Arif Ozkan - Academia.edu (original) (raw)

Papers by Arif Ozkan

Bitlis Eren Üniversitesi Fen Bilimleri Dergisi

Fuji prescale pressure sensitive films (FPPSF) are generally used in biomechanical applications t... more Fuji prescale pressure sensitive films (FPPSF) are generally used in biomechanical applications to measure the pressure distributions and the contact areas between two contact surfaces as in coloured stains. FPPSFs are usually calibrated based on the calibration methods using regression analysis to obtain a specific calibration curve. However, researchers in literature achieve different calibration curves based upon their tests and different processes. The purpose of this study is to examine the calibration stains (data) obtained experimentally using the FPPSF samples compressed between two smooth flat surfaces to indicate contact pressures. The gray-level co-occurrence matrix (GLCM) was used to evaluate the uniformity of the sample stains for quantitative evaluation of uniform distribution of the sample stains. Moreover, the generated calibration data is also compared and validated statistically with the related calibration curves presented in the available literature. As a result,...

DergiPark (Istanbul University), Sep 5, 2014

Mandibula kırıklarında miniplak kullanımı yaygın görülen müdahale yöntemlerinden biridir. Mandibu... more Mandibula kırıklarında miniplak kullanımı yaygın görülen müdahale yöntemlerinden biridir. Mandibula kemiği kırıklarında plak-fiksatör uygulaması öncesi tetkiklerde kullanılacak biyomalzemenin taşıyabileceği sınır değerlerinin ortaya konması gerekir. Plak ve fiksatörün, çenenin maksimum kuvvete ulaştığı durumlar dahil her türlü etkiye karşılık verir nitelikte olması istenmektedir. Cerrahi müdahale öncesinde kullanılacak malzeme ve plak geometrisinin belirlenmesi tüm bu etkenler nedeniyle istenilen cerrahi uygulamaya ulaşmak için gereklidir. Bu çalışmada, yaygın olarak kullanılan Titanyum Alaşım ile tasarlanmış ve "I" geometriye sahip plakların tespit konumları kıyaslanmıştır. Her bir model ve modele ait malzeme için ANSYS® sonlu elemanlar yazılımı ile gerilme ve deformasyon kapasiteleri karşılaştırılmıştır. In vitro çalışmaları kadar kullanılabilir değerler elde edilebilen sonlu elemanlar analizi sonuçları I tipi mandibula plakları ve malzemeleri için değerlendirilmiştir. İki farklı tip mandibula kırıklarında kullanılan I tipi plakların hangi şartlar altında tespit tercihinin uygun olduğu ifade edilmiştir.

With the advancement of technology, many prosthesis were developed to improve the life standard o... more With the advancement of technology, many prosthesis were developed to improve the life standard of a person who lost one or more limb. One of the most common limb loss is finger lose. Many finger prosthesis were developed to imitate the functionality of natural human fingers. But most of them are not personalised (does not fit perfectly to the user) and/or not easy to apply. Some finger prosthesis needs surgical operation to apply. The aim of this study is to design and manufacture accessible and sustainable finger prosthesis that is easy to apply and personalised. In this study, hand skeleton structure was modelled from computerized tomography images. Distal and middle phalanx bones were removed to show finger loss. Personalised finger prosthesis that fits perfectly to the user was designed on the hand skeleton structure. By using kinematic analysis, finger prosthesis movement capabilities are determined and general mathematic model was developed to be used in other patients. Befor...

Bu calismada, Dinamik Kalca Civisinin (DKC) sabitlenmesinde lag vidasinin farkli konumlarina gore... more Bu calismada, Dinamik Kalca Civisinin (DKC) sabitlenmesinde lag vidasinin farkli konumlarina gore intertrokanterik femur kiriklarinin kararliligi analitik olarak incelenmektedir. Bilgisayarli tomografi goruntuleri kullanilarak olusturulan insan femurunun uc boyutlu modelinin trokanterik bolgesinde intertrokanterik femur kirigi olusturulur. DKC implanti, Solidworks programinda uc boyutlu olarak olusturulup 10 farkli pozisyonda kirik femur modeline yerlestirilir. Elde edilen modeller uzerinden belirlenen noktalarin koordinatlari Solidwork programi ile belirlenir. Bu noktalardaki statik momentler yurume esnasinda femur basina etkiyen maksimum kuvvet uygulanarak analitik olarak hesaplanir. Femur bas kisminin inferior (alt) bolgesine yerlestirilen implantta dusuk momentler hesaplandi. En yuksek moment degerleri Superior (ust) bolgesine yerlestirilen lag vidasinda hesaplandi. Analitik analiz sunu gostermistir ki; kirik kararliligi acisindan lag vidasi femur basinin inferior (alt) ya da me...

Amac: Son yillarda biyo-malzeme alaninda kayda deger calismalar olmus, onemli mesafeler kat edilm... more Amac: Son yillarda biyo-malzeme alaninda kayda deger calismalar olmus, onemli mesafeler kat edilmistir. Biyo-malzemelerden kullanilacagi doku veya yere uyum saglayip istenilen en yuksek ozelliklerde performans gostermesi beklenir. Bu amaca yonelik olarak siklikla kullanilan kalca protezi femoral komponenti icin farkli malzemelerin gostermis oldugu yuk tasima kapasitesinin belirlenmesi, yer degisim miktarinin tayini ve kiyaslanmasi amaclanmistir. Materyal ve Metod: Bu calismada, total kalca protezi ve femur arayuzu bilgisayarli tomografi (BT) goruntuleri yardimiyla modellenmistir. Farkli malzemelerden olusturulmus ve femur ust bolgesine cerrahi prosedurler uygulanarak konumlandirilan kalca protezinin gerilme ve deplasman degerleri sonlu elemanlar yazilimi ANSYS Workbench yardimiyla incelenmistir. Bulgular ve Sonuc: Gercege yakinligi ve uygulanabilirligi ile diger yontemlerin onune gecen sonlu elemanlar metodu ile yapilan bu calismada, biyomedikal uygulamalarda siklikla kullanilan met...

Kompozit malzemeler; belirli bir amaca yonelik olarak en az iki farkli malzemenin bir araya getir... more Kompozit malzemeler; belirli bir amaca yonelik olarak en az iki farkli malzemenin bir araya getirilmesiyle meydana gelen malzeme grubudur. Uc boyutlu nitelikteki bu bir araya getirmede amac, bilesenlerin hic birinde tek basina mevcut olmayan bir ozelligin elde edilmesidir. Diger bir deyisle, amaclanan dogrultuda bilesenlerin daha ustun ozelliklere sahip bir malzeme uretilmesi hedeflenmektedir. Gun gectikce artan kullanim alanlarina cerrahi islem ve uygulamalar da eklenmektedir. Bu calisma ile kompozit malzemelerin agiz, yuz ve cene cerrahisinde kullaniminda meydana gelen egilme ve cekme ozelliklerinin karsilastirilmasi amaclanmistir. Ayrica yeni nesil olarak tabir edilen kompozit malzemelerin cene cerrahisi ve yuz doku kaybinda detek, ana unsur ve uygulama malzemesi olarak kullanilabilirligi arastirilacaktir. Cene cerrahisinde plak olarak kullanilan metal malzemelerin ve implant ust yapilarinin da kompozit malzeme olarak kullanilmasi durumundaki yeterlilikleri metal grubu olan benze...

The hip dysplasia is described by an irregular relation between the femoral head and the acetabul... more The hip dysplasia is described by an irregular relation between the femoral head and the acetabulum. Insufficient coverage of the femoral head by the acetabulum leads the development of dysplasia in the incongruity hip joint. Several osteotomies are carried out for treatment by changing with coverage angle of the femoral head in the hip joint. In this paper, the effects of osteotomy techniques used in the surgery applications on the coverage angle are investigated experimentally. Salter osteotomy technique was applied on a patient-specific artificial hip models manufactured at different osteotomy angles. The contact pressure distribution and area were measured by using Fuji Film Prescale sensor in the hip joint. The results were compared with each other. The average contact pressure expectedly decreases as long as osteotomy coverage angle increases but, the contact area decreases unexpectedly

Afyon Kocatepe University Journal of Sciences and Engineering, 2021

Omurga sorunlarında sıklıkla pedikül vida ve rod sistemleri kullanılır. Bu sistemlerin en büyük s... more Omurga sorunlarında sıklıkla pedikül vida ve rod sistemleri kullanılır. Bu sistemlerin en büyük sorunları vida kırılması ve vida gevşemesidir. Vida ve rod malzemesi olarak halihazırda metalik implantlar kullanılmaktadır ve metalik implantların elastik modüllerinin yüksek olması sebebi ile kemiğe yük aktarımında sıkıntılar oluşabilmektedir. Bu çalışmada, metalik implantlara göre elastiklik modülü daha düşük olan ve son zamanlarda kullanımı artan Polilaktik Asit (PLA) malzemesi ve bu malzemeden oluşturulan Polilaktik Asit/Hidroksiapatit (PLA/HA) kompozit malzemesinin pedikül vidalarında kullanılabilirliği mukavemet yönünden değerlendirilmiştir. Bu amaçla sonlu elemanlar yöntemi kullanılmıştır. T9 omurga modeli MIMICS yazılımı ile oluşturulmuş ve vida-rod modelleri ile ameliyat prosedürüne uygun olarak bilgisayar ortamında birleştirilmiştir. Sonlu elemanlar analizi için pedikül vida malzemeleri Ti6Al4V, PLA ve PLA/HA malzemeleri seçilmiştir. Ayrıca, pedikül vida modeli üzerinde tasarım değiştirerek iki farklı model daha analize katılmıştır. Yapılan 5 farklı analiz sonuçları karşılaştırılmış ve en uygun pedikül malzemesi/tasarımı belirlenmiştir. Sonuç olarak, PLA/HA kompozit malzeme kullanımı yeterli mukavemete ve rijitliğe sahip olmuştur. Ayrıca, vida tasarım değişikliği ile PLA malzemesi pedikül vidalar için kullanılabilir.

Düzce Üniversitesi Bilim ve Teknoloji Dergisi, 2018

Diz eklemini oluşturan tüm yapılar normal hareket edilmesinin sağlanmasında önemli rol oynarlar. ... more Diz eklemini oluşturan tüm yapılar normal hareket edilmesinin sağlanmasında önemli rol oynarlar. Ortopedik olarak normal bir insanın yürüme döngüsü femur ve tibia kemiklerinin bir dizi konum değişim entegrasyonu ile ortaya çıkmaktadır. Bu çalışmada, normal bir alt ekstremite dizilimine sahip bir insanın yürümesindeki dinamik kuvvet analizi yapılmış ve diz eklemi kinematik çözümlemesi ele alınmıştır. Diz eklemi yatay eksen etrafında fleksiyon ve ekstansiyon yaparken ön düzlemde içe doğru kayma adı verilen abdüksiyon hareketi ile dışa doğru kayma olarak tanımlanan addüksiyon hareketini yapar. Tıbbi terminoloji olarak medial-lateral olarak tanımlanmış olan iç ve dış düzlemde ise sınırlı dönme yapar [6-12]. Kabul edilen bir terminoloji ile anlık dönme merkezi, diz eklemine aktarılan yükün dik olarak etkime yapmasını ve bağlar üzerine aşırı kuvvet aktarılmasını engelleme görevi görür. Diz aktif olarak 140°, pasif olarak 160° fleksiyon yapabilir [5-10].

Duzce Universitesi Bilim Ve Teknoloji Dergisi, 2014

Bu çalışmada, Dinamik Kalça Çivisinin (DKÇ) sabitlenmesinde lag vidasının farklı konumlarına göre... more Bu çalışmada, Dinamik Kalça Çivisinin (DKÇ) sabitlenmesinde lag vidasının farklı konumlarına göre intertrokanterik femur kırıklarının kararlılığı analitik olarak incelenmektedir. Bilgisayarlı tomografi görüntüleri kullanılarak oluşturulan insan femurunun üç boyutlu modelinin trokanterik bölgesinde intertrokanterik femur kırığı oluşturulur. DKÇ implantı, Solidworks programında üç boyutlu olarak oluşturulup 10 farklı pozisyonda kırık femur modeline yerleştirilir. Elde edilen modeller üzerinden belirlenen noktaların koordinatları Solidwork programı ile belirlenir. Bu noktalardaki statik momentler yürüme esnasında femur başına etkiyen maksimum kuvvet uygulanarak analitik olarak hesaplanır. Femur baş kısmının inferior (alt) bölgesine yerleştirilen implantta düşük momentler hesaplandı. En yüksek moment değerleri Superior (üst) bölgesine yerleştirilen lag vidasında hesaplandı. Analitik analiz şunu göstermiştir ki; kırık kararlılığı açısından lag vidası femur başının inferior (alt) ya da medial (orta) bölgesinde ve femur uç (apeks) bölgesine yakın pozisyonlandırılmalıdır.

Nigerian Journal of Clinical Practice, 2016

Objective: The aim of the study was to evaluate the mechanical behavior of three different fixati... more Objective: The aim of the study was to evaluate the mechanical behavior of three different fixation methods used in the bilateral sagittal split ramus osteotomy. Materials and Methods: Three different three-dimensional finite element models were created, each corresponding to three different fixation methods. The mandibles were fixed with double straight 4-hole, square 4-hole, and 5-hole Y plates. 150 N incisal occlusal loads were simulated on the distal segments. ANSYS software ((v 10; ANSYS Inc., Canonsburg, PA) was used to calculate the Von Mises stresses on fixative appliances. Results: The highest Von Mises stress values were found in Y plate. The lowest values were isolated in double straight plate group. Conclusions: It was concluded that the use of double 4-hole straight plates provided the sufficient stability on the osteotomy site when compared with the other rigid fixation methods used in this study.

Acta of bioengineering and biomechanics / Wroclaw University of Technology

Blount's disease, or tibia vara, is the most common cause of pathologic genu varum in childre... more Blount's disease, or tibia vara, is the most common cause of pathologic genu varum in children and adolescents. Changes in the loading of knee structures such as tibial articular cartilage, menisci and subcondral bone are well documented in case of genu varum. But the mechanical effects of this condition on foot bones are still questionable. In this study, the authors hypothesized that stress distributions on foot bones might increase in patients with tibia vara when compared with patients who had normal lower extremity mechanical axis. Three-dimensional (3D) finite element analyses of human lower limb were used to investigate and compare the loading on foot bones in normal population and patient with tibia vara. The segmentation software, MIMICS was used to generate the 3D images of the bony structures of normal and varus malalignment lower extremity. Except the spaces between the adjacent surface of the phalanges fused, metatarsals, cuneiforms, cuboid, navicular, talus and cal...

Orthopaedics & Traumatology: Surgery & Research, 2014

Background: Surgeons have aimed to achieve strong repair so as to begin early active rehabilitati... more Background: Surgeons have aimed to achieve strong repair so as to begin early active rehabilitation programs for flexor tendon injury. Multi-strand suture techniques were developed to gain improved gap resistance and ultimate force compared with the respective two-strand techniques. In vivo studies indicate that multiple strands may cause ischemia during the intrinsic healing process by decreasing the total cross-sectional area of the injured site, unless the total cross-sectional area of the sutures is not decreased. Hypothesis: The hypothesis was to design an in vitro study to understand the biomechanical relationship between suture calibers of core sutures with increased number of suture strands and peripheral suture on final repair strength. Materials and methods: Sixty fresh sheep forelimb flexor digitorum profundus tendons were randomly placed into three groups (A, B, and C), each containing 20 specimens, for tendon repair. Two-, four-, and eight-strand suture techniques were respectively used in Groups A, B, and C. A simple running peripheral suture technique was used in Subgroups A2, B2, and C2. For each repaired tendon, the 2-mm gap-formation force, 2-mm gap-formation strength, maximum breaking force and maximum breaking strength were determined. Results: Differences in 2-mm gap-formation force and 2-mm gap-formation strength were found between Subgroups A1 and A2, B1 and B2, and C1 and C2. Between Groups A and B, A and C, and B and C, there was no difference as well. Conclusion: Both the number of strands and the ratio between the total suture volume and tendon volume at the repair site are important for ideal repair. If the total cross-sectional area of the sutures is equal in 2-strand, 4-strand, and 8-strand procedure, there is no difference in the strength of the repair. A decrease in caliber size suture requires more passes to achieve the same strength. Instead, it is much better to use peripheral suture techniques to improve the strength of the repair with larger diameter 2-strand core sutures.

The International Journal of Medical Robotics and Computer Assisted Surgery, 2013

Background Proximal tibial open wedge osteotomy (PTO) is a corrective operation used in the surge... more Background Proximal tibial open wedge osteotomy (PTO) is a corrective operation used in the surgery of lower extremities and is applied to patients with varus deformities for sufficient correction. The aim of the study was to evaluate whether the PTO can achieve decreased stress-bearing on the tibia and tarsal bones in addition to correcting the mechanical axis the of lower limb in patients with tibia vara. Methods Three-dimensional (3D) solid modelling of the lower extremity was carried out using computed tomography (CT) and magnetic resonance (MR)-containing images of all of the bony elements and non-bony structures. PTO was applied to the obtained deformed model in the computer environment and the correction was carried out. Results Stress distributions in menisci, tibia and tarsal bones were calculated. With respect to loading on the tarsal bones, the maximum equivalent stresses on all bones decreased except for the navicula in the PTO-simulated model in the current study. Conclusion These results clearly indicate that PTO can achieve decreased stresses on the tarsal bones in patients with tibia vara.

The Journal of Engineering Research, 2014

The aim of the present study is to compare the plate materials for calculating stress distributio... more The aim of the present study is to compare the plate materials for calculating stress distributions and displacements on the square type mini mandibular fixators. A model of the mandible was modeled aided with computed tomography (CT) images. The CT images were converted to the finite element model aided by reverse engineering methodology. 3 materials (Titanium Alloy, Chrome-Cobalt and Stainless Steel) for square type mini plate and fixators were designed. The finite element analyses (FEA) (In Slico) were performed with respect to displacement and stress distributions for both mandibular, and fixators its fixation screws. According to all FEA results, "Square" type fixators for linear fracture type had a minimum stress distribution. FEA is useful for comparing geometry and material variations of rigid mandibular fixations.

$Research paper thumbnail of The evaluation of the relation between dynamic hip screw positions and its failure in unstable femur fractures$

Australian Journal of Mechanical Engineering, 2019

In this study, effects of the Dynamic Hip Screw (DHS) positions on its failure are investigated i... more In this study, effects of the Dynamic Hip Screw (DHS) positions on its failure are investigated in unstable femur fracture using Finite Element Analysis (FEA). The failures of DHS were emphasised in the latest several case studies. In order to create 3D computerised models, the unstable femur fractures were generated in the trochanteric region of the femur obtained from Computerised Tomography Images. The DHS model in 3D CAD form was placed in nine different positions into the fractured femur. Two different Tip-Apex distances (TAD) (20 and 25 mm) were used for each DHS positions. In the FEA, muscles and body forces were applied to the femur according to the maximum value based on regular walking. The best position and TAD value were determined according to the von Mises stresses calculated on the DHS. The FEA calculation showed that the minimum stress value was obtained on the DHS placed in the middle and superior regions of femur head. Higher TAD value (25 mm) were decrease the von Mises stresses of the DHS. In conclusion, the calculated results suggest that the best DHS position is in the spherical centre of the femur head considering the failures of both femur and DHS together.

$Research paper thumbnail of How does the material variation of dynamic hip screw affect the cut-out risk in the treatment of intertrochanteric femoral fractures?$

International Journal of Experimental and Computational Biomechanics, 2016

The material selection of dynamic hip screw (DHS) is not usually considered from the point of mec... more The material selection of dynamic hip screw (DHS) is not usually considered from the point of mechanical effects. In this study, the effects of the titanium alloy and stainless steel DHS was investigated in the cut-out risk of femur using finite element analysis (FEA). Intertrochanteric femur fracture (IFF) (31-A2 type according to AO classification) was created in the 3D femur model obtained from computer tomography images. The DHS model was inserted to the fractured femur model in two different positions (inferior and middle). The material properties of DHS were defined for the FEA. The force applied to the femoral head was determined according to the maximum value that is observed during walking. The results show that the safest model was obtained in the middle placement of titanium alloy DHS according to the safety factor. Consequently, the use of stainless steel DHS for IFF could cause higher failure risk of DHS than the use of titanium alloy DHS.

Journal of Medical Engineering, 2016

Background. In this study, the cut-out risk of Dynamic Hip Screw (DHS) was investigated in nine d... more Background. In this study, the cut-out risk of Dynamic Hip Screw (DHS) was investigated in nine different positions of the lag screw for two fracture types by using Finite Element Analysis (FEA). Methods. Two types of fractures (31-A1.1 and A2.1 in AO classification) were generated in the femur model obtained from Computerized Tomography images. The DHS model was placed into the fractured femur model in nine different positions. Tip-Apex Distances were measured using SolidWorks. In FEA, the force applied to the femoral head was determined according to the maximum value being observed during walking. Results. The highest volume percentage exceeding the yield strength of trabecular bone was obtained in posterior-inferior region in both fracture types. The best placement region for the lag screw was found in the middle of both fracture types. There are compatible results between Tip-Apex Distances and the cut-out risk except for posterior-superior and superior region of 31-A2.1 fractur...