Injection of Autologous Adipose Stromal Vascular Fraction in Combination with Autologous Conditioned Plasma for the Treatment of Advanced Knee Osteoarthritis Significantly Improves Clinical Symptoms.

(1) Background: Osteoarthritis (OA) is the most common joint disease in the world. It is chronic, systemic, progressive and disabling. Orthobiologics have the potential to positively alter the course of this disease. Therefore, the aim of this study is to evaluate the efficacy of SVF/ACP in the treatment of advanced osteoarthritis of the knee in an unfiltered patient population. We hypothesize that this therapy can improve the symptoms associated with osteoarthritis of the knee. We also hypothesize that there are patient-related factors that influence the efficacy of therapy. (2) Methods: Two hundred and thirteen patients with moderate to severe OA of the knee and SVF/ACP injection were recruited for this study. Patients were excluded if they did not provide informed consent or were not receiving SVF/ACP therapy. Pain, function, symptoms and quality of life were assessed using standardized scores (KOOS, WOMAC) before and after treatment. (3) Results: The VAS pain score was significantly reduced by at least 30% (p < 0.001). Knee function, as measured by the KOOS daily activity and sport scores, showed significant increases of 21% and 45%, respectively, at 6 months (p < 0.04). (4) Conclusions: Treatment of knee OA with SVF/ACP injection positively modifies the disease by significantly reducing pain and improving function.

[Treatment of acute ankle distortion in footballers : Are we doing it particularly right or particularly wrong?] / Die Behandlung der akuten oberen Sprunggelenksdistorsion beim Fußballer : Machen wir es beim Profi besonders richtig oder besonders falsch?

BACKGROUND: Despite the high incidence of ankle sprains, the ideal treatment is controversial and a significant percentage of patients who have suffered an ankle sprain never fully recover. Even professional athletes are affected by this post-traumatic complication. There is strong evidence that permanent impairment after an ankle injury is often due to an inadequate rehabilitation and training program and too early return to sport. THERAPY AND REHABILITATION: Therefore, athletes should start a criteria-based rehabilitation after ankle sprain and gradually progress through the programmed activities, including e.g. cryotherapy, edema reduction, optimal load management, range of motion exercises to improve ankle dorsiflexion and digital guidance, stretching of the triceps surae with isometric exercises and strengthening of the peroneus muscles, balance and proprioception training, and bracing/taping. The fact that this is professional sport does not exempt it from consistent, stage-appropriate treatment and a cautious increase in load. However, there are a number of measures and tools that can be used in the intensive care of athletes to improve treatment and results.

Comparison of virtual reality and computed tomography in the preoperative planning of complex tibial plateau fractures.

INTRODUCTION: Preoperative planning is a critical step in the success of any complex surgery. The pur-pose of this study is to evaluate the advantage of VR glasses in surgical planning of complex tibial plateau fractures compared to CT planning. MATERIALS AND METHODS: Five orthopedic surgeons performed preoperative planning for 30 fractures using either conventional CT slices or VR visualization with a VR headset. Planning was performed in a randomized order with a 3-month interval between planning sessions. A standardized questionnaire assessed planned operative time, planning time, fracture classification and understanding, and surgeons' subjective confidence in surgical planning. RESULTS: The mean planned operative time of 156 (SD 47) minutes was significantly lower (p < 0.001) in the VR group than in the CT group (172 min; SD 44). The mean planning time in the VR group was 3.48 min (SD 2.4), 17% longer than in the CT group (2.98 min, SD 1.9; p = 0.027). Relevant parameters influencing planning time were surgeon experience (-0.61 min) and estimated complexity of fracture treatment (+ 0.65 min). CONCLUSION: The use of virtual reality for surgical planning of complex tibial plateau fractures resulted in significantly shorter planned operative time, while planning time was longer compared to CT planning. After VR planning, more surgeons felt (very) well prepared for surgery.

Promoting bone callus formation by taking advantage of the time-dependent fracture gap strain modulation.

Delayed union and non-union of fractures continue to be a major problem in trauma and orthopedic surgery. These cases are challenging for the surgeon. In addition, these patients suffer from multiple surgeries, pain and disability. Furthermore, these cases are a major burden on healthcare systems. The scientific community widely agrees that the stability of fixation plays a crucial role in determining the outcome of osteosynthesis. The extent of stabilization affects factors like fracture gap strain and fluid flow, which, in turn, influence the regenerative processes positively or negatively. Nonetheless, a growing body of literature suggests that during the fracture healing process, there exists a critical time frame where intervention can stimulate the bone's return to its original form and function. This article provides a summary of existing evidence in the literature regarding the impact of different levels of fixation stability on the strain experienced by newly forming tissues. We will also discuss the timing and nature of this "window of opportunity" and explore how current knowledge is driving the development of new technologies with design enhancements rooted in mechanobiological principles.

Analyzing Sex-Specific Dimorphism in Human Skeletal Stem Cells.

Sex-related differences are a current topic in contemporary science. In addition to hormonal regulation, cell-autonomous mechanisms are important in bone homeostasis and regeneration. In this study, human skeletal stem cells (SSCs) from female and male adults were cultured and analyzed with immunological assays and osteogenic differentiation assessments. Female SSCs exhibited a mean doubling time of 100.6 h, whereas male SSCs displayed a mean doubling time of 168.0 h. Immunophenotyping revealed the expression of the stem cell markers Nestin, CD133, and CD164, accompanied by the neural-crest marker SOX9. Furthermore, multiparameter flow cytometric analyses revealed a substantial population of multipotent SSCs, comprising up to 80% in both sexes. An analysis of the osteogenic differentiation potential demonstrated a strong mineralization in both male and female SSCs under physiological conditions. Recognizing the prevailing association of bone diseases with inflammatory processes, we also analyzed the osteogenic potential of SSCs from both sexes under pro-inflammatory conditions. Upon TNF-α and IL-1ß treatment, we observed no sexual dimorphism on osteogenesis. In summary, we demonstrated the successful isolation and characterization of SSCs capable of rapid osteogenic differentiation. Taken together, in vitro cultured SSCs might be a suitable model to study sexual dimorphisms and develop drugs for degenerative bone diseases.

Virtual Reality for Upper Extremity Rehabilitation-A Prospective Pilot Study.

Applications related to virtual reality are a rapidly growing area. Thus, these technologies are also increasingly used in the field of medicine and rehabilitation. The primary objective of this prospective pilot study was to investigate the feasibility, user experience and acceptance of a virtual-reality-based system for upper extremity rehabilitation. The study was conducted as a single-center trial over 16 weeks. The eligibility criteria included rehabilitants with upper extremity injuries of at least 18 years of age who were fluent in spoken and written German. After detailed instruction, each participant was asked to complete daily 30 min exercises over 15 training sessions with the virtual reality system consisting of three different training modules. Outcomes were assessed pre-study and post-study using standardized clinical measures. In addition, qualitative interviews with rehabilitants as well as therapists regarding user experience and acceptance were conducted. Six participants were recruited for the pilot study, of which five underwent virtual-reality-based rehabilitation. Overall, the clinical measures showed a positive tendency over the course of the study, even if the results were not significant. Furthermore, the virtual-reality-based training was well accepted by the participants as well as therapists. Given these findings, it will be beneficial to evaluate virtual reality for rehabilitation in further research.

AED delivery at night - Can drones do the Job? A feasibility study of unmanned aerial systems to transport automated external defibrillators during night-time.

BACKGROUND: In their recent guidelines the European Resuscitation Council have recommended the use of Unmanned Aerial systems (UAS) to overcome the notorious shortage of AED. Exploiting the full potential of airborne AED delivery would mandate 24 h UAS operability. However, current systems have not been evaluated for nighttime use. The primary goal of our study was to evaluate the feasibility of night-time AED delivery by UAS. The secondary goal was to obtain and compare operational and safety data of night versus day missions. METHODS: We scheduled two (one day, one night) flights each to ten different locations to assess the feasibility of AED delivery by UAS during night-time. We also compared operational data (mission timings) and safety data (incidence of critical events) of night versus day missions. RESULTS: All missions were completed without safety incident. The flights were performed automatically without pilot interventions, apart from manually choosing the landing site and correcting the descent. Flight distances ranged from 910 m to 6.960 m, corresponding mission times from alert to AED release between 3:48 min and 11:20 min. Night missions (T¯m:night = 7:26 ± 2:29 min) did not take longer than day missions (T¯m:day = 7:59 ± 2:27 min). Despite slightly inferior visibility of the target site, night landings (T¯land:night = 64 ± 15 sec) were on average marginally quicker than day landings (T¯land:day = 69 ± 11sec). CONCLUSIONS: Our results demonstrate the feasibility of UAS supported AED delivery during nighttime. Operational and safety data indicate no major differences between day- and night-time use. Future research should focus on integration of drone technology into the chain of survival.

Stabilization of Traumatic Iliosacral Instability Using Innovative Implants: A Biomechanical Comparison.

(1) Background: Demographic changes over the past decade have had a significant impact on pelvic ring fractures. They have increased dramatically in the orthogeriatric population. Surgeons are faced with implant fixation issues in the treatment of these fragility fractures. This study compares two innovative implants for stabilizing the iliosacral joint in a biomechanical setting. (2) Methods: An iliosacral screw with a preassembled plate allowing the placement of an additional short, angular stable screw in the ilium and a triangular fixation system consisting of a fenestrated ilium screw and an iliosacral screw quasi-statically inserted through the "fenestra" were instrumented in osteoporotic artificial bone models with a simulated Denis zone 1 fracture. Biomechanical testing was performed on a servo-hydraulic testing machine using increasing, synchronous axial and torsional sinusoidal cyclic loading to failure. (3) Results: The SI-Plate and TriFix showed comparable stiffness values. The values for fracture gap angle and screw tip cutout were significantly lower for the TriFix compared to the SI-Plate. In addition, the number of cycles to failure was significantly higher for the TriFix. (4) Conclusions: Implant anchorage and primary stability can be improved in iliosacral instability using the triangular stabilization system.

Impact of the First and Second Wave of the SARS-CoV-2 Pandemic on Severe Trauma and the Care Structures in the German TraumaNetzwerk DGU®.

(1) Background: The aim of this study was to investigate the effects of the pandemic on transfer rates of severely injured patients within the German TraumaNetzwerk of the DGU. Furthermore, cause of accident, rescue times, and trauma cases are compared to pre-pandemic times. (2) Methods: For this investigation patients documented in the TraumaRegister DGU® from 2018 to 2020 were analyzed. The years 2018 and 2019 served as a comparison to 2020, the first COVID-19 pandemic year. All primary admissions and transfers were included if treated on an intensive care unit. (3) Results: Demographics (age, sex) and injury severity in 2020 were comparable with 2018/2019. In 2020, a significant decrease (3.7%) in car accidents was found. In contrast, a significant increase (3.2%) in bicycle accidents was seen. During the second wave, there was a significant burden of COVID-19 patients on hospitals. In this time, we found a significant increase in early transfers of trauma patients primarily from small level 3 to large level 1 centers. There was also a small but significant increase in rescue time, especially during the 2nd wave. (4) Conclusions: Our data confirm the importance of the network structures established in the TraumaNetzwerk DGU®, especially during the pandemic. The established structures allow smaller hospitals to spread their resources and prevent internal collapse. Therefore, the structures of the TraumaNetzwerk DGU® play a prominent role in stabilizing the healthcare system by helping to maintain both surgical and critical care capacity and providing adequate emergency care.

COVID-19 after the first wave of the pandemic among employees from a German university hospital: prevalence and questionnaire data.

The SARS-CoV-2 pandemic has changed lives around the world. In particular, healthcare workers faced significant challenges as a result of the pandemic. This study investigates the seroprevalence of SARS-CoV-2 in March-April 2020 in Germany among healthcare workers and relates it to questionnaire data. In June 2020, all employees of the reporting hospital were offered a free SARS-CoV-2 antibody test. The first 2,550 test results were sent along with study documents. The response rate was 15.1%. The COVID-19 PCR test prevalence amongst health care workers in this study was 1.04% (95% CI 0.41-2.65%), higher by a factor of 5 than in the general population (p=0.01). The ratio of seroprevalence to PCR prevalence was 1.5. COVID-19-associated symptoms were also prevalent in the non-COVID-19-positive population. Only two symptoms showed statistically significant odds ratios, loss of smell and loss of taste. Health care workers largely supported non-pharmaceutical interventions during the initial lockdown (93%). Individual behavior correlated significantly with attitudes toward policy interventions and perceived individual risk factors. Our data suggest that healthcare workers may be at higher risk of infection. Therefore, a discussion about prioritizing vaccination makes sense. They also support offering increased SARS-CoV-2 testing to hospital workers. It is concluded that easier access to SARS-CoV-2 testing reduces the number of unreported cases. Furthermore, individual attitudes toward rules and regulations on COVID-19 critically influence compliance. Thus, one goal of public policy should be to maintain high levels of support for non-pharmaceutical interventions to keep actual compliance high.

[AED drones on the rise? : Use of drones to improve public access defibrillation]. / Kommt die Defi-Drohne? : Einsatz von Drohnen zur Verbesserung der Frühdefibrillationsrate.

BACKGROUND: The poor availability of automatic external defibrillators (AED) and the modest knowledge of lay persons in handling these devices has led to an insufficient spread of public access defibrillation in Germany. OBJECTIVE: This article examines whether the automated deployment of AED drones to out-of-hospital cardiac arrest can help to remedy this situation. METHODS: Narrative literature review, evaluation of statistics, analysis of relevant media reports, and discussion of key research. RESULTS: The present investigations are mainly located in the experimental field and demonstrate the feasibility and safety of drone use, as well as shorter times to first defibrillation, which is confirmed by initial clinical studies. Mathematical models also indicate cost-effectiveness of airborne AED delivery compared to ground dispatch. Integration into the chain of survival appears to be possible but adaptations to existing emergency medical service structures and close cooperation with regional first responder and AED schemes as well as local authorities is required to optimise patient benefit and efficiency. CONCLUSION: The use of AED drones could probably contribute to improving public access defibrillation in Germany. This applies to both rural and urban regions. The technological requirements are met but flight regulations still have to be amended. In order to explore the full potential of this novel technology, further field trials are required to achieve smooth integration into existing emergency medical services.

The Effect of Stabilization Procedures on Sports Discipline and Performance Level in Non-Elite Athletes after Acute Syndesmotic Injury: A Prospective Randomized Trial.

BACKGROUND: Suture button devices for tibiofibular syndesmosis injuries provide semirigid dynamic stabilization. The effect of stabilization procedures on sports discipline and performance level in non-elite athletes after acute syndesmotic injury has not been clarified in sports medicine research to date. METHODS: A total of 47 of 56 eligible patients were analyzed and completed the 1-year follow-up. The average age was 35.5 years (range, 18-60 years). The screw fixation and knotless suture button groups comprised 26 and 21 patients, respectively. Nine patients were lost to follow-up. Patients underwent clinical and radiological evaluations preoperatively and twice during the 1-year postoperative follow-up. Function was measured using the FADI sports scale, the FAAM sports module, and a visual analogue scale for pain and function in sports. Questionnaires were completed to assess preoperative and postoperative sports levels and to evaluate the sports discipline. RESULTS: All scores increased during the follow-up, but no significant differences were found in the FADI score, the FAAM sports module score and or the VAS score for pain and function during sport (p ≤ 0.05). Using Spearman's rank correlation coefficient, we found no significant correlation between the groups for age, injury mechanism, or body mass index. Differences were identified in sports discipline and performance level between the groups during the follow-up period. CONCLUSION: No statistically significant differences could be demonstrated between the two stabilization methods in terms of return to previous sport level and return to the original sport discipline, so both procedures can be regarded as equivalent at present.

Virtual Reality in the Rehabilitation of Patients with Injuries and Diseases of Upper Extremities.

Upper-extremity injuries and diseases rarely have life-threatening consequences, but failure to manage them properly can result in severe dysfunction. This article presents the current state of using virtual reality to support the rehabilitation process of patients with injuries and diseases of the upper extremities and points out their effects on upper-extremity functions. A scoping review was conducted to provide a comprehensive overview of the field of virtual reality for upper-extremity rehabilitation. PubMed, Web of Science, and the Cochrane Library were searched by two independent researchers between April and May 2021 to identify relevant publications and were examined according to inclusion and exclusion criteria. As a result of the literature review, 11 studies of various target groups were identified. Virtual-reality technologies were categorized into multisensory high-end systems and game-based systems. With respect to functional recovery, technologies based on virtual reality were not inferior to traditional rehabilitation. In addition, the users were highly motivated and satisfied. The results emphasize the need for stronger evidence-based virtual-reality technologies for rehabilitation of injuries and diseases of upper extremities.

Human Sex Matters: Y-Linked Lysine Demethylase 5D Drives Accelerated Male Craniofacial Osteogenic Differentiation.

Female sex is increasingly associated with a loss of bone mass during aging and an increased risk of developing nonunion fractures. Hormonal factors and cell-intrinsic mechanisms are suggested to drive these sexual dimorphisms, although underlying molecular mechanisms are still a matter of debate. Here, we observed a decreased capacity of calvarial bone recovery in female rats and a profound sexually dimorphic osteogenic differentiation in human adult neural crest-derived stem cells (NCSCs). Next to an elevated expression of pro-osteogenic regulators, global transcriptomics revealed Lysine Demethylase 5D (KDM5D) to be highly upregulated in differentiating male NCSCs. Loss of function by siRNA or pharmacological inhibition of KDM5D significantly reduced the osteogenic differentiation capacity of male NCSCs. In summary, we demonstrated craniofacial osteogenic differentiation to be sexually dimorphic with the expression of KDM5D as a prerequisite for accelerated male osteogenic differentiation, emphasizing the analysis of sex-specific differences as a crucial parameter for treating bone defects.

Local bone quality measure and construct failure prediction: a biomechanical study on distal femur fractures.

INTRODUCTION: The aim of this investigation was to better understand the differences in local bone quality at the distal femur and their correlation with biomechanical construct failure, with the intention to identify regions of importance to optimize implant anchorage. MATERIALS AND METHODS: Seven fresh-frozen female femurs underwent high-resolution peripheral quantitative computed tomography (HR-pQCT) to determine bone mineral density (BMD) within three different regions of interest (distal, intermedium, and proximal) at the distal femur. In addition, local bone quality was assessed by measuring the peak torque necessary to break out the trabecular bone along each separate hole of a locking compression plate (LCP) during its instrumentation. Finally, biomechanical testing was performed using cyclic axial loading until failure in an AO/OTA 33 A3 fracture model. RESULTS: Local BMD was highest in the distal region. This was confirmed by the measurement of local bone quality using DensiProbe™. The most distal holes represented locations with the highest breakaway torque resistance, with the holes on the posterior side of the plate indicating higher values than those on its anterior side. We demonstrated strong correlation between the cycles to failure and local bone strength (measured with DensiProbe™) in the most distal posterior screw hole, having the highest peak torque. CONCLUSION: The local bone quality at the distal femur indicates that in plated distal femur fractures the distal posterior screw holes seem to be the key ones and should be occupied. Measurement of the local bone strength with DensiProbe™ is one possibility to determine the risk of construct failure, therefore, thresholds need to be defined.

Effects of the first lockdown of the COVID-19 pandemic on the trauma surgery clinic of a German Level I Trauma Center.

PURPOSE: The effects of the first pandemic wave on a German Level I Trauma Center should be evaluated to find ways to redistribute structural, personnel, and financial resources in a targeted manner in preparation for the assumed second pandemic wave. METHODS: We examined the repercussions of the first wave of the pandemic on the trauma surgery clinic of a Level I Trauma Center and compared the data with data from 58 other trauma clinics. The results could aid in orientating the distribution of structural, financial, and human resources (HR) during the second wave. The period between March 16 and April 30, 2020 was compared with the data over the same period during 2019. Information was collected from the HR department, central revenue management, and internal documentation. RESULTS: The proportion of trauma surgical patients in the emergency room decreased by 22%. The number of polytrauma cases increased by 53%. Hospital days of trauma surgery patients in the intensive and intermediate care wards increased by 90%. The number of operations decreased by 15%, although the operating time outside of normal working hours increased by 44%. Clinics with more than 600 beds recorded a decrease in cases and emergencies by 8 and 9%, respectively, while the Trauma Center showed an increase of 19 and 12%. The results reflect the importance of level I trauma centers in the lockdown phase. CONCLUSION: To reduce the risk of an increased burden on the healthcare infrastructure, it suggests the care of trauma and COVID-19 patients should be separated locally, when possible.

[Medicine for people with disabilities : Special features of trauma surgical care of extremity injuries in people with severe mental and physical disabilities]. / Medizin für Menschen mit Behinderungen : Besonderheiten in der unfallchirurgischen Versorgung von Extremitätenverletzungen bei Menschen mit schwerer geistiger und körperlicher Behinderung.

The v. Bodelschwingh Foundation Bethel can look back on a tradition of more than 150 years in the treatment of people with disabilities. The trauma patient collective is regularly characterized by the most severe mental and physical developmental disorders and (multiple) disabilities, with and without behavioral disorders and concomitant internal diseases. This special combination requires treatment and indication assessment both medically and in nursing, which must be specifically weighed up and adapted in all treatment steps. Treatment guidelines or recommendations for this patient group do not exist in the literature. Furthermore, the treatment of fractures in people with disabilities cannot always follow established concepts. Due to a high postoperative complication rate, conservative treatment plays a crucial role. The decision for surgical treatment must be made on an interdisciplinary and individual basis, taking all factors into account. Special attention must be paid to the procedure to be chosen (stability, functional needs).

Instability of the posterior pelvic ring: introduction of innovative implants.

BACKGROUND: Increasing numbers of posterior pelvic ring fractures, especially in elderly patients, demonstrate the need for soft tissue protecting surgical techniques. Standard of care is iliosacral screw osteosynthesis. This type of osteosynthesis has its limitations especially in patients with reduced bone properties. Therefore, the development of new and straightforward surgical techniques and implant designs is favorable. METHODS: Introducing this modular system for the posterior pelvic ring, known complications of iliosacral screw osteosynthesis, such as implant loosening and malpositioning may be reduced, due to innovative mechanical characteristics. RESULTS: The shown cases demonstrate the potential benefits of the system with a wide range of treatment options due to its modularity. CONCLUSION: The modular implant system presented here can significantly facilitate and improve the stabilization of posterior pelvic ring instabilities.

Local heat generation during screw insertion into diaphyseal bone: a biomechanical study on different conditions (e.g. screw type, material, mode of insertion).

BACKGROUND: The implantation of screws is a standard procedure in musculoskeletal surgery. Heat can induce thermal osteonecrosis, damage the bone and lead to secondary problems like implant loosening and secondary fractures. The aim of this study was to investigate whether screw insertion generates temperatures that can cause osteonecrosis. METHODS: We measured the temperature of twenty human femur diaphysis in a total of 120 measurements, while screws of different material (stainless steel and titanium alloy) and different design (locking and cortex screw) were inserted in three different screwing modes (manual vs. machine screwing at full and reduced rotational speed) with 6 thermocouples (3 cis and 3 trans cortex). Each was placed at a depth of 2 mm with a distance of 1.5 mm from the outer surface of the screw. RESULTS: The screw design (cortical > locking), the site of measurement (trans-cortex > cis-cortex) and the type of screw insertion (hand insertion > machine insertion) have an influence on the increase in bone temperature. The screw material (steel > titanium), the site of measurement (trans-cortex > cis-cortex) and the type of screw insertion (machine insertion > hand insertion) have an influence on the time needed to cool below critical temperature values. The combination of the two parameters (maximum temperature and cooling time), which is particularly critical for osteonecrosis, is found only at the trans-cortex. CONCLUSION: Inserting a screw hast the potential to increase the temperature of the surrounding bone tissue above critical values and therefore can induce osteonecrosis. The trans-cortex is the critical area for the development of temperatures above the osteonecrosis threshold, making effective cooling by irrigation difficult. It would be conceivable to cool the borehole with cold saline solution before inserting the screw or to cool the screw in cold saline solution. If possible, insertion by hand should be considered.

Effect of Bone Morphogenetic Protein-2 in the Treatment of Long Bone Non-Unions.

BACKGROUND: Delayed fracture healing continues to cause significant patient morbidity and an economic burden to society. Biological stimulation of non-unions includes application of recombinant bone morphogenetic protein-2 (rhBMP-2). However, rhBMP-2 use continues to be a matter of controversy as literature shows scarce evidence for treatment effectiveness. QUESTIONS: The objective of this study was to evaluate the effectiveness of rhBMP-2 treatment on long bone non-unions measuring union rate and time to union. Furthermore, we assess risk factors for treatment failure. METHODS AND PATIENTS: A total of 91 patients with non-unions of long bones were treated with rhBMP-2 (n = 72) or standard care without BMP (n = 19) at our institution. Patient characteristics, comorbidities, nicotine consumption, and complications were recorded. Bone healing was assessed by plane X-rays and clinical examination. Patients were followed up with for 24 months. RESULTS: Overall, there was significantly faster bone healing after rhBMP-2 application compared to the no-BMP group (p < 0.001; HR = 2.78; 95% CI 1.4-5.6). Union rates differed significantly between rhBMP-2 compared to the no-BMP group (89% vs. 47%; p < 0.001). At the humerus, there was neither a significantly higher union rate in the rhBMP-2 (83%) compared to the no-BMP group (50%) (p = 0.26; n = 12) nor a faster bone healing with a median time of 9 months in both groups (HR = 2.01; 95% CI 0.49-8.61; p = 0.315). The 33 femora treated using rhBMP-2 healed significantly faster than 9 femora in the no-BMP group (HR = 2.93; 95% CI 1.00-8.4; p = 0.023) with significant differences in union rate with 85% and 44%, respectively (p = 0.022). Regarding tibia non-unions, 25 out of 27 (93%) healed with a median of 9 months after rhBMP-2 application with no significant difference in the no-BMP group (33%) in time to union (p = 0.097) but a significantly higher union rate (p = 0.039). There was no effect of comorbidities, age, sex, soft tissue damage, or nicotine use on time to union, union rate, or secondary interventions. CONCLUSION: Consistent with the literature, overall, significantly higher union rates with reduced time to union were achieved after rhBMP-2 application. Femoral and tibial non-unions in particular seem to profit from rhBMP-2 application.