Osteoid osteoma: treatment outcome and long-term follow-up after MRI-guided laser ablation.

Background: Aim of this study was to investigate short-term and long-term treatment outcome, complication rates, and patient satisfaction after MRI-guided laser ablation (LA) of osteoid osteoma (OO). Methods: Thirty-five patients with OO in typical and atypical localizations were treated by MRI-guided LA with MRI thermometry in an open 1.0 T system. Twenty-nine patients underwent a standardized telephone interview including questions about recurrence, residual pain or functional symptoms, and satisfaction for short-term follow-up after a mean of 31 months. Twenty-one of these patients were available for long-term telephone follow-up after a mean of 116 months. Results: Technical success of MRI-guided LA was 100% without major complications. Two minor complications included transient local inflammation and transient damage of the peroneal nerve associated with improper patient positioning during the procedure. Primary clinical success was 92% (11/12) in typically located OO and 82% (14/17) in atypically located OO. Secondary clinical success after repeat ablation was 100% regardless of OO location. Patient satisfaction and acceptance of the intervention were very good at both short-term (97%) and long-term (100%) follow-up. Conclusions: MRI-guided LA of OO is a safe and effective treatment option resulting in high short-term and long-term patient satisfaction and acceptance rates. Recurrence and adverse events were more common in patients with atypically located OO. Level of Evidence: Level 3, non-randomized follow-up study.

Burst fractures lead to a fracture-associated intervertebral vacuum phenomenon: a case series of 305 traumatic fractures of the thoracolumbar spine.

PURPOSE: Intervertebral vacuum phenomenon (IVP) is mainly seen as a sign of degenerative disc diseases. Although studies have shown that IVP also occurs after traumatic injuries to the spine, its clinical relevance in spinal fractures remains unknown. Therefore, the aim of this study was to analyse the prevalence, demographic parameters and fracture morphology in patients with fracture-associated IVP (FAVP) of the thoracolumbar spine. METHODS: In this retrospective cohort study, patients with traumatic fractures of the thoracolumbar spine who were admitted between January 2014 and December 2015 were included. CT scans were assessed for the presence of intervertebral areas of gaseous radiolucency, which were defined as IVP. Fractures were classified according to the AOSpine Thoracolumbar Spine Injury Classification System. Demographic and anamnestic data, including age, sex and trauma mechanism, were documented. RESULTS: A total of 201 patients with 305 fractures were included. Seventy-three patients with 98 fractures had follow-up CTs. Sixty-eight patients had IVP, of whom 46 patients had FAVP. On the follow-up CT, a significant correlation was found between A3 fractures and FAVP, while initial FAVP was significantly correlated with age and low-velocity trauma mechanisms. Initial degenerative IVP also showed a significant correlation with age. CONCLUSIONS: FAVP occurred significantly more often in burst fractures and therefore may lead to disc degeneration due to nutritional supply disturbances via the vertebral endplate. As surgical management strategies for burst fractures are intensively discussed, the appearance of FAVP should be taken in consideration.

Atypically Located Osteoid Osteoma: Characteristics and Therapeutic Success After Image-Guided Thermal Ablation. / Das atypisch lokalisierte Osteoidosteom: Charakteristiken und Therapieerfolg nach bildgesteuerter Thermoablation.

PURPOSE: While ostoeid osteomas (OO) are typically located in long tubular bones, OO occurring elsewhere are referred to as "atypical". Aim of our study was to review the characteristics of atypically located OO, course of symptoms and therapy, as well as clinical outcome, safety, and patient satisfaction of radiofrequency ablation (RFA). MATERIALS AND METHODS: In the period from 04/01 to 07/13, 33 patients were treated using thermal ablation (RFA or laser), partly with low temperature and short duration technique. Clinical records were analyzed. Additionally, 23 patients were interviewed via telephone. Primary endpoints were technical success, clinical success (recurrence rates), and adverse events. Secondary endpoints were course of symptoms and therapy as well as patient satisfaction. RESULTS: Mean follow-up was 22.1 ±â€Š21.5 months. Average patient age was 31.7 ±â€Š16.3 years. Localization: Most atypical OO (61 %) were located in the lower extremity, followed by axial skeleton (26 %) and upper extremity (13 %). Pain anamnesis: 74 % of patients stated that their pain occured predominantly at night and responded to NSAID, as typical for OO. Diagnostics: Patients consulted on average 4 different doctors and in 52 % patients, ≥ 3 different radiologic imaging techniques where used before the diagnosis "OO" was made. OUTCOME: Technical success of thermal ablation was 100 %. Primary clinical success was 91 %. Patient satisfaction was 100 %. No major complications occurred. CONCLUSION: In » of cases, atypical OO did not show the typical pain characteristics of OO. Image-guided thermal ablation is a promising and safe therapy also for patients with atypical OO. KEY POINTS: · Atypical OO are challenging regarding diagnostics and therapy. · Image-guided thermal ablation is a safe and effective procedure also for patients with atypical OO. · Image-guided thermal ablation shows high patient satisfaction. CITATION FORMAT: · Seemann RJ, Märdian S, Schwabe P et al. Atypically Located Osteoid Osteoma: Characteristics and Therapeutic Success After Image-Guided Thermal Ablation. Fortschr Röntgenstr 2020; 192: 335 - 342.

Mechanobiologically optimized 3D titanium-mesh scaffolds enhance bone regeneration in critical segmental defects in sheep.

Three-dimensional (3D) titanium-mesh scaffolds offer many advantages over autologous bone grafting for the regeneration of challenging large segmental bone defects. Our study supports the hypothesis that endogenous bone defect regeneration can be promoted by mechanobiologically optimized Ti-mesh scaffolds. Using finite element techniques, two mechanically distinct Ti-mesh scaffolds were designed in a honeycomb-like configuration to minimize stress shielding while ensuring resistance against mechanical failure. Scaffold stiffness was altered through small changes in the strut diameter only. Honeycombs were aligned to form three differently oriented channels (axial, perpendicular, and tilted) to guide the bone regeneration process. The soft scaffold (0.84 GPa stiffness) and a 3.5-fold stiffer scaffold (2.88 GPa) were tested in a critical size bone defect model in vivo in sheep. To verify that local scaffold stiffness could enhance healing, defects were stabilized with either a common locking compression plate that allowed dynamic loading of the 4-cm defect or a rigid custom-made plate that mechanically shielded the defect. Lower stress shielding led to earlier defect bridging, increased endochondral bone formation, and advanced bony regeneration of the critical size defect. This study demonstrates that mechanobiological optimization of 3D additive manufactured Ti-mesh scaffolds can enhance bone regeneration in a translational large animal study.

Quality and Dose Optimized CT Trauma Protocol - Recommendation from a University Level-I Trauma Center.

Purpose As a supra-regional level-I trauma center, we evaluated computed tomography (CT) acquisitions of polytraumatized patients for quality and dose optimization purposes. Adapted statistical iterative reconstruction [(AS)IR] levels, tube voltage reduction as well as a split-bolus contrast agent (CA) protocol were applied. Materials and Methods 61 patients were split into 3 different groups that differed with respect to tube voltage (120 - 140 kVp) and level of applied ASIR reconstruction (ASIR 20 - 50 %). The CT protocol included a native acquisition of the head followed by a single contrast-enhanced acquisition of the whole body (64-MSCT). CA (350 mg/ml iodine) was administered as a split bolus injection of 100 ml (2 ml/s), 20 ml NaCl (1 ml/s), 60 ml (4 ml/s), 40 ml NaCl (4 ml/s) with a scan delay of 85 s to detect injuries of both the arterial system and parenchymal organs in a single acquisition. Both the quantitative (SNR/CNR) and qualitative (5-point Likert scale) image quality was evaluated in parenchymal organs that are often injured in trauma patients. Radiation exposure was assessed. Results The use of IR combined with a reduction of tube voltage resulted in good qualitative and quantitative image quality and a significant reduction in radiation exposure of more than 40 % (DLP 1087 vs. 647 mGyxcm). Image quality could be improved due to a dedicated protocol that included different levels of IR adapted to different slice thicknesses, kernels and the examined area for the evaluation of head, lung, body and bone injury patterns. In synopsis of our results, we recommend the implementation of a polytrauma protocol with a tube voltage of 120 kVp and the following IR levels: cCT 5mm: ASIR 20; cCT 0.625 mm: ASIR 40; lung 2.5 mm: ASIR 30, body 5 mm: ASIR 40; body 1.25 mm: ASIR 50; body 0.625 mm: ASIR 0. Conclusion A dedicated adaptation of the CT trauma protocol (level of reduction of tube voltage and of IR) according to the examined body region (head, lung, body, bone) combined with a split bolus CA injection protocol allows for a high-quality CT examination and a relevant reduction of radiation exposure in the examination of polytraumatized patients Key Points · Dedicated adaption of the CT trauma protocol allows for an optimized examination.. · Different levels of iterative reconstruction, tube voltage and the CA injection protocol are crucial.. · A reduction of radiation exposure of more than 40 % with good image quality is possible.. Citation Format · Kahn J, Kaul D, Böning G et al. Quality and Dose Optimized CT Trauma Protocol - Recommendation from a University Level-I Trauma Center. Fortschr Röntgenstr 2017; 189: 844 - 854.

* Demineralized Bone Matrix as a Carrier for Bone Morphogenetic Protein-2: Burst Release Combined with Long-Term Binding and Osteoinductive Activity Evaluated In Vitro and In Vivo.

To allow bone defect regeneration, autologous bone grafting still represents the gold standard. However, autograft harvesting has limitations, including an additional surgery, donor site morbidity, and limited availability. Demineralized bone matrix (DBM) would represent an alternative, yet lacks sufficient osteoinductive properties. Combining DBM with a potent agent, such as bone morphogenetic protein-2 (BMP-2) might be a feasible alternative approach, optimizing an established grafting material with strong osteoinductive properties. A unique mixing device has been developed that enables perioperative handling to reach a homogeneous and standardized paste for bone defect filling. DBM proved in vitro to be a suitable carrier for BMP-2, with a documented release over 56 days at concentrations sufficient to stimulate osteogenic differentiation. At the end of the elution experiment, 56 days, bioactive BMP was still captured within the DBM. Using a sheep drill hole defect model, DBM perioperatively mixed with BMP-2 showed strong osteoinductive properties comparable to those of autologous bone and outnumbering the one of DBM alone or empty defects. Bone defect healing was enabled at diaphyseal and metaphyseal defects and thus BMP-2-doped DBM represented an easy perioperative enriching method and an efficient carrier for BMP-2. With the comparability to the clinical gold standard autologous bone, DBM mixed with BMP-2 might serve as possible alternative grafting material enabling a controlled osteogenic stimulation.

High-dose recombinant human bone morphogenetic protein-2 impacts histological and biomechanical properties of a cervical spine fusion segment: results from a sheep model.

The 'off-label' use of high-dose recombinant human bone morphogenetic protein-2 (rhBMP-2) in lumbar and cervical fusion leads to heterotopic bone formation and vertebral osteolysis. These radiographically assessed side-effects in patients were frequently associated with an over-dosage of BMP-2. However, little is so far known about the histological, functional or biomechanical tissue consequences of over-dosage of rhBMP-2 in these specific clinical situations. We hypothesized that a high dose of rhBMP-2 in cervical spinal fusion could induce substantial alterations in bone, leading to mechanical impairment. An anterior cervical spinal fusion (C3-C4 ACDF) model in 16 sheep (aged > 2.5 years; n = 8/group) was used to quantify the consequences of a high rhBMP-2 dose (6 mg rhBMP-2) on fusion tissue compared to the 'gold standard' of autologous, cancellous bone graft. The fusion site was assessed by radiography after 0, 8 and 12 weeks. Biomechanical non-destructive testing and (immuno)histological and histomorphometrical analyses were performed 12 weeks postoperatively. Although high-dose rhBMP-2 treatment led to an advanced radiological fusion result compared to autograft treatment, heterotopic bone formation and vertebral bone resorption were induced simultaneously. Histological evaluation unveiled highly active bone-forming processes ventral to the fusion segment after 12 weeks, while radiolucent areas showed still a partial loss of regular trabecular structure, with rare signs of remodelling and restoration. Despite qualitative alteration of the trabecular bone structure within the fusion site, the massive anterior heterotopic bone formation led to a substantial increase in mechanical stiffness compared to the autograft group. Copyright © 2015 John Wiley & Sons, Ltd.

Positive Outcome After a Small-Caliber Gunshot Fracture of the Upper Cervical Spine without Neurovascular Damage.

BACKGROUND: Gunshot wounds to the cervical spine most frequently concur with serious injuries to the spinal cord and cervical vessels and often have a fatal outcome. CASE REPORT: We describe the case of a 35-year-old male with a complex fracture of the C2 vertebra body and a mandibular fracture after a penetration gunshot to the cervical spine. Computed tomography (CT) at admission revealed the exact extent of the fractures and the small caliber bullet lodged next to the C2 vertebra. In this rare and extremely lucky case no collateral vascular or neurological damage was detected. Eighteen months after surgical bullet removal and posterior C1-C3 fusion complete bone healing of the C2 vertebra was achieved and there were no secondary neurovascular deficits. CONCLUSIONS: Immediate surgical C1-C3 fixation resulted in an excellent outcome without secondary neurovascular deficits in this rare case of traumatic complex C2 vertebral fracture caused by a gunshot injury.

Current concepts review: Fractures of the patella.

Fractures of the patella account for about 1% of all skeletal injuries and can lead to profound impairment due to its crucial function in the extensor mechanism of the knee. Diagnosis is based on the injury mechanism, physical examination and radiological findings. While the clinical diagnosis is often distinct, there are numerous treatment options available. The type of treatment as well as the optimum timing of surgical intervention depends on the underlying fracture type, the associated soft tissue damage, patient factors (i.e. age, bone quality, activity level and compliance) and the stability of the extensor mechanism. Regardless of the treatment method an early rehabilitation is recommended in order to avoid contractures of the knee joint capsule and cartilage degeneration. For non-displaced and dislocated non-comminuted transverse patellar fractures (2-part) modified anterior tension band wiring is the treatment of choice and can be combined - due to its biomechanical superiority - with cannulated screw fixation. In severe comminuted fractures, open reduction and fixation with small fragment screws or new angular stable plates for anatomic restoration of the retropatellar surface and extension mechanism results in best outcome. Additional circular cerclage wiring using either typical metal cerclage wires or resorbable PDS/non-resorbable FiberWires increases fixation stability and decreases risk for re-dislocation. Distal avulsion fractures should be fixed with small fragment screws and should be protected by a transtibial McLaughlin cerclage. Partial or complete patellectomy should be regarded only as a very rare salvage operation due to its severe functional impairment.

BMPs in bone regeneration: Less is more effective, a paradigm-shift.

Worldwide, the clinical application of BMP2 (bone morphogenetic protein 2) has helped an increasing number of patients achieve bone regeneration in a clinical area lacking simple solutions for difficult bone healing situations. In this review, the historical aspects and current critical clinical issues are summarized and positioned against new research findings on efficacy and function of BMP2. Knowledge concerning how the dose of this growth factor as well as its interaction with mechanical loading influences the efficacy of bone regeneration, might open possible future strategies in cases where bony bridging is unachievable so far. In conclusion, it is apparent that there is a substantial need for continued basic research to unravel the details of its function and the underlying signaling pathways involved, to make BMP2 even more relevant and safe in daily clinical use, even though this growth factor has been known for more than 125 years.

Sinus pilonidalis in patients of German military hospitals: a review.

Pilonidal sinus disease (PSD) most commonly presents in young men when hair follicles enter through damaged epithelium and cause an inflammatory reaction. This results in the formation of fistular tracts. We reviewed studies based on a shared cohort of patients who presented at German military hospitals with PSD. The effect of the morphology of the sinus, perioperative protocol, and aftercare of the surgical treatment on the recurrence of PSD were evaluated. The drainage of acute abscesses before surgery, the application of methylene blue during surgery and open wound treatment were generally found to reduce the recurrence rate. A positive family history, postoperative epilation and primary suture as the healing method were found to elevate the recurrence rate. Long-term follow up of over 15 years was found to be a vital component of patient care as only 60% of the overall recurrences recorded had taken place by year 5 postoperatively.

Piwi-interacting RNAs as novel prognostic markers in clear cell renal cell carcinomas.

BACKGROUND: Piwi-interacting RNAs (piRNAs) are small RNAs of 27-30 nucleotides mapping to transposons or clustering in repeat genomic regions. Preliminary studies suggest an important role in cancerogenesis. This study is the first one investigating their prognostic impact in clear cell renal cell cancer (ccRCC) patients. METHODS: Three piRNAs (piR-30924, piR-57125, and piR-38756) selected on the basis of initial piRNA microarray analyses were determined using RT-qPCR in non-metastatic (n = 76) and metastatic (n = 30) ccRCC tissue at the time of nephrectomy in comparison to normal renal tissue (n = 77) and tissue from distant ccRCC metastases (n = 13). Primary clinical end points were recurrence-free and overall survival. RESULTS: piR-57125 showed lower expression in metastatic than in non-metastatic tumors, whereas the expression of piR-30924 and piR-38756 increased in metastatic tumors. The higher expression of piR-30924 and piR-38756 as well as the lower expression of piR-57125 in metastatic primary tumors were significantly associated with tumor recurrence and overall survival. Multivariate Cox regression analyses revealed both piR-30924 and piR-57125 as independent prognostic predictors. This impact was even more pronounced in non-metastatic patients. CONCLUSIONS: This study demonstrates that the expression levels of these piRNAs in primary non-metastatic and metastatic ccRCC tissue can serve as potential prognostic biomarkers in combination with clinicopathological factors.

Complete major amputation of the upper extremity: Early results and initial treatment algorithm.

BACKGROUND: Traumatic major amputations of the upper extremity are devastating injuries. These injuries have a profound impact on patient's quality of life and pose a burden on social economy. The aims of the current study were to report about the initial management of isolated traumatic major upper limb amputation from the time of admission to definitive soft tissue closure and to establish a distinct initial management algorithm. METHODS: We recorded data concerning the initial management of the patient and the amputated body part in the emergency department (ED) (time from admission to the operation, Injury Severity Score [ISS], cold ischemia time from injury to ED, and total cold ischemia time). The duration, amount of surgical procedures, the time to definitive soft tissue coverage, and the choice of flap were part of the documentation. All intraoperative and postoperative complications were recorded. RESULTS: All patients were successfully replanted (time from injury to ED, 59 ± 4 minutes; ISS16; time from admission to operating room 57 ± 10 minutes; total cold ischemia time 203 ± 20 minutes; total number of procedures 7.3 ± 2.5); definitive soft tissue coverage could be achieved 23 ± 14 days after injury. Two thromboembolic complications occurred, which could be treated by embolectomy during revision surgery, and we saw one early infection, which could be successfully managed by serial debridements in our series. CONCLUSION: The management of complete major amputations of the upper extremity should be reserved for large trauma centers with enough resources concerning technical, structural, and personnel infrastructure to meet the demands of surgical reconstruction as well as the postoperative care. Following a distinct treatment algorithm is mandatory to increase the rate of successful major replantations, thus laying the foundation for promising secondary functional reconstructive efforts. LEVEL OF EVIDENCE: Therapeutic study, level V.

Adequate surgical treatment of periprosthetic femoral fractures following hip arthroplasty does not correlate with functional outcome and quality of life.

PURPOSE: This study aimed to analyse functional outcome and quality of life (QoL) after surgical treatment of periprosthetic femoral fractures (PPF) following total hip arthroplasty (THA). METHODS: This retrospective study assessed 67 patients from 2005 to 2012. Epidemiologic data, surgical details, comorbidities, deaths and postoperative complications were recorded. Functional assessment included Harris Hip Score (HHS) and range of motion (ROM); QoL was assessed using the Short-Form Health Survey of 36 questions (SF-36) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. RESULTS: Mean HHS was 69 ± 21 and ROM 96° ± 17°. Mean SF-36 and WOMAC scores revealed 44 ± 7.2 and 18.9 ± 19.6, respectively. The complication rate was 25.4%; 23.7% of patients died. Analysis revealed no statistical influence on final outcome as a function of fracture type or treatment strategy. Comorbidities seem to influence functional outcome. CONCLUSION: PPF following THA are accompanied by a perceptible decline of function and remarkably high complication rates. In contrast to fracture classification and treatment type, American Society of Anesthesiologists (ASA) score predicts outcome.

Outcome of angular stable locking plate fixation of tibial plateau fractures Midterm results in 101 patients.

BACKGROUND: Articular reconstruction and stable fixation of tibial plateau fractures and its various subtypes continue to represent a surgical challenge. Only few trials have studied results following angular stable plate fixation. The present study aimed to investigate the clinical, radiological, functional and quality of life results following tibial plateau fractures using angular stable plate fixation. MATERIALS AND METHODS: 101 patients were retrospectively studied using functional (ROM; KSS; VAS), radiographic (osteoarthritis score, loss of reduction) and quality of life (WOMAC; Lysholm) scores. There were 46 males and 55 females. The average of patients was 51 years (range 22-77 years). Study groups were assigned according to the AO fracture classification. RESULTS: Mean followup was 57 ± 30 months. Fracture type distribution revealed a significantly (P < 0.001) increased number of type B- (62.4%) compared to C-fractures. Functional assessment showed a significantly better total KSS (84.1 ± 15.6 vs. 74.7 ± 18.0; P = 0.01) as well as ROM (active: 124°±17° vs. 116°±15°, P = 0.014; passive: 126°±18° vs. 118 ± 14°, P = 0.017) in the B-fracture group. VAS was found to be markedly higher (P = 0.0039) following type C-fractures. Rating osteoarthritis secondary to a tibial plateau fracture as a function of injury severity (r = 0.485; P < 0.001) and relating the loss of reduction to the grade of evolving osteoarthritis (r = 0.643; P < 0.001) a positive correlation was found. Quality of life showed significantly improved results for Lysholm score (P = 0.004) following B-fractures with low overall values for the WOMAC score. CONCLUSION: Presented data provide sufficient evidence that anatomic restoration of tibial plateau fractures with angular stable plate fixation result in decreased loss of reduction and declined incidence of posttraumatic osteoarthritis, thereby providing acceptable mid to long term outcome.

Influence of wound drainage in primary total knee arthroplasty without tourniquet.

PURPOSE: Although it remains the golden standard, several authors have questioned the role of pneumatic tourniquets in primary knee arthroplasty in recent studies. An intra-articular wound drainage is widely used in the field of total knee arthroplasty although the benefit of postoperative wound drainage is controversial in the literature. This study questioned whether the use of an intra-articular drain is an advance over the lack of a drain in total knee arthroplasty which is performed without a tourniquet. METHODS: We documented the ROM, the knee circumference at the upper patellar pole pre-operatively and on days two, four and six postoperatively. The blood volume and loss was calculated. As surrogate parameter for wound healing we counted the number of days until no residual secretion was observed via the wound/drainage site. RESULTS: The results of our investigation showed a significantly better wound healing without the use of a drain. All other parameters revealed no significant differences. CONCLUSION: The data of this study demonstrate a faster wound healing without the use of a postoperative wound drain in primary total knee arthroplasty which is performed without a tourniquet. Other parameters could not show any significant differences thus indicating that a postoperative wound drain has no significant advantage and the risk of a retrograde bacterial colonisation is well documented. Based on these data we recommend performing a primary total knee arthroplasty without a postoperative drain if the procedure is done without a tourniquet.

Long-term functional outcome and quality of life after successful surgical treatment of tibial nonunions.

PURPOSE: Our aim was to evaluate quality of life (QoL) and functional outcome of patients with tibial nonunions after completion of surgical treatment with an average follow-up of five years. METHODS: The following data of 64 patients were retrospectively evaluated: fracture type, type and duration of surgical therapy, range of motion of the knee and ankle and American Orthopaedic Foot and Ankle Society (AOFAS) score. QoL was evaluated with the Short-Form Health Survey (SF-36) questionnaire; pain intensity, patient satisfaction and impairments of daily, professional and sport activities with a ten point visual analogue scale. RESULTS: QoL, even in cases with successfully completed treatment, was significantly reduced compared with the normal general population. Pain intensity and limited ankle dorsal extension, despite the absence of intra-articular fractures, were significantly correlated with inferior QoL. CONCLUSIONS: This study emphasises the long-term negative impact of tibial nonunions on patient QoL, even after successful surgical treatment.

Impact of high prevalence of pseudomonas and polymicrobial gram-negative infections in major sub-/total traumatic amputations on empiric antimicrobial therapy: a retrospective study.

INTRODUCTION: Emergency treatment of major sub-/total traumatic amputations continue to represent a clinical challenge due to high infection rates and serious handicaps. Effective treatment is based on two columns: surgery and antimicrobial therapy. Detailed identification of pathogen spectrum and epidemiology associated with these injuries is of tremendous importance as it guides the initial empiric antibiotic regimen and prevents adverse septic effents. METHODS: In this retrospective study 51 patients with major traumatic amputations (n = 16) and subtotal amputations (n = 35) treated from 2001 to 2010 in our trauma center were investigated. All patients received emergency surgery, debridement with microbiological testing within 6 h after admission and empircic antimicrobial therapy. Additionally to baseline patient characteristics, the incidence of positive standardized microbiologic testing combined with clinical signs of infection, pathogen spectrum, administered antimicrobial agents and clinical complications were analyzed. RESULTS: 70.6% of the patients (n = 36) acquired wound infection. In 39% wounds were contaminated on day 1, whereas the mean length of duration until first pathogen detection was 9.1 ± 13.4 days after injury. In 37% polymicrobial colonization and 28% Pseudomonas were responsible for wound infections during hospitalization. In 45% the empirc antimicrobial therapy focussed on Gram positive strains did not cover the detected bacteria, according antimicrobial resistogram. It was significantly more often found in infections associated with Pseudomonas (p 0.02) or polymicrobial wound infections. CONCLUSIONS: This epidemiologic study reveals a pathogen shift from Gram-positive to Gram-negative strains with high incidence of Pseudomonas and polymicrobial infections in sub-/total major traumatic amputations. Therefore, empiric antimicrobial treatment historically focussing on Gram-positive strains must be adjusted. We recommend the use of Piperacillin/Tazobactam for these injuries. As soon as possible antimicrobial treatment should be changed from empiric to goal directed therapy according to the microbiological tests and resistogram results.

A pilot study investigating the histology and growth factor content of human non-union tissue.

PURPOSE: The reason for the formation of an atrophic non-union is not clear and an altered vascularization as well as a deregulation of endogenous growth factors is hypothesized. To obtain more information, we analysed human non-union tissue regarding the histology and quantity of several growth factors. METHODS: Tissue from patients with an atrophic non-union (n = 44) or with a healed fracture (n = 13) was analysed. Using histological and immunohistochemical methods the tissue composition was investigated. On the protein level the amount of several growth factors important for bone healing was analysed. RESULTS: The tissue composition was very inhomogeneous containing fibrous, cartilaginous and bony tissue. Vessels were present in all investigated samples without a difference between the tissue from non-union and control patients. The growth factor BMP-2 was below the detection limit in all samples, whereas IL-6 and IGF-I were measured only in a few samples of both groups. TGF-ß1, VEGF-A and BMP-4 were detectable in the majority of the samples of both groups with a high variability in the amount but no difference between the groups. The quantity of both growth factors, BMP-7 and PDGF-AB, was significantly lower in the non-union tissue compared to the healed controls. CONCLUSION: The reduced quantity of BMP-7 and PDGF-AB might be responsible for the impaired healing. Further studies analysing material from more patients and investigating the early healing phases, however, are necessary to obtain further information and consequently improve healing strategies.

Three-dimensional fluoroscopy-navigated percutaneous screw fixation of acetabular fractures.

OBJECTIVE: Anatomic reduction and articular restoration after acetabular fractures occur (Ac-Fxs) are accepted predictors for good function and slow progression of posttraumatic osteoarthritis of the hip. The aim of this study was to retrospectively analyze Ac-Fxs, which were treated with closed reduction and percutaneous (three-dimensional) fluoroscopy-based navigated screw fixation. DESIGN: Level 4, retrospective clinical and radiographic assessment. SETTING: Level 1 trauma center. PATIENTS: Twelve patients (male/female: 9/3; mean age: 60 years; range: 16-80 years) with moderately displaced Ac-Fxs were included. INTERVENTION: In enrolled patients, the treatment involved percutaneous three-dimensional fluoroscopy-based navigated lag screw positioning. Closed reduction was achieved by lag screws, or reduction was aided by the insertion of percutaneous Schanz pins. MAIN OUTCOME MEASUREMENTS: The quality of the reduction and screw positions were assessed using intraoperative and postoperative computed tomography scans. Functional outcome was assessed using the Harris hip score, the visual analog scale for pain, and the Tegener activity scale. RESULTS: A total of 22 periacetabular screws were placed (mean: 1.8 ± 1.1 screws/patient, range: 1-5). The mean follow-up was done for 30 (16-72) months. The postoperative reduction was anatomical in all patients, and the mean fracture displacement was significantly reduced (gap: 4.1 ± 1.8 mm to 0.4 ± 0.7 mm/step: 1.4 ± 0.6 mm to 0.2 ± 0.4 mm). No secondary dislocations or malunions/nonunions were found. All screws correctly addressed the fracture morphology and corresponded to preoperative planning. The Harris hip score, the visual analog scale (motion), and Tegener activity scale showed excellent to very good results (92.4 ± 6.8, 1.9 ± 1.3, and 3.8 ± 1.6, respectively). CONCLUSIONS: The navigated, percutaneous screw fixation of selected Ac-Fxs is a promising method that allows for closed reduction and fixation while obtaining a very good radiographic and functional outcome. LEVEL OF EVIDENCE: Therapeutic level 4.