Key aspects of soft tissue management in fracture-related infection: recommendations from an international expert group

A judicious, well-planned bone and soft tissue debridement remains one of the cornerstones of state-of-the-art treatment of fracture-related infection (FRI). Meticulous surgical excision of all non-viable tissue can, however, lead to the creation of large soft tissue defects. The management of these defects is complex and numerous factors need to be considered when selecting the most appropriate approach. This narrative review summarizes the current evidence with respect to soft tissue management in patients diagnosed with FRI. Specifically we discuss the optimal timing for tissue closure following debridement in cases of FRI, the need for negative microbiological culture results from the surgical site as a prerequisite for definitive wound closure, the optimal type of flap in case of large soft tissue defects caused by FRI and the role of negative pressure wound therapy (NPWT) in FRI. Finally, recommendations are made with regard to soft tissue management in FRI that should be useful for clinicians in daily clinical practice.Level of evidence Level V.

Severe necrotizing soft tissue infections-Is wound microbiology a prognostic factor for clinical outcome?

Necrotizing soft tissue infections (NSTIs) represent similar pathophysiological features, but the clinical course might range from subacute to a rapidly progressive, fulminant sepsis. Initial wound microbiology is the base for the Guiliano classification. The timeline of microbiological colonization has not been described during the clinical course. The role of the different microbiological pathogens on the outcome and mortality is unclear. One hundred eighty patients were included with septic inflammation response syndrome on admission. Initial wound microbiology and the changes in wound microbiology were analysed during the clinical course and correlated with outcome and risk indicators. Overall mortality was 35%. Higher age, a high Charlson Comorbidity Index or ASA score and truncal infections were highly prognostic for a lethal outcome. Microbiological findings revealed significant differences in the persistence of bacteria during the course of disease. Streptococci were only detectable within the first 5 days, whereas other bacteria persisted over a longer period of time. Initial microbiological findings correlated with better prognosis when no causative agent was identified and for gram-negative rods. Varying survival rates were observed for different Streptococci, Staphylococci, Enterococci and other bacteria. The highest odds ratio for a lethal outcome was observed for Enterococci and fungi. Microbiological colonization changes during the clinical course of NSTIs and some microbiologic pathogens are predictive for worsening the outcome and survival. Streptococcus pyogenes is only detectable in the very early phase of NSTI and after 6 days not anymore detectable. Later Enterococci and fungi showed the highest odds ratios for a lethal outcome. Enterococci bacteria and fungi have yet not been considered of clinical relevance in NSTI or even as indicator for worsening the outcome.

Risk of Interprosthetic Femur Fracture Is Associated with Implant Spacing-A Biomechanical Study

BACKGROUND

Ipsilateral revision surgeries of total hip or knee arthroplasties due to periprosthetic fractures or implant loosening are becoming more frequent in aging populations. Implants in revision arthroplasty usually require long anchoring stems. Depending on the residual distance between two adjacent knee and hip implants, we assume that the risk of interprosthetic fractures increases with a reduction in the interprosthetic distance. The aim of the current study was to investigate the maximum strain within the femoral shaft between two ipsilateral implants tips.

METHODS

A simplified physical model consisting of synthetic bone tubes and metallic implant cylinders was constructed and the surface strains were measured using digital image correlation. The strain distribution on the femoral shaft was analyzed in 3-point- and 4-point-bending scenarios. The physical model was transferred to a finite element model to parametrically investigate the effects of the interprosthetic distance and the cortical thickness on maximum strain. Strain patterns for all parametric combinations were compared to the reference strain pattern of the bone without implants.

RESULTS

The presence of an implant reduced principal strain values but resulted in distinct strain peaks at the locations of the implant tips. A reduced interprosthetic distance and thinner cortices resulted in strain peaks of up to 180% compared to the reference. At low cortical thicknesses, the strain peaks increased exponentially with a decrease in the interprosthetic distance. An increasing cortical thickness reduced the peak strains at the implant tips.

CONCLUSIONS

A minimum interprosthetic distance of 10 mm seems to be crucial to avoid the accumulation of strain peaks caused by ipsilateral implant tips. Interprosthetic fracture management is more important in patients with reduced bone quality.

Advances in the Treatment of Implant-Associated Infections of the Pelvis: Eradication Rates, Recurrence of Infection, and Outcome

INTRODUCTION

Surgical site infections after operative stabilization of pelvic and acetabular fractures are rare but serious complications. The treatment of these infections involves additional surgical procedures, high health care costs, a prolonged stay, and often a worse outcome. In this study, we focused on the impact of the different causing bacteria, negative microbiological results with wound closure, and recurrence rates of patients with implant-associated infections after pelvic surgery.

MATERIAL AND METHODS

We retrospectively analyzed a study group of 43 patients with microbiologically proven surgical site infections (SSI) after surgery of the pelvic ring or the acetabulum treated in our clinic between 2009 and 2019. Epidemiological data, injury pattern, surgical approach, and microbiological data were analyzed and correlated with long-term follow-up and recurrence of infection.

RESULTS

Almost two thirds of the patients presented with polymicrobial infections, with staphylococci being the most common causing agents. An average of 5.7 (±5.4) surgical procedures were performed until definitive wound closure. Negative microbiological swabs at time of wound closure were only achieved in 9 patients (21%). Long-term follow-up revealed a recurrence of infection in only seven patients (16%) with an average interval between revision surgery and recurrence of 4.7 months. There was no significant difference of recurrence rate for the groups of patients with positive/negative microbiology in the last operative revision (71% vs. 78%). A positive trend for a correlation with recurrent infection was only found for patients with a Morel-Lavallée lesion due to run-over injuries (30% vs. 5%). Identified causing bacteria did not influence the outcome and rate of recurrence.

CONCLUSION

Recurrence rates after surgical revision of implant-associated infections of the pelvis and the acetabulum are low and neither the type of causing agent nor the microbiological status at the timepoint of wound closure has a significant impact on the recurrence rate.

The Influence of Human Factors Training in Air Rescue Service on Patient Safety in Hospitals: Results of an Online Survey

Background: Air rescue crew members work equally in aviation and medicine, and thus occupy an important interface between the two work environments of aviation and medicine. The aim of this study was to obtain responses from participants to a validated online-based questionnaire regarding whether hospitals may benefit from the commitment of a medical hospital staff which is also professionally involved in the aviation system as emergency physicians and Helicopter Emergency Medical Services Technical Crew Members (HEMS TC). Furthermore, it focused on the question of whether the skills acquired through Crew Resource Management (CRM) training in the air rescue service might also be used in the ground-based rescue service and, if so, whether they may have a positive effect. Methods: Medical air rescue staff of 37 German air rescue stations was included. Between 27 November 2020 and 03 March 2021, 253 out of 621 employees (response rate: 40.7%) participated voluntarily in a validated anonymized online survey. A quantitative test procedure was performed using the modified questionnaire on teamwork and patient safety (German version). Results: The examination and interpretation of the internal consistency (Cronbach's alpha) resulted in the following reliabilities: Factor I (Cooperation): α = 0.707 (good); Factor II (Human factors): α = 0.853 (very good); Factor III (Communication): α = 0.657 (acceptable); and Factor IV (Safety): α = 0.620 (acceptable). Factor analysis explained 53.1% of the variance. Conclusions: The medical clinicians participating in this online survey believed that the skills they learned in human factors training such as CRM are helpful in their daily routine work in hospitals or other medical facilities, as well as in their ground-based rescue service activities. These findings may result in the recommendation to make CRM available on a regular to the medical staff in all medical facilities and also to ground-based rescue service staff aiming to increase patient safety and employee satisfaction.

[Techniques and results of primary hip arthroplasty in geriatric acetabular fractures]

As a result of demographic changes, there is an increase in geriatric acetabular fractures [1, 2]. Geriatric patients often have comorbidities, such as pre-existing coxarthritis, reduced bone quality or limited compliance, which makes injury-adapted follow-up treatment difficult [3]. As a result joint-preserving interventions often fail at an early stage, so that hip arthroplasty is necessary in the short term. The 1‑year mortality after surgically stabilized acetabular fractures is 8.1%, a significant increase by a factor of 4 compared to the age group [4]. This illustrates that differentiated criteria for the indication of joint-preserving surgery versus arthroplasty are necessary to avoid reoperations and complications. Criteria for the indications for primary arthroplasty are fracture type, pre-existing coxarthritis, poor bone quality, limited compliance and patient age (> 75 years) [5, 6].In the following article, three treatment strategies for geriatric acetabular fractures and periprosthetic acetabular fractures are presented; the 1‑stage prosthesis implantation without osteosynthesis, the 1‑stage prosthesis implantation with osteosynthesis and the 2‑stage approach with limited osteosynthesis and early total arthroplasty. The advantages and disadvantages of these options are presented based on cases and the various aspects of the treatment. The treatment of geriatric acetabular fractures is an operative challenge for the surgeon and requires a high level of expertise in both special trauma surgery and revision arthroplasty and thus represents a special interface in the fields of orthopedics and trauma surgery.

Biomechanical comparison of acetabular fracture fixation with stand-alone THA or in combination with plating

PURPOSE

A common surgical treatment in anterior column acetabular fractures with preexisting osteoarthritis is THA, which is commonly combined with plate osteosynthesis. Implantation of a solitary revision cup cranially fixed to the os ilium is less common. The purpose of this study was to compare the stabilization of anterior column acetabular fractures fixed with a cranial socket revision cup with flange and iliac peg or with a suprapectineal plate osteosynthesis combined with an additional revision cup.

METHODS

In 20 human hemipelves, an anterior column fracture was stabilized by either a cranial socket revision cup with integrated flange (CF = Cup with Flange) or by a suprapectineal plate combined with a revision cup (CP = Cup and Plate). Each specimen was loaded under a stepwise increasing dynamic load protocol. Initial construct stiffness, interfragmentary movements along the fracture line, as well as femoral head movement in relation to the acetabulum were analyzed.

RESULTS

Both groups showed comparable initial construct stiffness (CP: 3180 ± 1162 N/mm and CF: 3754 ± 668 N/mm; p = 0.158). At an applied load of 1400 N, interfragmentary movements at the acetabular (p = 0.139) and the supraacetabular region (p = 0.051) revealed comparable displacement for both groups and remained below 1 mm. Femoral head movement in relation to the acetabulum also remained below 1 mm for both test groups (p = 0.260).

CONCLUSION

From a biomechanical point of view, both surgical approaches showed comparable fracture reduction in terms of initial construct stiffness and interfragmentary movement. The potential benefit of the less-invasive cranial socket revision cup has to be further investigated in clinical studies.

[End-of-stem pain in hip and knee arthroplasty]

End-of-stem pain after knee and hip arthroplasty with diaphyseal supportive stems is a frequently overlooked and potentially underestimated complication. A commonly recurring clinical phenome is the symptom-free interval after surgery of weeks to months, with new onset of symptoms under stress only later. The patient is often again reliant on walking sticks. End-of-stem pain is a diagnosis of exclusion. Pain is projected into the tip of the stem, and if differential diagnoses such as loosening are excluded, then the patient might be treated with a "bending-plate". Since bone cement has a similar elastic modulus to human cortical bone, a change of method to a cemented implant can also be expedient. In the primary situation, in addition to cemented stems, the use of "split-stems" could be useful. After revision surgery of any kind, a timely cessation of pain confirms the diagnosis.

[Anterolateral approach to femoral neck fractures in children]

OBJECTIVE

Anatomic reduction and stable fixation of pediatric femoral neck fractures.

INDICATIONS

All unstable and displaced femoral neck fractures (AO classification 31-E/1.1, 31-E/1.2, 31-M/2.1 I-III, 31-M/3.1 I-III, 31-M/3.2 II-III).

CONTRAINDICATIONS

Relative: Stable and nondisplaced femoral neck fractures.

SURGICAL TECHNIQUE

The anterolateral approach uses the muscle interval between the gluteus medius and minimus muscles and the tensor fascia lata. It provides access to the anterior part of the hip joint for open reduction and allows the retention and osteosynthesis from the lateral aspect of the femur. By incision of the anterior capsule the blood supply of the femoral head is preserved and the fracture can be visualized. An anatomic reduction should be achieved and a stable osteosynthesis according to the age of child and fracture type and location should be performed.

POSTOPERATIVE MANAGEMENT

After stable fixation additional immobilization is not required. Young children are mobilized in a wheel chair with no weight bearing; older children are mobilized with partial weight bearing with crutches. According to the age of the child and fracture type full weight bearing can be allowed after 4-8 weeks after radiographic follow-up.

RESULTS

Fractures of the femoral neck in children are rare and often associated with high-energy traumata. Complication rates are high such as avascular necrosis (AVN) of the femoral head, premature epiphyseal closure, nonunion, secondary displacement, coxa vara or infection. Different factors influence the outcome, including initial displacement, fracture classification, timing of reduction, stability of fixation or quality of reduction. However, especially in the lateral fractures the femoral head necrosis can be avoided by protecting the vascular supply. The reader of the article should be enabled to reduce the rate of AVNs by knowledge of the controllable risk factors and no longer accept AVN as predestined. There is a controversial discussion on the benefit of hematoma evacuation of the hip joint capsule and its influence on the rate of femoral head necrosis.

Factitious Disorders in Everyday Clinical Practice

BACKGROUND

The pathological feigning of disease can be seen in all medical disciplines. It is associated with variegated symptom presentations, self-inflicted injuries, forced but unnecessary interventions, unusual and protracted recoveries, and frequent changes of treating physician. Factitious illness is often difficult to distinguish from functional or dissociative disorders on the one hand, and from malingering on the other. Many cases, even fatal ones, probably go unrecognized. The suspicion that a patient's problem may be, at least in part, factitious is subject to a strong taboo and generally rests on supportive rather than conclusive evidence. The danger of misdiagnosis and inappropriate treatment is high.

METHODS

On the basis of a selective review of current literature, we summarize the phenomenology of factitious disorders and present concrete strategies for dealing with suspected factitious disorders.

RESULTS

Through the early recognition and assessment of clues and warning signs, the clinician will be able to judge whether a factitious disorder should be considered as a differential diagnosis, as a comorbid disturbance, or as the suspected main diagnosis. A stepwise, supportive confrontation of the patient with the facts, in which continued therapeutic contact is offered and no proofs or confessions are demanded, can help the patient set aside the sick role in favor of more functional objectives, while still saving face. In contrast, a tough confrontation without empathy may provoke even more elaborate manipulations or precipitate the abrupt discontinuation of care-seeking.

CONCLUSION

Even in the absence of systematic studies, which will probably remain difficult to carry out, it is clearly the case that feigned, falsified, and induced disorders are underappreciated and potentially dangerous differential diagnoses. If the entire treating team successfully maintains an alert, transparent, empathic, and coping-oriented therapeutic approach, the patient will, in the best case, be able to shed the pretense of disease. Above all, the timely recognition of the nature of the problem by the treating team can prevent further iatrogenic harm.

Primary Total Hip Arthroplasty in Severe Dysplastic Hip Osteoarthritis With a Far Proximal Cup Position

BACKGROUND

Developmental hip dysplasia is the most common cause of secondary hip osteoarthritis. Due to severe acetabular bone deficiency, cup positioning in total hip arthroplasty (THA) of dysplastic hips remains a surgical challenge. The aim was to analyze the functional outcome of far proximal cup positions in primary THA.

METHODS

Fifty patients (61 hips) with THA for severe dysplastic osteoarthritis and a far proximal cup position were included. Patients were divided according to the heights of the implanted cups with increasing vertical distance from the interteardrop line (group A: 55-65 mm, group B: 65-75 mm, group C: >75 mm). Functional outcome was assessed at latest follow-up (38 ± 16 months) by Lower Extremity Functional Score, Tegner Activity Score, and Harris Hip Score (HHS). Patients answered a Patient Satisfaction Questionnaire. Leg length discrepancy was estimated radiographically.

RESULTS

The Lower Extremity Functional Score significantly decreased in C (45.3 ± 25) compared to A (66.7 ± 15.3) and B (67.9 ± 9.9). The Tegner Activity Score significantly increased in all subgroups from preoperative to postoperative (2.2 ± 1.3 to 4.1 ± 1.4; P < .05). The mean overall HHS was 89.3 ± 14.7 (A: 89.5 ± 14.3, B: 94.3 ± 6.5, C: 78.3 ± 22.1). The HHS domains of activity of daily life and gait were significantly reduced in C (P < .05). Patients described a high satisfaction level with the surgery. No significant differences were found with regard to preoperative and postoperative leg lengthening (P = .881). Neither dislocations, impingement problems nor neurologic complications were observed.

CONCLUSION

Primary THA without any concomitant surgical interventions with a far proximal cup position offers a safe and effective treatment option in severe dysplastic hip osteoarthritis.

Long-term Outcomes after Primary Radial Head Resection Arthroplasty vs. Acute Radial Head Resection vs. Secondary Prosthetic Removal in Comminuted Radial Head Fractures

BACKGROUND

Aim of this study was to compare the clinical and radiological long-term outcomes following operative treatment of comminuted radial head fractures using 1) primary radial head resection arthroplasty, 2) acute radial head resection, or 3) necessary secondary prosthetic removal. Additionally, we evaluated complex radial head fractures combined with elbow dislocation and verified the hypothesis of whether primary radial head resection arthroplasty could contribute to ligament healing.

METHODS

In a comparative retrospective cohort study between 2004 and 2014, 87 (33 female, 54 male) patients with comminuted radial head fractures with a median age of 45 (range 18-77) years were included and followed-up clinically and radiologically. Functional results were evaluated according to MEPS, DASH, Broberg and Morrey, and VAS scores.

RESULTS

After a median range of 46 months postoperatively, 48 patients (group 1) obtained an acute radial head resection arthroplasty (MEPS: 70 points, Broberg and Morrey: 63 points, DASH: 34 points, VAS: 3.3 points). Twenty patients (group 2) were treated by radial head resection (MEPS: 63 points, Broberg and Morrey: 50 points, DASH: 49 points, VAS 4.2 points) and 19 patients (group 3) needed secondary prosthesis removal (MEPS: 73 points, Broberg and Morrey: 66 points, DASH: 38 points, VAS: 2.8 points). The overall outcome demonstrated a trend towards better results and the Kellgren-Lawrence grade of postoperative osteoarthritis was significantly better in groups 1 and 3 compared to group 2 (P=0.02).

CONCLUSION

Clinical and radiological long-term results of this study demonstrate a trend towards a better outcome after acute radial head resection arthroplasty compared to primary radial head resection, especially in complex fractures associated with elbow dislocation. Furthermore, our results encourage the use of primary radial head replacement in cases of comminuted non-reconstructable radial head fractures.

[Current Concepts for the Treatment of Skin and Soft Tissue Infections in Orthopaedic and Trauma Surgery]

Skin and soft tissue infections include the skin as well as fascia, muscles, ligaments, tendons, synovial membranes, fat, blood vessels, nerves, and fibrous tissues. They range from superficial infections to deep infections with a necrotizing clinical course. These infections can promptly progress with severe systemic complications, requiring rapid management, and proper surgical and medical treatment. This manuscript provides recommendations based on current practice guidelines for diagnosis and treatment of surgically relevant skin and soft tissue infections in adults. Furthermore, it deals with a clinical guide of immediate identification of life threatening necrotizing clinical courses, detection of pathogens and the use of appropriate surgical, antimicrobial, and adjuvant treatment options.

Fracture-related infection: A consensus on definition from an international expert group

Fracture-related infection (FRI) is a common and serious complication in trauma surgery. Accurately estimating the impact of this complication has been hampered by the lack of a clear definition. The absence of a working definition of FRI renders existing studies difficult to evaluate or compare. In order to address this issue, an expert group comprised of a number of scientific and medical organizations has been convened, with the support of the AO Foundation, in order to develop a consensus definition. The process that led to this proposed definition started with a systematic literature review, which revealed that the majority of randomized controlled trials in fracture care do not use a standardized definition of FRI. In response to this conclusion, an international survey on the need for and key components of a definition of FRI was distributed amongst all registered AOTrauma users. Approximately 90% of the more than 2000 surgeons who responded suggested that a definition of FRI is required. As a final step, a consensus meeting was held with an expert panel. The outcome of this process led to a consensus definition of FRI. Two levels of certainty around diagnostic features were defined. Criteria could be confirmatory (infection definitely present) or suggestive. Four confirmatory criteria were defined: Fistula, sinus or wound breakdown; Purulent drainage from the wound or presence of pus during surgery; Phenotypically indistinguishable pathogens identified by culture from at least two separate deep tissue/implant specimens; Presence of microorganisms in deep tissue taken during an operative intervention, as confirmed by histopathological examination. Furthermore, a list of suggestive criteria was defined. These require further investigations in order to look for confirmatory criteria. In the current paper, an overview is provided of the proposed definition and a rationale for each component and decision. The intention of establishing this definition of FRI was to offer clinicians the opportunity to standardize clinical reports and improve the quality of published literature. It is important to note that the proposed definition was not designed to guide treatment of FRI and should be validated by prospective data collection in the future.

Knee arthrodesis versus above-the-knee amputation after septic failure of revision total knee arthroplasty: comparison of functional outcome and complication rates

BACKGROUND

After septic failure of total knee arthroplasty (TKA) and multiple revision operations resulting in impaired function, bone and/or soft-tissue damage a reconstruction with a revision arthroplasty might be impossible. Salvage procedures to regain mobility and quality of life are an above-the-knee amputation or knee arthrodesis. The decision process for the patient and surgeon is difficult and data comparing arthrodesis versus amputation in terms of function and quality of life are scarce. The purpose of this study was to analyse and compare the specific complications, functional outcome and quality of life of above-the-knee amputation (AKA) and modular knee-arthrodesis (MKA) after septic failure of total knee arthroplasty.

METHODS

Eighty-one patients treated with MKA and 32 patients treated with AKA after septic failure of TKA between 2003 and 2012 were included in this cohort study. Demographic data, comorbidities, pathogens and complications such as re-infection, implant-failure or revision surgeries were recorded in 55MKA and 20AKA patients. Functional outcome with use of the Lower-Extremity-Functional-Score (LEFS) and the patients reported general health status (SF-12-questionnaire) was recorded after a mean interval of 55 months.

RESULTS

A major complication occurred in more than one-third of the cases after MKA and AKA, whereas recurrence of infection was with 22% after MKA and 35% after AKA the most common complication. Patients with AKA and MKA showed a comparable functional outcome with a mean LEFS score of 37 and 28 respectively (p = 0.181). Correspondingly, a comparable physical quality of life with a mean physical SF-12 of 36 for AKA patients and a mean score of 30 for MKA patients was observed (p = 0.080). Notably, ten AKA patients that could be fitted with a microprocessor-controlled-knee-joint demonstrated with a mean LEFS of 56 a significantly better functional outcome than other amputee patients (p < 0.01) or MKA patients (p < 0.01).

CONCLUSION

Naturally, the decision process for the treatment of desolate situations of septic failures following revision knee arthroplasty is depending on various factors. Nevertheless, the amputation should be considered as an option in patients with a good physical and mental condition.

[Pyoderma gangrenosum after intramedullary nailing of tibial shaft fracture: A differential diagnosis to necrotizing fasciitis]

Pyoderma gangrenosum is a rare non-infectious neutrophilic dermatitis, whereas necrotizing fasciitis is a life-threatening bacterial soft tissue infection of the fascia and adjacent skin. As in the case described here after intramedullary nailing, the clinical appearance of both diseases can be similar. Because of the completely different therapeutic approach and a worse outcome in the case of false diagnosis, pyoderma gangrenosum should always be taken into consideration before treating necrotizing fasciitis.

Biofilm formation increases treatment failure in Staphylococcus epidermidis device-related osteomyelitis of the lower extremity in human patients

The ability to form biofilm on the surface of implanted devices is often considered the most critical virulence factor possessed by Staphylococcus epidermidis in its role as an opportunistic pathogen in orthopaedic device-related infection (ODRI). Despite this recognition, there is a lack of clinical evidence linking outcome with biofilm forming ability for S. epidermidis ODRIs. We prospectively collected S. epidermidis isolates cultured from patients presenting with ODRI. Antibiotic resistance patterns and biofilm-forming ability was assessed. Patient information was collected and treatment outcome measures were determined after a mean follow-up period of 26 months. The primary outcome measure was cure at follow-up. Univariate logistic regression models were used to determine the influence of biofilm formation and antibiotic resistance on treatment outcome. A total of 124 patients were included in the study, a majority of whom (n = 90) involved infections of the lower extremity. A clear trend emerged in the lower extremity cohort whereby cure rates decreased as the biofilm-forming ability of the isolates increased (84% cure rate for infections caused by non-biofilm formers, 76% cure rate for weak biofilm-formers, and 60% cure rate for the most marked biofilm formers, p = 0.076). Antibiotic resistance did not influence treatment cure rate. Chronic immunosuppression was associated with a statistically significant decrease in cure rate (p = 0.044).

CLINICAL SIGNIFICANCE

The trend of increasing biofilm-forming ability resulting in lower cure rates for S. epidermidis ODRI indicates biofilm-forming ability of infecting pathogens does influence treatment outcome of infections of the lower extremity. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1905-1913, 2016.

The unstable thoracic cage injury: The concomitant sternal fracture indicates a severe thoracic spine fracture

INTRODUCTION

The thoracic cage is an anatomical entity composed of the upper thoracic spine, the ribs and the sternum. The aims of this study were primarily to analyse the combined injury pattern of thoracic cage injuries and secondarily to evaluate associated injuries, trauma mechanism, and clinical outcome. We hypothesized that the sternal fracture is frequently associated with an unstable fracture of the thoracic spine and that it may be an indicator for unstable thoracic cage injuries.

PATIENTS AND METHODS

Inclusion criteria for the study were (a) sternal fracture and concomitant thoracic spine fracture, (b) ISS≥16, (c) age under 50 years, (d) presence of a whole body computed-tomography performed at admission of the patient to the hospital. Inclusion criteria for the control group were as follows: (a) thoracic spine fracture without concomitant sternal fracture, (b)-(d) same as study cohort.

RESULTS

In a 10-year-period, 64 patients treated with a thoracic cage injury met inclusion criteria. 122 patients were included into the control cohort. In patients with a concomitant sternal fracture, a highly unstable fracture (AO/OTA type B or C) of the thoracic spine was detected in 62.5% and therefore, it was significantly more frequent compared to the control group (36.1%). If in patients with a thoracic cage injury sternal fracture and T1-T12 fracture were located in the same segment, a rotationally unstable type C fracture was observed more frequently. The displacement of the sternal fracture did not influence the severity of the concomitant T1-T12 fracture.

CONCLUSIONS

The concomitant sternal fracture is an indicator for an unstable burst fracture, type B or C fracture of the thoracic spine, which requires surgical stabilization. If sternal and thoracic spine fractures are located in the same segment, a highly rotationally unstable type C fracture has to be expected.

[18F]FDG PET accurately differentiates infected and non-infected non-unions after fracture fixation

Purpose

Complete fracture healing is crucial for good patient outcomes. A major complication in the treatment of fractures is non-union. The pathogenesis of non-unions is not always clear, although implant-associated infections play a significant role, especially after surgical treatment of open fractures. We aimed to evaluate the value of [¹⁸F]FDG PET in suspected infections of non-union fractures.

Methods

We retrospectively evaluated 35 consecutive patients seen between 2000 and 2015 with suspected infection of non-union fractures, treated at a level I trauma center. The patients underwent either [¹⁸F]FDG PET/CT (N = 24), [¹⁸F]FDG PET (N = 11) plus additional CT (N = 8), or conventional X-ray (N = 3). Imaging findings were correlated with final diagnosis based on intraoperative culture or follow-up.

Results

In 13 of 35 patients (37 %), infection was proven by either positive intraoperative tissue culture (N = 12) or positive follow-up (N = 1). [¹⁸F]FDG PET revealed 11 true-positive, 19 true-negative, three false-positive, and two false-negative results, indicating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 85 %, 86 %, 79 %, 90 %, and 86 %, respectively. The SUV_max was 6.4 ± 2.7 in the clinically infected group and 3.0 ± 1.7 in the clinically non-infected group (p <0.01). The SUV_ratio was 5.3 ± 3.3 in the clinically infected group and 2.6 ± 1.5 in the clinically non-infected group (p <0.01).

Conclusion

[¹⁸F]FDG PET differentiates infected from non-infected non-unions with high accuracy in patients with suspected infections of non-union fractures, for whom other clinical findings were inconclusive for a local infection. [¹⁸F]FDG PET should be considered for therapeutic management of non-unions.

Staphylococcal orthopaedic device-related infections in older patients

INTRODUCTION

Staphylococci are the most common pathogens causing orthopaedic device-related infections (ODRI). The treatment of these infections often involves multiple surgical procedures combined with systemic antibiotic therapy to treat the infection and restore functionality. Older patients frequently present with a compromised health-status and/or low bone quality, and despite growing importance their outcomes are not well described to date. The primary aim of the current study is to describe outcomes in older patients with ODRIs and to determine if they demonstrate lower cure rates and greater risk for complications in contrast to younger patients.

PATIENTS AND METHODS

Patients treated with an ODRI of the lower extremity at our institution were included in this study. Demographic data, comorbidities and infecting organisms were recorded. Older adult patients were defined as those aged 60 and older. At two-year follow-up post-discharge, we recorded the clinical course, the Lower-Extremity-Functional-Score, the patient reported general health status (SF-12-questionnaire) and the status of infection. The antibiotic resistance pattern of the disease causing pathogens was analysed and compared between the two age groups.

RESULTS

In total, 163 patients (age: 19-94 years) with a staphylococcal ODRI were included. Sixty-four of these infections occurred in older patients, which showed a significantly higher mortality rate (9%). Within follow-up period recurrence of infection occurred significantly more frequently in younger patients (41%) than in older patients (17%). At two-years follow-up cure, which was defined as eradication of infection and terminated therapy, was achieved in 78% of younger and 75% of older patients. However, an ODRI resulted in older patients in a significantly worse functional outcome and impaired physical quality of live, as well as more frequently in an on-going infection, such as a persisting fistula (14% versus 3% in younger patients). Disease causing staphylococci, isolated from older patients showed more frequently a methicillin or multi-drug resistance than those associated with infections in younger patients.

CONCLUSIONS

ODRIs in older patients demonstrated higher morality rates rate, poor functional outcome and higher rates of persistent infections. A compromised health status and a poor bone quality may play a crucial role in this specific patient cohort.

FDG PET/CT dataset for navigation on femoral bone: a feasibility study

FDG PET/CT has become a valuable tool in the diagnosis of the activity of chronic osteomyelitis. The surgical strategy in the treatment of chronic osteomyelitis is the identification of the bone focus and radical debridement of sequesters. The aim of the current study was the registration and use of the FDG PET/CT imaging datasets on a navigation system to provide diagnostic imaging based feedback during surgical procedures. For the present study, FDG PET/CT scans were acquired from artificial bones and cadaver bones with a local focus of activity. The DICOM data sets were merged using a navigation system. The referenced regions of interest were matched with fluoroscopic pictures to register the PET/CT DICOM datasets to the bone and direct visual control. Navigated targeting led to accurate results when verified with fluoroscopic images by targeting previously inserted reference points in artificial and cadaver bone. FDG PET/CT datasets are suitable for navigation and compatible with conventional planning and navigation software. The combination of diagnostic FDG PET/CT imaging with surgical navigation techniques could be a valuable tool for the accurate treatment of chronic osteomyelitis.

Breakage of cephalomedullary nailing in operative treatment of trochanteric and subtrochanteric femoral fractures

INTRODUCTION

Mechanical breakage of cephalomedullary nail osteosynthesis is a rare complication attributed to delayed fracture union or nonunion. This study presents a series of cases of breakage and secondary lag screw dislocation after cephalomedullary nailing. The aim of this study was to identify factors that contribute to cephalomedullary nail breakage.

MATERIALS AND METHODS

In a retrospective case series review between 02/2005 and 12/2013, we analyzed 453 patients with trochanteric and subtrochanteric fracture who had been treated by cephalomedullary nailing. Fractures were classified according to AO/OTA classification. 13 patients with cephalomedullary nail breakage were included (failure rate 2.9 %).

RESULTS

Seven patients were women, and six men with a mean age of 72 years (range 35-94). Implant breakage occurred 6 months postoperatively (range 1-19 months). In ten cases, breakage was secondary to delayed or nonunion, which was thought to be mainly due to insufficient reduction of the fracture, and in two cases due to loss of the lag screw because of missing set screw. In one case, breakage was apparent during elective metal removal following complete fracture healing. Short-term outcome was evaluated 6 months after operative revision using Harris hip score in 11 out of 13 patients showing a mean score of 84 %. Complete radiological fracture healing has been found in 11 patients available for follow-up within 6 months after revision surgery.

DISCUSSION

Breakage of cephalomedullary nail osteosynthesis of trochanteric fractures is a severe complication. The results of our study demonstrate that revision surgery provides good clinical and radiological short-term results. Predominately, failures of trochanteric fractures are related to lack of surgeon performance. Therefore, application of the implant requires accurate preoperative planning, advanced surgical experience to evaluate the patient and the fracture classification, and precise surgical technique including attention to detail and anatomical reduction of the fracture fragments.

Reamed intramedullary exchange nailing: treatment of choice of aseptic femoral shaft nonunion

BACKGROUND

The aim of this study was to evaluate a standardized method of treatment of femoral nonunion of the isthmal femur excluding non-united metaphyseal fractures.

METHODS

Between 2003 and 2010, 72 consecutive patients with nonunion of the femoral shaft were operated using a standardized protocol in our trauma department and followed up for successful union and functional result.

RESULTS

Osseous healing was observed in 71 patients (98%). Only one patient was lacking bone healing following a time period of 24 months after the first exchange nailing and 5 months after the second exchange nailing. In 59 patients (82%), uneventful and timely bone healing after exchange nailing was detected. In 18% of patients (n = 13), delayed bone healing was observed and required additional therapy. In the majority of patients (61%), bone healing occurred within the first 2 to 5 months, only 18% of patients' duration of bone healing exceeded 8 months. In 62 patients (86%), no relevant or clinically apparent leg-length discrepancy prior to and after exchange nailing was detected as well as no significant axis deviation or malrotation. Functional studies including simple clinical gait and standing analysis, return to activities of daily life, return to sports activities, and return to work were all reached on a satisfying level.

DISCUSSION

Reamed intramedullary exchange nailing as described in this study is the treatment of choice for aseptic femoral shaft nonunion with a high rate of bone healing and a low rate of complications including length discrepancy or malrotation and a good functional outcome.

Clinical course, complication rate and outcome of segmental resection and distraction osteogenesis after chronic tibial osteitis

INTRODUCTION

Radical segmental resection and subsequent distraction osteogenesis are considered the gold standard in the treatment of chronic tibial osteitis. We investigated the clinical course of treatment, particularly with respect to patients' quality of life, and the complication rate associated with this technique.

METHODS

In this prospective case series, 25 patients (22 men, 3 women, average age: 46 years) with chronic post-traumatic tibial osteitis were managed operatively from 2006 to 2009. Standardised treatment included bacterial eradication by segmental resection, bone transport using Ilizarov apparatus, and docking manoeuvre. The follow-up rates during bacterial eradication, bone transport, post docking, and complete osseous consolidation were 100% while follow-up two years after completed consolidation was 76%. The main outcome measurements consisted of the quality of life (Medical Outcomes Study 36-Item Short Form Health Survey (SF-36 score)) and the virtual analogue scale (VAS) of pain during the five stages of therapy. Additionally, all complications and difficulties were documented.

RESULTS

The average defect size was 5.3 cm (range: 3-13). The healing index was 57 days per cm transport (range: 18-172). The overall treatment time averaged 93 weeks (range: 38-183). Patients suffered 22 minor and 13 major complications including one amputation. The average complication rate per patient consisted of 0.88 minor and 0.52 major complications. After the period of bone transport, the physical and mental component summary scores increased continuously. After completed consolidation, the average mental summary score was comparable to a normal collective.

CONCLUSIONS

Distraction osteogenesis is challenging for both the patient and the surgeon. The arduous and demanding nature of the clinical course subjects the patient to considerable mental and physical stress. Thankfully, the average physical and mental status of health continues to improve during the clinical course of treatment. The 2-year success rate of the distraction osteogenesis in an infected tibia is 96%.

Procalcitonin ratio as a predictor of successful surgical treatment of severe necrotizing soft tissue infections

BACKGROUND

Necrotizing soft tissue infections often are characterized by fulminant presentation and lethal outcomes. Besides critical care support and antibiotic therapy, aggressive surgical treatment is important for the therapy of necrotizing fasciitis. The aim of this study was to develop a procalcitonin (PCT) ratio indicating successful surgical intervention.

METHODS

The study group consisted of 38 patients treated with clinical signs of sepsis caused by a necrotizing soft tissue infection. All patients received radical surgical treatment, and serum levels of PCT and C-reactive protein were monitored postoperatively. The ratio of day 1 to day 2 was calculated and correlated with the successful elimination of the infectious source and clinical recovery.

RESULTS

An eradication of the infectious focus was successfully performed in 84% of patients, averaging 1.9 operations (range 1 to 6) to achieve an elimination of the infectious source. The PCT ratio was significantly higher in the group of patients with successful surgical intervention (1.665 vs .9, P < .001). A ratio higher than the calculated cutoff of 1.14 indicated successful surgical treatment with a sensitivity of 83.3% and a specificity of 71.4%. The positive predictive value was 75.8%, and the negative predictive value was 80.0%.

CONCLUSIONS

The PCT ratio of postoperative day 1 to day 2 following major surgical procedures for necrotizing soft tissue infections represents a valuable clinical tool indicating successful surgical eradication of the infectious focus.

Biomechanical evaluation of subtalar fusion: the influence of screw configuration and placement

Common surgical procedures for subtalar fusion include joint resection, autologous bone grafting, and osteosynthesis with screws in a parallel screw configuration. Although fusion is a routine procedure, the reported rates of nonunion have been high. The present study assessed different screw configurations in terms of their rotational and bending stability in an artificial bone model and cadaver bone. Arthrodesis was always performed with 2 screws. Three different screw configurations were tested: parallel, counter-parallel, and a delta configuration. Two different screw designs were used: a cannulated, partially threaded screw (6.5-mm and 8.0-mm diameter) and a solid screw with a different thread design. Eight experimental groups were investigated as pilot studies in artificial bones and then 3 groups in cadaver bones. The parameters were the primary stiffness and deflection of the construct for loads simulating the internal-external rotation and supination-pronation. Delta positioning of the screws resulted in the greatest biomechanical stiffness and the lowest degrees of deflection of the arthrodesis in the artificial bones and cadaver bones. Increasing the screw diameter from 6.5 to 8.0 mm resulted in no additional stability of the arthrodesis in the artificial bones. The results of the present study have indicated that the delta configuration for arthrodesis results in the greatest construct stiffness and lower relative deflection between the talus and calcaneus in the positions tested.

Posttraumatic arthrodesis of the subtalar joint--outcome in workers compensation and rates of non-union

BACKGROUND

Regardless of the simple surgical technique, the success of the subtalar arthrodesis is limited by the rate of non-unions of the arthrodesis. The functional outcome of workers compensation is known to be poorer compared to patients without pending litigation. The aim of this study was to quantify the rate of non-unions and to determine risk factors leading to failure of the osseous consolidation after arthrodesis of the subtalar joint. The outcome assessed is a general health assessment with the SF-36 questionnaire and more illness specific with the AOFAS hindfoot score. Secondly, the influence of the health insurance status of the patients with or without worker's compensation on the outcome was tested.

METHODS AND RESULTS

The inclusive criterion was an arthrodesis of the subtalar joint with and without autologous cancellous bone grafting and screw osteosynthesis. This cohort study included the clinical course of 115 patients with posttraumatic osteoarthritis from 2000 to 2006. The average age of the patients (n=115) was 47±11.0 years, 83% of the treated patients were men. 68% of the patients suffered of secondary osteoarthritis after calcaneal fracture. The time interval from trauma to presenting at the physician due to therapy resistant pain was in the average 5.5±9.9 years. After primary arthrodesis (n=101) of the subtalar joint osseous consolidation was proved in 55% cases, consolidation was questionable in 21% and the rate of no consolidation with revision was remarkable high with 24%. The duration of osseous consolidation was proved by plain projection radiography or computer tomography and clinical reduction of pain. For primary arthrodesis osseous consolidation was reached after 6.4±6.3 month, after secondary arthrodesis osseous consolidation was reached after 9.4±13.1 month. After revision surgery 57% of the arthrodesis healed, 12% the osseous consolidation was questionable, and the failure rate was still 12%.

CONCLUSION

The outcome measures of the patients with SF-36 and the more functional related AOFAS hindfoot score showed poor outcome rates after subtalar fusion in posttraumatic osteoarthritis. The AOFAS hindfoot score was 47±24 points after primary arthrodesis and 46±17 points after secondary arthrodesis of the subtalar joint. The patients regained their former ability to work only in 30% after fusion of the subtalar joint. If revision surgery was necessary 8% of the patients got back to their work prior to the injury.

17 degrees Celsius body temperature--resuscitation successful?

The resuscitation of patients with accidental profound hypothermia is challenging. A 17-year-old man got lost on the first of January, after a New Year's Eve party in the foothills of the Alps. After a search of four hours, he was found unconscious with fixed pupils, a Glasgow Coma Scale of three points, and a body temperature below 20° Celsius. There were no signs for traumatic injuries. Initial electrocardiogram (ECG) showed no heart activity. Basic life support was begun by the mountain rescue service and continued by the medical helicopter team. The patient was transferred under continuous cardiac massage, airway management with intubation and intravenous line via external jugular vein by helicopter to the nearest hospital for analysis of serum potassium. Body temperature was 17°C measured by urinary bladder electronic thermometer. The serum potassium was 7.55 mmol/L, therefore the patient was transferred by helicopter to the next cardiovascular center for rewarming with extracorporal circulation (ECC). Under the rewarming process with ECC, the heart activity restarted at 25°C with external defibrillation. The patient was rewarmed to 37.2°C after four hours of ECC. Cerebral CT scans after 24 h and 48 h revealed no significant hypoxia and after extubation the early rehabilitation process started. After six weeks, the patient regained the ability to walk and started to communicate on a basic level. After 54 days the patient presented signs of septic shock. After initial stabilization and CT diagnostic, a laparotomy was performed. The intraoperative finding was a total necrosis of the small bowel and colon. The patient died on the same day. Post mortem examination showed a necrotizing enterocolitis with transmural necrosis of the bowel. Survivors of uncontrolled profound hypothermia below 20°C core temperature are rare. The epicrisis is often prolonged by complications of different causes. The present case reports a necrotizing enterocolitis with a non-occlusive mesenteric ischemia (NOMI) as a medium-term complication of profound hypothermia.

Anatomical plate configuration affects mechanical performance in distal humerus fractures

BACKGROUND

Because of strong loads acting in the elbow joint, intraarticular fractures with a methaphyseal comminuted fracture site at the distal humerus demand a lot from the osteosynthetic care. Ambiguities arise concerning to the anatomic position of the implants and the resulting mechanic performance. The aim of this biomechanical study was to compare the performance of different anatomical plate configurations for fixation of comminuted distal humerus fractures within one system.

METHODS

In an artificial bone model two perpendicular and one parallel plating configuration of a dedicated elbow plating system were compared with respect to system rigidity (flexion and extension) and dynamic median fatigue limit (extension). The flexion tests were conducted under 75° and the extension tests under 5°. Furthermore, the relative displacements were recorded. As a fracture model an AO C 2.3-fracture on an artificial bone (4th Gen. Sawbone) was simulated via double osteotomy in sagittal and transversal plane.

FINDINGS

Large differences in mechanical performance were observed between flexion and extension loading modes. In extension the parallel configuration with lateral and medial plates achieved the highest bending stiffness and median fatigue limit. In flexion the highest bending stiffness was reached by the construct with a medial and a postero-lateral plate. Failure of the implant system predominantly occurred at the screw-bone interface or by fatigue of the plate around the screw holes.

INTERPRETATION

All three plate configurations provided sufficient mechanical stability to allow early postoperative rehabilitation with a reduced loading protocol. Although the individual fracture pattern determines the choice of plate configuration, the parallel configuration with lateral and medial plates revealed biomechanical advantages in extension only.

Fiber optical spatial filter anemometry--intravital measurement of red blood flow velocity (RBCV) in the microcirculation

The fiberoptical spatial filter anemometry (SFA) is a common technique based on an optical grid to measure the velocity of corpuscular components in a multiphase flow, e.g. in the microvessels. The technical innovation is the analysis of flow velocities using an optical grid sensor and frequency analysis by Fast Fourier Transformation (FFT). This study describes a non-invasive, on-line technique to measure RBCV in the microcirculation. The sensor's validity was proven by in vitro measurements using a rotation disk of an exactly defined velocity with a correlation coefficient of 0.99967. For validation of RBCV measurements in the microcirculation in vivo, the setup was adapted to an intravital microscope. RBCV was measured in arterioles, capillaries, and postcapillary venules ranging from 8-140 microm diameter. As reference method for velocity measurements a computer assisted imaging system was used to measure the RBC-velocity in the identical vessels by frame to frame analysis. Both methods revealed a high significant correlation using transillumination technique for capillaries (r=0.986, p<0.001) and venules (r=0.952, p<0.001) as well as epiillumination technique (capillaries r=0.939, venules r=0.975, p<0.001).

Human bacterial arthritis caused by Streptococcus zooepidemicus: report of a case

Septic arthritis caused by Streptococcus zooepidemicus is a rare event in humans. Of the four cases reported in the literature, only two patients had direct animal contact, and the portal of entry remained unclear in all cases. We report herein the case of a patient who suffered a purulent arthritis of the left shoulder caused by S. zooepidemicus, successfully treated in our department. A diagnostic FDG-PET-CT scan ruled out other foci of infection, but detected a hyperkeratotic plantar chronic soft tissue lesion of the left foot, acquired in a paragliding accident 10 years earlier. The fact that the patient habitually took care of his horses barefoot in boots, identifies the cutaneous portal of entry as most likely. To our knowledge this is the first report of a septic arthritis caused by S. zooepidemicus where a cutaneous entry route is described.

Type of hip fracture determines load share in intramedullary osteosynthesis

The choice of the appropriate implant continues to be critical for fixation of unstable hip fractures. Therefore, the goal of this study was to develop a numerical model to investigate the mechanical performance of hip fracture osteosynthesis. We hypothesized that decreasing fracture stability results in increasing load share of the implant and therefore higher stress within the implant. We also investigated the relationship of interfragmentary movement to the fracture stability. A finite element model was developed for a cephalomedullary nail within a synthetic femur and simulated a pertrochanteric fracture, a lateral neck fracture, and a subtrochanteric fracture. The femur was loaded with a hip force and was constrained physiologically. The FE model was validated by mechanical experiments. All three fractures resulted in similar values for stiffness (462-528 N/mm). The subtrochanteric fracture resulted in the highest local stress (665 MPa), and the pertrochanteric fracture resulted in a lower stress (621 MPa) with even lower values for the lateral neck fracture (480 MPa). Thus, intramedullary implants can stabilize unstable hip fractures with almost the same amount of stiffness as seen in stable fractures, but they have to bear a higher load share, resulting in higher stresses in the implant.

Bilateral Sacroiliac Joint Dislocation in an Adolescent after a Skiing Accident

A bilateral sacroiliac joint (SI joint) dislocation is a rare injury pattern, in contrast to bilateral fracture dislocations of the SI joint. The incidence of pelvic dislocation of the SI joint without significant bone structural damage would most likely be observed in young children or adolescents after receiving a blunt, high energy impact. These young patients often suffer life threatening injuries to the intestines, neural or vascular systems or severe injury of the urinary tract. In these scenarios, plain projection radiographic imaging often leads to an inconclusive diagnosis making computer tomography indispensable to plan the treatment strategy. These strategies vary and the optimal approach is a subject to dispute. A surgical treatment of these injuries should ensure an immediate primary stability to allow early ambulation. The following study reports a unique trauma pattern with an isolated bilateral SI dislocation without fracture of the posterior or anterior pelvic ring nor concomitant injuries. This rare injury is a consequence of a pure vertical shear impact. This case report describes a technical pitfall of the iliolumbar transfixation and a solution to the problem. A dorso-ventro-dorsal approach, which utilizes both iliolumbar transfixation and ventral bilateral double plating osteosynthesis will be presented.

Effects of Diaspirin Crosslinked Hemoglobin (DCLHb) on microcirculation and local tissue pO2 of striated skin muscle following resuscitation from hemorrhagic shock

The hemoglobin based oxygen carrier (HBOC) Diaspirin Crosslinked Hemoglobin (DCLHb) has been developed to substitute not only the blood volume, but also to restore the oxygen-carrying properties of blood during hemorrhagic shock. However, it has been suggested that HBOCs may enhance the formation of free oxygen radicals through the release of free iron ions via the Haber-Weiss reaction. The aim of this study was to investigate the effects of DCLHb on the microcirculation, leukocyte-endothelial cell interaction and local tissue oxygenation in striated skin muscle of Syrian golden hamsters during and after resuscitation from hemorrhagic shock. In particular we focused on the local tissue oxygenation after resuscitation with DCLHb (hemoglobin content 10 g%) compared to resuscitation using autologous blood diluted to a hemoglobin content of 10 g%. Hemorrhagic shock was induced for 45 minutes by bleeding the animals at a rate of 33 ml/kg BW maintaining a mean arterial pressure of 30 +/- 5 mmHg. Animals were resuscitated either with 33 ml/kg BW 6% Dextran-60.000 or with 10 g% DCLHb. The control group received shed blood diluted with Ringers to a hemoglobin content of 10 g%. Intravital microscopy was used for investigation of the microcirculatory parameters and a multiwire platinum surface electrode for measurement of local tissue pO2 in striated skin muscle in the dorsal skinfold chamber of Syrian golden hamsters. Resuscitation from hemorrhagic shock with 10 g% AUB revealed significant increase of leukocytes rolling in postcapillary venules at 30 to 120 minutes after resuscitation compared to baseline values. DCLHb turned out to reduce the number of firmly adherent leukocytes after resuscitation compared to 10 g% AUB. Microvascular permeability as an indicator for functional endothelial integrity revealed no significant differences between the groups. DCLHb and 10 g% AUB led to a significant increase in local tissue oxygenation after resuscitation from hemorrhagic shock. However, 10 g% AUB turned out to be most effective to restore the local tissue pO2 compared to Dx-60. Our findings indicate that DCLHb restores microvascular perfusion after critical hemorrhagic shock as efficient as Dx-60 and 10 g% AUB. The absence of enhanced leukocyte-endothelium interaction after resuscitation with DCLHb implies that this HBOC does not exacerbate formation of oxygen free radicals during reperfusion. DCLHb effectively increases local tissue pO2 after resuscitation from hemorrhagic shock; however, not as effectively as 10 g% AUB.