Annals of Advances in Automotive Medicine, Oct 1, 2009
ABSTRACT For years, information and motivation campaigns have been conducted in order to increase... more ABSTRACT For years, information and motivation campaigns have been conducted in order to increase the frequency of use of helmets for bicyclists. Observation of two-wheeler traffic in 2005 involving more than 13,000 cyclists showed an incidence of helmet use in only 6% of the cases. This may be the reason for the fact that there are no comparative studies from Germany that prove the protective effect of the helmet by comparing victims of road accidents who wore a bicycle helmet and those who did not. For this purpose, data collected at the site of accidents (in the German In-Depth Accident Study) have been used for the first time in 10 years during which accidents with helmeted bicyclists could be documented; scientific researchers drove to the scenes of the accidents using specially equipped emergency vehicles and documented vehicle deformations and accident traces in addition to the injuries. A comprehensive accident reconstruction supplies the data concerning the speed and injury mechanisms. The data are processed representatively for the road traffic situation in Germany by means of statistic random sampling and statistic weighing and are stored in a database. An evaluation of 4049 injured bicyclists documented between the years 1999 and 2006 shows at first a decreasing and then an increasing use of bicycle helmets amongst traffic accident victims (1999: 14.2%; 2001: 3.6%; 2006: 9.5%); 518 children up to 15 years of age and 2979 adult cyclist constitute the total population available for analysis. This evaluation contains the representation of the injury situations of child and adult cyclists. Accident severity and injury samples are represented in detail, and the possible effectiveness of a bicycle helmet is discussed. The detailed data collection of accidents allows for, amongst others, the identification of the damages to the protective helmet and the analysis of head injuries in the absence of the protective helmet according to type, severity and location. For identical accident severities and accident constellations as well as relatively identical total injury severities, a lower-injury-severity Maximum Abbreviated Injury Score of cyclists and a more-frequent intactness of the head can be registered amongst bicycle helmet users (with helmet 72.7%, without helmet 61.3%). Severe injury Abbreviated Injury Score > 3 occurred 50% more frequently without helmet than with helmet (without helmet: 1.8%; with helmet: 1.2%).
Academic careers often place the burden of research on top of clinical work. This conflict denote... more Academic careers often place the burden of research on top of clinical work. This conflict denotes a demanding task especially in surgical disciplines, such as orthopaedics and traumatology. Driven by changes in the social system, concerning, e.g., leisure and parentship, the future organisation of the academic workplace needs to address these individual issues. With the aim to evaluate individual motivation towards combining research, clinical work and private life and to receive suggestions for improvement we conducted a survey addressing residents employed in the orthopaedic and traumatological departments of German university hospitals. With the support of the "Junges Forum der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU)", a survey, containing 21 questions about occupational and private issues, was sent out to the orthopaedic and traumatologic departments of 25 university hospitals in Germany. The focus of the questions was set on motivation, priorities and personal resources. It was possible to answer the questions by e-mail; later an anonymous online version of the survey was set in action as well. Completely answered forms were received from n = 105 physicians, of which 88 % were judged as active researchers. Over 50 % of the participants were satisfied with their clinical career and with their research results. 96 % of the survey participants felt sure that most of the research could only be managed during spare time. A majority of the participants supported the idea of receiving leave of absence from clinical duties for research in order to serialise the scientific and clinical careers. Interestingly, when focusing on priority settings, salary aspects were ranked as low as research interests, falling behind the wish for a more intensive surgical training and more leisure time. Individual solutions seem to be necessary to achieve a scheduled efficiency of clinical and research careers. This includes structural developments (like a professionally headed lab) and the establishment of dynamic clinical structures. It seems possible that the clinical organisation of physicians in teams might offer solutions to cope with the demands of surgical training and clinical care on the one hand and research on the other hand.
Advances in biochemical engineering/biotechnology, 2013
For the regeneration of bone and cartilage, mesenchymal stem cells are currently used invitro and... more For the regeneration of bone and cartilage, mesenchymal stem cells are currently used invitro and in-vivo. For bone, the existence of viable cells, scaffolds, mechanical environment, growth factors and vascularization are of paramount importance. Mesenchymal stem cells can be harvested from the bone marrow using minimally invasive techniques. Centrifugation can increase the number of transplanted cells per volume. The use of cell therapy is under current clinical investigation and the benefit from these systems has to be proven in level I studies. For cartilage, current techniques recruiting stem cells from the subchondral bone have been demonstrated to be nearly as effective as autologous chondrocyte transplantation, requiring less invasive surgery. The efficacy of mesenchymal stem cell concentrates remains to be proven. There is high potential for tissue engineered joint surfaces to become an option for joint surface defects and degeneration.
Zeitschrift für Orthopädie und Unfallchirurgie, 2010
Academic careers often place the burden of research on top of clinical work. This conflict denote... more Academic careers often place the burden of research on top of clinical work. This conflict denotes a demanding task especially in surgical disciplines, such as orthopaedics and traumatology. Driven by changes in the social system, concerning, e.g., leisure and parentship, the future organisation of the academic workplace needs to address these individual issues. With the aim to evaluate individual motivation towards combining research, clinical work and private life and to receive suggestions for improvement we conducted a survey addressing residents employed in the orthopaedic and traumatological departments of German university hospitals. With the support of the "Junges Forum der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU)", a survey, containing 21 questions about occupational and private issues, was sent out to the orthopaedic and traumatologic departments of 25 university hospitals in Germany. The focus of the questions was set on motivation, prior...
Within a study of accident data from GIDAS (German In-Depth Accident Study), vulnerable road user... more Within a study of accident data from GIDAS (German In-Depth Accident Study), vulnerable road users are investigated regarding injury risk in traffic accidents. GIDAS is the largest in-depth accident study in Germany. Due to a well-defined sampling plan, representativeness with respect to the federal statistics is also guaranteed. A hierarchical system ACASS (Accident Causation Analysis with Seven Steps) was developed in GIDAS, describing the human causation factors in a chronological sequence. The accordingly classified causation factors - derived from the systematic of the analysis of human accident causes ("7 steps") - can be used to describe the influence of accident causes on the injury outcome. The bases of the study are accident documentations over ten years from 1999 to 2008 with 8204 vulnerable road users (VRU), of which 3 different groups were selected as pedestrians n=2041, motorcyclists n=2199 and bicyclists n=3964, and analyzed on collisions with cars and trucks as well as vulnerable road users alone. The paper will give a description of the injury pattern and injury mechanisms of accidents. The injury frequencies and severities are pointed out considering different types of VRU and protective measures of helmet and clothes of the human body. The impact points are demonstrated on the car, following to conclusion of protective measures on the vehicle. Existing standards of protection devices as well as interdisciplinary research, including accident and injury statistics, are described. With this paper, a summarization of the existing possibilities on protective measures for pedestrians, bicyclists and motorcyclists is given and discussed by comparison of all three groups of vulnerable road users. Also the relevance of special impact situations and accident causes mainly responsible for severe injuries are pointed out, given the new orientation of research for the avoidance and reduction of accident patterns.
The purpose of the current study was to evaluate the influence of internal and external knee rota... more The purpose of the current study was to evaluate the influence of internal and external knee rotation on tibial tunnel position measurements in anterior cruciate ligament reconstruction using the Amis and Jakob line. Anatomic double bundle ACL reconstruction was performed in seven cadaveric knees. Afterwards, the knees were CT scanned, and 3D CT models were established. Utilizing these models, strict lateral and radiographs with the knees in 5°, 10°, and 20° of internal as well as external rotation were established. Using these radiographs, the positions of the anteromedial (AM) and posterolateral (PL) tibial tunnels were measured using the Amis and Jacob line. The tunnel positions of the strict lateral were compared to the rotated radiographs. To assess the inter- and intraobserver reliability, two independent observers measured the tunnel positions, and one observer measured twice. Significant differences for the AM tunnel position were observed if more than 10° of external or 20° of internal rotation were applied. For the PL tunnel position, no significant differences were found between the strict lateral and the rotated radiographs. Inter- and intraobserver reliability was good. The accuracy of the Amis and Jakob line is dependent on the degree of knee rotation and the position of the measured tunnel. Therefore, when using the Amis and Jakob line to determine the tibial tunnel position during surgery, attention should be paid to rotational alignment of lateral radiographs. However, the maximum rotation tested in the present study (20°) showed only a difference in tunnel position of 3.3 % compared to optimal rotational alignment. Thus, in most cases, the effects of minor malrotation on tunnel position measurement should be of minimal clinical significance.
Stem loosening in both cemented and uncemented total hip arthroplasty is the hallmark of the Vanc... more Stem loosening in both cemented and uncemented total hip arthroplasty is the hallmark of the Vancouver type B2 classification of periprosthetic hip fractures. We discuss the technique we use at our institution for treating these fractures. Periprosthetic femoral-shaft fractures are associated with a relatively high mortality rate, approximating that of patients with hip fractures. Outcomes are directly associated with early mobilisation and construct stability. We recommend performing the procedure only when the surgeon is proficient in revision hip surgery and trauma care. A well-selected portfolio of different stem designs and an array of osteosynthesis devices should be available, as well.
Press-fit fixation of anterior cruciate ligament autografts is an interesting technique because n... more Press-fit fixation of anterior cruciate ligament autografts is an interesting technique because no hardware is necessary. A total of 168 cadaveric human patellar, quadriceps and hamstring tendons (average age 49.2 +/- 18.5 years) were used and 15 different fixation methods were tested. Constructs were cyclically stretched and then loaded until failure. Maximum load to failure, stiffness and elongation during failure testing and cyclical loading were compared. Some techniques showed comparable biomechanical qualities to interference screw fixation. All investigated double bundle fixation techniques were equal in terms of maximum load to failure, stiffness and elongation. All techniques exhibited greater elongation during initial cyclical loading. Some of the press-fit fixation techniques investigated exhibited comparable biomechanical properties and preconditioning of the constructs is critical. Press-fit fixation enhances tendon to bone contact at the entry of the bone tunnel to the...
Ceramic heads are widely used in modern total hip arthroplasty (THA). Although a rare complicatio... more Ceramic heads are widely used in modern total hip arthroplasty (THA). Although a rare complication, fractures of ceramic heads are described in the literature, evoking uncertainties regarding the in vivo stability of this material, especially when impaction of a fractured ceramic head can lead to disastrous results. In this case report, we present a fracture of a ceramic head after trauma. A misinterpretation of the initial radiographs led to severe fragmentation of the ceramic head two weeks after the incident, later resulting in complete destruction of the arthroplasty. Remarkably, radiographs obtained more than one year after the trauma led to this delayed diagnosis. A single radiographic evaluation, especially in patients with persistent pain after major trauma, with a ceramic head in a THA, seems to be insufficient.
Annals of Advances in Automotive Medicine, Oct 1, 2009
ABSTRACT For years, information and motivation campaigns have been conducted in order to increase... more ABSTRACT For years, information and motivation campaigns have been conducted in order to increase the frequency of use of helmets for bicyclists. Observation of two-wheeler traffic in 2005 involving more than 13,000 cyclists showed an incidence of helmet use in only 6% of the cases. This may be the reason for the fact that there are no comparative studies from Germany that prove the protective effect of the helmet by comparing victims of road accidents who wore a bicycle helmet and those who did not. For this purpose, data collected at the site of accidents (in the German In-Depth Accident Study) have been used for the first time in 10 years during which accidents with helmeted bicyclists could be documented; scientific researchers drove to the scenes of the accidents using specially equipped emergency vehicles and documented vehicle deformations and accident traces in addition to the injuries. A comprehensive accident reconstruction supplies the data concerning the speed and injury mechanisms. The data are processed representatively for the road traffic situation in Germany by means of statistic random sampling and statistic weighing and are stored in a database. An evaluation of 4049 injured bicyclists documented between the years 1999 and 2006 shows at first a decreasing and then an increasing use of bicycle helmets amongst traffic accident victims (1999: 14.2%; 2001: 3.6%; 2006: 9.5%); 518 children up to 15 years of age and 2979 adult cyclist constitute the total population available for analysis. This evaluation contains the representation of the injury situations of child and adult cyclists. Accident severity and injury samples are represented in detail, and the possible effectiveness of a bicycle helmet is discussed. The detailed data collection of accidents allows for, amongst others, the identification of the damages to the protective helmet and the analysis of head injuries in the absence of the protective helmet according to type, severity and location. For identical accident severities and accident constellations as well as relatively identical total injury severities, a lower-injury-severity Maximum Abbreviated Injury Score of cyclists and a more-frequent intactness of the head can be registered amongst bicycle helmet users (with helmet 72.7%, without helmet 61.3%). Severe injury Abbreviated Injury Score > 3 occurred 50% more frequently without helmet than with helmet (without helmet: 1.8%; with helmet: 1.2%).
Academic careers often place the burden of research on top of clinical work. This conflict denote... more Academic careers often place the burden of research on top of clinical work. This conflict denotes a demanding task especially in surgical disciplines, such as orthopaedics and traumatology. Driven by changes in the social system, concerning, e.g., leisure and parentship, the future organisation of the academic workplace needs to address these individual issues. With the aim to evaluate individual motivation towards combining research, clinical work and private life and to receive suggestions for improvement we conducted a survey addressing residents employed in the orthopaedic and traumatological departments of German university hospitals. With the support of the "Junges Forum der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU)", a survey, containing 21 questions about occupational and private issues, was sent out to the orthopaedic and traumatologic departments of 25 university hospitals in Germany. The focus of the questions was set on motivation, priorities and personal resources. It was possible to answer the questions by e-mail; later an anonymous online version of the survey was set in action as well. Completely answered forms were received from n = 105 physicians, of which 88 % were judged as active researchers. Over 50 % of the participants were satisfied with their clinical career and with their research results. 96 % of the survey participants felt sure that most of the research could only be managed during spare time. A majority of the participants supported the idea of receiving leave of absence from clinical duties for research in order to serialise the scientific and clinical careers. Interestingly, when focusing on priority settings, salary aspects were ranked as low as research interests, falling behind the wish for a more intensive surgical training and more leisure time. Individual solutions seem to be necessary to achieve a scheduled efficiency of clinical and research careers. This includes structural developments (like a professionally headed lab) and the establishment of dynamic clinical structures. It seems possible that the clinical organisation of physicians in teams might offer solutions to cope with the demands of surgical training and clinical care on the one hand and research on the other hand.
Advances in biochemical engineering/biotechnology, 2013
For the regeneration of bone and cartilage, mesenchymal stem cells are currently used invitro and... more For the regeneration of bone and cartilage, mesenchymal stem cells are currently used invitro and in-vivo. For bone, the existence of viable cells, scaffolds, mechanical environment, growth factors and vascularization are of paramount importance. Mesenchymal stem cells can be harvested from the bone marrow using minimally invasive techniques. Centrifugation can increase the number of transplanted cells per volume. The use of cell therapy is under current clinical investigation and the benefit from these systems has to be proven in level I studies. For cartilage, current techniques recruiting stem cells from the subchondral bone have been demonstrated to be nearly as effective as autologous chondrocyte transplantation, requiring less invasive surgery. The efficacy of mesenchymal stem cell concentrates remains to be proven. There is high potential for tissue engineered joint surfaces to become an option for joint surface defects and degeneration.
Zeitschrift für Orthopädie und Unfallchirurgie, 2010
Academic careers often place the burden of research on top of clinical work. This conflict denote... more Academic careers often place the burden of research on top of clinical work. This conflict denotes a demanding task especially in surgical disciplines, such as orthopaedics and traumatology. Driven by changes in the social system, concerning, e.g., leisure and parentship, the future organisation of the academic workplace needs to address these individual issues. With the aim to evaluate individual motivation towards combining research, clinical work and private life and to receive suggestions for improvement we conducted a survey addressing residents employed in the orthopaedic and traumatological departments of German university hospitals. With the support of the "Junges Forum der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU)", a survey, containing 21 questions about occupational and private issues, was sent out to the orthopaedic and traumatologic departments of 25 university hospitals in Germany. The focus of the questions was set on motivation, prior...
Within a study of accident data from GIDAS (German In-Depth Accident Study), vulnerable road user... more Within a study of accident data from GIDAS (German In-Depth Accident Study), vulnerable road users are investigated regarding injury risk in traffic accidents. GIDAS is the largest in-depth accident study in Germany. Due to a well-defined sampling plan, representativeness with respect to the federal statistics is also guaranteed. A hierarchical system ACASS (Accident Causation Analysis with Seven Steps) was developed in GIDAS, describing the human causation factors in a chronological sequence. The accordingly classified causation factors - derived from the systematic of the analysis of human accident causes ("7 steps") - can be used to describe the influence of accident causes on the injury outcome. The bases of the study are accident documentations over ten years from 1999 to 2008 with 8204 vulnerable road users (VRU), of which 3 different groups were selected as pedestrians n=2041, motorcyclists n=2199 and bicyclists n=3964, and analyzed on collisions with cars and trucks as well as vulnerable road users alone. The paper will give a description of the injury pattern and injury mechanisms of accidents. The injury frequencies and severities are pointed out considering different types of VRU and protective measures of helmet and clothes of the human body. The impact points are demonstrated on the car, following to conclusion of protective measures on the vehicle. Existing standards of protection devices as well as interdisciplinary research, including accident and injury statistics, are described. With this paper, a summarization of the existing possibilities on protective measures for pedestrians, bicyclists and motorcyclists is given and discussed by comparison of all three groups of vulnerable road users. Also the relevance of special impact situations and accident causes mainly responsible for severe injuries are pointed out, given the new orientation of research for the avoidance and reduction of accident patterns.
The purpose of the current study was to evaluate the influence of internal and external knee rota... more The purpose of the current study was to evaluate the influence of internal and external knee rotation on tibial tunnel position measurements in anterior cruciate ligament reconstruction using the Amis and Jakob line. Anatomic double bundle ACL reconstruction was performed in seven cadaveric knees. Afterwards, the knees were CT scanned, and 3D CT models were established. Utilizing these models, strict lateral and radiographs with the knees in 5°, 10°, and 20° of internal as well as external rotation were established. Using these radiographs, the positions of the anteromedial (AM) and posterolateral (PL) tibial tunnels were measured using the Amis and Jacob line. The tunnel positions of the strict lateral were compared to the rotated radiographs. To assess the inter- and intraobserver reliability, two independent observers measured the tunnel positions, and one observer measured twice. Significant differences for the AM tunnel position were observed if more than 10° of external or 20° of internal rotation were applied. For the PL tunnel position, no significant differences were found between the strict lateral and the rotated radiographs. Inter- and intraobserver reliability was good. The accuracy of the Amis and Jakob line is dependent on the degree of knee rotation and the position of the measured tunnel. Therefore, when using the Amis and Jakob line to determine the tibial tunnel position during surgery, attention should be paid to rotational alignment of lateral radiographs. However, the maximum rotation tested in the present study (20°) showed only a difference in tunnel position of 3.3 % compared to optimal rotational alignment. Thus, in most cases, the effects of minor malrotation on tunnel position measurement should be of minimal clinical significance.
Stem loosening in both cemented and uncemented total hip arthroplasty is the hallmark of the Vanc... more Stem loosening in both cemented and uncemented total hip arthroplasty is the hallmark of the Vancouver type B2 classification of periprosthetic hip fractures. We discuss the technique we use at our institution for treating these fractures. Periprosthetic femoral-shaft fractures are associated with a relatively high mortality rate, approximating that of patients with hip fractures. Outcomes are directly associated with early mobilisation and construct stability. We recommend performing the procedure only when the surgeon is proficient in revision hip surgery and trauma care. A well-selected portfolio of different stem designs and an array of osteosynthesis devices should be available, as well.
Press-fit fixation of anterior cruciate ligament autografts is an interesting technique because n... more Press-fit fixation of anterior cruciate ligament autografts is an interesting technique because no hardware is necessary. A total of 168 cadaveric human patellar, quadriceps and hamstring tendons (average age 49.2 +/- 18.5 years) were used and 15 different fixation methods were tested. Constructs were cyclically stretched and then loaded until failure. Maximum load to failure, stiffness and elongation during failure testing and cyclical loading were compared. Some techniques showed comparable biomechanical qualities to interference screw fixation. All investigated double bundle fixation techniques were equal in terms of maximum load to failure, stiffness and elongation. All techniques exhibited greater elongation during initial cyclical loading. Some of the press-fit fixation techniques investigated exhibited comparable biomechanical properties and preconditioning of the constructs is critical. Press-fit fixation enhances tendon to bone contact at the entry of the bone tunnel to the...
Ceramic heads are widely used in modern total hip arthroplasty (THA). Although a rare complicatio... more Ceramic heads are widely used in modern total hip arthroplasty (THA). Although a rare complication, fractures of ceramic heads are described in the literature, evoking uncertainties regarding the in vivo stability of this material, especially when impaction of a fractured ceramic head can lead to disastrous results. In this case report, we present a fracture of a ceramic head after trauma. A misinterpretation of the initial radiographs led to severe fragmentation of the ceramic head two weeks after the incident, later resulting in complete destruction of the arthroplasty. Remarkably, radiographs obtained more than one year after the trauma led to this delayed diagnosis. A single radiographic evaluation, especially in patients with persistent pain after major trauma, with a ceramic head in a THA, seems to be insufficient.
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