain to failure obtained from the load-displacement curves. The finding may be useful in the studies of quantitative assessments of the strength and toughness of small animal bones.
    Matched MeSH terms: Biomechanical Phenomena
  13. Fulltext Principal Component Analysis of the Running Ground Reaction Forces With Different Speeds
    Yu L, Mei Q, Xiang L, Liu W, Mohamad NI, István B, et al.
    Front Bioeng Biotechnol, 2021;9:629809.
    PMID: 33842444 DOI: 10.3389/fbioe.2021.629809
    Ground reaction force (GRF) is a key metric in biomechanical research, including parameters of loading rate (LR), first impact peak, second impact peak, and transient between first and second impact peaks in heel strike runners. The GRFs vary over time during stance. This study was aimed to investigate the variances of GRFs in rearfoot striking runners across incremental speeds. Thirty female and male runners joined the running tests on the instrumented treadmill with speeds of 2.7, 3.0, 3.3, and 3.7 m/s. The discrete parameters of vertical average loading rate in the current study are consistent with the literature findings. The principal component analysis was modeled to investigate the main variances (95%) in the GRFs over stance. The females varied in the magnitude of braking and propulsive forces (PC1, 84.93%), whereas the male runners varied in the timing of propulsion (PC1, 53.38%). The female runners dominantly varied in the transient between the first and second peaks of vertical GRF (PC1, 36.52%) and LR (PC2, 33.76%), whereas the males variated in the LR and second peak of vertical GRF (PC1, 78.69%). Knowledge reported in the current study suggested the difference of the magnitude and patterns of GRF between male and female runners across different speeds. These findings may have implications for the prevention of sex-specific running-related injuries and could be integrated with wearable signals for the in-field prediction and estimation of impact loadings and GRFs.
    Matched MeSH terms: Biomechanical Phenomena
  14. Fulltext Friction Performance of Aged T-BFRP Composite for Bearing Applications
    Nirmal U
    Polymers (Basel), 2018 Sep 25;10(10).
    PMID: 30960991 DOI: 10.3390/polym10101066
    The current work is an attempt to reduce friction coefficient of the treated betelnut fibre reinforced polyester (T-BFRP) composites by aging them in twelve different solutions with different kinematic viscosities. The test will be performed on a pin on disc (POD) wear test rig using different applied loads (5⁻30 N), different sliding distances (0⁻6.72 km) at sliding speed of 2.8 m/s subjected to a smooth stainless steel counterface (AISI-304). Different orientations of the fibre mats such as anti-parallel (AP) and parallel (P) orientations subjected to the rotating counterface will be considered. The worn surfaces were examined through optical microscopy imaging and it was found that the aged specimens had significantly lower damages as compared to neat polyester (NP) and the unaged samples. Besides, P-O samples revealed lower friction coefficients as compared to AP-O, i.e., reduction was about 24.71%. Interestingly, aging solutions with lower kinematic viscosities revealed lower friction coefficients of the aged T-BFRP composites when compared to the ones aged in higher kinematic viscosities.
    Matched MeSH terms: Biomechanical Phenomena
  15. Effects of Running Surface Stiffness on Three-Segment Foot Kinematics Responses with Different Shod Conditions
    Abdul Yamin NAA, Basaruddin KS, Salleh AF, Salim MS, Wan Muhamad WZA
    Appl Bionics Biomech, 2021;2021:8842591.
    PMID: 33603827 DOI: 10.1155/2021/8842591
    Objective: The aim of this study was to investigate the effects of surface stiffness on multisegment foot kinematics and temporal parameters during running.

    Methods: Eighteen male subjects ran on three different surfaces (i.e., concrete, artificial grass, and rubber) in both heeled running shoes (HS) and minimal running shoes (MS). Both these shoes had dissimilar sole profiles. The heeled shoes had a higher sole at the heel, a thick base, and arch support, whereas the minimal shoes had a flat base sole. Indeed, the studied biomechanical parameters responded differently in the different footwear during running. Subjects ran in recreational mode speed while 3D foot kinematics (i.e., joint rotation and peak medial longitudinal arch (MLA) angle) were determined using a motion capture system (Qualysis, Gothenburg, Sweden). Information on stance time and plantar fascia strain (PFS) was also collected.

    Results: Running on different surface stiffness was found to significantly affect the peak MLA angles and stance times for both HS and MS conditions. However, the results showed that the joint rotation angles were not sensitive to surface stiffness. Also, PFS showed no relationship with surface stiffness, as the results were varied as the surface stiffness was changed.

    Conclusion: The surface stiffness significantly contributed towards the effects of peak MLA angle and stance time. These findings may enhance the understanding of biomechanical responses on various running surfaces stiffness in different shoe conditions.

    Matched MeSH terms: Biomechanical Phenomena
  16. Fulltext Comparison of lower limb kinematics during early and late phases of 2km time trial on stationary rowing ergometer among male national rowers
    Amirah Zahiran, Fara Liana Zainuddin, Shazlin Shaharudin
    Malaysian Journal of Medicine and Health Sciences, 2020;16(3):3-7.
    MyJurnal
    Introduction: In this study, we evaluated the kinematics of lower limb during early and late phases of 2km time trial on stationary rowing ergometer among Malaysian male rowers. Methods: Seventeen national-level rowers voluntari- ly participated. Three dimensional lower limb kinematics data were collected to represent the first 400 m (i.e., early) and the last 400m (i.e., late) phases of 2km time trial on a stationary ergometer. The kinematics data at sagittal, frontal and transverse planes of dominant leg during catch and finish positions were compared across early and late phases of the time trial using paired T-test. Results: The kinematics of lower limb joints at three planes were not significantly different during early versus late phases of 2km time trial among male senior rowers except for hip flexion at finish (p=0.411), ankle rotation at catch (p=0.779) and ankle abduction at finish (p=0.677). Conclusion: Lower limb kine- matics particularly the hip flexion, ankle rotation and ankle abduction may change across early and late phases of 2km time trial due to fatigue. Coaches and rowers should monitor these motions during fatiguing rowing piece and develop necessary injury prevention measures.
    Matched MeSH terms: Biomechanical Phenomena
  17. A preliminary investigation on upper limb exoskeleton assistance for simulated agricultural tasks
    Harith HH, Mohd MF, Nai Sowat S
    Appl Ergon, 2021 Sep;95:103455.
    PMID: 33991852 DOI: 10.1016/j.apergo.2021.103455
    Manual harvesting is still prevalent in the agricultural industry. Accordingly, it is one of the largest contributors toward work-related musculoskeletal disorder. The cutting task in oil palm harvesting uses a long pole and involves repetitive and forceful motion of the upper limbs. Exoskeleton technology is increasingly explored to assist manual tasks performance in manufacturing and heavy industries, mainly for reducing discomfort and injuries, and improving productivity. This paper reports an initial investigation on the feasibility of using an upper limb exoskeleton to assist oil palm harvesting tasks. Previous studies highlighted that exoskeletons for agricultural activities should be adaptable to changing field tasks, tools and equipment. The immediate difference in the activity of three muscles were analyzed for a range of harvesting-simulated tasks. Lower activities were observed for tasks involving overhead work when using the prototype. Nevertheless, users' feedback highlighted that its design should be optimized for better acceptance.
    Matched MeSH terms: Biomechanical Phenomena
  18. An exploratory investigation of patellofemoral joint loadings during directional lunges in badminton
    Yu L, Mei Q, Mohamad NI, Gu Y, Fernandez J
    Comput Biol Med, 2021 05;132:104302.
    PMID: 33677166 DOI: 10.1016/j.compbiomed.2021.104302
    Anterior knee pain is a commonly documented musculoskeletal disorder among badminton players. However, current biomechanical studies of badminton lunges mainly report kinetic profiles in the lower extremity with few investigations of in-vivo loadings. The objective of this study was to evaluate tissue loadings in the patellofemoral joint via musculoskeletal modelling and Finite Element simulation. The collected marker trajectories, ground reaction force and muscle activation data were used for musculoskeletal modelling to compute knee joint angles and quadricep muscle forces. These parameters were then set as boundary conditions and loads for a quasistatic simulation using the Abaqus Explicit solver. Simulations revealed that the left-forward (LF) and backward lunges showed greater contact pressure (14.98-29.61%) and von Mises stress (14.17-32.02%) than the right-forward and backward lunges; while, loadings in the left-backward lunge were greater than the left-forward lunge by 13-14%. Specifically, the stress in the chondral layer was greater than the contact interface, particularly in the patellar cartilage. These findings suggest that right-side dominant badminton players load higher in the right patellofemoral joint during left-side (backhand) lunges. Knowledge of these tissue loadings may provide implications for the training of badminton footwork, such as musculature development, to reduce cartilage loading accumulation, and prevent anterior knee pain.
    Matched MeSH terms: Biomechanical Phenomena
  19. The effect of asymmetrical gait induced by unilateral knee brace on the knee flexor and extensor muscles
    Yap YT, Gouwanda D, Gopalai AA, Chong YZ
    Med Biol Eng Comput, 2021 Mar;59(3):711-720.
    PMID: 33625670 DOI: 10.1007/s11517-021-02337-7
    Asymmetrical stiff knee gait is a mechanical pathology that can disrupt lower extremity muscle coordination. A better understanding of this condition can help identify potential complications. This study proposes the use of dynamic musculoskeletal modelling simulation to investigate the effect of induced mechanical perturbation on the kneeand to examine the muscle behaviour without invasive technique. Thirty-eight healthy participants were recruited. Asymmetrical gait was simulated using knee brace. Knee joint angle, joint moment and knee flexor and extensor muscle forces were computed using OpenSim. Differences inmuscle force between normal and abnormal conditions were investigated using ANOVA and Tukey-Kramer multiple comparison test.The results revealed that braced knee experienced limited range of motion with smaller flexion moment occuring at late swing phase. Significant differences were found in all flexormuscle forces and in several extensor muscle forces (p<0.05). Normal knee produced larger flexor muscle force than braced knee. Braced knee generated the largest extensor muscle force at early swing phase. In summary, musculoskeletal modelling simulation can be a computational tool to map and detect the differences between normal and asymmetrical gaits.
    Matched MeSH terms: Biomechanical Phenomena
  20. Fulltext Impact of Bone Cement Augmentation on the Fixation Strength of TFNA Blades and Screws
    Sermon A, Hofmann-Fliri L, Zderic I, Agarwal Y, Scherrer S, Weber A, et al.
    Medicina (Kaunas), 2021 Aug 28;57(9).
    PMID: 34577822 DOI: 10.3390/medicina57090899
    Background and Objectives: Hip fractures constitute the most debilitating complication of osteoporosis with steadily increasing incidences in the aging population. Their intramedullary nailing can be challenging because of poor anchorage in the osteoporotic femoral head. Cement augmentation of Proximal Femoral Nail Antirotation (PFNA) blades demonstrated promising results by enhancing cut-out resistance in proximal femoral fractures. The aim of this study was to assess the impact of augmentation on the fixation strength of TFN-ADVANCEDTM Proximal Femoral Nailing System (TFNA) blades and screws within the femoral head and compare its effect when they are implanted in centre or anteroposterior off-centre position. Materials and Methods: Eight groups were formed out of 96 polyurethane low-density foam specimens simulating isolated femoral heads with poor bone quality. The specimens in each group were implanted with either non-augmented or cement-augmented TFNA blades or screws in centre or anteroposterior off-centre positions, 7 mm anterior or posterior. Mechanical testing was performed under progressively increasing cyclic loading until failure, in setup simulating an unstable pertrochanteric fracture with a lack of posteromedial support and load sharing at the fracture gap. Varus-valgus and head rotation angles were monitored. A varus collapse of 5° or 10° head rotation was defined as a clinically relevant failure. Results: Failure load (N) for specimens with augmented TFNA head elements (screw/blade centre: 3799 ± 326/3228 ± 478; screw/blade off-centre: 2680 ± 182/2591 ± 244) was significantly higher compared with respective non-augmented specimens (screw/blade centre: 1593 ± 120/1489 ± 41; screw/blade off-centre: 515 ± 73/1018 ± 48), p < 0.001. For both non-augmented and augmented specimens failure load in the centre position was significantly higher compared with the respective off-centre positions, regardless of the head element type, p < 0.001. Augmented off-centre TFNA head elements had significantly higher failure load compared with non-augmented centrally placed implants, p < 0.001. Conclusions: Cement augmentation clearly enhances the fixation stability of TFNA blades and screws. Non-augmented blades outperformed screws in the anteroposterior off-centre position. Positioning of TFNA blades in the femoral head is more forgiving than TFNA screws in terms of failure load.
    Matched MeSH terms: Biomechanical Phenomena
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