B7-1 and PlGF-1 are two possible new biomarkers to identify fracture-associated trauma patients at higher risk of developing complications: a cohort study.

BACKGROUND: Around 10% of fractures lead to complications. With increasing fracture incidences in recent years, this poses a serious burden on the healthcare system, with increasing costs for treatment. In the present study, we aimed to identify potential 'new' blood markers to predict the development of post-surgical complications in trauma patients following a fracture. METHODS: A total of 292 trauma patients with a complete three-month follow-up were included in this cohort study. Blood samples were obtained from 244 of these patients. Two complication groups were distinguished based on the Clavien-Dindo (CD) classification: CD grade I and CD grade III groups were compared to the controls (CD 0). The Mann-Whitney U test was used to compare the complication groups to the control group. RESULTS: Analysis of the patients' data revealed that risk factors are dependent on sex. Both, males and females who developed a CD III complication showed elevated blood levels of B7-1 (p = 0.015 and p = 0.018, respectively) and PlGF-1 (p = 0.009 and p = 0.031, respectively), with B7-1 demonstrating greater sensitivity (B7-1: 0.706 (male) and 0.692 (female), PlGF-1: 0.647 (male) and 0.615 (female)). Further analysis of the questionnaires and medical data revealed the importance of additional risk factors. For males (CD 0: 133; CD I: 12; CD III: 18 patients) alcohol consumption was significantly increased for CD I and CD III compared to control with p = 0.009 and p = 0.007, respectively. For females (CD 0: 107; CD I: 10; CD III: 12 patients) a significantly increased average BMI [kg/m2] from 25.5 to 29.7 with CD III was observed, as well as an elevation from one to three comorbidities (p = 0.003). CONCLUSIONS: These two potential new blood markers hold promise for predicting complication development in trauma patients. Nevertheless, further studies are necessary to evaluate the diagnostic utility of B7-1 and PlGF-1 in predicting complications in trauma patients and consider sex differences before their possible use as routine clinical screening tools.

Sildenafil, a phosphodiesterase-5 inhibitor, stimulates angiogenesis and bone regeneration in an atrophic non-union model in mice.

Non-union formation represents a major complication in trauma and orthopedic surgery. The phosphodiesterase-5 (PDE-5) inhibitor sildenafil has been shown to exert pro-angiogenic and pro-osteogenic effects in vitro and in vivo. Therefore, the aim of the present study was to analyze the impact of sildenafil in an atrophic non-union model in mice. After creation of a 1.8 mm segmental defect, mice femora were stabilized by pin-clip fixation. Bone regeneration was analyzed by means of X-ray, biomechanics, photoacoustic and micro-computed tomography (µCT) imaging as well as histological, immunohistochemical and Western blot analyses at 2, 5 and 10 weeks after surgery. The animals were treated daily with either 5 mg/kg body weight sildenafil (n = 35) or saline (control; n = 35) per os. Bone formation was markedly improved in defects of sildenafil-treated mice when compared to controls. This was associated with a higher bending stiffness as well as an increased number of CD31-positive microvessels and a higher oxygen saturation within the callus tissue. Moreover, the bone defects of sildenafil-treated animals contained more tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts and CD68-positive macrophages and exhibited a higher expression of the pro-angiogenic and pro-osteogenic markers cysteine rich protein (CYR)61 and vascular endothelial growth factor (VEGF) when compared to controls. These findings demonstrate that sildenafil acts as a potent stimulator of angiogenesis and bone regeneration in atrophic non-unions.

"Bring Your Own Device"-A New Approach to Wearable Outcome Assessment in Trauma.

Background and Objectives: Outcome data from wearable devices are increasingly used in both research and clinics. Traditionally, a dedicated device is chosen for a given study or clinical application to collect outcome data as soon as the patient is included in a study or undergoes a procedure. The current study introduces a new measurement strategy, whereby patients' own devices are utilized, allowing for both a pre-injury baseline measure and ability to show achievable results. Materials and Methods: Patients with a pre-existing musculoskeletal injury of the upper and lower extremity were included in this exploratory, proof-of-concept study. They were followed up for a minimum of 6 weeks after injury, and their wearable outcome data (from a smartphone and/or a body-worn sensor) were continuously acquired during this period. A descriptive analysis of the screening characteristics and the observed and achievable outcome patterns was performed. Results: A total of 432 patients was continuously screened for the study, and their screening was analyzed. The highest success rate for successful inclusion was in younger patients. Forty-eight patients were included in the analysis. The most prevalent outcome was step count. Three distinctive activity data patterns were observed: patients recovering, patients with slow or no recovery, and patients needing additional measures to determine treatment outcomes. Conclusions: Measuring outcomes in trauma patients with the Bring Your Own Device (BYOD) strategy is feasible. With this approach, patients were able to provide continuous activity data without any dedicated equipment given to them. The measurement technique is especially suited to particular patient groups. Our study's screening log and inclusion characteristics can help inform future studies wishing to employ the BYOD design.

Development of an ischemic fracture healing model in mice.

BACKGROUND AND PURPOSE: In fracture healing, ischemia caused by vascular injuries, chronic vascular diseases, and metabolic comorbidities is one of the major risk factors for delayed union and non-union formation. To gain novel insights into the molecular and cellular pathology of ischemic fracture healing, appropriate animal models are needed. Murine models are of particular interest, as they allow to study the molecular aspects of fracture healing due to the availability of both a large number of murine antibodies and gene-targeted animals. Thus, we present the development of an ischemic fracture healing model in mice. MATERIAL AND METHODS: After inducing a mild ischemia by double ligature of the deep femoral artery in CD-1 mice, the ipsilateral femur was fractured by a 3-point bending device and stabilized by screw osteosynthesis. In control animals, the femur was fractured and stabilized without the induction of ischemia. The femora were analyzed at 2 and 5 weeks after fracture healing by means of radiology, biomechanics, histology, and histomorphometry. RESULTS: The surgically induced ischemia delayed and impaired the process of fracture healing. This was indicated by a lower Goldberg score, decreased bending stiffness, and reduced bone callus formation in the ischemic animals when compared with the controls. INTERPRETATION: We introduce a novel ischemic femoral fracture healing model in mice, which is characterized by delayed bone healing. In future, the use of this model may allow both the elucidation of the molecular aspects of ischemic fracture healing and the study of novel treatment strategies.

[Delegation and the Efficient Use of Medical Personnel - Ideas During Times of Physician Shortage]. / Überlegungen und Berechnungen zur Effizienz des Einsatzes von Ärzten für delegierbare, nichtärztliche Tätigkeiten ­ ein Denkanstoß in Zeiten des Nachwuchsmangels.

BACKGROUND: Patient care is a cost intensive process and an important fraction of these costs is the salary of medical staff. Efficient use, especially in times of physician shortage, should thus be of great importance to hospital management. We aim to calculate the costs and resulting saving potential from delegation of tasks, that are performed by medical personnel, but could in principle be delegated. MATERIALS AND METHODS: The calculation is based on the survey "Nachwuchsumfrage" of the Berufsverband and German Society of Surgery (n = 708). Satisfaction, limiting factors and time spent on tasks that could be delegated were assessed. From the average physician's salary and the salary of personnel that could be delegated to costs and potential savings were calculated. RESULTS: The surveyed surgeons spent an average of 124 min per day on tasks that could in principle be delegated. In total, costs through unused delegation were calculated at over 16,000 € per year and staff member, with a saving potential of up to 7,000 € despite full delegation. DISCUSSION: Our simple calculation shows the saving potential through adequate task delegation. Apart from the monetary aspects, a positive effect on physician staff satisfaction can be assumed, as unused delegation potential was the leading cause for decreased satisfaction.

Predictors for secondary hip osteoarthritis after acetabular fractures-a pelvic registry study.

PURPOSE: Secondary hip osteoarthritis after acetabular fractures requiring total arthroplasty (THA) poses a huge burden on the affected patients as well as health systems. The present study aimed to assess risk factors associated with THA after acetabular fractures based on the data from the German Pelvic Trauma Registry. METHODS: Retrospective analysis of 678 acetabular fracture cases without concomitant pelvic ring fracture treated and followed-up between January 2004 and May 2015 at six large trauma centres. Multivariate Cox regression analysis was performed assessing the association of patient/treatment characteristics with THA likelihood at an average follow-up of 2.7 years (range 0.4-9.5 years; SD 1.8 years). RESULTS: Overall, the rate of secondary osteoarthritis was 19.8%. The likelihood for THA increased with 6% per age year (95% CI 1.04-1.09) and with 21% per millimetre subluxation (95%CI 1.09-1.33). This likelihood was 3.54 (95% CI 1.77-7.08) and 3.68 times (95% CI 1.87-7.47) higher if the posterior wall was involved and a contusion and/or impaction of the femoral head was present. Other covariates (sex, ISS, trauma type, AO/OTA and Letournel classification, initial displacement, surgical approach, intra-articular fragments, contusion and/or impaction to the acetabulum, reduction, intervention type, duration of surgery, soft tissue damage, residual fracture step/gap, and prevention of heterotopic ossifications) were not significantly associated (p > 0.15). CONCLUSIONS: Twenty percent of patients with acetabular fractures require THA. The associated risk factors are patient age, femoral head lesion/subluxation, and involvement of the posterior wall. The identified risk factors support previous research and should be minded when treatment of acetabular fractures is planned.

Long-term pathological gait pattern changes after talus fractures - dynamic measurements with a new insole.

PURPOSE: The aim of the current study was to describe long-term gait changes after talus fractures, identify patterns associated with poor outcome and discuss possible treatment options based on dynamic gait analysis. METHODS: Twenty-seven patients were followed-up clinically and via gait analysis after talus fracture osteosynthesis. Continuous dynamic pedobarography with a gait analysis insole was performed on a standardized parcours consisting of different gait tasks and matched to the outcome. RESULTS: Mean follow-up was 78.3 months (range 21-150), mean AOFAS and Olerud-Molander scores 66 (range 20-100) and 54 (range 15-100). Significant correlations between fracture classification and osteoarthritis (Hawkins: rs = 0.67 / Marti-Weber: rs = 0.5) as well as several gait differences between injured and healthy foot with correlations to outcome were seen: decreased step load-integral/maximum-load; associations between centre-of-pressure displacement and outcome as well as between temporospatial measures and outcome. Overall, pressure-distribution was lateralized in patients with subtalar joint injury (Δ: 0.5765 N/cm2, p = 0.0475). CONCLUSIONS: Talus fractures lead to chronic gait changes and restricted function. Dynamic pedobarography can identify patterns associated with poor results. The observed gait patterns suggest that changes can be addressed by physical therapy and customized orthoses to improve overall outcome. The presented insole and measurement protocol are immediately feasible as a diagnostic and rehabilitation aid.

Should I Stay or Should I Go? A Prospective, Blinded Study Comparing the Diagnostic Capability of Dynamic and Stationary Pedobarography in Plantar Fasciitis.

The aim of this study was to determine the diagnostic capability of a dynamic gait analysis insole and compare its ability to detect clinical correlations to a common stationary analysis tool. Twenty-five patients with chronic plantar fasciitis were included in this prospective, blinded, diagnostic study. Conventional, stationary gait analysis on a force plate on an even surface and continuous dynamic pedobarography on a standardized course consisting of different gait tasks were performed and correlated to the disease severity. Mean patient age was 53.6 (range 41 to 68) years, with a mean pain level of 6.1 (range 4 to 10) on the Visual Analogue Scale and a calcaneodynia score of 48.7 (range 33 to 66). Significant correlations were seen between several dynamic gait values and clinical scoring: cadence (rs = 0.56, p = .004), stance time (rs = -0.6, p = .002), center-of-pressure velocity (rs = 0.44, p = .046), and double support time (rs = 0.42, p = .042). No significant correlations were seen between any force plate gait analysis values and clinical scoring. In this study setting, dynamic gait analysis was able to identify clinically relevant correlations to plantar fasciitis disease severity that standard force plate measurements could not.

Weight-bearing recommendations after operative fracture treatment-fact or fiction? Gait results with and feasibility of a dynamic, continuous pedobarography insole.

PURPOSE: Rehabilitation after lower-extremity fractures is based on the physicians' recommendation for non-, partial-, or full weight-bearing. Clinical studies rely on this assumption, but continuous compliance or objective loading rates are unknown. The purpose of this study was to determine the compliance to weight-bearing recommendations by introducing a novel, pedobarography system continuously registering postoperative ground forces into ankle, tibial shaft and proximal femur fracture aftercare and test its feasibility for this purpose. METHODS: In this prospective, observational study, a continuously measuring pedobarography insole was placed in the patients shoe during the immediate post-operative aftercare after ankle, tibial shaft and intertrochanteric femur fractures. Weight-bearing was ordered as per the institutional standard and controlled by physical therapy. The insole was retrieved after a maximum of six weeks (28 days [range 5-42 days]). Non-compliance was defined as a failure to maintain, or reach the ordered weight-bearing within 30%. RESULTS: Overall 30 patients were included in the study. Fourteen (47%) of the patients were compliant to the weight-bearing recommendations. Within two weeks after surgery patients deviated from the recommendation by over 50%. Sex, age and weight did not influence the performance (p > 0.05). Ankle fracture patients (partial weight-bearing) showed a significantly increased deviation from the recommendation (p = 0.01). CONCLUSIONS: Our study results show that, despite physical therapy training, weight-bearing compliance to recommended limits was low. Adherence to the partial weight-bearing task was further decreased over time. Uncontrolled weight-bearing recommendations should thus be viewed with caution and carefully considered as fiction. The presented insole is feasible to determine weight bearing continuously, could immediately help define real-time patient behaviour and establish realistic, individual weight-bearing recommendations.

Predictive value of clinical scoring and simplified gait analysis for acetabulum fractures.

BACKGROUND: Fractures of the acetabulum show a high, long-term complication rate. The aim of the present study was to determine the predictive value of clinical scoring and standardized, simplified gait analysis on the outcome after these fractures. METHODS: Forty-one patients with acetabular fractures treated between 2008 and 2013 and available, standardized video recorded aftercare were identified from a prospective database. A visual gait score was used to determine the patients walking abilities 6-m postoperatively. Clinical (Merle d'Aubigne and Postel score, visual analogue scale pain, EQ5d) and radiological scoring (Kellgren-Lawrence score, postoperative computed tomography, and Matta classification) were used to perform correlation and multivariate regression analysis. RESULTS: The average patient age was 48 y (range, 15-82 y), six female patients were included in the study. Mean follow-up was 1.6 y (range, 1-2 y). Moderate correlation between the gait score and outcome (versus EQ5d: rs = 0.477; versus Merle d'Aubigne: rs = 0.444; versus Kellgren-Lawrence: rs = -0.533), as well as high correlation between the Merle d'Aubigne score and outcome were seen (versus EQ5d: rs = 0.575; versus Merle d'Aubigne: rs = 0.776; versus Kellgren-Lawrence: rs = -0.419). Using a multivariate regression model, the 6 m gait score (B = -0.299; P < 0.05) and early osteoarthritis development (B = 1.026; P < 0.05) were determined as predictors of final osteoarthritis. A good fit of the regression model was seen (R2 = 904). CONCLUSIONS: Easy and available clinical scoring (gait score/Merle d'Aubigne) can predict short-term radiological and functional outcome after acetabular fractures with sufficient accuracy. Decisions on further treatment and interventions could be based on simplified gait analysis.

Wearable activity data can predict functional recovery after musculoskeletal injury: Feasibility of a machine learning approach.

Delayed functional recovery after injury is associated with significant personal and socioeconomic burden. Identification of patients at risk for a prolonged recovery after a musculoskeletal injury is thus of high relevance. The aim of the current study was to show the feasibility of using a machine learning assisted model to predict functional recovery based on the pre- and immediate post injury patient activity as measured with wearable systems in trauma patients. Patients with a pre-existing wearable (smartphone and/or body-worn sensor), data availability of at least 7 days prior to their injury, and any musculoskeletal injury of the upper or lower extremity were included in this study. Patient age, sex, injured extremity, time off work and step count as activity data were recorded continuously both pre- and post-injury. Descriptive statistics were performed and a logistic regression machine learning model was used to predict the patient's functional recovery status after 6 weeks based on their pre- and post-injury activity characteristics. Overall 38 patients (7 upper extremity, 24 lower extremity, 5 pelvis, 2 combined) were included in this proof-of-concept study. The average follow-up with available wearable data was 85.4 days. Based on the activity data, a predictive model was constructed to determine the likelihood of having a recovery of at least 50 % of the pre-injury activity state by post injury week 6. Based on the individual activity by week 3 a predictive accuracy of over 80 % was achieved on an independent test set (F1=0,82; AUC=0,86; ACC=8,83). The employed model is feasible to assess the principal risk for a slower recovery based on readily available personal wearable activity data. The model has the potential to identify patients requiring additional aftercare attention early during the treatment course, thus optimizing return to the pre-injury status through focused interventions. Additional patient data is needed to adapt the model to more specifically focus on different fracture entities and patient groups.

Wearable Sensors in Other Medical Domains with Application Potential for Orthopedic Trauma Surgery-A Narrative Review.

The use of wearable technology is steadily increasing. In orthopedic trauma surgery, where the musculoskeletal system is directly affected, focus has been directed towards assessing aspects of physical functioning, activity behavior, and mobility/disability. This includes sensors and algorithms to monitor real-world walking speed, daily step counts, ground reaction forces, or range of motion. Several specific reviews have focused on this domain. In other medical fields, wearable sensors and algorithms to monitor digital biometrics have been used with a focus on domain-specific health aspects such as heart rate, sleep, blood oxygen saturation, or fall risk. This review explores the most common clinical and research use cases of wearable sensors in other medical domains and, from it, derives suggestions for the meaningful transfer and application in an orthopedic trauma context.

Case Studies of a Simulation Workflow to Improve Bone Healing Assessment in Impending Non-Unions.

Background: The healing potential of a fracture is determined by mechanical and biological factors. Simulation-based workflows can help assess these factors to assist in predicting non-unions. The aim of this study was the introduction of two use cases for a novel patient-specific simulation workflow based on clinically available information. Methods: The used software is an extension of the "Ulm Bone Healing model" and was applied in two cases with non-union development after fracture fixation to show its principal feasibility. The clinical and radiographic information, starting from initial treatment, were used to feed the simulation process. Results: The simulation predicted non-union development and axial deviation in a mechanically driven non-union. In the case of a biological non-union, a slow, incomplete healing course was correctly identified. However, the time offset in callus bridging was discordant between the simulation and the distinctly slower healing response in the clinical case. Conclusions: The simulation workflow presented in the two clinical use cases allowed for the identification of fractures at risk for impending non-union immediately after the initial fixation based on available clinical and radiographic information. Further validation in a large non-union cohort is needed to increase the model's precision, especially in biologically challenging cases, and show its validity as a screening instrument.

[Non-unions of the upper extremities]. / Pseudarthrosen der oberen Extremität.

The diagnosis and treatment of non-unions still represents an interdisciplinary challenge. Therefore, prevention, early detection and specific treatment are of great importance. Non-unions of the upper extremities, although less common than that of the lower extremities, requires special attention for successful treatment due to the central role of the shoulder girdle and arm in day to day activities. Successful treatment of non-unions requires a comprehensive evaluation of the patient's medical history, a thorough clinical examination and in particular radiological imaging. In order to effectively treat the pseudarthrosis it is crucial to distinguish between pseudarthroses that are suspected to be due to infections and those that are not. This article presents a treatment algorithm for managing both pseudarthrosis due to infection and pseudarthrosis without infection in the upper extremities.

[Nonunions after intertrochanteric and subtrochanteric femoral fractures]. / Pseudarthrosen nach per- und subtrochantären Femurfrakturen.

INTRODUCTION: The overall frequency of proximal femoral fractures means that we are repeatedly confronted with failed healing and implant failure, despite a relatively low nonunion rate especially in intertrochanteric fractures (< 5%). The aim of this paper is to present our approach to treating these nonunions of the proximal femur and discuss the treatment results. MATERIAL AND METHODS: Between 2009 and 2023, patients with nonunion of the proximal femur were retrospectively identified and analyzed. Age, gender, time to revision, the Weber-Cech classification of pseudarthrosis and radiographic imaging before and after revision were analyzed. RESULTS: A total of 66 patients were analyzed. The mean age was 58 years (range 25-88 years). The overall healing rate was 88% with a mean consolidation time of 8 months (range 2-29 months). The main osteosynthesis procedures were plate osteosynthesis (n = 45, of which 44 were blade plates), and nail replacement (n = 12). Other procedures included augmentative plate osteosyntheses (n = 4), isolated cancellous bone graft (n = 2), nail dynamization (n = 2), and the use of a dynamic hip screw (n = 1). DISCUSSION: The analysis of our treatment data as well as the current literature, revealed a trend towards intramedullary revision procedures. Implants that can be used to correct the CCD angle, such as the blade plate, remain a predictable option to achieve correction, especially in nonunions with an increased degree of varus. Particularly in the subtrochanteric region, fractures can also be treated in a targeted manner by a combination of mechanical and biological methods with a reamed nail change to a larger caliber implant.

Sildenafil delays bone remodeling of fractured femora in aged mice by reducing the number and activity of osteoclasts within the callus tissue.

The elderly exhibit a reduced healing capacity after fracture, which is often associated with delayed or failed bone healing. This is due to a plethora of factors, such as an impaired bone vascular system and delayed angiogenesis. The phosphodiesterase-5 (PDE-5) inhibitor sildenafil exerts pro-angiogenic and pro-osteogenic effects. Hence, we herein investigated in aged mice whether sildenafil can improve fracture healing. For this purpose, 40 aged CD-1 mice (16-18 months) were daily treated with 5 mg/kg body weight sildenafil (n = 20) or vehicle (control, n = 20) by oral gavage. The callus tissue of their femora was analyzed at 2 and 5 weeks after fracture by X-ray, biomechanics, micro-computed tomography (µCT), histology, immunohistochemistry as well as Western blotting. These analyses revealed a significantly increased bone volume and higher ratio of callus to femoral bone diameter in sildenafil-treated mice at 5 weeks after fracture when compared to controls. This was associated with a reduced number and activity of osteoclasts at 2 weeks after fracture, most likely caused by an increased expression of osteoprotegerin (OPG). Taken together, these findings indicate that sildenafil does not improve fracture healing in the elderly but delays the process of bone remodeling most likely by reducing the number and activity of osteoclasts within the callus tissue.

Weight-bearing Restrictions after Distal Femur Fractures - Review of Current Literature. / Belastungsvorgaben nach distaler Femurfraktur - eine aktuelle Literaturübersicht.

The incidence of distal femur fractures increases in the geriatric patient. The primary treatment goal in these fractures is early mobilisation to prevent secondary injuries associated with immobility. In light of the increasing spectrum of therapeutic options for postoperative fracture treatment, including double plating, nail-plate combination and distal femur replacement as postoperative treatments, weight-bearing recommendations are becoming increasingly important. The aim of this study was thus to analyse the weight-bearing recommendations and associated therapy results within the literature of the past 9 years and compare the recommendations to our own approach.

Experiences in the Use of Motorized Intramedullary Nails after Complex Injuries to the Extremities. / Erfahrungen bei der Anwendung motorisierter Marknägel nach komplexen Extremitätenverletzungen.

The treatment of complex injuries of the extremities after comminuted fractures or non-unions is a challenging area in the field of trauma surgery. Internal, motorized implants nowadays enable a patient-oriented and progressive treatment of these cases. The present article aims to present modern treatment strategies of complex injuries of the extremities, support the use of novel, motorized intramedullary nails and provide experiences for the handling with lengthening nails or transport nails. For this purpose, the preoperative planning including selection of patients, presentation of internal lengthening and transport systems and the most important factors during preparation of the surgery are described. Moreover, critical steps during the implantation of motorized nails and also during potential follow-up interventions are highlighted and the postoperative protocol including precise recommendations for the transport und consolidation phase are provided. Finally, the experiences are illustrated by presentation of the four different cases. The use of internal, motorized implants represents the latest step in the treatment of complex injuries of the extremities. These implants improve the quality of life and the authors recommend its use. However, these implants require a high expertise and adaption of established treatment protocols in these challenging trauma cases. Follow-up analyses with a considerably large number of cases are necessary and the research on implants to solve persisting problems in the area of complex injuries of the extremities has to be pursued intensively.

The modified 5-item frailty index determines the length of hospital stay and accompanies with mortality rate in patients with bone and implant-associated infections after trauma and orthopedic surgery.

BACKGROUND: Bone and implant-associated infections are severe complications after trauma and orthopedic surgery. The modified 5-item frailty index (mFI-5) is an easily applicable score to predict adverse outcome after surgery. The current literature regarding mFI-5 is focused on a period of 30-days postoperative. PURPOSE: This study aims to assess the impact of frailty in orthopedic trauma patients with bone and implant-associated infections. mFI-5 was calculated from a database, which prospectively collects data about factors potentially correlated with peri- and postoperative complications since 2014. METHODS: In a level I trauma center a total of 345 patients with surgical site infections were enrolled in this study. Hereof, patients with fracture-related infections after osteosynthesis, periprosthetic joint infections of the hip and knee and post-operative osteomyelitis were included. Extensive medical baseline examination was performed in 2013/14, a three-year follow-up was organized as a telephone interview. The mFI-5 score was calculated based on the 5 factor-principle as established by Subramaniam. The nutritional status was assessed using the Nutritional Risk Screening (NRS-2002). RESULTS: 130 patients were included, whereof seven had died, resulting in 123 patients. A grouping of our patients was performed in mFI-5 = 0 (n = 46; 36,4%), mFI-5 = 1 (n = 41; 33,3%) or mFI-5 ≥ 2 (n = 36; 29,3%). Sex distribution showed 69,1% male and 30,9% female patients. Frailty did neither impact on the re-admission (p = 0,433) nor the reoperation (p = 0,327) rate in our cohort. The mortality risk nearly doubled (1,7 times) in frail patients, but did not reach significance. In hospital stay was prolonged due to frailty (12,1 ± 11,8; p = 0,004) compared to those with a mFI-5 = 0 (5,9 ± 5,1) or mFI-5 = 1 (6,9 ± 5,9). Frailty goes along with a risk of malnutrition and increases with age. CONCLUSION: The modified 5-item frailty index is not a suitable screening tool for predicting revision rate, re-admission rate, and mortality in our orthopedic trauma patient population with bone and implant-associated infections. Nevertheless, frailty is associated with an increased risk of malnutrition and increases with age.

Intermittent Exposure to a 16 Hz Extremely Low Frequency Pulsed Electromagnetic Field Promotes Osteogenesis In Vitro through Activating Piezo 1-Induced Ca2+ Influx in Osteoprogenitor Cells.

Exposure to extremely low frequency pulsed electromagnetic fields (ELF-PEMF) is supposed to simulate local EMF generated during mechanical stimulation of bone and may therefore be used to improve bone regeneration. This study aimed at optimizing the exposure strategy and investigating the underlying mechanisms of a 16 Hz ELF-PEMF, previously reported to boost osteoblast function. Comparing influences of daily continuous (30 min every 24 h) and intermittent (10 min every 8 h) exposure to the 16 Hz ELF-PEMF on osteoprogenitor cells revealed that the intermittent exposure strategy enhanced the 16 Hz ELF-PEMF effects regarding cell numbers and osteogenic function. Gene expression of piezo 1 and related Ca2+ influx were significantly increased in SCP-1 cells with the daily intermittent exposure. Pharmacological inhibition of piezo 1 with Dooku 1 largely abolished the positive effect of the 16 Hz ELF-PEMF exposure on osteogenic maturation of SCP-1 cells. In summary, the intermittent exposure strategy enhanced the positive effects of 16 Hz continuous ELF-PEMF exposure in terms of cell viability and osteogenesis. This effect was shown to be mediated by an increased expression of piezo 1 and related Ca2+ influx. Thus, the intermittent exposure strategy is a promising way to further optimize the therapeutic effects of the 16 Hz ELF-PEMF regarding fracture healing or osteoporosis.