Cho Hong, James Goh
Email Address
biegohj@nus.edu.sg
Organizational Units
ENGINEERING
faculty
COLLEGE OF DESIGN & ENG
faculty
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Publication Correlation of axial impact forces with knee joint forces and kinematics during simulated ski-landing(2011-08) Yeow, C.-H.; Kong, C.-Y.; Lee, P.V.-S.; Goh, J.C.-H.; BIOENGINEERINGAnterior cruciate ligament (ACL) rupture, during ski-landing, is caused by excessive knee joint forces and kinematics, like anterior tibial translation, internal tibial rotation, and valgus rotation. It is not well understood how these forces/kinematics are directly related to ski-landing impact. In the present study, we applied simulated ski-landing impact to knee specimens, and examined joint force/kinematic responses and their correlations with impact force. Ten human cadaveric knees were subjected to axial impact loading at 70° of flexion to simulate ski-landing impact. Impact was repeated with incremental magnitude until ACL failure. Axial impact forces, anterior-posterior and medial-lateral tibial forces were measured using a tri-axial load cell. Anterior-posterior tibial translation, internal-external tibial rotation, and valgus-varus rotation were determined using a motion-capture system. We found positive correlations of axial impact force with anterior tibial force, medial tibial force, anterior tibial translation, internal tibial rotation, and valgus joint rotation. Axial impact forces were more strongly correlated with anterior tibial forces (R2 = 0.937 ± 0.050), anterior tibial translation (R2 = 0.916 ± 0.059), and internal tibial rotation (R2 = 0.831 ± 0.141) than medial tibial force (R2 = 0.677 ± 0.193) and valgus joint rotation (R2 = 0.630 ± 0.271). During ski-landing, these joint forces/kinematics can synergistically act to increase ACL injury risk, whereby the failure mechanism would be dominated by anterior tibial forces, anterior tibial translation, and internal tibial rotation. © 2011 Taylor & Francis.Publication Bioengineering education @NUS: A design-centered curriculum(2011) Toh, S.L.; Goh, J.C.H.; BIOENGINEERINGIn resonance with the NUS Mission, the aim of the Bioengineering undergraduate degree program is to produce engineers with a strong foundation in the relevant engineering, sciences and technology, who are able to contribute to the biomedical sciences through innovation, enterprise and leadership. Our educational program in Bioengineering is characterised by a strong emphasis on scientific and engineering fundamentals and a high degree of flexibility which can provide a wide diversity of educational experiences. By providing graduates with a combination of broad-based fundamentals and specialized knowledge, the Bioengineering program strives to graduate versatile engineers who would be best positioned to lead and be an integral part of the Bioengineering industries in the future. This paper describes the bioengineering program, both at undergraduate and postgraduate levels in the Division of Bioengineering at Faculty of Engineering in National University of Singapore. © 2011 IEEE.Publication Preventing anterior cruciate ligament failure during impact compression by restraining anterior tibial translation or axial tibial rotation(2009) Yeow, C.H.; Khan, R.S.; Lee, P.V.S.; Goh, J.C.H.; ORTHOPAEDIC SURGERY; LIFE SCIENCES INSTITUTE; BIOENGINEERINGAnterior cruciate ligament injury is highly prevalent in activities that involve large and rapid landing impact loads. We hypothesize that restraining anterior tibial translation or axial tibial rotation can prevent the anterior cruciate ligament from failing at the range of peak compressive load that can induce ligament failure when both factors are unrestrained. Sixteen porcine knee specimens were mounted onto a material-testing system at 70-deg flexion. Single 10-Hz haversine impact compression was successively repeated with incremental actuator displacement until ligament failure/visible bone fracture was noted. During impact compression, rotational and translational data of the knee joint was obtained using motion-capture system via markers attached to the setup. Specimens were randomly classified into four test groups: Q (unrestrained setup), A (anterior tibial translation restraint), R (axial tibial rotation restraint) and C (combination of both restraints). The same impact protocol was applied to all specimens. Q specimens incurred anterior cruciate ligament failure in the form of femoral avulsion; the peak compressive forces during failure ranged from 1.4-4.0 kN. A, R and C specimens underwent visible bone fracture with ligament intact; the peak compressive force during fracture ranged from 2.2-6.9 kN. The posterior femoral displacement and axial tibial rotation for A and R specimens respectively were substantially lower relative to Q specimens. Both factors were significantly diminished in C specimens but the peak compressive force was larger compared to Q specimens. Significant restraining of these factors was able to prevent anterior cruciate ligament failure in an impact setup that can induce ligament failure with the factors unrestrained.Publication Minimizing the severity of rhBMP-2-induced inflammation and heterotopic ossification with a polyelectrolyte carrier incorporating heparin on microbead templates(2013-08-01) Wang, M.; Abbah, S.A.; Hu, T.; Toh, S.Y.; Lam, R.W.M.; Goh, J.C.-H.; Wong, H.-K.; BIOENGINEERINGStudy Design. A rodent model of posterior spinal fusion. Objective. The aim of this study was to evaluate the efficacy of low-dose recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered with a heparin based polylectrolyte complex (PEC) carrier in facilitating posterior spinal fusion while concurrently minimizing seroma and heterotopic ossification. Summary of Background Data. rhBMP-2 is being used to augment spinal fusion. However, complications such as heterotopic ossification and local soft tissue swellings have been reported. These are attributed to supraphysiological amount of rhBMP-2 and the poor modulation capacity of absorbable collagen sponge. Methods. Forty rats were randomized into 6 groups as follows. Group I: absorbable collagen sponge without rhBMP-2 (n = 4); group II: positive control, absorbable collagen sponge + 10 μg rhBMP-2 (n = 4); group III: alginate-(poly-L-lysine)-heparin (PEC) without rhBMP-2 (n = 8); group IV: PEC + 4.5 μg rhBMP-2 (n = 8); group V: PEC + 1.5 μg rhBMP-2 (n = 8); group VI: PEC + 0.5 μg rhBMP-2 (n = 8). Results. Between postoperative days 5 and 7, seroma was observed in all rhBMP-2 implanted groups irrespective of carrier and dose. However, the rate and size of seroma differed considerably. Although all animals (100%) in positive control group showed seroma, only one animal (12.5%) in group VI developed seroma at the implant site. The size of seroma in group VI was significantly smaller than that in positive control group. Micro-computed tomography evaluation revealed comparable mean fusion scores in all rhBMP-2 implanted groups. More importantly, although new bone was well contained within the cage in group VI, heterotopic ossification beyond the cage was observed in positive control group. Conclusion. A new carrier has demonstrated capacity to minimize seroma formation as well as heterotopic ossification associated with rhBMP-2 by reducing the efficacious dose needed for consistent fusion. The results of this study indicate that PEC alginate microbeads may represent a new opportunity to define an efficient rhBMP-2 carrier. © 2013, Lippincott Williams & Wilkins.Publication The relationship between femoral neck strength, bone mineral content and fracture fixation strength: An in vitro study(1993) Shah, K.M.; Goh, J.; Bose, K.; ORTHOPAEDIC SURGERYPublication Manpower development for the biomedical industry space(2013) Goh, J.C.H.; BIOENGINEERINGThe Biomedical Sciences (BMS) Cluster is one of four key pillars of the Singapore economy. The Singapore Government has injected research funding for basic and translational research to attract companies to carry out their commercial R&D activities. To further intensify the R&D efforts, the National Research Foundation (NRF) was set up to coordinate the research activities of different agencies within the larger national framework and to fund strategic R&D initiatives. In recent years, funding agencies began to focus on support of translational and clinical research, particularly those with potential for commercialization. Translational research is beginning to have traction, in particular research funding for the development of innovation medical devices. Therefore, the Biomedical Sciences sector is projected to grow which means that there is a need to invest in human capital development to achieve sustainable growth. In support of this, education and training programs to strengthen the manpower capabilities for the Biomedical Sciences industry have been developed. In recent years, undergraduate and graduate degree courses in biomedical engineering/bioengineering have been developing at a rapid rate. The goal is to train students with skills to understand complex issues of biomedicine and to develop and implement of advanced technological applications to these problems. There are a variety of career opportunities open to graduates in biomedical engineering, however regardless of the type of career choices, students must not only focus on achieving good grades. They have to develop their marketability to employers through internships, overseas exchange programs, and involvement in leadership-type activities. Furthermore, curriculum has to be developed with biomedical innovation in mind and ensure relevance to the industry. The objective of this paper is to present the NUS Bioengineering undergraduate program in relation to manpower development for the biomedical industry in Singapore. © 2013 IEEE.Publication Surface contact studies of Asian cadaveric hips(1990) Das, De S.; Bose, K.; Balasubramaniam, P.; Goh, J.C.H.; ORTHOPAEDIC SURGERYPublication Assembly of bone marrow stromal cell sheets with knitted poly (L-lactide) scaffold for engineering ligament analogs(2005-11) Ouyang, H.W.; Toh, S.L.; Goh, J.; Tay, T.E.; Moe, K.; ORTHOPAEDIC SURGERY; BIOENGINEERING; MECHANICAL ENGINEERINGThe current cell seeding technique lias several disadvantages, such as low efficiency of cell attachment to scaffolds and the limited strength of cell-gel composite adhesion to scaffold. These problems warrant further study to improve the assembly of cell to scaffold. Therefore this study aims to fabricate a bone marrow stromal cells (bMSCs) sheet and assemble it on a knitted poly (L-lactide) (PLLA) scaffold for engineering ligament analogs. bMSCs were cultured to form a cell sheet in the presence of ascorbic acid. Once a sheet of bMSCs was obtained, it was assembled onto the knitted scaffold by a wrapping technique. Then the assembled structure was held in place in a spinner flask for 4 weeks. The macromorphology, histology, and biomechanics of the grafts were evaluated. The composite of cell sheet/PLLA scaffold constructs had transformed into tissuelike ligament analogs. Immunohistochemical analysis showed that the components of the analogs were similar to that of ligament tissues, consisting primarily of collagen type I and small amount of collagen type III and tenascin. The failure force of the cell/scaffold assembly under tension (46.68 ± 2.29 N) was higher than that of the scaffold group (43.58 ± 2.41 N; p < 0.05), but tensile stiffness of the cell/scaffold group (20.6 ±1.417 N/mm) was significantly lower than that of the scaffold group (27.6 ±1.449 N/mm; p < 0.05). These data showed that the incorporation of bMSCs sheet onto the PLLA scaffold could make the analog stronger and more stretchable. Therefore the approach of assembling bMSCs sheet onto knitted PLLA scaffold is promising for producing tissuelike and functional ligament analogs under dynamic fluid situation for the purpose of anterior cruciate ligament (ACL) reconstruction. © 2005 Wiley Periodicals, Inc.Publication Internal model approach for gait modeling and classification(2005) Xu, J.-X.; Wang, W.; Goh, J.C.H.; Lee, G.; ORTHOPAEDIC SURGERY; ELECTRICAL & COMPUTER ENGINEERINGIn this paper, we present a novel approach to model and classify gait patterns based on internal models. An internal model consists of two sets of differential equations and a neural network in between. It can effectively describe dynamic movement primitives (DMP), hence is able to model the temporal-spatial gait patterns. An interesting feature of the internal model is, the nonlinear map generated by the neural network can also serve the purpose for gait pattern classification. In this work we use a single hidden layer feed-forward network (SLFN), and show that the characteristics of gait patterns can be captured via the output layer weights. The experiment results based on EMGs of gait patterns at five different walking speeds are used to validate the internal model approach. © 2005 IEEE.Publication A novel nano-microfibre PLGA scaffold for tendon/ ligament tissue engineering(2004) Sahoo, S.; Ouyang, H.W.; Toh, S.L.; Goh, J.C.; Tay, T.E.; ORTHOPAEDIC SURGERY; BIOENGINEERING; MECHANICAL ENGINEERINGThe development of a biodegradable nano-microfiber polymer scaffold for tendon/ligament tissue engineering by electrospinning poly(D,L-lactide-co- glycolide) (PLGA) nanofibers, was described. About six knitted scaffolds of 20 mm width and 30 mm length were fabricated by knitting PLGA fibers comprising filaments of 25 μm diameter. The scaffolds were characterized by phase contrast microscopy and scanning electron microscopy (SEM). The phase contrast microscopy and SEM revealed that nanofibers ranging in diameters from 300 to 900 nm were randomly spread over the surface of the knitted scaffold. The results show that the developed scaffold holds promise in tissue engineering of tendon/ligament while the microfibers provide mechanical strength.