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1

Effect of elliptical deformation of the acetabulum on the stress distribution in the components of hip resurfacing surgery

Stempin R., Dragan S. Ł., Kulej M., Filipiak J., Dragan S.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 4

35--41

EN

Hip resurfacing surgery is a matter of controversy. Some authors present very good late results of 99% survival outcomes. However, national records of implants point to the series of complications connected with biomechanical flaws of the implant. These results implicate the experimental research on biomechanical properties of HRS. The aim of the research was to define the nature of cooperation between the components of hip resurfacing surgery (HRS) and the influence of the deformation of acetabulum, the size of the implant and the nature of the bone surface on the stress distribution in the acetabulum and the femoral component. The calculations were run with the use of the finite element method (FEM), using the ANSYS bundle for this purpose. Four decrete models of the studied system were made: a model with the elements of the system connected with glue, a perfect spherical model with cooperating surfaces, a model reflecting an elliptical deformation of the acetabulum, and a model with different sizes of the implant. The results indicate that the stress values obtained for models with the ideally spherical acetabulum cannot cause significant deformation of cooperating implants. In the case of loads of the elliptically deformed acetabulum significant point stress concentrations can be observed in the spots of joint. The size of the acetabular and femoral components of HRS has influence on the stress concentration on the internal surface of the acetabulum as well as in the bone tissue surrounding the madrel of the femoral component. Moreover, physical properties of the base surface surrounding the HRS components have influence on the size of stress in the acetabulum and the femoral component.

2

Results and biomechanical consideration of treatment of congenital lower limb shortening and deformity using the Ilizarov method

Morasiewicz P., Morasiewicz L., Stępniewski M., Orzechowski W., Morasiewicz M., Pawik Ł., Wrzosek Z., Dragan S.

Acta of Bioengineering and Biomechanics

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2014

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Vol. 16, no. 1

133--140

EN

One of the applications of the Ilizarov apparatus is the correction of congenital shortening and deformities. Ilizarov external fixator produces biomechanical structure with surrounding tissue, which is the reason why very important is correct stability of fixator. Large distraction in the case of high value of lengthening, and large deformity corection result in shear stresses that occur additionally in the regenerate, which can potentially lead to damage of the regenerating nutritive microcirculation of bone tissue and bone fragment displacements. Our objective was to assess the results of the Ilizarov method in the treatment of congenital shortening taking into account treatment strategy and the size of the axis of lengthening and correction. Our research problems include presenting the effects of biomechanics of musculoskeletal deformations on treatment results, presenting complications and their treatment. Between 1989 and 2009, 62 patients underwent surgery to correct congenital lower limb deficiencies at our Clinic; 33 patients were followed-up. In total, there were 70 surgeries (2.12/patient). Axial correction was performed in 26 patients (78.79%). Average age at the start of the treatment was 15.58 years. Mean follow-up was 8.58 years. Mean lengthening per surgery was 3.17 cm with the lengthening index of 50.7 day/cm. Results were very good for 23 patients, good for 7 patients, satisfactory for 3 patients. Complications appeared in 24 patients, problems occurred in 74.42% of the cases, obstacles in 4.65% of cases, and true complications in 20.93% of the cases. The best results were achieved in the treatment of patients with two-stage and two-segment lengthening with a total elongation of less than 7 cm, and without correction of the axis. Congenital shortening of the lower limb should be treated comprehensively because the shortening applies to all segments, and disturbs biomechanics of all lower limb. In the case of axial correction and large amount of elongation high soft tissue forces counteract the distraction forces. Hybrid construction may help to shorten treatment time, increase fixator stability and decrease rate of complications. We suggest use of hybrid Ilizarov fixator, especially when large elongation and axis corection are planned.

3

Pedobarographic evaluation of body weight distribution on the lower limbs and balance after derotation corticotomies using the Ilizarov method

Morasiewicz P., Dragan S

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 2

91--96

EN

Distortion of the axis and shortening of the limbs result in multiple musculoskeletal pathologies. Rotation disorders should also be included among the disorders of the axis of the lower limb. In the case of rotational distortion, only derotation osteotomy can effectively correct torsion-associated deformations. Rotational distortion correction is accompanied by translational displacement and torsion, which results in more complex biomechanics. Using the pedobarographic platform, it is possible to evaluate static and dynamic posture and gait, percentage of body weight distribution on the lower limbs, and balance. Physiological gait and distribution of weight on the lower extremities are symmetrical. Balance is one of the determinants of proper biomechanics of the musculoskeletal system. An important aspect of treatment evaluation is pedobarographic assessment of balance and body weight distribution on the lower extremities ratio. The aim of this work was to evaluate the pedobarographic assessment of body weight distribution on the lower limbs and balance in patients with derotation corticotomies using the Ilizarov method. The study examined a group of 56 patients, who underwent derotation corticotomy using the Illizarov method between 1996 and 2012 at the Clinic of Orthopaedics and Traumatology of the Musculoskeletal System in Wrocław. The control group consisted of 54 patients, who were treated with correctional derotation-free corticotomy using the Ilizarov. Distribution of body weight on the lower limbs and balance were assessed with the pedobarographic platform. Following derotation corticotomy, the amount of body weight placed on the operated limb by subjects from the study group averaged 47.81%, 52.19% in the case of the healthy limb. These differences were not statistically significant. The difference between the average percentage of body weight placed on the diseased and healthy limb in the study group and the controls were not found to be statistically significant. There were no statistical differences in the average length of the gravity line or in the average surface area of the center of gravity position between the study and control groups. Balanced distribution of body weight on the lower limbs was achieved following derotation corticotomies using the Ilizarov method. Derotation corticotomies performed with the Ilizarov method allow for achieving normalization of body weight distribution on the lower limbs and balance, with values similar to those resulting from Ilizarov method derotation-free osteotomy.

4

Implementation of experimental method of determining modal characteristics of surface mining machinery in the modernization of the excavating unit

Rusinski E., Dragan S., Moczko P., Pietrusiak D.

Archives of Civil and Mechanical Engineering

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2012

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Vol. 12, no. 4

471--476

EN

This paper presents a method of determining modal characteristics of surface mining machines, which was used to establish the optimal number of buckets based on experimental studies of an existing machine. An experimental and operational modal analysis was implemented to determine the dynamic characteristics. Based on the technical requirements of the excavator, the quantity of buckets was set so as to avoid resonance during operation.

5

Evaluation of kinematics of SUV to pedestrian impact - Lower leg impactor and dummy approach

Ptak M., Rusiński E., Karliński J., Dragan S.

Archives of Civil and Mechanical Engineering

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2012

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Vol. 12, no. 1

68--73

EN

The paper describes the evaluation of the pedestrian kinematics after a collision with a Sport Utility Vehicle (SUV) with a high bumper. To meet the goal two approaches were chosen. First, the authors carried out the SUV to pedestrian strike simulation using the certified, finite element lower legform impactor. The impact procedure mirrored the car vs. pedestrian collision described in the current Regulation (EC) 78/2009. However, it has been earlier noticed that the overall pedestrian kinematics response may vastly differ if the lower legform impactor hits a car with a high bumper. To evaluate this, an ellipsoid, standing Hybrid III dummy model was also investigated. Subsequent tests of the dummy model, impacted by the high-bonnet vehicle, confirmed that the stand-alone subsystem test with impactors leads to inaccurate assessment of the actual, after impact, pedestrian kinematics.

6

Technologia wytwarzania i skład chemiczny preparatów wapniowych ze skorup jaj i dolomitu

Dolińska B., Mikulska A., Dragan S., Dobrzański Z., Trziszka T., Ryszka F.

Przemysł Chemiczny

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2011

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T. 90, nr 5

726-730

7

Preliminary evaluation of selected biologic properties of TiO2 and SiO2 layers on metallic substrates

Urbański W., Dragan S., Gębarowska E., Dzięgiel P., Krzak-Roś J., Miller M., Pezowicz C., Będziński R.

Engineering of Biomaterials

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2010

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Vol. 13, no. 96-98

129--133

EN

Despite of applying modern biomaterials during constructing long term orthopaedic implants, in clinical practice there are still present wide range of complications, particularly concerning matter of implant - tissue interactions. Since interaction between implant and living tissue depends mainly on biomaterial surface features, we decided to modify orthopaedic alloys to improve their biological properties. The object of this experiment was in vitro evaluation of selected biological properties, particularly cytotoxicity of titanium alloy and 316L stainless steel substrates coated with SiO2 or TiO2 thin films. The coatings were synthesized by sol-gel method. Each samples was placed into mouse fibroblast culture. The cultures in presence of tested materials were maintained for three days. We found no distinct toxic effect of tested biomaterials. We noticed increase of fibroblast proliferation in cultures with uncoated titanium and particularly SiO2 coated titanium plates.

8

Ocena przyczyn urazów u pacjentów Kliniki Ortopedii i Traumatologii Narządu Ruchu Akademii Medycznej we Wrocławiu - analiza na podstawie rocznych obserwacji

Matyja M., Skrzek A., Dragan S.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2008

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Vol. 14, nr 1

38-42

PL

Wstęp. W pracy podjęto próbę wskazania najczęstszych okoliczności występowania urazów kości i stawów w zależności od pici i wieku pacjentów. Celem pracy była również analiza innych wybranych czynników, takich jak pochodzenie, aktywność zawodowa, BMI (body mass index) w aspekcie ryzyka wystąpienia urazów w obrębie narządu ruchu. Materiał i metody. Badaniami objęto 490 pacjentów z rozpoznaniem złamania w obrębie układu kostnego, leczonych w Klinice Ortopedii i Traumatologii Narządu Ruchu Akademii Medycznej we Wrocławiu. Materiał został pozyskany z archiwum Kliniki. Dane wykorzystane w badaniach zostały zebrane na podstawie historii chorób pacjentów leczonych w roku 2002. Wyniki. Analiza badanego materiału wykazała, że najczęstszą przyczyną doznawanych urazów byty wypadki w domu, odnotowane w najstarszej grupie wiekowej. Drugą pod względem częstości przyczyną powstałych urazów byty wypadki komunikacyjne, zdarzające się najczęściej w najmłodszej grupie pacjentów - do 30. roku życia. Mając na względzie wartości BMI, liczba urazów była najwyższa u osób z prawidłowym wskaźnikiem BMI. Na podstawie badanego materiału stwierdzono, że najwięcej urazów zdarza się wśród osób zamieszkujących tereny miejskie. Ponad 57% badanych przypadków urazów zaobserwowano u osób nieaktywnych zawodowo, w większości kobiet po 60. roku życia. Wnioski. Częstość występowania urazów w obrębie narządu ruchu wykazuje związek z płcią i wiekiem pacjentów w badanym materiale. W badanym materiale nie zaobserwowano oczekiwanego związku między częstością doznanych urazów a względnym wskaźnikiem masy ciała (BMI).

EN

Background. The aim of the study was concerned with the identification of the main causes of injuries of bones and joints, with regard to the age and gender. The influeunce of body mass index BMI was analyzed, as well. Material and methods. The experimental group consisted of 490 patients admitted in 2002 to Orthopaedic and Traumatology Hospital of Medical University in Wrocław with fractures in skeletal system. Results. The materials analysis indicated that the most frequent causes of injuries were the following: falls at home in the group of older patients (older than 60, prevalently women). The second cause of injuries were traffic accidents. observed mostly in younger patients, under 30. Regarding BMI the highest number of cases was observed in patients with normal BMI index. The majority of injuries happened to patients living in urban areas. Over 57 % of examined cases related to older female patients (over 60) inactive professionally. Conclusions. There is a correlation between age and gender and frequency of injuries. The correlation between frequency of injuries and BMI was not observed in this study

9

Application of thermography in diagnostics and prognostication of scoliosis treatment

Dragan S., Konik H., Prastowski A., Orzechowski W.

Acta of Bioengineering and Biomechanics

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2002

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Vol. 4, nr 1

63-70

EN

The paper deals with the thermography applied to monitor the course of scoliosis treatment. In the research, 403 children and teenagers in the 9-17 age range (m = 13.4) were examined. The orthopaedic and thermovision examination was carried out once in the group of healthy children, whereas the children with the spine curvature, undergoing conservative and operative treatment, were examined orthpeadically, roentgenographically and thermovisionally before and after the treatment. Cobb's method and the Gruca categorisation of the degree of scoliosis were employed to assess the type and the level of the primary and the secondary curvature. The analysis of the thermographic pictures was carried out using the computer program for such an analysis of the back in relation to mechanic and anatomic axis of the spine. The results were analysed statistically and presented in the form of histograms. Based on the research, the thermographic model of the back and spine was constructed. The relation between the degree of the primary and the secondary curvature and the pattern of temperature distribution of the back was found as well as the thermographic features characteristic of the development of the scoliosis were identified.

10

Densitometric evaluation of bone regenerate in the experimental process of distractive osteogenesis by means of the Ilizarov method

Dragan S, Wall A., Kuryszko J., Krawczyk A.

Acta of Bioengineering and Biomechanics

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1999

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Vol. 1, nr 2

107-110

EN

The paper deals with the densitometric, histological and X-ray microanalyses undertaken in order to examine the mineralization process of bone regenerate during the distractive bone osteogenesis. Testing was carried out on 20 sheep on Merynos breed whose tibiae were elongated by means of distractive osteogenesis according to the Ilizarov method. Various methods of bone cross-cutting, i.e., open and closed coricotomy, were employed.