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Fulltext Finite element modelling and simulation for lower limb of human bone: a review

Muhammad Hanif Ramlee

Malaysian Journal of Medicine and Health Sciences, 2020;16(3):262-271.
MyJurnal

Most orthopaedic cases that involved with bone fracture are normally treated with medical implants. To be noticed that some precautions in terms of biomechanical and biomaterial properties are necessary for a successful post-sur- gery process. The biomechanical evaluation of implants could be carried out using computing and engineering technologies. However, in the computer simulation, some assumptions are needed as the limitations on computer resources and data input. This review focuses on the current method of developing the finite element model for patients with specific values of material properties for lower limb part such as hip, knee and ankle joint. Previous literature was reviewed from which keywords and search engines were identified. In this review, inclusion and exclusion criteria were used to limit the literature search. We reviewed the state-of-the-art in this area and provide recommendations for future research. In conclusion, the previous published reports illustrated different methods to develop numerical models.
Energy, exergy and efficiency analysis of a flat plate solar collector used as air heater

Maazullah Khan, Abdurab, Muhammad Hanif, Mansoor Khan Khattak, Muhammad Ramzan

Sains Malaysiana, 2018;47:1061-1067.

Air heating by solar collectors is renewable technology providing hot air for different purposes. The present research
emphasizes on analysis of energy, exergy and efficiency of a flat plate solar air heater. The analysis model was tested
on five different air mass flow rates of 0.5 (Natural), 1.31, 2.11, 2.72 and 3.03 kgs-1 under three different tilt angles of
25, 35 (Recommended) and 50o
. The data was replicated three times making a total of 45 treatments. A two factorial
completely randomized design was used to find if there is any significant difference among the treatments. The results
showed that the solar collector gave better performance at air mass flow of 3.03 kgs-1 under tilt of 35o
. At maximum
air mass flow rate of 3.03 kgs-1and optimum tilt angle of 35o
the maximum energetic efficiency of 51%, while minimum
exergetic efficiency of 24% and maximum overall efficiency of 71% were recorded. It was concluded that to get maximum
thermal efficiencies of 71% from flat plate solar collector used as an air heater must be operated at high air mass flow
rates of 3.03 kgs-1under 35o
tilt angle at Peshawar, Pakistan.
Processing and properties optimisation of carbon nanofibre-reinforced magnesium composites for biomedical applications

Tuminoh H, Hermawan H, Ramlee MH

J Mech Behav Biomed Mater, 2022 Nov;135:105457.
PMID: 36116340 DOI: 10.1016/j.jmbbm.2022.105457

In the last decade, magnesium alloys have been considered as absorbable metals for biomedical applications, while some have reached their clinical use as temporary bone implants. However, their widespread use is still limited by its strength and degradability. One way of improvement can be done by reinforcing magnesium alloys with carbon nanofibres to form composites. This work aims at developing carbon nanofibre-reinforced magnesium-zinc (Mg-Zn/CNF) composites with optimum strength and degradability while ensuring their biocompatibility. A response surface method was used to determine their optimum process parameters (composition, compaction pressure, and sintering temperature), and analyse the resulting properties (elastic modulus, hardness, weight loss, and cytocompatibility). Results showed that the optimal parameters were reached at 1.8% of CNF, 425 MPa of compaction pressure, and 500 °C of sintering temperature, whereby it gave an elastic modulus of 5 GPa, hardness of 60 Hv, and a weight loss of 51% after three days immersion in PBS. The composites exhibited a hydrophobic surface that controlled the liberation of Mg2+ and Zn2+ ions, leading to more than 70% osteoblast cells viability up to seven days of incubation. This study can also serve as a starting point for future researchers interested in finding methods to fabricate Mg-Zn/CNF composites with high mechanical characteristics, corrosion resistance, and biocompatibility.
Fulltext Spatial-temporal pattern of mosquito-borne disease occurrence based on epidemiological data: a case study from Terengganu

Nik Muhammad Hanif Nik Abdull Halim, Nazri Che Dom, Rahmat Dapari

Malaysian Journal of Medicine and Health Sciences, 2020;16(4):153-161.
MyJurnal

Introduction: The trend of several mosquito-borne diseases in Malaysia has shown an increasing pattern over the past few years despite close monitoring and continuous control initiatives by public health authority. The objective of this study is to determine the spatial and temporal epidemiology of mosquito-borne disease in Terengganu from the year 2009 to 2018. Terengganu has been selected because it is geographically unique and experiences two monsoon seasons per year. Methods: Weekly surveillance data of mosquito-borne diseases which include dengue fever, malaria, filariasis, Japanese Encephalitis (JE) and chikungunya from 2009 to 2018 were collected from the Terengganu State Health Department. The variables included in the dataset mainly comprises of disease onset, di- agnosis, case category, area (district) and site of onset. The data has been monitored spatial and temporal in which to explore the distribution pattern of the disease. The annual average for each type of mosquito-borne disease was determined using time-series and is further analysed by using geographical information system (GIS) tools to form spatial statistical analysis. Results: Results indicate that the temporal distribution of the mosquito-borne disease in Terengganu increases slightly despite a fluctuating pattern from the year 2009 to 2018 and there are between each type of mosquito-borne disease. Spatial analysis showed different stratification between seasons as well as the areas that are more susceptible to each disease. Conclusion: The results obtained in this present study through spatial and temporal analysis revealed that mosquito-borne diseases show a dynamic pattern in distribution. It can be concluded that the occurrence of the diseases depends on the geographical area and the weather within the region. This study provides public health authorities with a comprehensive assessment that will be useful for surveillance and monitor- ing, as well as for predicting and managing mosquito-borne disease outbreaks effectively.
Fulltext Fabrication and characterization of Mg-Zn alloys reinforced with carbon nanofiber for orthopaedics implant application: a study on the different compositions

Muhammad Al Kahfi Edrus, Muhammad Sallehuddin Mohd Azman, Herman Tuminoh, Ahmad Kafrawi Nasution, Muhammad Hanif Ramlee

Malaysian Journal of Medicine and Health Sciences, 2020;16(4):252-258.
MyJurnal

Introduction: Biodegradable materials, such as Mg-based, Fe-based, and Zn-based, bring as much attention as bone-implant materials due to its biocompatibility and biodegradability characteristics. Among them, the Mg is the most abundant elements in human body and primarily found in the bones. However, the Mg has a lower mechanical properties and resistances to fracture compared to the other biodegradable and non-biodegradable metals. Therefore, the aim of this study was to develop a possible biodegradable material made of Mg-Zn alloys reinforced with carbon nano fiber (CNF) and later tested with several testing procedures. Methods: The powder metallurgy method (PM) was utilized to fabricate a total of 24 samples of Mg-Zn alloys reinforced with 1.0%wt, 1.2%wt, 1.4%wt, 1.6%wt, 1.8%wt and 2.0%wt of CNF. The PM method was involved with the process of grinding using ball milling, compaction under 400MPa pressure and sintered under 400 °C. Compression testing was done to measure the mechanical strength meanwhile scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) was used to identify the microstructural of samples. Results: From this study, it was found that Mg-Zn alloys with 1.6 wt% of CNF produce the highest Young's modulus (2687.91MPa) with acceptable yield strength (84.91MPa). For microstructural analysis, the results showed a compact surface for 1.2, 1.4 and 1.6 wt% of CNF and non-homogeneous structure of all the samples. Conclusion: In conclusion, this study has successfully shown the promising use of Mg-Zn-CNF composite as new materials for implant in terms of suitable strength and structure.
Fulltext Prevalence of cognitive impairment among the members of the national council of senior citizens’ Malaysia in day care centres within the Klang Valley

Sharifah Zainiyah, S.Y., Gunasegaran, M., Muhammad Hanif, M.Z., Nuramalina, N., Seow, H.C., Bharathi, V.

Malaysian Journal of Public Health Medicine, 2011;11(2):43-48.
MyJurnal

Cognitive Impairment is common in late life and may be due to the normal process of ageing, or associated with physical or mental disorder which contributes to a decrease in quality of life, neuropsychiatric symptoms, increased disability and increased healthcare cost. The aim of this study is to determine the prevalence of cognitive impairment among the elderly members in NACSCOM in Day Care Centres within the Klang Valley and its associated socio-demographic factors such as age, gender and educational level. This cross-sectional study was conducted on 101 members of NACSCOM in Day Care Centres of Damansara,Subang Jaya and Setapak using assisted questionnaires as the research tool. The questionnaire comprising of a total of 10 questions based on Elderly Cognitive Assessment Questionnaires (ECAQ), consisted of three parts, memory, orientation and recall. One correctly answered question earned the respondent one mark. The total score for ECAQ is 10 where respondents with scores of 5 and below were identified as having cognitive impairment. Data collected was analyzed using Chi-square test (SPSS version 18). The prevalence of cognitive impairment among the elderly members of NACSCOM in Day Care Centres within the Klang Valley was 4.0%. This study also showed that there was no statistically significant association between cognitive impairment and sociodemographic factors such as age, gender and education. Prevalence of cognitive impairment among the members of NACSCOM in Day Care Centres within the Klang Valley was found to be low. This could be attributed to the fact that members actively participated in activities organized by NACSCOM. The study also did not find any statistically significant association between cognitive impairment and age, gender and education.
The effects of additional hollow cylinder coated to external fixator screws for treating pilon fracture: A biomechanical perspective

Ramlee MH, Seng GH, Ros Felip A, Abdul Kadir MR

Injury, 2021 Aug;52(8):2131-2141.
PMID: 33745700 DOI: 10.1016/j.injury.2021.03.017

An external fixator is a promising medical device that could provide optimum stability and reduce the rate of complications in treating bone fracture during intervention period. It is noted that the biomechanics behaviour of device can be altered by introducing more features such as material suitability and additional components. Therefore, this study was conducted via finite element method to investigate the effects of additional hollow cylinder coated with external fixator screws in treating Type III pilon fracture. Finite element models which have been validated with experimental data were used to simulate stresses at the pin-bone interface and relative micromovement at interfragmentary fractures during swing (70 N load) and stance phases (350 N load). All bones and external fixators were assigned with isotropic material properties while the cartilages were simulated with hyper-elastic. For the hollow cylinder, polyethylene was assigned due to its properties which are equivalent to the bone. From the results, it is found that stresses at the pin-bone interface for the coated screws were reduced to 54% as compared to the conventional fixator. For the micromovement, there was no difference between both models, whereby the value was 0.03 mm. The results supported previously published literature, in which high stresses are unavoidable at the interface, fortunately, those stresses did not exceed the ultimate strength of bone, which is safe for treating patients. In conclusion, if patients are allowed to bear weight bearing, the external fixator with coated screws is a more favourable option to be fixed into the bone to avoid complications at the interface.
Finite element analysis of the wrist in stroke patients: the effects of hand grip

Ramlee MH, Beng GK, Bajuri N, Abdul Kadir MR

Med Biol Eng Comput, 2018 Jul;56(7):1161-1171.
PMID: 29209961 DOI: 10.1007/s11517-017-1762-3

The provision of the most suitable rehabilitation treatment for stroke patient remains an ongoing challenge for clinicians. Fully understanding the pathomechanics of the upper limb will allow doctors to assist patients with physiotherapy treatment that will aid in full arm recovery. A biomechanical study was therefore conducted using the finite element (FE) method. A three-dimensional (3D) model of the human wrist was reconstructed using computed tomography (CT)-scanned images. A stroke model was constructed based on pathological problems, i.e. bone density reductions, cartilage wane, and spasticity. The cartilages were reconstructed as per the articulation shapes in the joint, while the ligaments were modelled using linear links. The hand grip condition was mimicked, and the resulting biomechanical characteristics of the stroke and healthy models were compared. Due to the lower thickness of the cartilages, the stroke model reported a higher contact pressure (305 MPa), specifically at the MC1-trapezium. Contrarily, a healthy model reported a contact pressure of 228 MPa. In the context of wrist extension and displacement, the stroke model (0.68° and 5.54 mm, respectively) reported a lower magnitude than the healthy model (0.98° and 9.43 mm, respectively), which agrees with previously reported works. It was therefore concluded that clinicians should take extra care in rehabilitation treatment of wrist movement in order to prevent the occurrence of other complications. Graphical abstract ᅟ.
Finite element analysis of three commonly used external fixation devices for treating Type III pilon fractures

Ramlee MH, Kadir MR, Murali MR, Kamarul T

Med Eng Phys, 2014 Oct;36(10):1322-30.
PMID: 25127377 DOI: 10.1016/j.medengphy.2014.05.015

Pilon fractures are commonly caused by high energy trauma and can result in long-term immobilization of patients. The use of an external fixator i.e. the (1) Delta, (2) Mitkovic or (3) Unilateral frame for treating type III pilon fractures is generally recommended by many experts owing to the stability provided by these constructs. This allows this type of fracture to heal quickly whilst permitting early mobilization. However, the stability of one fixator over the other has not been previously demonstrated. This study was conducted to determine the biomechanical stability of these external fixators in type III pilon fractures using finite element modelling. Three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones were reconstructed from previously obtained CT datasets. Bones were assigned with isotropic material properties, while the cartilage was assigned as hyperelastic springs with Mooney-Rivlin properties. Axial loads of 350 N and 70 N were applied at the tibia to simulate the stance and the swing phase of a gait cycle. To prevent rigid body motion, the calcaneus and metatarsals were fixed distally in all degrees of freedom. The results indicate that the model with the Delta frame produced the lowest relative micromovement (0.03 mm) compared to the Mitkovic (0.05 mm) and Unilateral (0.42 mm) fixators during the stance phase. The highest stress concentrations were found at the pin of the Unilateral external fixator (509.2 MPa) compared to the Mitkovic (286.0 MPa) and the Delta (266.7 MPa) frames. In conclusion, the Delta external fixator was found to be the most stable external fixator for treating type III pilon fractures.
Biomechanical evaluation of two commonly used external fixators in the treatment of open subtalar dislocation--a finite element analysis

Ramlee MH, Kadir MR, Murali MR, Kamarul T

Med Eng Phys, 2014 Oct;36(10):1358-66.
PMID: 25092623 DOI: 10.1016/j.medengphy.2014.07.001

Subtalar dislocation is a rare injury caused by high-energy trauma. Current treatment strategies include leg casts, internal fixation and external fixation. Among these, external fixators are the most commonly used as this method is believed to provide better stabilization. However, the biomechanical stability provided by these fixators has not been demonstrated. This biomechanical study compares two commonly used external fixators, i.e. Mitkovic and Delta. CT imaging data were used to reconstruct three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones. The 3D models of the bones and cartilages were then converted into four-noded linear tetrahedral elements, whilst the ligaments were modelled with linear spring elements. Bones and cartilage were idealized as homogeneous, isotropic and linear. To simulate loading during walking, axial loading (70 N during the swing and 350 N during the stance phase) was applied at the end of diaphyseal tibia. The results demonstrate that the Mitkovic fixator produced greater displacement (peak 3.0mm and 15.6mm) compared to the Delta fixator (peak 0.8mm and 3.9 mm), in both the swing and stance phase, respectively. This study demonstrates that the Delta external fixator provides superior stability over the Mitkovic fixator. The Delta fixator may be more effective in treating subtalar dislocation.
Fulltext Role of Pre-Synaptic NMDA Receptors in the Modulation of Inhibitory Synaptic Transmission in Sensory-Motor and Visual Cortical Pyramidal Neurons in Brain Slices of Young Epileptic Mice

Lah MHC, Reza F, Begum T, Abdullah JM

Malays J Med Sci, 2018 May;25(3):27-39.
PMID: 30899185 MyJurnal DOI: 10.21315/mjms2018.25.3.4

Background: Previous studies from animal models have shown that pre-synaptic NMDA receptors (preNMDARs) are present in the cortex, but the role of inhibition mediated by preNMDARs during epileptogenesis remains unclear. In this study, we wanted to observe the changes in GABAergic inhibition through preNMDARs in sensory-motor and visual cortical pyramidal neurons after pilocarpine-induced status epilepticus.
Methods: Using a pilocarpine-induced epileptic mouse model, sensory-motor and visual cortical slices were prepared, and the whole-cell patch clamp technique was used to record spontaneous inhibitory post-synaptic currents (sIPSCs).
Results: The primary finding was that the mean amplitude of sIPSC from the sensory-motor cortex increased significantly in epileptic mice when the recording pipette contained MK-801 compared to control mice, whereas the mean sIPSC frequency was not significantly different, indicating that post-synaptic mechanisms are involved. However, there was no significant pre-synaptic inhibition through preNMDARs in the acute brain slices from pilocarpine-induced epileptic mice.
Conclusion: In the acute case of epilepsy, a compensatory mechanism of post-synaptic inhibition, possibly from ambient GABA, was observed through changes in the amplitude without significant changes in the frequency of sIPSC compared to control mice. The role of preNMDAR-mediated inhibition in epileptogenesis during the chronic condition or in the juvenile stage warrants further investigation.
Giardia lamblia Immunoassay: Systematic review and meta-analysis

Aziz AFE, Roshidi N, Muhammad Hanif MDH, Tye GJ, Arifin N

Clin Chim Acta, 2024 Jul 15;561:119839.
PMID: 38964570 DOI: 10.1016/j.cca.2024.119839

Immunoassays are important tools in diagnosing giardiasis, though there are several controversies inherent in the existing methods. We conducted a systematic review and meta-analysis to assess the pooled diagnostic accuracy of immunoassays in detecting the gastrointestinal disease-causing parasite Giardia lamblia. Our comprehensive search, which included PubMed, Scopus, and ScienceDirect from 2000 up until 2023, resulted in 34 studies reporting the performance of 24 different immunoassays. The overall pooled sensitivity and specificity of immunoassays and subgroup analyses were determined. Notably, ImmunoCardSTAT® and RIDASCREEN® Giardia were the most used assays (n = 6 studies each). They exhibited sensitivity and specificity of 84 % and 99 % and 93 % and 99 %, respectively. Sub-group analysis on the type of immunoassays (without the case-control studies) showed that commercial ELISA had higher sensitivity (96 %) compared to a commercial immunochromatographic (88 %), which justifies the difference of sensitivity between ImmunoCardSTAT® and RIDASCREEN® Giardia. However, the applicability between these two in clinical settings, replacing the gold standard, should be considered including the time, equipment requirement, and budget. Samples from symptomatic patients showed higher sensitivity (92 %) compared to asymptomatic patients (79 %). Overall, immunoassays can be a practical replacement for the current gold standard, but more information should be gathered regarding the cost of providing more conclusive suggestions on these findings.
Fulltext Investigation on three-dimensional printed prosthetics leg sockets coated with different reinforcement materials: analysis on mechanical strength and microstructural

Ramlee MH, Ammarullah MI, Mohd Sukri NS, Faidzul Hassan NS, Baharuddin MH, Abdul Kadir MR

Sci Rep, 2024 Mar 21;14(1):6842.
PMID: 38514731 DOI: 10.1038/s41598-024-57454-8

Previous research has primarily focused on pre-processing parameters such as design, material selection, and printing techniques to improve the strength of 3D-printed prosthetic leg sockets. However, these methods fail to address the major challenges that arise post-printing, namely failures at the distal end of the socket and susceptibility to shear failure. Addressing this gap, the study aims to enhance the mechanical properties of 3D-printed prosthetic leg sockets through post-processing techniques. Fifteen PLA + prosthetic leg sockets are fabricated and reinforced with four materials: carbon fiber, carbon-Kevlar fiber, fiberglass, and cement. Mechanical and microstructural properties of the sockets are evaluated through axial compression testing and scanning electron microscopy (SEM). Results highlight superior attributes of cement-reinforced sockets, exhibiting significantly higher yield strength (up to 89.57% more than counterparts) and higher Young's modulus (up to 76.15% greater). SEM reveals correlations between microstructural properties and socket strength. These findings deepen the comprehension of 3D-printed prosthetic leg socket post-processing, presenting optimization prospects. Future research can focus on refining fabrication techniques, exploring alternative reinforcement materials, and investigating the long-term durability and functionality of post-processed 3D-printed prosthetic leg sockets.
Fulltext Seafood poisoning symptom, treatment and prevention

Yoshida, Teruaki, Zarinah Waheed, Mohd Yusof Ibrahim, Mohammad Illzam Elahee, Shahjee Hussain, Sharifa Mariam Uma Abdullah, et al.

Borneo Journal of Marine Science and Aquaculture, 2018;2(1):64-69.
MyJurnal

Food related disease or food poisoning is prevalent worldwide and is associated with high mortality. It can be caused by bacteria, viruses, parasites, enterotoxins, mycotoxins, chemicals, histamine poisoning (scombroid) ciguatera and harmful algal bloom (HAB). Illness can also result by red tide while breathing in the aerosolized brevitoxins (i.e. PbTx or Ptychodiscus toxins). Bacterial toxin food poisoning can affect within 1-6 hours and 8-16 hours, and illness can be with or without bloody diarrhea. The common symptoms of food poisoning include abdominal cramps, vomiting and diarrhea. Diagnosis includes examination of leftover food, food preparation environment, food handlers, feces, vomitus, serum and blood. Treatment involves oral rehydration, antiemetic, and anti-peristaltic drugs. Antimicrobial agents may be needed in the treatment of shigellosis, cholera, lifesaving invasive salmonellosis and typhoid fever. Proper care in handling and cooking is important to prevent any food borne diseases.
A finite element study: Finding the best configuration between unilateral, hybrid, and ilizarov in terms of biomechanical point of view

Abd Aziz AU, Abdul Wahab AH, Abdul Rahim RA, Abdul Kadir MR, Ramlee MH

Injury, 2020 Nov;51(11):2474-2478.
PMID: 32798038 DOI: 10.1016/j.injury.2020.08.001

In an open fracture, the external fixator is one of the definitive treatment options as it could provide the initial stabilisation of the fractured bone. Limited literature discussing on the biomechanical stability between unilateral, hybrid and Ilizarov configurations, principally in treating a femoral fracture. Thus, this study aims to analyse the biomechanical stability of different external fixators via the finite element method (FEM). The present study portrays that different configurations of fixators possess different biomechanical stability, hence leading to different healing rates and complication risks. For the methodology, three-dimensional models of three different external fixators were reconstructed where axial loads were applied on the proximal end of the femur, simulating the stance phase. From the results, the unilateral configuration provides better stability compared to the hybrid and Ilizarov, where it displaced the least with an average percentage difference of 50% for the fixator's frame and 23% for the bone. The unilateral configuration also produced the least interfragmentary movement (0.48 mm) as compared to hybrid (0.62 mm) and Ilizarov (0.61 mm) configurations. Besides, the strain and stress of the unilateral configuration were superior in terms of stability compared to the other two configurations. As a conclusion, the unilateral configuration had the best biomechanical stability as it was able to assist the bone healing process as well as minimising the risk of pin tract infection while treating a femoral fracture.
Biomechanical evaluation of three different configurations of external fixators for treating distal third tibia fracture: Finite element analysis in axial, bending and torsion load

Abdul Wahab AH, Wui NB, Abdul Kadir MR, Ramlee MH

Comput Biol Med, 2020 12;127:104062.
PMID: 33096298 DOI: 10.1016/j.compbiomed.2020.104062

External fixators have been widely used in treating open fractures and have produced excellent outcomes, as they could successfully heal bones. The stability of external fixators lies greatly in their construction. Factors that associated with the stability of the external fixators includes stress, displacement, and relative micromotion. Three-dimensional (3D) models of bone and external fixators were constructed by using 3D modelling software, namely Materialise and SolidWorks, respectively. Three different configurations of external fixators namely Model 1, Model 2, and Model 3 were analysed. Three load cases were simulated to assess the abovementioned factors at the bone, specifically at the fracture site and at the external fixator. Findings showed that the double-cross configuration (Model 3) was the most promising in axial, bending, and torsion load cases as compared to the other two configurations. The no-cross configuration (Model 1) had the highest risk of complication due to high stress, relative micromotion, and displacement in the bending and torsion load cases. On the other hand, the single-cross configuration (Model 2) had the highest risk of complication when applied with axial load. In conclusion, the double-cross locking construct (Model 3) showed the biggest potential to be a new option for medical surgeons in treating patients associated with bone fracture. This new double-cross locking construct showed superior biomechanical stability as compared to single-cross and no-cross configurations in the axial, bending, and torsion load cases.
Stress Distributions and Micromovement of Fragment Bone of Pilon Fracture Treated With External Fixator: A Finite Element Analysis

Ramlee MH, Gan HS, Daud SA, Abdul Wahab A, Abdul Kadir MR

J Foot Ankle Surg, 2020 7 1;59(4):664-672.
PMID: 32600559 DOI: 10.1053/j.jfas.2019.09.006

Osteoporosis and osteoarthritis are common pathological problems of the human bone tissue. There are some cases of pilon fractures associated with these 2 pathological conditions. In terms of treatment, for a normal and healthy bone with pilon fracture, the use of the Delta external fixator is a favorable option because it can allow early mobilization for patients and provide stability for the healing process. However, the stability of the external fixator differs when there is low bone stiffness, which has not been previously investigated. Therefore, this study was conducted to determine the stability of the external fixator to treat pilon fracture associated with osteoporosis and osteoarthritis, particularly to differentiate the stress distribution and micromovement of fracture fragment. Three-dimensional finite element models of the ankle and foot bones were reconstructed based on the computed tomography datasets. The bones consisted of 5 metatarsal, 3 cuneiform, and 1 each of cuboid, navicular, calcaneus, talus, fibula, and tibia bones. They were assigned with linear isotropic behavior. The ankle joint consisted of ligament and cartilage, and they were assigned with the use of linear links and the Mooney-Rivlin model, respectively. During simulation of the gait cycle, 70 N and 350 N were applied axially to the tibia bone to represent the swing and stance phases, respectively. The metatarsal and calcaneus bones were fixed to prevent any movement of the rigid body. The study found that the greatest von Mises stress value was observed at the pin-bone interface for the osteoporosis (108 MPa) model, followed by the osteoarthritis (87 MPa) and normal (44 MPa) models, during the stance phase. For micromovement, the osteoporosis model had the largest value at 0.26 mm, followed by the osteoarthritis (0.09 mm) and normal (0.03 mm) models. In conclusion, the greatest magnitudes of stress and micromovement were observed for the osteoporosis bone and extra care should be taken to treat pilon fracture associated with this pathological condition.
Biomechanical analysis of three different types of fixators for anterior cruciate ligament reconstruction via finite element method: a patient-specific study

Zainal Abidin NA, Abdul Wahab AH, Abdul Rahim RA, Abdul Kadir MR, Ramlee MH

Med Biol Eng Comput, 2021 Sep;59(9):1945-1960.
PMID: 34392448 DOI: 10.1007/s11517-021-02419-6

Complication rates of anterior cruciate ligament reconstruction (ACL-R) were reported to be around 15% although it is a common arthroscopic procedure with good outcomes. Breakage and migration of fixators are still possible even months after surgery. A fixator with optimum stability can minimise those two complications. Factors that affect the stability of a fixator are its configuration, material, and design. Thus, this paper aims to analyse the biomechanical effects of different types of fixators (cross-pin, interference screw, and cortical button) towards the stability of the knee joint after ACL-R. In this study, finite element modelling and analyses of a knee joint attached with double semitendinosus graft and fixators were carried out. Mimics and 3-Matic softwares were used in the development of the knee joint models. Meanwhile, the graft and fixators were designed by using SolidWorks software. Once the meshes of all models were finished in 3-Matic, simulation of the configurations was done using MSC Marc Mentat software. A 100-N anterior tibial load was applied onto the tibia to simulate the anterior drawer test. Based on the findings, cross-pin was found to have optimum stability in terms of stress and strain at the femoral fixation site for better treatment of ACL-R.
Biomechanical features of six design of the delta external fixator for treating Pilon fracture: a finite element study

Ramlee MH, Sulong MA, Garcia-Nieto E, Penaranda DA, Felip AR, Kadir MRA

Med Biol Eng Comput, 2018 Oct;56(10):1925-1938.
PMID: 29679256 DOI: 10.1007/s11517-018-1830-3

Pilon fractures can be caused by high-energy vertical forces which may result in long-term patient immobilization. Many experts in orthopedic surgery recommend the use of a Delta external fixator for type III Pilon fracture treatment. This device can promote immediate healing of fractured bone, minimizing the rate of complications as well as allowing early mobilization. The characteristics of different types of the Delta frame have not been demonstrated yet. By using the finite element method, this study was conducted to determine the biomechanical characteristics of six different configurations (Model 1 until Model 6). CT images from the lower limb of a healthy human were used to reconstruct three-dimensional models of foot and ankle bones. All bones were assigned with isotropic material properties and the cartilages were assigned to exhibit hyperelasticity. A linear link was used to simulate 37 ligaments at the ankle joint. Axial loads of 70 and 350 N were applied at the proximal tibia to simulate the stance and swing phase. The metatarsals and calcaneus were fixed distally in order to prevent rigid body motion. A synthetic ankle bone was used to validate the finite element model. The simulated results showed that Delta3 produced the highest relative micromovement (0.09 mm, 7 μm) during the stance and swing phase, respectively. The highest equivalent von Mises stress was found at the calcaneus pin of the Delta4 (423.2 MPa) as compared to others. In conclusion, Delta1 external fixator was the most favorable option for type III Pilon fracture treatment. Graphical abstract ᅟ.
Unifying the seeds auto-generation (SAGE) with knee cartilage segmentation framework: data from the osteoarthritis initiative

Gan HS, Sayuti KA, Ramlee MH, Lee YS, Wan Mahmud WMH, Abdul Karim AH

Int J Comput Assist Radiol Surg, 2019 May;14(5):755-762.
PMID: 30859457 DOI: 10.1007/s11548-019-01936-y

PURPOSE: Manual segmentation is sensitive to operator bias, while semiautomatic random walks segmentation offers an intuitive approach to understand the user knowledge at the expense of large amount of user input. In this paper, we propose a novel random walks seed auto-generation (SAGE) hybrid model that is robust to interobserver error and intensive user intervention.
METHODS: Knee image is first oversegmented to produce homogeneous superpixels. Then, a ranking model is developed to rank the superpixels according to their affinities to standard priors, wherein background superpixels would have lower ranking values. Finally, seed labels are generated on the background superpixel using Fuzzy C-Means method.
RESULTS: SAGE has achieved better interobserver DSCs of 0.94 ± 0.029 and 0.93 ± 0.035 in healthy and OA knee segmentation, respectively. Good segmentation performance has been reported in femoral (Healthy: 0.94 ± 0.036 and OA: 0.93 ± 0.034), tibial (Healthy: 0.91 ± 0.079 and OA: 0.88 ± 0.095) and patellar (Healthy: 0.88 ± 0.10 and OA: 0.84 ± 0.094) cartilage segmentation. Besides, SAGE has demonstrated greater mean readers' time of 80 ± 19 s and 80 ± 27 s in healthy and OA knee segmentation, respectively.
CONCLUSIONS: SAGE enhances the efficiency of segmentation process and attains satisfactory segmentation performance compared to manual and random walks segmentation. Future works should validate SAGE on progressive image data cohort using OA biomarkers.

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