Mohd Yusof Baharuddin

Morphology Study of the Proximal Femur in Malay Population

Problemas con respecto al tamano de los implantes en relacion a cada poblacion se han convertido en una cuestion esencial para la sociedad ortopedica. Varios factores han sido identificados en la literatura, los que pueden afectar la estabilidad del implante, especialmente en el femur proximal. Se estudio prospectivamente 120 caderas mediante imagenes de tomografia computarizada. Sesenta sujetos fueron reclutados, edad media 25±5,18 anos, peso de 61,48±13,84 kg y altura de 1,65±9,63m. Los criterios de exclusion para este estudio incluyeron a mujeres embarazadas, quienes hubiesen experimentado lesiones cadera, uso de implantes o protesis. Nuestros datos se compararon usando las pruebas de Anderson-Darling y t-test. Los parametros medidos fueron diametro de la cabeza femoral (FHD), longitud del cuello femoral (FNL), ancho del cuello femoral (FNW) y el angulo cuello-diafisial (CDA). Los resultados de los femures masculinos y femeninos fueron los siguientes: FHD 43,6 ± 3,1 mm y 38,9 ± 2,2 mm, FNL 91,1 ± 5,7 mm y 81,8 ± 4,3 mm, FNW 28,9 ± 3,4 mm y 26,0 ± 4,3 mm; CDA 132.3 ± 3.4 y 129.9 ± 4,. Este estudio prospectivo y transversal centrado en la poblacion malaya, proporciono informacion esencial sobre el valor normal de la porcion proximal del femur, datos que mejoraran el conocimiento de los aspectos anatomicos y, finalmente, ayuden al diseno del vastago femoral en la artroplastia total de cadera (ATC). Los resultados proporcionaran una nueva comprension por parte del cirujano ortopedico.

Motion analysis of arm movement during badminton smash

In badminton, it demands excellent physical fitness and good motor coordination for the development of sophisticated racquet movement. This project aims at identifying the difference of forehand overhead smash performed by male and female players. The parameters to study were focused on upper arm, forearm and wrist segments. Qualisys Track Manager (QTM) software and five Oqus camera system were used to record and analyze the performance of e subjects. Eight male and eight female participants served as the subjects. Reflective markers were attached at the key locations on the subjects arm to observe the arm movement during the execution of smash. The subject was directed to stand on the position of the smashing area within the measurement volume and his/her partner who was assigned to serve was directed to stand in the serving area. A sequence of badminton smash movements, from the position of holding racket to smashing motion was captured by the camera. The results obtained indicated that the male subject has higher racquet grip velocity than the female subject. The movement of shoulder abduction and elbow extension were anticipated to be the key contributor for the male players to perform a rapid smash. The female subjects showed a synchronized and significant range of motion especially in the wrist rotation.

Morphological Study of the Newly Designed Cementless Femoral Stem

A morphology study was essential to the development of the cementless femoral stem because accurate dimensions for both the periosteal and endosteal canal ensure primary fixation stability for the stem, bone interface, and prevent stress shielding at the calcar region. This paper focused on a three-dimensional femoral model for Asian patients that applied preoperative planning and femoral stem design. We measured various femoral parameters such as the femoral head offset, collodiaphyseal angle, bowing angle, anteversion, and medullary canal diameters from the osteotomy level to 150 mm below the osteotomy level to determine the position of the isthmus. Other indices and ratios for the endosteal canal, metaphyseal, and flares were computed and examined. The results showed that Asian femurs are smaller than Western femurs, except in the metaphyseal region. The canal flare index (CFI) was poorly correlated (r < 0.50) to the metaphyseal canal flare index (MCFI), but correlated well (r = 0.66) with the corticomedullary index (CMI). The diversity of the femoral size, particularly in the metaphyseal region, allows for proper femoral stem design for Asian patients, improves osseointegration, and prolongs the life of the implant.

Fabrication of Low-Cost, Cementless Femoral Stem 316L Stainless Steel Using Investment Casting Technique

Total hip arthroplasty is a flourishing orthopedic surgery, generating billions of dollars of revenue. The cost associated with the fabrication of implants has been increasing year by year, and this phenomenon has burdened the patient with extra charges. Consequently, this study will focus on designing an accurate implant via implementing the reverse engineering of three-dimensional morphological study based on a particular population. By using finite element analysis, this study will assist to predict the outcome and could become a useful tool for preclinical testing of newly designed implants. A prototype is then fabricated using 316L stainless steel by applying investment casting techniques that reduce manufacturing cost without jeopardizing implant quality. The finite element analysis showed that the maximum von Mises stress was 66.88 MPa proximally with a safety factor of 2.39 against endosteal fracture, and micromotion was 4.73 μm, which promotes osseointegration. This method offers a fabrication process of cementless femoral stems with lower cost, subsequently helping patients, particularly those from nondeveloped countries.

Primary Stability Recognition of the Newly Designed Cementless Femoral Stem Using Digital Signal Processing

Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA) is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM) to determine the primary stability of the implant. We measured strain with triaxial rosette at the metaphyseal region and micromotion with linear variable direct transducer proximally and distally using composite femora. The root mean squares technique is used to feed the classifier which provides maximum likelihood estimation of amplitude, and radial basis function is used as the kernel parameter which mapped the datasets into separable hyperplanes. The results showed 100% pattern recognition accuracy using SVM for both strain and micromotion. This indicates that DSP could be applied in determining the femoral stem primary stability with high pattern recognition accuracy in biomechanical testing.

Finite Element Study on the Micromotion of Cementless Total Hip Arthroplasty

Major problem associated with the cementless design is the lack of stability. Several design features were introduced to provide the much needed stability for bone integration. These include fins, fiber mesh, beads, indentations and collars. The use of collar has been a subject of controversy with mixed reports of clinical outcomes. In this study, the effectiveness of collar in terms of providing stability was analysed using finite element method. Three dimensional model of a human femur was constructed from CT dataset and hip arthroplasty was simulated. With an applied joint contact load simulating physiological gait, micromotion of the implant relative to the bone was calculated via an experimentally validated algorithm. Results showed that collar did not improve stability of the whole stem but only around the medial calcar region.

Finite Element Study on the Stability of Cementless Acetabular Cup

The primary cause of Total Hip Replacement (THR) failure for younger patients is aseptic loosening and more specifically the loosening is twice more likely in acetabular cup than in femoral stem. The micromotion between bone and implant will cause loosening which depend in patient activities, age and bone. In this project, study about the effect on the acetabular system which is consisted of cup, liner and head being carried out to fine new design and material to counter the problem occurs in THR. Commercial acetabular cup design from Wright Company such as Spiked, Superfix and Quadrafix have been analyzed using MARC software. From these results, the new design of acetabular cup proposed and analyzed to get better osseointegration between bones and implant interface. The pelvis bone was scan using Computed Tomography (CT) datasets and reconstructed using Materialize software. The diameter of acetabular cup is based on diameter of acetabulum rim to make sure the component really fit to acetabulum cavity. Result from the simulation shown, purpose acetabular cup designs are more stable compare others design in stress and displacement aspects. Finally, the new proposed design can be produce and considered as an alternative design for THR.

Mathematical Modeling of Caspase Activated DNAase (CAD) Regulation Towards Apoptosis

Caspase activated deoxyribonuclease (CAD) is the protein that transmit nuclear localization signal which will induced DNA fragmentation. Both CAD and its inhibitor ICAD is the key for apoptosis. As CAD is binding on RNA, ICAD-L will bind to its budding chain improving the folding. Once CAD synthesis is done, ICAD-L will still bind with CAD forming DFF which is the CAD: ICAD complex. On the contrary, ICAD-S couldn’t bind with CAD budding chain, therefore do not form DFF. When Caspase-3 is activated downstream in Caspase-3 Cascade, ICAD-L will cleaved and release active CAD to degrade DNA.