Influence of materials for fixation implants on local infection. An experimental study of steel versus titanium DCP in rabbits.

Resistance to infection may be influenced by foreign bodies such as devices for fracture fixation. It is known that stainless steel and commercially-pure titanium have different biocompatibilities. We have investigated susceptibility to infection after a local bacterial challenge using standard 2.0 dynamic compression plates of either stainless steel or titanium in rabbit tibiae. After the wounds had been closed, various concentrations of a strain of Staphylococcus aureus were inoculated percutaneously. Under otherwise identical experimental conditions the rate of infection for steel plates (75%) was significantly higher than that for titanium plates (35%) (p < 0.05).

Infection after intramedullary nailing: an experimental investigation on rabbits.

The purpose of this study was to investigate three relevant aspects of intramedullary nailing in terms of their effect on the occurrence of local infection. In an infection model on the rabbit tibia, the following were compared: a hollow and a solid nail (Experiment I), a reamed with an unreamed technique (Experiment II), and a steel with a titanium nail (Experiment III). In order to minimize the number of animals required, a grouped sequential procedure combined with an "up and down" dosage technique was applied. Microbiological evaluation was both qualitative and quantitative. The results in Experiment 1 (n = 44) indicated an infection rate for the hollow nail (59%) almost double that of the solid nail (27%) (P < or = 0.05). Experiment II (n = 44) produced an infection rate of 50% for the unreamed technique compared to 64% for the reamed technique, a difference which, on the basis of the number of bacteria present, was also statistically significant (P < or = 0.05). In Experiment III (n = 44) an infection rate of 82% was recorded for the steel nail compared to 59% for the titanium nail (P < or = 0.05). The results of the three experiments are only partially comparable with each other because of the grouped sequential procedure and the different inocula used. Nonetheless it would seem that the dead space inherent in the design of the hollow nail represents a considerable risk with regard to the occurrence of local infection. Reaming the medullary cavity with the attendant reduction in local vascularity and necrosis and the lesser biocompatibility of steel compared to titanium may be additional risk factors which should not be overlooked.

Infection after open reduction and internal fixation with dynamic compression plates--clinical and experimental data.

Infection rates for open reduction and internal fixation (ORIF) with the DCP in clinical studies are based on heterogeneous data on general risk factors and do not take into account the direct effect of the implant (material, design, surface, technique). The initial degree of bacterial contamination is generally unknown and the applied definition of the term infection is not mentioned. In our own prospective randomized clinical study including 281 cases of ORIF with the DCP (154 steel vs 127 titanium), the influence of the implant material on susceptibility to local infection was examined in relation to initial bacteria contamination (109 non-contaminated / 172 contaminated). Although in the group of contaminated DCPs the difference in the infection rates for stainless steel (sSt) and commercially pure titanium (cpTi) showed no statistical significance, a tendency was apparent. In an animal experiment, the lower rates of infection for c.p.Ti-DCP compared to sSt-DCP in the presence of a local bacterial challenge could be demonstrated with statistical significance. The need for further experimental research in the field of implant related local infection after ORIF will be discussed and strategies for further investigations proposed.

Influence of reaming versus nonreaming in intramedullary nailing on local infection rate: experimental investigation in rabbits.

The question of whether the impairment of the endosteal blood supply, which is induced by nailing with reaming of the medullary cavity, increases the risk of a postoperative infection cannot be conclusively answered by studying existing literature. The aim of this study was to investigate the effect of medullary reaming on the occurrence of local infection based on an infection model in the rabbit tibia (n = 44). An infection rate of 50% was found after unreamed nailing, as opposed to an infection rate of 64% after medullary reaming. The number of bacteria observed after reaming was significantly higher than after nail insertion without previous reaming. The differing susceptibilities to infection as observed in this model are statistically significant (p < or = 0.05).

[Standards, guidelines and principles for clinical trials: medical products]. / Standards, Richtlinien und Prinzipien für die klinische Prüfung medizinischer Produkte.

In addition to existing legislation there have been valid european and international Good Clinical Practice (GCP) guidelines and standards for the planning management and evaluation of clinical research projects and of clinical investigation of medical products since the 1990's. GCP regulates patient protection, the responsibilities of the sponsors, information management, data processing and quality assurance. The Draft International Standard (ISO/DIS 14155) and the European Standard (CEN/EN 540) stipulate the prerequisites and conditions for the clinical testing of medical products and devices. The essential documents for any research or investigative project include the trial protocol and the investigator's brochure. Observation of the guidelines and standards must be emphasized chiefly for reasons of publication suitability and the international recognition of the research and development findings.

[Alpine skiing--accident--and equipment studies]. / Alpinski--Unfall- und Ausrüstungsstudien.

According to medical statistics over the last two decades, skiing is still associated with a certain risk of accident and injury. A review of studies carried out in Davos on alpine skiing accidents covering two decades aimed at assessing the effect of safety improvements in ski bindings combined with ski shoes and skis in view of injury statistics. Five comprehensive research studies included almost 10,000 injured and non-injured skiers and experience with nearly 29,000 injured skiers treated the Davos hospital. Firstly, the causes and preceptating factors of skiing accidents were determined and the role of binding release tests assessed. Then the effect of the skier on the accident was investigated. The function of ski binding adjustments was also studied. In a fourth step comprehensive data on multicentric research project were obtained. With the growing popularity of safety bindings in the 1970's and the results of research projects, the frequency of skiing accidents seemed to diminish or at least stagnate. The annual statistics from 1974 to 93 show a reduction in the frequency of tibial fractures and simultaneous rapid increase in the frequency of injuries of the knee joint, the upper limbs and the trunk. The situation demonstrate that measurements to control the accident rate cannot be based only on accident statistics and technical developments, but must rely on further studies of the mechanism of the fall and analyses of the long-term consequences of injuries.

Effect of bone size, not density, on the stiffness of the proximal part of normal and osteoporotic human femora.

Proximal femur fractures in the elderly lead to a high rate of hospitalization. In studying the operative treatment of such fractures, it is first necessary to understand the relationship between the morphologic properties of this part of the femur (related to both geometry and density) and its mechanical properties. Numerous investigations showed that femoral strength correlates with bone mass; however, the dimension of the bones was not taken into account. We measured the relationship between the stiffness of the proximal femur under physiologic load and its geometry and density. Conventional x-rays and quantitative computed tomography (QCT) were carried out on pairs of human cadaver femora. Eight pairs were instrumented with strain gauges. Bones were subjected to an eccentric load that simulates moderate weight bearing (single-leg stance), and the strain parallel to the bone axis was plotted as a function of the load applied. An apparent bone stiffness was calculated as the ratio between the strain gradient within the section and the load applied. Strong correlation was found between x-ray densitometry and QCT. The bone stiffness also correlates strongly with the geometry (area) and slightly with bone mass; however, an unexpectedly low correlation was found between stiffness and density. We chose stiffness as a mechanical parameter (not strength) because it describes the "normal" bone behavior under load. Our results clearly demonstrate that the cross-sectional size of the bones must be taken into account when establishing the relationship between the mechanical characteristics of the bone and its morphology. In accordance with previous predictions, our results support that bone loss due to osteoporosis is compensated for by an increase in bone diameter.

[The ski accident in the last 15 years. Correlations with equipment]. / Der Skiunfall in den letzten 15 Jahren. Zusammenhänge mit der Ausrüstung.

In the region of Davos/Klosters an extensive epidemiological study has been performed on winter sports-accidents, especially from alpine skiing during the last 15 years. The ski-accidents have been related to the skiers activity, measured by the kilometers of altitude (vertical drop) in downhill-skiing. The injuries are still mainly located on the extremities, fractures of the lower leg have significantly decreased but serious ligamentous injuries of the knee have replaced them in high numbers. The severity of the injuries has been evaluated considering multiple factors and a decrease could be noted. Permanent disability does occur but fortunately only rarely. The incidence of ski-accidents as well as the high costs of treatment highly demand continuation of research activities for the benefit of the safety of the skiers.

Skiing accidents in the past 15 years.

For the last 15 years a statistical analysis of distances skied and of alpine skiing accidents has been performed in the Davos-Klosters skiing area, a 'closed' skiing area, where every skier has to return from the top to the bottom station. Distance skied is measured by vertical drop in 10(6) km determined by calculations from frequency surveys by lift-operators. About 2.5 million km per season have been skied during the past years, a number remaining constant for the last 15 years. In the same time the requirement for rescue-transports in this area has shown a decline of 46% to 288 transports per season due to a decrease of the number of injuries with initial immobilization. Therefore the so-called transport-quotient (one rescue-transport per 10(4) km of vertical drop skied) has decreased from its initial value of 4 to 1 per 10(4) km. During the same time all winter sport injuries were analysed at the hospital of Davos. About 90% are injuries caused by alpine skiing resulting in a total of 17,246 alpine skiing injuries for the last 15 years. There is a great decline in the incidence of lower leg fractures with a contrary development of knee injuries. Today half of the lower leg injuries are knee injuries (280 knee injuries out of a total of 1250 alpine skiing accidents per season). There is a gradual increase of upper extremity injuries from 17% of all skiing injuries in 1972 to 35% in 1976. A Swiss multicentre study on skiing safety shows comparable injury patterns in other skiing areas. The average injury-severity measured by several parameters is declining.(ABSTRACT TRUNCATED AT 250 WORDS)

[Acute myocardial infarct in a metropolitan area]. / Akuter Herzinfarkt in der Grossstadt.

In a retrospective study the course of acute myocardial infarction was investigated in 1840 patients treated in 1980 in eleven Hamburg hospitals (90% of hospitals admitting emergencies). 71% of patients were over 60 years of age, infarction frequency reached its peak in the eighth decade. Compared to prior investigations the percentage of women was higher both as a whole and in patients over 70 years of age (ratio men to women = 1.8 : 1). In comparison with the overall population of Hamburg, infarction rate was not increased in certain social classes. Frequency of "silent" infarctions was 4 to 5 times higher in patients of 70 years of age than in younger ones. Left ventricular failure and conduction disturbances increased with age, while extrasystoles occurred at all ages without difference. Hospital mortality of acute infarction was 29% for men and 37% for women. Striking results are the higher mortality of younger women and the considerable increase of mortality in patients over 70 years of age, probably due to change of age structure, the large number of acute reinfarctions (29%), and the short admission time. 40% of patients of all age-groups were admitted within 3 hours after onset of infarction.

[Heart infarction in persons over 70. Epidemiologic studies of the clinical course]. / Herzinfarkt bei über 70jährigen. Epidemiologische Untersuchung zum klinischen Verlauf.

1158 patients with acute myocardial infarction hospitalized in 6 clinics at Hamburg were analyzed retrospectively with special regard to older patients. 46% of all patients were older than 70 years. In contrast to former investigations the rate of myocardial infarction of women over 70 is arised. The reason of admission was reinfarction in 39%. The most frequent risk factors were hypertension and diabetes mellitus; but hypertension is not more frequent than in this age-group of the whole population. A so-called "silent" myocardial infarction occurred in 10-15% of patients over 70 years. The clinical course of acute myocardial infarction was injured by hemodynamic complications in 66%. Ventricular fibrillation was more frequent in younger than in older patients. The reanimation of older patients was successful in 25% primary, but the inhospital mortality was unchanged high (50%). In contrast to younger patients 40% of cases of death occurred after the acute phase in the 2.-4. week of hospital treatment.

[Clinical effects and tolerance of etofylline clofibrate]. / Klinische Wirkungen und Verträglichkeit von Etofyllinclofibrat.

The efficacy of 1-(theophyllin-7-yl)-ethyl-2-[2-(p-chlorophenoxy)-2-methylpropionate] (etofylline clofibrate, Duolip) was investigated in 47 hyperlipidaemic patients of type II--V in an open within-patient study. All patients were dietary adapted before the preliminary wash-out period of 4 weeks and received etofylline clofibrate in a dosage of 500 mg/day (2x1 capsule) over 4 weeks, and 750 mg/day (3 x 1 capsule) over further 4 months. Depending on type reductions of cholesterol between 15 and 23% and of triglycerides between 24 and 52% were achieved. The total lipids were reduced, too, between 14 and 31%. Except for type IIb, all reductions were statistically significant. The rate of responders was between 47 and 80%. The higher dose (750 mg) only affected the cases of type III and IV, in which a higher rate of responders was found coinciding with more pronounced lipid level reductions. However, the influence of the treatment duration on this increased activity may play an important role. Etofylline clofibrate did not show any side effects and was well tolerated. This clinical finding coinciding with the results of the preceding pilot study on the human tolerability in 10 volunteers. From all parameters tested only GPT and cholesterol showed significant alterations (reduction).

[Therapeutic experiences in the treatment of hyperlipoproteinaemia with etofylline clofibrate (author's transl)]. / Therapeutische Erfahrungen bei der Behandlung der Hyperlipoproteinämie mit Etofyllinclofibrat.

Efficacy and tolerance of 1-(theophyllin-7-yl)-ethyl-2-[2-(p-chlorophenoxy)-2-methylpropionate] (etofylline clofibrate, Duolip) was investigated in 100 patients under practitioner conditions, out of whom 50 patients received daily 500 mg (2 x 1 capsule etofylline clofibrate and 50 patients daily 750 mg (3 x 1 capsule) over a therapeutic period of 8 weeks each. The whole group consisted of patients of type IIa, IIb and IV. The effect on blood lipids was determined in the parameters cholesterol, triglycerides and total-beta-lipoproteins. In patients of type II high and significant reduction of cholesterol and of total-beta-lipoproteins (27%) were found, in type IV especially significant reductions of triglycerides and total-beta-lipoproteins of 37 and 24%, resp. The rate of responders in type II was between 50 and 100%. Common blood parameters of tolerance did not show remarkable alterations. Unspecific gastrointestinal side effects were only observed in 3 patients. For the therapy of hypolipoproteinaemia etofylline clofibrate was established as a highly active, low-dosed drug.

[On the uricosuric activity of etofylline clofibrate (author's transl)]. / Zur Frage der harnsäuresenkenden Wirkung von Etofyllinclofibrat.

In a review study including altogether 5 clinical trials with a total of 221 hyperlipidaemic patients the influence of 1-(theophyllin-7-yl)-ethyl-2-[2-(p-chlorophenoxy)-2-methylpropionate] (etofylline clofibrate, Duolip) treatment on serum uric acid level was investigated. 73 patients thereof, i.e., one-third of the hyperlipidaemic patients, had increased values of uric acid. In all studies a statistically significant and clinically relevant uricosuric activity was established.