Biomedical subjects

C Krettek

Publications and source records attributed to C Krettek.

At least 55 records · Page 3Linked to original sources

PubMed2005

[The importance of cytokines in the posttraumatic inflammatory reaction].

Alterations in the immune response after multiple trauma, posttraumatic sepsis and surgery are recognized as physiological reactions of the organism to restore homeostasis. The level of these immunological changes correlates with the degree of tissue damage as well as with the severity of haemorrhage and ischaemia. Cytokines are known to be integral components of this immune response. The local release of pro- and antiinflammatory cytokines after severe trauma indicates their potential to induce systemic immunological alterations. It appears that the balance or imbalance of these different cytokines partly controls the clinical course in these patients. Overproduction of either proinflammatory cytokines or antiinflammatory mediators may result in organ dysfunction. Whereas predominance of the proinflammatory response leads to the systemic inflammatory response syndrome (SIRS), the antiinflammatory reaction may result in immune suppression with an enhanced risk of infectious complications. Systemic inflammation, as well as immune suppression, are thought to play a decisive role in the development of multiple organ dysfunction syndrome (MODS). The major proinflammatory cytokines involved in the response to trauma and surgery include tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6 and IL-8. These cytokines, which are predominantly produced by monocytes and macrophages, mediate a variety of frequently overlapping effects, and their actions can be additive. TNF-alpha and IL-1beta are early regulators of the immune response and both induce the release of secondary cytokines, such as IL-6 and IL-8. IL-10 is an antiinflammatory cytokine which reduces the synthesis of proinflammatory mediators. Other important antiinflammatory mediators are soluble TNF receptors and the IL-1 receptor antagonist, which interfere with the effects of TNF-alpha and IL-1beta.Early evaluation of the prognosis of polytraumatized patients and assessment of their clinical status is known to be difficult. Therefore, in several clinical studies, cytokine levels during the posttraumatic course have been determined with the aim of finding predictive markers of patient outcome. The purpose of this review was to highlight our current knowledge on the interaction of posttraumatic immune reactivity and the development of complications. A better understanding of these mechanisms might lead to the introduction of preventive and therapeutic strategies into clinical practice.

Adaptation, Physiological↗

PubMed2005

[Soft tissue management in knees with varus deformity. Computer-assisted sequential medial ligament release].

BACKGROUND: Knees with severe varus deformities and contractures of the medial and lateral collateral ligaments and the posterior capsule require special soft tissue management to gain a stable knee over the full range of movement. The introduction of navigation systems into knee surgery has now made precise measurement of the leg axis and gap size possible. METHODS: Ten knee joints received a computer-assisted total knee replacement (Ci navigation system DePuy) I-Orthopaedics, Munich). The change of the leg axis and the size of the mediolateral gaps were measured and documented when performing a standardized medial ligament release sequence. RESULTS: We found a significant effect after each release step regarding the change of the leg axis as well as the gap width (p<0.001). The highest effect was seen for the 6-cm capsule release in extension and the release of the medial collateral ligament in 90 degrees flexion. CONCLUSION: Implementation of computer-assisted navigation facilitates visualization and quantification of the effect of the sequential medial soft tissue release in total knee arthroplasty.

Arthroplasty, Replacement, Knee↗

PubMed2005

Open pelvic fractures: epidemiology, current concepts of management and outcome.

Open pelvic fractures constitute one of the most devastating injuries in musculo-skeletal trauma and must be treated aggressively, incorporating a multidisciplinary approach. Early treatment, focusing on prevention of haemorrhage and sepsis, is essential. The management of associated soft tissue injuries must also be aggressive, including early administration of broad-spectrum antibiotics and repeated, meticulous wound debridement and irrigation. Selective faecal diversion, based on wound location, is compulsory and safe, minimising the risk of sepsis and reducing mortality rates.

Algorithms↗

PubMed2005

The impact of injuries below the knee joint on the long-term functional outcome following polytrauma.

Previous studies have suggested that the lower-extremities are among the most frequently injured body regions in polytrauma patients and have a major impact on the functional recovery following polytrauma. In particular, injuries to the distal part of the lower-extremity appear to be associated with a poor functional outcome. Therefore, the goal of this study was to evaluate the impact of injuries below the knee joint on the long-term functional outcome following polytrauma. Three hundred eighty-nine polytrauma patients with associated lower-extremity fractures and a minimum follow-up of 10 years were included in this study. All patients were examined by a doctor, using a patient questionnaire and a standardised physical examination. Significantly, inferior outcomes were seen in patients with fractures below the knee joint as measured by the modified Karlström-Olerud score, Lysholm score, range of motion, weight bearing status, Hannover score for polytrauma outcome (HASPOC), SF-12, Tegner activity score, and inability to work (P < 0.05). Fractures below the knee joint have a significant impact on the functional recovery following polytrauma. We suggest that delayed treatment, thin soft tissue envelope below the knee joint, high-energy trauma, unfavorable blood supply, and complex fracture patterns contribute to these unfavorable outcomes.

Adult↗

PubMed2005

Analysis of forces of ACL reconstructions at the tunnel entrance: is tunnel enlargement a biomechanical problem?

Bone tunnel enlargement is a common phenomenon following reconstruction of the anterior cruciate ligament (ACL). Biomechanical and biological factors have been reported as potential causes of this problem. However, there is no analysis of forces between the graft and bone, as the graft changes direction at the bone tunnel entrance. The purpose of this study was to study these 'redirecting forces'. Magnetic resonance images of 10 patients with an ACL reconstruction (age: 26+/-6.8 years) were used to determine the angle between graft and drill holes. Vector analysis was used to calculate the direction and magnitude of the perpendicular component of the force between the bone tunnel and the graft at the entrance of the bone tunnel. Force components were projected into the radiographically important sagittal and coronal planes. Tension of ACL reconstructions was recorded during passive knee motion in 10 cadaveric knee experiments (age: 28.9+/-10.6 years) and the tension multiplied with the force component for each plane. Results are reported for the coronal and sagittal planes, respectively: For -10 degrees of extension, the percentages of graft tension were determined to be 17+/-7 (max: 26; min: 7%) and 26+/-9 (max: 39; min: 16%) for the tibia. They were 59+/-6 (max: 66; min: 48%) and 99+/-1 (max: 1.00; min: 99%) for the femur. Force components were 14.68+/-6.54 and 25.73+/-12.96 N for the tibial tunnel. For the femoral tunnel, they were 52.48+/-19.03 and 90.77+/-32.06 N. Percentages of graft tension and force components were significantly higher for the femoral tunnel compared with the tibial tunnel. Moreover, in the sagittal direction, force components for the femoral tunnel were significantly higher compared with the coronal plane (Wilcoxon test, p < 0.01). The differences in force components calculated in this study corresponds with the amount of tunnel enlargement in the radiographic planes in the literature providing evidence that biomechanical forces play a key role in postoperative tunnel expansion.

Adolescent↗

PubMed2005

[Intraoperative three-dimensional imaging with an isocentric mobile C-arm at the wrist].

In addition to conventional radiological C-arm image amplifiers used for intraoperative imaging, now a new mobile C-arm image amplifier with an option for three dimensional imaging (Iso-C 3D) is available to visualize reduction of fractures and position of implants. In a wrist-model three titanium pins were placed and three holes of different length were drilled. Distances between the pins and the depths of the drilled holes were calculated in conventional computer tomographic scans and Iso-C 3D scans in perpendicular, 30 degree and 90 degree position of the gantry and compared to actual distances and depths. There were no significant differences between the actual measured distances and those measured by CT scans and Iso-C 3D scans. Furthermore, gantry position had no significant effect upon the results. Iso-C 3D scans are as reliable as conventional CT scans for intraoperative controlling of implant positioning.

Analysis of Variance↗

PubMed2005

[Prevention of school sport injuries--an analysis of ballsports with 2234 injuries].

PURPOSE: Ball sport school injuries account for a significant morbidity among children and adolescents. MATERIALS AND METHODS: During a school year 2234 school sport injuries have been reported to the Gemeinde Unfall Versicherung (GUV) Niedersachsen, Germany. RESULTS: Regarding the non-gender-specific distribution of the ball sport disciplines, basketball leads with 32 % (n = 431), followed by soccer (24 %, n = 316), volleyball (17 %, n = 232), handball (8.3 %, n = 110) and hockey (4.9 %, n = 65). Sprains (27 %) dominate in basketball, followed by ligament distorsions and ruptures (23 %) and fractures (21 %), with frequent finger injuries (61 %) without contact of an opponent, and injuries of the lower extremity (28 %). Soccer leads to contusions (29 %), in 52 % of the lower extremity frequently after collision with an opponent (22 %) or the ball (20 %). In volleyball upper extremity injuries (71 %) dominate with 53 % finger sprains in individual volleyball play. CONCLUSION: Ball school sport injuries account for a significant morbidity with frequent finger injuries. Proprioceptive deficits may play a role in those finger injuries in basketball, volleyball and handball. During hockey, severe dental and facial injuries were apparent. A prospective proprioceptive training program aiming on fingers and the ankle region may therefore be a preventive measure such as helmets with facial protection in hockey school sport.

Adolescent↗

PubMed2005

[Prospective proprioceptive and coordinative training for injury reduction in elite female soccer].

PURPOSE: Does a prospective proprioceptive-coordinative additional training intervention in elite female soccer changes frequency and pattern of injuries? MATERIALS AND METHODS: 24 female soccer players of the German first division team of FC Bayern München were thoroughly supervised during the season 2003/04 regarding injuries resulting in an absence from at least one scheduled training session or game. During the winter break an additional proprioceptive-coordinative training program was initiated, which was performed on a regular basis during the second half of the season. Furthermore, we evaluated jump&reach, throwing power, coordinative skills, and flexibility. RESULTS: All evaluated fitness results increased significantly during the season after the training intervention, such as jump&reach 44 +/- 4 cm vs. 38 +/- 10 cm (p < 0.05), coordinative power left and right leg, respectively (71 +/- 44 s vs. 45 +/- 37 s, 80 +/- 41 s vs. 50 +/- 32 s, both p < 0.05), flexibility left and right hip (89 +/- 8 degrees vs. 78 +/- 13 degrees and 88 +/- 9 degrees vs. 79 +/- 10 degrees, p < 0.05). Comparing the 1st to the 2nd half of the season, 25 vs. 26 injuries after foulplay and 69 vs. 52 without contact occur (p < 0.05). Muscle injuries resulting in game or training absence were significantly reduced by 400% (12 vs. 3, p < 0.05). In the 1st half of the season, 2 anterior cruciate ruptures (ACL) occur vs. none in the 2nd half after the training intervention. CONCLUSION: An additional proprioceptive-coordinative training intervention increases coordinative abilities, jump power, throwing power, and flexibility during a half season. After initiation of the proprioceptive-coordinative training the incidence of muscle injuries resulting in an absence of at least one game or practice session was reduced significantly by 400 %. Regarding the reduced incidence of ACL injuries after proprioceptive-coordinative training in female elite soccer players, further studies have to be performed to elucidate the value of this training intervention.

Adult↗

PubMed2005

[Non-invasive determination of cardiac output by continuous wave Doppler in air rescue service].

BACKGROUND: Determination of cardiac output (CO) enables to assess the hemodynamic situation as well as to administer optimal catecholamine therapy especially in critically compromised patients with hemodynamic instability. Invasive determination of CO is possible via a Swan-Ganz-catheter with its associated risk of implantation in the hospital. Using the Doppler technique, we evaluated the feasibility of the USCOM-system for non-invasive CO determination in preclinical emergency medicine in air rescue service. METHODS: In 32 patients (17 months to 92-years-old) cardiac output was determined non-invasively (USCOM) at the scene and during the helicopter transport at Christoph 4, based at Hannover Medical School. Simultaneously, blood pressure, ECG and oxygen saturation were determined. Non-invasive CO was assessed by a suprasternal access aiming at the aorta ascendens. 19 patients were unconscious due to cardial and non-cardial reasons, and 13 were conscious (sepsis, status epilepticus, anaphylactic reaction). 7 patients were hemodynamically unstable. In three patients the monitor was used during interhospital transfer by helicopter. RESULTS: Non-invasively determined CO via the USCOM system was 4.8 +/- 0.7 l/min with a cardiac index of 2.4 +/- 0.3 l/m (2). Highest CO values were determined in a patient with sepsis and during a grand-mal-status in epilepsy (CO 8.2 l/min). All examinations were done by the same emergency physician of the emergency helicopter Christoph 4 immediately after arrival at the scene. The examination took on average 25 seconds. During the helicopter transport, several consecutive CO measurements were performed to assess volume and catecholamine therapy with increase of stroke volume after volume load with colloidal fluids. CONCLUSIONS: Using the USCOM system it is possible to determine the beat-to-beat cardiac output in air rescue service non-invasively. The emergency physician gains additional crucial hemodynamic information to diagnose and treat adequately by administration of volume load and catecholamines at the scene and during flight conditions. Further preclinical prospective trials are mandatory to elucidate the value of this novel device in emergency medicine.

Adolescent↗

PubMed2005

Single lateral locked screw plating of bicondylar tibial plateau fractures.

We prospectively followed a case series of 68 patients with 69 AO/ASIF 41-C-type fractures treated with the Less Invasive Stabilization System for the proximal lateral tibia. We assessed malreduction, secondary loss of reduction, and infection rates in patients with a locked screw plate for unilateral fixation of bicondylar fractures. Sixty-two (91%) patients returned for final followup (range, 11-13 months). Malreduction and malalignment were defined as an intraarticular step-off of 2 mm or greater, or as a malalignment in the frontal or sagittal plane greater than 5 degrees . Fourteen fractures were open. Primary bone grafting was done in 13 patients. Significant malreduction was seen in 16 patients. There were four superficial infections and one deep infection. One fracture did not heal, and nine patients had substantial loss of reduction. Unilateral locked screw plating is a good alternative for treatment of problematic fractures of the tibial plateau that are associated with soft tissue damage and metaphyseal comminution. The reduction technique for exact alignment is demanding.

Adolescent↗

PubMed2004

Effects of cyclic longitudinal mechanical strain and dexamethasone on osteogenic differentiation of human bone marrow stromal cells.

The aim of the study was to investigate the effect of cyclic mechanical strain on differentiation markers in the presence or absence of dexamethasone. Human bone marrow stromal cells (BMSC) from seven donors (32.5+/-6.2 years) were cultivated with (D+) or without (D-) dexamethasone. A cyclic mechanical strain with an elongation of 2% (D+2; D-2) or 8% (D+8; D-8) was applied for three days with a stimulation time of three times two hours each day. Levels of alkaline phosphatase (ALP) and osteocalcin (OC) were compared after time intervals of four and seven days. mRNA expression of Collagen I, III and Cbfa1 was investigated after one, four, and seven days. ALP levels were significantly increased in the D+8 group after four and seven days (147.1+/-6.3%; p<0.05 and 168.6+/-6,5%; p<0.03) and in the D-8 group after 7 days (197.4+/-10.4; p<0.04). Cyclic strain had a significant influence on ALP-secretion (F=7.5; p<0.01). In the D-8 group there was a significant increase in OC secretion after 4 days (140.9+/-12.5%; p<0.05).; p<0.01). The effect of stretching was significantly stronger than that of dexamethasone (F=17.2 vs. 1.8). Collagen I (Col I) expression was upregulated in D+8 cultures after 4 days (215.0+/-53.3 p<0.04) and after seven days (166.7+/-55.7; p<0.04). Collagen III (Col III) expression was upregulated in D+2 and D+8 cultures after 4 days (200.7+/-16.3 and 185.9+/-12.7; p<0.04) and after seven days (154.4+/-10.1 and 118.8+/-16.4; p<0.04). There was a significant increase of Cbfa1 expression in D+8 cultures at all investigated time intervals (day 1: 105.5+/-3.7%; day 4: 104.7+/-3.0%; day 7: 104.4+/-2.1%; p<0.03). Stretching (F=20.0; p<0.01) was a stronger contributor to Cbfa-1 expression than dexamethasone (F=12.1; p<0.01). Cyclical mechanical stimulation with 8% elongation increases ALP and OC levels and upregulates Col I and III synthesis and Cbfa1 expression. In the short term, cyclical stretching is a stronger differentiation factor than dexamethasone. Cyclical stretching and dexamethasone both enhance the osteogenic commitment of hBMSC.

Adult↗

PubMed2004

[Computer-assisted surgery for pelvic injuries].

For pelvic fractures, pre- and postoperative imaging includes spiral computed tomography, providing high resolution and accuracy. In conventional pelvic operations, these image data cannot be used directly. Intraoperative imaging is limited with fluoroscopy and visualization by the approaches. One solution in terms of precision and reduction of radiation exposure could be computer-assisted surgery (CAS). This method can be divided into navigation, which requires active registration, CT based navigation and registration-free fluoroscopy-based or Iso-C-3D-based navigation. Applications for CAS in the pelvis include sacroiliac screw osteosynthesis in pelvic ring fractures, navigated periacetabular screw fixation, and correction operations for malhealed pelvic ring fractures. Nowadays, CAS is still costly and frequently requires additional staff. However, it helps to reduce complications caused by implant placement. With the introduction of new health care requirements in Germany, this may be an economic argument as well. Current developments focusing on accurate navigated reduction will provide new indications for CAS, further decrease complication rates, and help to reduce the invasiveness of pelvis operations.

Acetabulum↗

PubMed2004

[Restoration of the ability to walk through bilateral triple arthrodesis in marked spastic pes equinovarus].

A tendon transfer is the method of choice in easily reducible pes equinovarus. However, in long-time persisting deformities with spasms, a plantigrade position can not be maintained with these procedures. Therefore, we perform an additional bilateral triple arthrodesis in a patients with such bilateral deformities. A 55-year-old woman developed, within the scope of several surgical procedures on the cervical spine, marked bilateral pes equinovarus and flexion contractures of the knees. The patient's ambulation was limited to a wheelchair for 3 years. Then, in an interval of 1 year, we performed an unilateral soft tissue release, z-tenotomy of the Achilles tendon, triple arthrodesis with correction of the deformity, and posterior tibial tenden transfer. At follow-up 5 years after the second procedure, the 61-year-old patient was able to walk alone with two walking sticks. In the case described, the correction of a marked pes equinovarus with spasms, which was achieved by an extensive soft tissue release, could be stabilized through a triple arthrodesis in such way that the plantigrade position of the foot could be controlled through a posterior tibial tendon transfer.

Arthrodesis↗

PubMed2004

[Osteotomy of the iliac fossa in the treatment of a hip dislocation associated with a two-column acetabular fracture. Modification of the ilioinguinal approach to avoid an extended surgical approach].

Open reduction and internal fixation is the treatment of choice for displaced acetabular fractures. The surgical approach depends on the fracture type, concomitant injuries, and general condition of the patient. The ilioinguinal approach provides a good exposure to the medial wall and is associated with an acceptable degree of surgical trauma. Exposure of the joint surface, however, is difficult when using the ilioinguinal approach. We report a case of a polytraumatized 39-year-old patient who sustained a posterior hip displacement and a two-column acetabular fracture. An osteotomy of the iliac ala was performed via an ilioinguinal approach to fragments of the acetabular surface that were displaced distally. Thereby, reposition of a craniolateral fragment was achieved without the need to extend the surgical approach or to perform a second incision.

Acetabulum↗

PubMed2004

[Reosteosynthesis in dens pseudarthrosis. Case report and review of the literature].

According to general recommendations, unstable nonunions of the odontoid are treated by posterior fusion of the segments C1/C2 and transarticular screwosteosynthesis. The aim of the surgical procedure is to obtain secure reduction stabilization, and fusion of the nonunion. We present a case of secondary atlanto-axial instability treatment following of an odontoid nonunion. In this situation stability of C1/C2 was achieved by atlanto-axial fusion by transarticular screw fixation. The ventral parts of the broken implants were left in place. Diagnosis, treatment and complications of pseudarthrosis of the dens axis are discussed in the context of this case and of literature.

Bone Screws↗

PubMed2004

[Extensive reconstruction of the acetabular dome after redisplacement of an acetabular fracture. Case report].

Anatomical reconstruction and stable internal fixation is the treatment of choice in displaced acetabular fractures. Marginal impaction zones are of negative prognostic value. They are normally treated with a cancellous bone graft from the greater trochanter. In the presented case, a secondarily failed acetabular reconstruction with redisplacement of the acetabular dome was treated with several corticocancellous blocks filled in the dome defect. In this case, a comminuted area and secondary displacement could be successfully treated with anatomical reconstruction. This resulted in joint congruency and an acceptable long-term result after 16 years.

Acetabulum↗

PubMed2004

[DRG reimbursement for multiple trauma patients -- a comparison with the comprehensive hospital costs using the German trauma registry].

UNLABELLED: The introduction of diagnosis related groups (DRG) will radically change the payment system for German hospitals. In 2002 the values for most DRG's were published for the german system (G-DRG). The polytrauma working group of the German Trauma Society developed a calculating algorithm to estimate the comprehensive hospital costs for every patient in the German trauma registry. The aim of this study was to compare these costs with the reimbursement according the the G-DRG's for a standardized population of polytrauma patients. MATERIAL AND METHODS: For polytrauma patients treated at Hannover Medical School in 2000 and 2001 the reimbursement according to the G-DRG's was calculated using a base value of 2900 euro. In the same patients the total cost of inpatient treatment was calculated according to the algorithm developed by the polytrauma working group of the German Trauma Society. The difference between these values represents the economic result. This was calculated as an overall result, but also for specific subgroups of patients (injury severity, mortality, G-DRG grouping). RESULTS: Datasets of 103 polytrauma patients were included. The following G-DRG's were most frequently occuring: A06Z (n=41), A07Z (n=16), W01Z (n=13). All other G-DRG's were documented less than 3 times. The mean reimbursement according to the G-DRG was 21.380+/-12.300 euro for a polytrauma patient. However, the mean hospital cost accounted to 34.274+/-22.501 euro, which resulted in a mean deficit of 12.893+/-15.534 euro. Analysis of subgroups revealed, that an ISS of more than 35 points, patients with a prolonged hospital stay and patients of the G-DRG group A06Z show a particularly negative result. CONCLUSION: The comprehensive hospital costs for treating polytrauma patients are on average 12.893 euro higher than the reimbursement according the G-DRG's. For hospitals to be fully reimbursed G-DRG values have to be reconfigured according to the German health care system. Thus, inclusion criteria to specific G-DRG have to be changed and a specific G-DRG group for very severely injured patients needs to be established.

Adult↗

PubMed2004

[Fracture of the medial femoral condyle as a complication of retrograde femoral nail removal].

A 26-year-old female patient with a femoral shaft fracture underwent retrograde femoral nailing. Nail removal was performed 2 years later, after fracture healing. An intraoperative fracture of the medial condyle of the femur occurred. This complication has not been previously described in the literature. Screw osteosynthesis of the fracture was performed and articular congruence reestablished. After 6 weeks of fractional weight bearing, the patient proceeded up to full weight bearing without complication. The case demonstrates that the removal of retrograde femoral nails is not without complications. The decision to undertake implant removal should be made carefully.

Adult↗