Displaying publications 1 - 20 of 33 in total

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  1. Tan B, Shanmugam R, Gunalan R, Chua Y, Hossain G, Saw A
    Malays Orthop J, 2014 Jul;8(2):35-9.
    PMID: 25279090 DOI: 10.5704/MOJ.1407.012
    Taylor's spatial frame (TSF) and Ilizarov external fixators (IEF) are two circular external fixator commonly used to address complex deformity and fractures. There is currently no data available comparing the biomechanical properties of these two external fixators. This study looks into the mechanical characteristics of each system. TSF rings with 6 oblique struts, 4 tube connectors, 4 threaded rods, and 6 threaded rods were compared to a standard IEF rings with 4 threaded rods. Compression and torsional loading was performed to the frame as well as construct with Polyvinylchloride tubes. TSF rings with 4 tube connectors had the highest stiffness (3288 N/mm) while TSF rings with 6 struts was the least stiff. The situation was reversed for torsion where TSF rings with 6 oblique struts had the highest torsional stiffness (82.01 Nm/Degree) and frame Ilizarov rings with 4 threaded rods the least. Standard TSF construct of two ring with 6 oblique struts have better torsional stiffness and lower axial stiffness compared to the standard IEF.
    Matched MeSH terms: External Fixators
  2. Siow YS, Ahmad TS, Goh SY
    Hand Surg, 1999 Dec;4(2):167-174.
    PMID: 11089175
    Three patients with severe fixed flexion deformity of the fingers caused by trauma were reported. As an alternative treatment, a new mini external fixator was used to correct the deformities. The use of this device has made treatment of contractures simpler and more predictable. Gradual distraction and straightening was applied to loosen and extend the joints, followed by a period of mobilisation while still on the device. In all the three patients, this experimental device and approach led to improvement of the fixed flexion deformities. With use of this device, surgical release may not be necessary.
    Matched MeSH terms: External Fixators
  3. 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.
    Matched MeSH terms: External Fixators
  4. 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.
    Matched MeSH terms: External Fixators
  5. 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.
    Matched MeSH terms: External Fixators
  6. 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.
    Matched MeSH terms: External Fixators
  7. Saw, A., Manimaran, S., Faizal S., Bulgiba, A.M.
    Malays Orthop J, 2008;2(1):44-48.
    MyJurnal
    Bone lengthening with distraction osteogenesis involves prolonged application of an external fixator frame. Qualitative and quantitative evaluation of callus has been described using various imaging modalities but there is no simple reliable and readily available method. This study aims to investigate the use of a densitometer to analyze plain radiographic images and correlate them with the rate of new bone formation as represented by the bone healing index. A total of 34 bone lengthening procedures in 29 patients were retrospectively reviewed. We used an X-Rite 301 densitometer to measure densities of new callus on plain radiographs taken at 4 and 8 weeks after surgery. Patients aged below 16y had significantly lower BHIs indicating faster bone healing and shorter duration of treatment. The ratio of radiographic densities between centre and edge of the new bone measured from plain radiographs taken at 8 weeks correlated positively with the eventual BHI of the patient. This method provides a simple and easy way to predict the rate of bone healing at an early stage of treatment and may also allow remedial action to be taken for those with poor progress in bone formation.
    Matched MeSH terms: External Fixators
  8. Shahrulazua, A., Ariff, M.S., Aziz, M.A.
    Malays Orthop J, 2010;4(1):35-38.
    MyJurnal
    Fat embolism syndrome is a well-recognised sequela of long bone trauma as well as intramedullary orthopaedic procedures. However, it has rarely been described following manipulation, reduction of fracture, and application of external fixator. Furthermore, bilateral ocular blindness is seldom the first manifestation; instead respiratory and other cerebral symptoms being most common. We describe a case with this rare presentation in a patient who underwent a trial of closed reduction, then open reduction of a femur fracture, followed by external fixation performed at day 47 post-initial trauma.
    Matched MeSH terms: External Fixators
  9. Tan, B. B., Shanmugam, R., Chua, Y. P., Hossain, G., Saw, A.
    Malays Orthop J, 2014;8(2):35-39.
    MyJurnal
    Taylor’s spatial frame (TSF) and Ilizarov external fixators (IEF) are two circular external fixator commonly used to address complex deformity and fractures. There is currently no data available comparing the biomechanical properties of these two external fixators. This study looks into the mechanical characteristics of each system. TSF rings with 6 oblique struts, 4 tube connectors, 4 threaded rods, and 6 threaded rods were compared to a standard IEF rings with 4 threaded rods. Compression and torsional loading was performed to the frame as well as construct with Polyvinylchloride tubes. TSF rings with 4 tube connectors had the highest stiffness (3288 N/mm) while TSF rings with 6 struts was the least stiff. The situation was reversed for torsion where TSF rings with 6 oblique struts had the highest torsional stiffness (82.01 Nm/Degree) and frame Ilizarov rings with 4 threaded rods the least. Standard TSF construct of two ring with 6 oblique struts have better torsional stiffness and lower axial stiffness compared to the standard IEF.
    Matched MeSH terms: External Fixators
  10. Siti Nazira Masrom, Mohd Hariri Arifin, Abd Rahim Harun, Abdul Rahim Samsudin
    Sains Malaysiana, 2011;40:1223-1229.
    Survei keberintangan geoelektrik ini telah dijalankan di kawasan Bukit Tenggek, Setiu, Terengganu untuk mengesan kemungkinan wujudnya terowong lama yang dipercayai berada di kawasan berkenaan. Kaedah keberintangan geoelektrik ini bukanlah asing dan didapati amat berkesan di dalam eksplorasi mencari bahan arkeologi dan struktur terkambus di bawah tanah (terowong dan bahan artifak). Survei keberintangan geoelektrik ini dijalankan dengan menggunakan peralatan ABEM Terrameter SAS1000 dan susun atur elektrod jenis Wenner. Kawasan kajian terletak di kawasan lembah yang lembap dan terdapat anak sungai yang merentasi kawasan tersebut. Imej keberintangan 2-D menunjukkan wujudnya beberapa kawasan beranomali yang boleh dikaitkan dengan struktur yang dicari. Nilai keberintangan yang rendah mewakili kawasan yang dianggarkan wujudnya terowong lama. Manakala anomali yang menunjukkan bentuk gugusan dianggarkan berasosiasi dengan lokasi tong/bahan artifak. Profil keberintangan 3-D menunjukkan anomali yang mungkin disebabkan oleh wujudnya satu terowong mendatar dan dua terowong menegak. Namun, kerja galicari perlu dilakukan bagi menentukan punca sebenar anomali tersebut.
    Matched MeSH terms: External Fixators
  11. Munajat I, Sulaiman AR, Mohd EF, Zawawi M
    Malays Orthop J, 2020 Mar;14(1):49-54.
    PMID: 32296482 DOI: 10.5704/MOJ.2003.008
    Introduction: Submuscular plating after lengthening shortened the period of external fixation in distraction osteogenesis of the femur. In the femur, where monolateral or ring fixators had been used for the distraction, plates, could be inserted laterally, anteriorly or medially. Specific technical modification of the plate insertion, however, would be necessary to accommodate the femoral varus angular correction created at the end of the distraction, in the pelvic support osteotomy lengthening.

    Material and Methods: We reviewed a series of eight cases with standard and modified techniques of plating after lengthening. The amount of lengthening, the period of distraction, the external fixator index and the associated complications were assessed.

    Results: The mean lengthening was 5cm, with a range of 3cm to 9cm. The external fixation index, the period of external fixators in days in relation to the length of distraction in cm, was between 18 days/cm to 58 days/cm. One patient with quadriceps contracture, underwent quadriceplasty to improve knee flexion. Three patients with transient knee stiffness had resolution with aggressive physiotherapy. One patient with transient hypoesthesia recovered spontaneously. None of the patients developed joint subluxation, deep infection, re-fracture or implant failures.

    Conclusion: Standard and modified techniques of plating after lengthening were safe and required only a short period of external fixation. The modified technique offered an easier way of plate insertion in a deformed bone.

    Matched MeSH terms: External Fixators
  12. Norliyana, M., Mohd Yazid, B., Abdul Muhaimin, A.
    Medicine & Health, 2018;13(1):279-285.
    MyJurnal
    Brachymetatarsia is a conditioned which has been described as abnormal short metatarsal bone due to premature closure of the epiphyseal growth plate. It usually involves a single metatarsal bone with the fourth metatarsal being the most common. It may be congenital or acquired. We here report a case in a 53-yearold lady who presented with foot pain and shoe wearing problem. Examination revealed shortening of the bilateral fourth toe and the toes were tilted dorsally. She was diagnosed with bilateral brachymetatarsia and operation was done mainly for cosmetic reasons. Gradual lengthening with distraction osteogenesis was performed using a MiniRail external fixator (Orthofix) and K-wiring of the right fourth metatarsophalangeal joint. Adequate length of fourth metatarsal and good bony union were achieved at the end of treatment.
    Matched MeSH terms: External Fixators
  13. Gooi SG, Wang CS, Saw A, Zulkiflee O
    Malays Orthop J, 2017 Mar;11(1):79-81.
    PMID: 28435583 MyJurnal DOI: 10.5704/MOJ.1703.015
    Missed Monteggia fracture leading to chronic radial head dislocation is a known complication. The surgical treatment options remain challenging. The aim of treatment is to reduce the radial head and to maintain the stability of the elbow in all ranges of motion. A few surgical techniques have been described with complications. We report the case of a 13 years old boy with chronic radial head dislocation as a result of an unrecognised Monteggia fracture-dislocation for eight years. We successfully reduced the radial head and corrected the cubital valgus from 45 degrees to 10 degrees with a proximal ulna osteotomy and gradual distraction with 2-pin Monotube external fixator. The correction was uneventful with good functional outcome.
    Matched MeSH terms: External Fixators
  14. Mohd Bakrynizam Abu Bakar Siddiq, Kamarul Izham Kamarudin, Kamarul Al Haq, Suresh Chopr
    MyJurnal
    Limb length discrepancy (LLD) is quite common.
    Lower limb shortening is one of the causes of limb
    length discrepancy. The common treatment that is
    used is the llizarov technique for bone lengthening.
    The new technique uses an intramedullary nail with
    a monoplanar external fixator. Using this technique,
    bone lengthening duration in patients can be reduced
    and knee joint mobility can be improved without
    jeopardizing bone regeneration. We report a case of a
    27-year-old gentleman who had right femur shortening
    from childhood and was referred to us for corrective
    deformity. He underwent bone lengthening on the nail
    which lenghthens and equalizes the leg while avoiding
    stiffness and reduces joint mobility which leads to good
    patient satisfaction outcome. The use of the external
    fixator with intramedullary nailing to lengthen the
    femur is one method that can reduce patient burden
    mentally and physically. However although it has many
    advantages we must watch out for the complications
    during the regular visits to ensure good outcome.
    Matched MeSH terms: External Fixators
  15. Jalila A, Redig PT, Wallace LJ, Ogema TR, Bechtold JE, Kidder L
    Med J Malaysia, 2004 May;59 Suppl B:125-6.
    PMID: 15468850
    Avian demineralized bone matrix (ADBM) powder prepared from chicken, pigeon, and turkey sources induced bone formation via endochondral and intramembranous processes, as in mammalian studies. There were no significant differences in percentage of new bone, percentage of cartilage, surface-forming osteoblast area, or osteoclast count between gaps treated with chicken, pigeon, and turkey DBM. However, there was a significantly (p<0.05) higher percentage of inflammatory area in gaps treated with chicken DBM than in gaps treated with pigeon DBM.
    Matched MeSH terms: External Fixators*
  16. Aik S, Sengupta S
    Med J Malaysia, 2000 Sep;55 Suppl C:86-92.
    PMID: 11200049
    We are describing 21 limb reconstruction procedures performed in 18 patients with the use of external fixators from 1996 to 1998. The average age of patients was 21, ranging from 1 to 50 years old. Indications for surgery included short limb, non-union, pseudoarthrosis and bone or soft tissue deformities. Average length obtained for cases of limb lengthening was 6 cm. All the seven clubfoot deformities in five children were fully corrected. Equinus deformity recurred in one foot and was treated with supramalleolar osteotomy. Out of the seven cases with infected nonunion and bone loss, three failed to achieve union and required additional bone grafting procedures. One patient with unilateral external fixator for the correction of tibia shortening developed valgus deformity.
    Matched MeSH terms: External Fixators*
  17. Masbah O, Noor MA
    Med J Malaysia, 1992 Jun;47(2):122-7.
    PMID: 1494332
    The results of treatment using a locally-designed external fixator in 20 patients are presented. Open fractures were the main indications for external fixation. Pin tract infection occurred in 8 patients. Only 2 patients had unstable fixation which required removal of the device. One third of patients developed malunion exceeding 15 degrees and two thirds had joint stiffness after conversion to plaster cast. This external fixator is adequate in the treatment of most open fractures of the tibia. However, improved techniques of pin insertion and cast application upon removal of the external fixator may help to reduce the incidence of pin tract infections and malunion.
    Matched MeSH terms: External Fixators*
  18. 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.
    Matched MeSH terms: External Fixators*
  19. 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.
    Matched MeSH terms: External Fixators*
  20. 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.
    Matched MeSH terms: External Fixators*
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