Long-Term Outcomes Following Single-Stage Reamed Intramedullary Exchange Nailing in Apparently Aseptic Femoral Shaft Nonunion with Unsuspected Proof of Bacteria.

Background: The aim of this study was to evaluate detection rates and risk factors for unsuspected proof of bacteria, as well as clinical and radiologic outcomes following femoral shaft nonunion without clinical signs of infection treated by a single-stage surgical revision procedure including reamed intramedullary exchange nailing. Methods: A retrospective cohort study was performed in a European level I trauma center between January 2015 and December 2022. Fifty-eight patients were included who underwent reamed intramedullary exchange nailing as a single-step procedure for surgical revision of posttraumatic diaphyseal femoral nonunion without any indications of infection in medical history and without clinical signs of local infection. Clinical details of the patients were analyzed and functional and radiologic long-term outcomes were determined. Results: In all patients, with and without proof of bacteria osseous, healing could be observed. The physical component summary of the SF-12 demonstrated significantly better results at least one year after the final surgical revision in case of a negative bacterial culture during exchange nailing. Conclusions: Clinical long-term outcomes demonstrated a trend towards better results following femoral shaft nonunion revision if there was no evidence for the presence of low-grade infected nonunion. In this case, a single-stage surgical procedure may be recommended.

[Diagnostic and therapeutic work-up of infected tibial nonunion]. / Diagnostik und Therapie der infizierten Tibia-Pseudarthrose.

BACKGROUND: The failure of bone fracture healing is one of the major complications of fracture treatment, especially of the tibia due to its limited soft tissue coverage and high rate of open injuries. Although implant development is constantly progressing and modern surgical techniques are continuously improving, infected tibial nonunion plays a decisive role in terms of its variable clinical presentation. OBJECTIVE: This article provides guidelines for the successful surgical treatment of infected tibial nonunion. MATERIAL AND METHOD: Strategies are presented to identify infection as a cause of failure of fracture healing and to achieve infection and bone healing. RESULTS: A significant amount of tibial nonunions primarily thought to be aseptic ultimately turn out to be infected nonunions. CONCLUSION: The treatment of infected tibial nonunion requires extensive clinical, radiological and laboratory diagnostics as well as a profound biomechanical and biological understanding of the bone situation. This is the only way to achieve rapid osseous healing with as few revision interventions as possible.

The value of sonication in the differential diagnosis of septic and aseptic femoral and tibial shaft nonunion in comparison to conventional tissue culture and histopathology: a prospective multicenter clinical study.

BACKGROUND: Septic and aseptic nonunion require different therapeutic strategies. However, differential diagnosis is challenging, as low-grade infections and biofilm-bound bacteria often remain undetected. Therefore, the examination of biofilm on implants by sonication and the evaluation of its value for differentiating between femoral or tibial shaft septic and aseptic nonunion in comparison to tissue culture and histopathology was the focus of this study. MATERIALS AND METHODS: Osteosynthesis material for sonication and tissue samples for long-term culture and histopathologic examination from 53 patients with aseptic nonunion, 42 with septic nonunion and 32 with regular healed fractures were obtained during surgery. Sonication fluid was concentrated by membrane filtration and colony-forming units (CFU) were quantified after aerobic and anaerobic incubation. CFU cut-off values for differentiating between septic and aseptic nonunion or regular healers were determined by receiver operating characteristic analysis. The performances of the different diagnostic methods were calculated using cross-tabulation. RESULTS: The cut-off value for differentiating between septic and aseptic nonunion was ≥ 13.6 CFU/10 ml sonication fluid. With a sensitivity of 52% and a specificity of 93%, the diagnostic performance of membrane filtration was lower than that of tissue culture (69%, 96%) but higher than that of histopathology (14%, 87%). Considering two criteria for infection diagnosis, the sensitivity was similar for one tissue culture with the same pathogen in broth-cultured sonication fluid and two positive tissue cultures (55%). The combination of tissue culture and membrane-filtrated sonication fluid had a sensitivity of 50%, which increased up to 62% when using a lower CFU cut-off determined from regular healers. Furthermore, membrane filtration demonstrated a significantly higher polymicrobial detection rate compared to tissue culture and sonication fluid broth culture. CONCLUSIONS: Our findings support a multimodal approach for the differential diagnosis of nonunion, with sonication demonstrating substantial usefulness. LEVEL OF EVIDENCE: Level 2 Trial registration DRKS00014657 (date of registration: 2018/04/26).

Evidence on treatment of clavicle fractures.

Depending on the severity of the injury and the involvement of the soft tissue envelope, clavicle fractures can be treated operatively or non-operatively. In the past, displaced fractures of the clavicle shaft in adults have been treated non-operatively. However, the rate of nonunion following non-operative treatment seems to be higher than previously reported. In addition, publications reporting better functional outcomes following operative treatment are increasing. In recent years this has led to a paradigm shift towards an increase of operative fracture treatment. The aim of this review article was to summarize the currently available evidence on the treatment of clavicle fractures. Classifications, indications, and treatment options for different fracture patterns of the medial, midshaft, and lateral clavicles are presented and discussed.

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.

[Development and principles of intramedullary and extramedullary segmental bone transport: overview and clinical results]. / Entwicklung und Prinzipien des intra- und extramedullären Knochensegmenttransports: Überblick und klinische Resultate.

BACKGROUND: Segmental bone transport using intramedullary or extramedullary techniques is one of the most commonly used procedures for bone defect management in the diaphyseal region of long bones. OBJECTIVE: The purpose of this work is to provide an overview of the historical development and general principles as well as the current status of extramedullary and intramedullary techniques of bone segment transport. In addition, own results on internal segmental bone transport are presented. MATERIAL AND METHODS: A retrospective database analysis included all patients between May 2019 and January 2021 who underwent segmental bone transport via a fully implantable intramedullary segment transport nail system. In addition to the radiological outcome, the clinical outcome was assessed using the lower extremity functional scale (LEFS). RESULTS: A total of 9 patients (8 male, 1 female; age 41.7 ± 3.9 years) could be included. The cause of the segmental bone defect was chronic fracture-related infection in all cases. The segmental defect size was 62 ± 10 mm. Sufficient bridging of the bone defect was achieved in all patients, with a mean distraction rate of 0.9 ± 0.1 mm per day. Bony consolidation of the regeneration was achieved after 292 ± 57 days, and final bony consolidation of the docking zone was achieved after 469 ± 116 days. At 22 ± 3 months after implantation of the segmental transport nail, the LEFS demonstrated a result of 59 ± 4 points. No recurrence of infection or regeneration failure occurred. CONCLUSION: The aim of treating segmental bone defects, in addition to reconstructing a load-bearing bone, is to restore correct joint angles, leg length, and leg axis without torsional deviation and can be achieved via classical external segmental bone transport. In recent years, internal segmental bone transport has been developed as an alternative. It remains to be seen whether the preliminary and reproducibly good clinical and radiological results of segmental transport nails can be confirmed for widespread use in the future.

[Plate-assisted bone segment transport for bone defects of the lower extremities : Possibilities and limitations of treatment]. / "Plate-assisted bone segment transport" bei Knochendefekten an der unteren Extremität : Möglichkeiten und Grenzen der Behandlung.

Large bone defects of the lower extremities are challenging for both patients and the treating orthopedic surgeons. The treatment is determined by the size and location of the defect; however, patient-specific factors, such as the soft tissue situation and the presence of systemic comorbidities must be taken into consideration in the treatment strategy. Osteodistraction is an excellent technique especially for large bone defects exceeding 3 cm; however, it is time-consuming and required external fixation prior to the development of motorized distraction nails. This article describes the procedure for the treatment of large bone defects of the lower extremities, with its possibilities and limitations, using the novel plate-assisted bone segment transport (PABST) procedure.

Internal Fixation of Garden Type III Femoral Neck Fractures with Sliding Hip Screw and Anti-Rotation Screw: Does Increased Valgus Improve Healing?

Background and Objectives: The aim of this study was to compare the effect of valgus versus anatomic reduction on internal fixation of Garden type III femoral neck fractures using the sliding hip screw (SHS) and anti-rotation screw (ARS) regarding the radiographic and therapeutic outcome. Patients and Methods: A retrospective case-controlled study was performed in a level I trauma center. All patients between 2006 and 2020 aged younger than 70 years with a Garden type III femoral neck fracture and a Kellgren-Lawrence score under grade III stabilized using SHS and ARS were identified. One-hundred and nine patients were included, with a group distribution of sixty-eight patients in group A (anatomic reduction) and forty-one patients in group B (valgus reduction). Results: Mean age was 55 years, and the mean Kellgren-Lawrence score was 1 in both groups. Mean femoral neck angle was 130.5 ± 3.8° in group A and 142.8 ± 4.3° in group B (p = 0.001), with an over-correction of 12° in group B. Tip-apex distance was 10.0 ± 2.8 mm in group A versus 9.3 ± 2.8 mm in group B (p = 0.89). Healing time was 9 weeks in group A compared to 12 weeks in group B (p = 0.001). Failure rate was 4.4% in group A and 17.1% in group B (p = 0.027). Conclusions: Anatomic reduction of Garden type III femoral neck fractures in patients younger than 70 years treated using SHS and ARS resulted in significantly lower failure rates and shorter healing times than after valgus reduction. Therefore, it can be recommended to achieve anatomic reduction.

[Infected nonunion: diagnostic and therapeutic work-up]. / Infizierte Pseudarthrose: diagnostischer und therapeutischer Ablauf.

BACKGROUND: Septic nonunion is one of the major complications in fracture healing. The challenge is to identify the infection as the cause of nonunion first and then to achieve healing of the infection and the bone. OBJECTIVE: Because of the more heterogeneous appearance of an infected nonunion, the prevalence of germ detection in surgical nonunion revision is often underestimated. MATERIAL AND METHODS: In a retrospective study between 2010 and 2017, 86 patients with radiologically confirmed femoral shaft nonunion without clinical evidence and unremarkable medical history of a florid infection as the cause of nonunion, who had undergone primary single-stage surgical nonunion revision were analyzed. At least four intraoperatively obtained samples were evaluated for microbiological diagnosis. A distinction was made between tissue samples with subsequent 48­h short-term incubation and tissue samples with 14-day long-term cultivation. The finding "germ detection" was made if at least two of the samples demonstrated bacterial growth. RESULTS: In 18 of 86 patients with a nonunion preoperatively judged to be aseptic, positive bacterial evidence was obtained after short-term incubation. After long-term cultivation, positive bacterial detection was possible in 38 of 86 patients with a femoral shaft nonunion initially classified as aseptic. Regarding potential risk factors, the two groups demonstrated no relevant differences. In 29 patients, 1 pathogen was isolated from the obtained samples, whereas in the remaining 9 patients, a mixed culture with an average of 2.9 ± 0.5 different bacteria was detected. Identification revealed mainly low-virulence bacteria, most commonly Staphylococcus epidermidis. CONCLUSION: If the preoperative diagnostics including clinical, laboratory and radiological examination as well as a careful anamnesis reveal indications of a possible infectious event, the surgical nonunion revision should be performed in two stages with specimen collection before definitive nonunion revision. For microbiological diagnosis, several representative tissue samples should independently be obtained from the nonunion site and incubated for 14 days. Only in the absence of evidence of septic nonunion is a single-stage procedure suggested.

The role of low-grade infection in the pathogenesis of apparently aseptic tibial shaft nonunion.

PURPOSE: Aim of this study was to determine the rate of low-grade infection in patients with primarily as aseptic categorized tibial shaft nonunion and lack of clinical signs of infection. METHODS: In a retrospective study between 2006 and 2013, all patients who underwent revision surgery for treatment of tibial shaft nonunion without clinical evidence of infection were assessed. Bacterial cultures harvested during nonunion revision, C-reactive protein (CRP) and/or white blood cell (WBC) values at hospital admission, outcome, and epidemiological data were analyzed. RESULTS: In 88 patients with tibial shaft nonunion without any clinical signs of infection, bacterial samples remained negative in 51 patients. In 37 patients, microbiological diagnostic studies after long-term culturing demonstrated positive bacterial cultures whereas after short-term culturing for 2 days only 17 positive cultures were observed. In 12 cases a mixed culture with 2.3 different bacteria on average was detected. Among patients with negative bacterial cultures bone healing was achieved after 13.2 months. Nonunion with positive bacterial cultures required 19 (range 2-42) months until osseous healing (p = 0.009). Furthermore, nonunion with positive bacterial cultures require statistically more surgical revisions to achieve healing (2.9 ± 0.5 vs. 1.3 ± 0.1 additional procedure; (p = 0.003). Hematological studies carried out before surgical intervention did not demonstrate significant differences in CRP values (negative vs. positive cultures: 0.3 (range 0.3-2.8) mg/dl vs. 0.5 (range 0.3-5.7) mg/dl (p = 0.181) and in WBC values (negative vs. positive cultures: 7.4 (range 3.5-11.9) /nl vs. 7.3 (range 3.7-11.1) /nl (p = 0.723). Limitations of this study may include the varying amount of the at least four samples for microbiological diagnostics as well as the circumstance that for diagnosing low-grade infection swabs and tissue samples were included in this evaluation as being equivalent. CONCLUSION: The pathogenesis of nonunion may originate from low-grade infection even in patients without clinical signs of infection. In addition, nonunion with positive bacterial cultures require statistically more surgical revisions to achieve healing. Therefore, during any revision surgery, multiple bacterial samples are intended to be harvested for long-term culturing. Particularly, in tibial shaft nonunion following Gustilo-Anderson type III open fractures, low-grade infection should be suspected. TRIAL REGISTRATION NUMBER: DRKS00014657. DATE OF REGISTRATION: 04/26/2018 retrospectively registered.

Custom-made polyurethane-based synthetic bones mimic screw cut-through of intramedullary nails in human long bones.

Intramedullary nails are considered the gold standard for the treatment of tibial shaft fractures. Thereby, the screw-bone interface is considered the weakest link. For biomechanical evaluation of osteosyntheses synthetic bones are often used to overcome the disadvantages of human specimens. However, commercially available synthetic bones cannot adequately mimic the local mechanical properties of human bone. Thus, the aim of this study was to develop and evaluate novel cortical bone surrogate materials that mimic human tibial shafts in the screw-loosening mechanisms of intramedullary nails. Bone surrogates, based on two different polyurethanes, were developed and shaped as simple tubes with varying cortical thicknesses to simulate the diaphyseal cortex of human tibiae. Fresh frozen human tibiae and commercially available synthetic bones with similar cortical thickness were used as references. All specimens were treated with a nail dummy and bicortical locking screws to simulate treatment of a distal tibia shaft fracture. The nail-bone construct was loaded in a combined axial-torsional-sinusoidal loading protocol to simulate the physiological load during human gait. The loads to failure as well as the number of load cycles were evaluated. Furthermore, the cut-through length of the screws was analysed by additional micro computed -tomography images of the tested specimens. The failure load of custom made synthetic bone tubes with 6 mm cortical thickness (3242 ± 136 N) was in accordance with the failure load of human samples (3300 ± 307 N, p = 0.418) with a similar cortical thickness of 4.9 ± 1.4 mm. Commercially available synthetic bones with similar cortical thickness of 4.5 ± 0.7 mm were significantly stronger (4575 ± 795 N, p = 0.008). Oval-shaped migration patterns were "cut" into the cortices by the screws due to the cyclical loading. The cut-through length of the self-developed synthetic bones with 6 mm cortices (0.8 ± 0.6 mm, p = 0.516) matched the cut-through of the human tibiae (0.7 ± 0.6 mm). The cut-through of commercially available epoxy-based synthetic bones deviated from the human reference (0.2 ± 0.1 mm, p < 0.001). The results of this study indicate that the novel bone surrogates realistically mimic the failure and screw migration behaviour in human tibiae. Thus, they offer a new possibility to serve as substrate for biomechanical testing. The use of commercially available surrogates is discouraged for biomechanical testing as there is a risk of drawing incorrect conclusions.

External fixation of the lower extremities: Biomechanical perspective and recent innovations.

The concept of supporting fractured long bones externally with mechanical fixation has been evidentially applied for over 2000 years, and since been expanded on in the mid-19th century by percutaneous bone fixation. Surgical techniques, external fixator systems, and materials have made continued progress since. The benefits of traditional external fixation have been enhanced in recent years with the introduction of hexapod-style fixators, innovative configurations, and pin modifications, among other things. It is generally agreed upon that biomechanical testing of advancements in external fixation must be inclusive of transverse or torsional loading to simulate construct behaviour in realistic scenarios. Biomechanical studies indicate that hexapod-style fixators show comparable axial stiffness to Ilizarov-style systems and improved performance under torsional and transverse forces. The addition of configuration elements to fixators, inclusion of certain carbon fibre chemical compositions, and techniques intended to augment ring thickness have also been investigated, in hopes of increasing construct stiffness under loading. Novel external fixators attempt to broaden their applications by rethinking bone mounting mechanisms and either expanding on or simplifying the implementation of 3D bone segment transport for corrective osteotomy. Older and seemingly unconventional fixation techniques are being rediscovered and evolved further in order to increase patient comfort by improving everyday usability. The development of new pin coatings can potentially enhance the pin-bone interface while lowering infection rates typically expected at thicker soft tissue envelopes. Although complication, malunion, and nonunion rates have decreased over the past 50 years, the clinical results of external fixation today can still be optimized. Unsatisfactory healing in the lower extremities has especially been reported at locations such as the distal tibia; however, advancements such as osteoinductive growth hormone treatment may provide improved results. With the current progression of technology and digitization, it is only a matter of time before 'smart', partly-autonomous external fixation systems enter the market. This review article will provide a versatile overview of biomechanically proven fixator configurations and some carefully selected innovative systems and techniques that have emerged or been established in the past two decades.

Biomechanics of Femoral Neck Fractures and Implications for Fixation.

Fractures of the femoral neck can occur in young healthy individuals due to high loads occurring during motor vehicle accidents, impacts, or falls. Failure forces are lower if impacts occur sideways onto the greater trochanter as compared with vertical loading of the hip. Bone density, bone geometry, and thickness of cortical bone at the femoral neck contribute to its mechanical strength. Femoral neck fractures in young adults require accurate reduction and stable internal fixation. The available techniques for fracture fixation at the femoral neck (cannulated screws, hip screw systems, proximal femur plates, and cephallomedullary nails) are reviewed with respect to their competence to provide biomechanical stability. Mechanically unstable fractures require a load-bearing implant, such as hip screws, with antirotational screws or intramedullary nails. Subcapital or transcervical fracture patterns and noncomminuted fractures enable load sharing and can be securely fixed with cannulated screws or solitary hip screw systems without compromising fixation stability.

Long-term outcome following additional rhBMP-7 application in revision surgery of aseptic humeral, femoral, and tibial shaft nonunion.

BACKGROUND: Surgical revision concepts for the treatment of aseptic humeral, femoral, and tibial diaphyseal nonunion were evaluated. It was analyzed if the range of time to bone healing was shorter, and if clinical and radiological long-term outcome was better following application of additional recombinant human Bone Morphogenetic Protein-7 (rhBMP-7) compared to no additional rhBMP-7 use. METHODS: In a retrospective comparative study between 06/2006 and 05/2013, 112 patients diagnosed with aseptic diaphyseal humerus (22 patients), femur (41 patients), and tibia (49 patients) nonunion were treated using internal fixation and bone graft augmentation. For additional stimulation of bone healing, growth factor rhBMP-7 was locally administered in 62 out of 112 patients. Follow-up studies including clinical and radiological assessment were performed at regular intervals as well as after at least one year following nonunion surgery. RESULTS: One hundred and two out of 112 (humerus: 19, femur: 37, tibia: 47) nonunion healed within 12 months after revision surgery without any significant differences between the cohort groups. According to the DASH outcome measure for the humerus (p = 0.679), LEFS for the femur (p = 0.251) and the tibia (p = 0.946) as well as to the SF-12 for all entities, no significant differences between the treatment groups were found. CONCLUSIONS: Aseptic diaphyseal nonunion in humerus, femur, and tibia healed irrespectively of additional rhBMP-7 application. Moreover, the results of this study suggest that successful nonunion healing can be linked to precise surgical concepts using radical removal of nonunion tissue, stable fixation and restoration of axis, length and torsion, rather than to the additional use of signaling proteins. TRIAL REGISTRATION: This clinical trial was conducted according to ICMJE guidelines as well as to the approval of the National Medical Board (Ethics Committee of the Bavarian State Chamber of Physicians; TRN: 2016-104) and has been retrospectively registered with the German Clinical Trails Register (TRN: DRKS00012652 ).

Comparative study suggests that human bone morphogenetic proteins have no influence on the outcome of operative treatment of aseptic clavicle non-unions.

PURPOSE: The purpose of this study was to evaluate the clinical and radiological outcome following compression plate fixation in combination with autologous bone grafting, with and without additional application of recombinant human bone morphogenetic protein (rhBMP) for treatment of aseptic clavicle non-union. METHODS: Between April 2004 and April 2015, 82 patients were treated for clavicle fracture and had developed aseptic clavicle non-union. Seventy-three out of 82 patients were available for follow-up at least one year after revision surgery; among them, 27 women and 46 men, with a median age of 49 (range, 19-86) years. Forty-five patients received compression plate osteosynthesis with autologous bone grafting, and 28 patients obtained compression plate fixation with autologous bone grafting and additional application of rhBMP-2 (3/28 patients) or rhBMP-7 (25/28 patients). RESULTS: Seventy out of 73 non-unions (96 %) healed within 12 months after revision surgery. Functional outcome according to the DASH Outcome Measure (with rhBMP, 33.16 ± 1.17 points; without rhBMP, 30.58 ± 2.12 points [mean ± SEM]; p = 0.81), non-union healing (p = 0.86), time interval between revision surgery and bone healing (p = 0.37), as well as post-operative complications, did not demonstrate relevant differences between the treatment groups and were not age-dependent. DISCUSSION: Functional and radiological results demonstrate that successful healing of aseptic clavicle non-union is dependent on radical resection of non-union tissue, restoration of length of the shoulder girdle and application of stable locking-plate osteosynthesis in combination with autologous bone grafting, but not dependent on application of additional rhBMP.

Antibiotic Resistance of Commensal Staphylococcus aureus and Coagulase-Negative Staphylococci in an International Cohort of Surgeons: A Prospective Point-Prevalence Study.

Nasal colonization with antibiotic resistant bacteria represents both a risk factor for the colonized individual and their immediate contacts. Despite the fact that healthcare workers such as orthopedic surgeons are at a critical interface between the healthcare environment and an at-risk patient population, the prevalence of antibiotic resistant bacteria within the surgical profession remains unclear. This study offers a snapshot of the rate of nasal colonization of orthopedic surgeons with multi-resistant staphylococci including methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS). We performed a prospective, observational study obtained at a single time point in late 2013. The participants were active orthopedic, spine and head & neck surgeons from 75 countries. The prevalence of nasal carriage of the different bacteria and the corresponding 95% confidence interval were calculated. From a cohort of 1,166 surgeons, we found an average S. aureus nasal colonization rate of 28.0% (CI 25.4;30.6) and MRSA rate of 2.0% (CI 1.3;2.9), although significant regional variations were observed. The highest rates of MRSA colonization were found in Asia (6.1%), Africa (5.1%) and Central America (4.8%). There was no MRSA carriage detected within our population of 79 surgeons working in North America, and a low (0.6%) MRSA rate in 657 surgeons working in Europe. High rates of MRCoNS nasal carriage were also observed (21.4% overall), with a similar geographic distribution. Recent use of systemic antibiotics was associated with higher rates of carriage of resistant staphylococci. In conclusion, orthopedic surgeons are colonized by S. aureus and MRSA at broadly equivalent rates to the general population. Crucially, geographic differences were observed, which may be partially accounted for by varying antimicrobial stewardship practices between the regions. The elevated rates of resistance within the coagulase-negative staphylococci are of concern, due to the increasing awareness of their importance in hospital acquired and device-associated infection.

The missing effect of human recombinant Bone Morphogenetic Proteins BMP-2 and BMP-7 in surgical treatment of aseptic forearm nonunion.

INTRODUCTION: In this cohort study, the surgical revision concept of open compression plating and autologous bone grafting with and without additional application of BMP for treatment of aseptic ulna and/or radius shaft nonunion was evaluated. The purpose was to evaluate the clinical and radiological outcome, and to determine any difference in osseous healing, range of time between revision surgery and bone healing, and postoperative complications between the cohort groups. PATIENTS AND METHODS: Between 01/2005 and 03/2015, a prospective, randomised, controlled cohort study was performed in a Level I Trauma Centre. Forty-nine patients were treated with the diagnosis of aseptic diaphyseal ulnar and/or radial shaft nonunion using compression plating and autologous bone grafting. Additional biological augmentation using BMP-2 or BMP-7 was performed in 24 patients. Clinical and radiological follow-up was performed six weeks, three and six months after revision surgery in accordance to the system by Anderson. RESULTS: The study group consisted of 38 men and 11 women with a median age of 44 years (range 19-77). Twenty-four out of 49 patients obtained compression plating either with autologous iliac crest bone grafting (11/24 patients) or cancellous bone grafting (13/24 patients) and additional application of BMP-2 (4/24 patients) or BMP-7 (20/24 patients). The remaining 25 patients did not receive any additional application of BMP, but autologous bone grafting. The median follow-up was 15 months (range 6-54 months). Forty-six out of 49 nonunion healed within 12 months after revision surgery with a median time to union of six months. The clinical outcome, as assessed using the system by Anderson, as well as osseous healing, duration of time interval between revision surgery and bone healing, and postoperative complications did not demonstrate significant differences between the cohort groups. DISCUSSION: Atrophic/oligotrophic forearm nonunion healed irrespective of additional application of BMP combined with autologous bone grafting. For successful treatment, radical resection of fibrous nonunion tissue and internal compression plate fixation is required with the aim of achieving high degree of rigid stability. Also, correction of angular deformities, restoration of length, and precise axial alignment of the distal radio-ulnar joint are mandatory prerequisites to successfully achieve bone healing.

Surgical treatment of ipsilateral multi-level femoral fractures.

BACKGROUND: Concurrent ipsilateral fractures of the proximal and shaft of the femur are rare complex fracture combinations. In this prospective cohort study, we evaluated clinical and radiological long-term results after operative treatment using several surgical strategies: the so-called "rendezvous" surgical technique, e.g., the combination of retrograde intramedullary nailing and dynamic hip screw (DHS) osteosynthesis, or the all-in-one device technique, e.g., long cephalomedullary nail, compared with two non-overlapping implants (e.g., conventional technique). METHODS: In a 10-year-period from 2004 to 2013, we treated 65 patients with complex ipsilateral multi-level femoral fractures. Median age was 45 years (range 19-90 years). Fractures were classified according to the AO/OTA classification. Four patients died during intensive care unit treatment due to multi-organ failure prior to definitive osteosynthesis. Clinical long-term outcome using the functional system of Friedman/Wyman as well as radiological outcome was evaluated 2 years after trauma (range 13-42 months). RESULTS: All-in-one device was used in 36 patients, "rendezvous" technique in 9 patients, and the conventional technique in the remaining 16 patients. Two years after trauma, complete fracture healing was found in 57 out of 61 patients ("rendezvous": 9, all-in-one device: 33, conventional: 15; p-value: 0.66). There was no significant difference regarding the complication rate in the cohort groups ("rendezvous": 3, all-in-one device: 13, conventional: 5; p-value: 0.94). Using the functional assessment system of Friedman/Wyman 2 years after trauma, a good clinical result was found in 77.7% in the "rendezvous" group, in 77.8% in the all-in-one device group, and in 75% in the conventional group. CONCLUSION: The indication for operative stabilization of ipsilateral multi-level femoral fractures is considered an urgent and emergency procedure. Based on the successful long-term results of this study, we prefer the "rendezvous" technique with fracture stabilization from distally to proximally. Both fracture components require stable fixation. It is advisable to stabilize the shaft fracture primarily using external fixation (damage control orthopedics) and the proximal femoral fracture using early definitive internal fixation. In a second and staged operation, the external fixator is removed and the shaft fracture is stabilized using retrograde nail osteosynthesis with overlapping of the DHS and nail implants.

Norrin mediates neuroprotective effects on retinal ganglion cells via activation of the Wnt/beta-catenin signaling pathway and the induction of neuroprotective growth factors in Muller cells.

Norrin is a secreted protein that binds to frizzled 4 and controls development of capillaries in retina and inner ear. We provide evidence that Norrin has distinct neuroprotective properties that are independent from its effects on vascular development. The function of Norrin was investigated in a mouse model of excitotoxic retinal ganglion cell (RGC) damage after intravitreal injection of NMDA, and in cultured Müller glia or immortalized RGC-5 cells. Intravitreal injection of Norrin significantly increased the number of surviving RGC axons in the optic nerve and decreased apoptotic death of retinal neurons following NMDA-mediated damage. This effect could be blocked by adding dickkopf (DKK)-1, an inhibitor of the Wnt/beta-catenin signaling pathway. Treatment of eyes with combined Norrin/NMDA activated Wnt/beta-catenin signaling and increased the retinal expression of leukemia inhibitory factor and endothelin-2, as well as that of neurotrophic growth factors such as fibroblast growth factor-2, brain-derived neurotrophic factor, lens epithelium-derived growth factor, and ciliary neurotrophic factor. A similar activation of Wnt/beta-catenin signaling and an increased expression of neurotrophic factors was observed in cultured Müller cells after treatment with Norrin, effects that again could be blocked by adding DKK-1. In addition, conditioned cell culture medium of Norrin-treated Müller cells increased survival of differentiated RGC-5 cells. We conclude that Norrin has pronounced neuroprotective properties on retinal neurons with the distinct potential to decrease the damaging effects of NMDA-induced RGC loss. The effects of Norrin involve activation of Wnt/beta-catenin signaling and subsequent induction of neurotrophic growth factors in Müller cells.