In vivo study to assess fat embolism resulting from the Reamer-Irrigator-Aspirator 2 system compared to a novel aspirator-based concept for intramedullary bone graft harvesting.

INTRODUCTION: Fat embolism (FE) following intramedullary (IM) reaming can cause severe pulmonary complications and sudden death. Recently, a new harvesting concept was introduced in which a novel aspirator is used first for bone marrow (BM) aspiration and then for subsequent aspiration of morselized endosteal bone during sequential reaming (A + R + A). In contrast to the established Reamer-Irrigator-Aspirator (RIA) 2 system, the new A + R + A concept allows for the evacuation of fatty BM prior to reaming. In this study, we hypothesized that the risk of FE, associated coagulopathic reactions and pulmonary FE would be comparable between the RIA 2 system and the A + R + A concept. MATERIALS AND METHODS: Intramedullary bone graft was harvested from intact femora of 16 Merino sheep (age: 1-2 years) with either the RIA 2 system (n = 8) or the A + R + A concept (n = 8). Fat intravasation was monitored with the Gurd test, coagulopathic response with D-dimer blood level concentration and pulmonary FE with histological evaluation of the lungs. RESULTS: The total number and average size of intravasated fat particles was similar between groups (p = 0.13 and p = 0.98, respectively). D-dimer concentration did not significantly increase within 4 h after completion of surgery (RIA 2: p = 0.82; A + R + A: p = 0.23), with an interaction effect similar between groups (p = 0.65). The average lung area covered with fat globules was similar between groups (p = 0.17). CONCLUSIONS: The use of the RIA 2 system and the novel A + R + A harvesting concept which consists of BM evacuation followed by sequential IM reaming and aspiration of endosteal bone, resulted in only minor fat intravasation, coagulopathic reactions and pulmonary FE, with no significant differences between the groups. Our results, therefore, suggest that both the RIA 2 system and the new A + R + A concept are comparable technologies in terms of FE-related complications.

Complications associated using the reamer-irrigator -aspirator (RIA) system: a systematic review and meta-analysis.

INTRODUCTION: Complications associated with the application of the Reamer-irrigator-Aspirator (RIA) system are described in the literature. However, to date a systematic review and meta-analysis to assess prevalence of complications associated with the use of the RIA system have not been conducted. MATERIALS AND METHODS: The review is registered with PROSPERO (CRD42021269982). MEDLINE, the Web of Science Core Collection, and Embase were searched from the inception to 10 August 2021. The primary objective was to assess complications and blood loss associated with the use of the RIA system. RESULTS: Forty-seven studies involving 1834 procedures performed with the RIA system were finally included. A total of 105 complications were reported, with a pooled estimated overall prevalence of 1.7% with a 95% confidence interval (CI) of 0.40 to 3.60, with cortex perforation being the largest reported complication with a total of 34 incidences. A significant subgroup difference was observed (p = 0.02). In subgroup 1 (bone graft harvesting), complication prevalence was 1.4% (95% CI 0.2-3.4); in subgroup 2 (clearance intramedullary canal) it was 0.7% (95% CI 0.00-6.30) and in subgroup 3 (reaming with RIA system prior to nail fixation) 11.9% (95% CI 1.80-26.40). No statistically significant difference for tibia and femur as RIA system application site was observed (CI 0.69-4.19). In studies reporting blood loss, a mean volume of 803.29 ml, a mean drop of hemoglobin of 3.74 g/dl and a necessity of blood transfusion in 9.72% of the patients were observed. CONCLUSIONS: The systematic review and meta-analysis demonstrate a low overall prevalence rate of complications associated with the RIA system. However, especially the risk of cortical perforation and the frequently reported relevant intraoperative blood loss are complications that should be anticipated in perioperative management and ultimately considered when using the RIA system.

[Fall prevention in old people through occupational therapy home assessment, consultation and modification: a process outline]. / Sturzprävention bei älteren Menschen durch ergotherapeutische Wohnraumanalyse, -beratung und -anpassung: eine Prozessdarstellung.

Falls occur frequently in old people and are associated with relevant short-term and long-term trauma sequelae. Particularly in the light of demographic change, preventive measures such as falls prevention are increasingly gaining in importance. Occupational therapy home assessments enable the evaluation of external and behavioral risk factors for falls in the context of environmental prevention. Environmental prevention is an effective measure in preventing morbidity and mortality related to falls in old people and the increase in healthcare costs associated with falls. Occupational therapy home assessments effectively reduce fall risk and fall rate among older people at risk of falling and can be implemented in the context of existing regulatory frameworks. The aim of this overview is to illustrate the optimal process of home assessment and adaptation for patients at risk of falling by general practitioners, orthopedic surgeons and occupational therapists.

Care of Geriatric Patients with Lumbar Spine, Pelvic, and Acetabular Fractures before and after Certification as a Geriatric Trauma Center DGU®: A Retrospective Cohort Study.

Background: More than 750,000 fragility fractures occur in Germany every year, with an expected increase in the following years. Interdisciplinary care pathways for geriatric patients are increasingly established to improve the treatment process and outcome, but there has been only limited evaluation of their use. Objectives: This study aimed to compare patient care before and after the implementation of a geriatric trauma center (GTC) in conformity with the German Society for Trauma Surgery (DGU®). Patients and Methods: We performed a retrospective single-center cohort study, including 361 patients >70 years old with lumbar spine, pelvic, and acetabular fractures, admitted between January 2012 and September 2019. Patients were divided into a usual care cohort (UC, n = 137) before implementation and an ortho-geriatric care cohort (OGC, n = 224) after implementation of the GTC DGU®. We recorded and compared demographic data, fracture type, geriatric assessment and management, therapy, complications, and various clinical parameters, e.g., length of stay, time to surgery, hours admitted to ICU, and change in walking ability. Results: The geriatric assessment revealed significant geriatric co-morbidities and a need for geriatric intervention in 75% of the patients. With orthogeriatric co-management, a significant increase in the detection of urological complications (UC: 25.5% vs. OGC: 37.5%; p = 0.021), earlier postoperative mobilization (UC: 57.1% vs. OGC: 86.3%; p < 0.001), an increased prescription of anti-osteoporotic treatment at discharge (UC: 13.1% vs. OGC: 46.8%; p < 0.001), and lower rates of revision surgery (UC: 5.8% vs. OGC: 3.1%; p = 0.012) could be seen. Conclusions: Our results emphasize the improvement in patient care and clinical outcome by implementing a GTC DGU® and provide opportunities for future improvement in ortho-geriatric patient care.

In-Hospital Clinical Outcomes in Patients with Fragility Fractures of the Lumbar Spine, Thoracic Spine, and Pelvic Ring: A Comparison of Data before and after Certification as a DGU® Geriatric Trauma Centre.

Background and Objectives: The implementation of orthogeriatric co-management (OGCM) reflects the demand for interdisciplinary collaborations due to the increasing comorbidities of geriatric trauma patients. This study aimed to assess clinical in-hospital outcomes in lumbar spine, thoracic spine, and pelvic ring fragility fracture patients before and after the implementation of a Geriatric Trauma Centre (GTC) certified by the German Trauma Society (DGU®). Materials and Methods: In this observational, retrospective cohort study, geriatric trauma patients (>70 years of age) were stratified into either a pre-GTC group (hospital admission between 1 January 2012 and 31 December 2013) or a post-GTC group (hospital admission between 1 January 2017 and 31 December 2018). Patients' pre-injury medical complexity was measured by ASA class (American Society of Anaesthesiologists classification), the use of anticoagulant medication, and the ACCI (Age-adjusted Charlson Comorbidity Index). Outcome parameters were patients' in-hospital length of stay (LOS) and mortality rates, as well as new in-hospital findings and diagnoses. Further, the necessity of deviation from initial management plans due to complications was assessed using the Adapted Clavien-Dindo Scoring System in Trauma (ACDiT score of ≥1). Results: Patients in the post-GTC group (n = 111) were older (median age 82.0 years) compared to the pre-GTC group (n = 108, median age 80.0 years, p = 0.016). No differences were found in sex, body mass index, ASA class, or ACCI (all p > 0.05). Patients in the post-GTC group used vitamin K antagonists or direct oral anticoagulants more frequently (21.3% versus 10.8%). The incidence of non-surgical treatment and mortality was comparable between groups, while LOS tended to be shorter in the post-GTC group (7.0 days versus 9.0 days, p = 0.076). In the post-GTC group, the detection of urinary tract infections (UTI) increased (35.2% versus 16.2%, p = 0.001), and the delirium diagnoses tended to increase (13.0% versus 6.3%, p = 0.094), while an ACDiT score of ≥1 was comparable between groups (p = 0.169). Conclusions: In this study including lumbar spine, thoracic spine, and pelvic ring geriatric fragility fractures, patients in the post-GTC group were more medically complex. More UTIs and the tendency for increased delirium detection was observed in the post-GTC group, likely due to improved diagnostic testing. Nonetheless, the necessity of deviation from initial management plans (ACDiT score of ≥1) was comparable between groups, potentially a positive result of OGCM.

How Framing Bias Impacts Preferences for Innovation in Bone Tissue Engineering.

It is currently unknown if surgeons and biomaterial scientists &or tissue engineers (BS&orTE) process and evaluate information in similar or different (un)biased ways. For the gold standard of surgery to move "from bench to bedside," there must naturally be synergies between these key stakeholders' perspectives. Because only a small number of biomaterials and tissue engineering innovations have been translated into the clinic today, we hypothesized that this lack of translation is rooted in the psychology of surgeons and BS&orTE. Presently, both clinicians and researchers doubt the compatibility of surgery and research in their daily routines. This has led to the use of a metaphorical expression "squaring of the circle," which implies an unsolvable challenge. As bone tissue engineering belongs to the top five research areas in tissue engineering, we choose the field of bone defect treatment options for our bias study. Our study uses an online survey instrument for data capture such as incorporating a behavioral economics cognitive framing experiment methodology. Our study sample consisted of surgeons (n = 208) and BS&orTE (n = 59). And we used a convenience sampling method, with participants (conference attendants) being approached both in person and through email between October 22, 2022, and March 13, 2023. We find no distinct positive-negative cognitive framing differences by occupation. That is, any framing bias present in this surgical decision-making setting does not appear to differ significantly between surgeon and BS&orTE specialization. When we explored within-group differences by frames, we see statistically significant (p < 0.05) results for surgeons in the positive frame ranking autologous bone graft transplantation lower than surgeons in the negative frame. Furthermore, surgeons in the positive frame rank Ilizarov bone transport method higher than surgeons in the negative frame (p < 0.05).

Advances in implants and bone graft types for lumbar spinal fusion surgery.

The increasing prevalence of spinal disorders worldwide necessitates advanced treatments, particularly interbody fusion for severe cases that are unresponsive to non-surgical interventions. This procedure, especially 360° lumbar interbody fusion, employs an interbody cage, pedicle screw-and-rod instrumentation, and autologous bone graft (ABG) to enhance spinal stability and promote fusion. Despite significant advancements, a persistent 10% incidence of non-union continues to result in compromised patient outcomes and escalated healthcare costs. Innovations in lumbar stabilisation seek to mimic the properties of natural bone, with evolving implant materials like titanium (Ti) and polyetheretherketone (PEEK) and their composites offering new prospects. Additionally, biomimetic cages featuring precisely engineered porosities and interconnectivity have gained traction, as they enhance osteogenic differentiation, support osteogenesis, and alleviate stress-shielding. However, the limitations of ABG, such as harvesting morbidities and limited fusion capacity, have spurred the exploration of sophisticated solutions involving advanced bone graft substitutes. Currently, demineralised bone matrix and ceramics are in clinical use, forming the basis for future investigations into novel bone graft substitutes. Bioglass, a promising newcomer, is under investigation despite its observed rapid absorption and the potential for foreign body reactions in preclinical studies. Its clinical applicability remains under scrutiny, with ongoing research addressing challenges related to burst release and appropriate dosing. Conversely, the well-documented favourable osteogenic potential of growth factors remains encouraging, with current efforts focused on modulating their release dynamics to minimise complications. In this evidence-based narrative review, we provide a comprehensive overview of the evolving landscape of non-degradable spinal implants and bone graft substitutes, emphasising their applications in lumbar spinal fusion surgery. We highlight the necessity for continued research to improve clinical outcomes and enhance patient well-being.

An innovative intramedullary bone graft harvesting concept as a fundamental component of scaffold-guided bone regeneration: A preclinical in vivo validation.

Background: The deployment of bone grafts (BGs) is critical to the success of scaffold-guided bone regeneration (SGBR) of large bone defects. It is thus critical to provide harvesting devices that maximize osteogenic capacity of the autograft while also minimizing graft damage during collection. As an alternative to the Reamer-Irrigator-Aspirator 2 (RIA 2) system - the gold standard for large-volume graft harvesting used in orthopaedic clinics today - a novel intramedullary BG harvesting concept has been preclinically introduced and referred to as the ARA (aspirator + reaming-aspiration) concept. The ARA concept uses aspiration of the intramedullary content, followed by medullary reaming-aspiration of the endosteal bone. This concept allows greater customization of BG harvesting conditions vis-à-vis the RIA 2 system. Following its successful in vitro validation, we hypothesized that an ARA concept-collected BG would have comparable in vivo osteogenic capacity compared to the RIA 2 system-collected BG. Methods: We used 3D-printed, medical-grade polycaprolactone-hydroxyapatite (mPCL-HA, wt 96 %:4 %) scaffolds with a Voronoi design, loaded with or without different sheep-harvested BGs and tested them in an ectopic bone formation rat model for up to 8 weeks. Results: Active bone regeneration was observed throughout the scaffold-BG constructs, particularly on the surface of the bone chips with endochondral bone formation, and highly vascularized tissue formed within the fully interconnected pore architecture. There were no differences between the BGs derived from the RIA 2 system and the ARA concept in new bone volume formation and in compression tests (Young's modulus, p = 0.74; yield strength, p = 0.50). These results highlight that the osteogenic capacities of the mPCL-HA Voronoi scaffold loaded with BGs from the ARA concept and the RIA 2 system are equivalent. Conclusion: In conclusion, the ARA concept offers a promising alternative to the RIA 2 system for harvesting BGs to be clinically integrated into SGBR strategies. The translational potential of this article: Our results show that biodegradable composite scaffolds loaded with BGs from the novel intramedullary harvesting concept and the RIA 2 system have equivalent osteogenic capacity. Thus, the innovative, highly intuitive intramedullary harvesting concept offers a promising alternative to the RIA 2 system for harvesting bone grafts, which are an important component for the routine translation of SGBR concepts into clinical practice.

Adherence to the transfer recommendations of the German Trauma Society in severely injured children: a retrospective study from the TraumaRegister DGU.

Particularly for pediatric trauma patients, it is of utmost importance that the right patient be treated in the right place at the right time. While unnecessary interhospital transfers must be avoided, the decision against transfer should not lead to higher complication rates in trauma centers without added pediatric qualifications. We therefore identified independent predictive factors for an early transfer of severely injured patients and compared these factors with the current transfer recommendations of the German Trauma Society. Additionally, the quality of the self-assessment based on the mortality of children who were not transferred was evaluated. A national dataset from the TraumaRegister DGU® was used to retrospectively identify factors for an early interhospital transfer (< 48 h) to a superordinate trauma center. Severely injured pediatric patients (age < 16 years) admitted between 2010 and 2019 were included in this analysis. Adjusted odds ratios (OR) with 95% confidence intervals (CI) for early transfer were calculated from a multivariable model. Prognostic factors for hospital mortality in non-transferred patients were also analyzed. In total, 6069 severely injured children were included. Of these, 65.2% were admitted to a Level I trauma center, whereas 27.7% and 7.1% were admitted to Level II and III centers, respectively. After the initial evaluation in the emergency department, 25.5% and 50.1% of children primarily admitted to a Level II or III trauma center, respectively, were transferred early. Statistically significant predictors of an early transfer were: Serious traumatic brain injury (OR 1.76, 95% CI 1.28-2.43), Injury severity score (ISS) ≥ 16 points (ISS 16-24: OR 2.06, 95% CI 1.59-2.66; ISS 25-33: OR 3.0, 95% CI 2.08-4.31; ISS 34-75: OR 5.42, 95% CI 3.0-9.81, reference category: ISS 9-15), age < 10 years (age 0-1: OR 1.91, 95% CI 1.34-2.71; age 2-5: 2.04, 95% CI 1.50-2.78; age 6-9: 1.62, 95% CI 1.23-2.14; reference category: age 10-15). The most important independent factor for mortality in non-transferred patients was age < 10 years (age 0-1: 5.35, 95% CI 3.25-8.81; age 2-5: 2.46, 95% CI 1.50-4.04; age 6-9: OR 1.7, 95% CI 1.05-2.75; reference category: age 10-15). Knowing the independent predictors for an early transfer, such as a young patient's age, a high injury severity, serious traumatic brain injury (TBI), may improve the choice of the appropriate trauma center. This may guide the rapid decision for an early interhospital transfer. There is still a lack of outcome data on children with early interhospital transfers in Germany, who are the most vulnerable group.

Histological and Immunohistochemical Characterization of Osteoimmunological Processes in Scaffold-Guided Bone Regeneration in an Ovine Large Segmental Defect Model.

Large-volume bone defect regeneration is complex and demands time to complete. Several regeneration phases with unique characteristics, including immune responses, follow, overlap, and interdepend on each other and, if successful, lead to the regeneration of the organ bone's form and function. However, during traumatic, infectious, or neoplastic clinical cases, the intrinsic bone regeneration capacity may exceed, and surgical intervention is indicated. Scaffold-guided bone regeneration (SGBR) has recently shown efficacy in preclinical and clinical studies. To investigate different SGBR strategies over periods of up to three years, we have established a well-characterized ovine large segmental tibial bone defect model, for which we have developed and optimized immunohistochemistry (IHC) protocols. We present an overview of the immunohistochemical characterization of different experimental groups, in which all ovine segmental defects were treated with a bone grafting technique combined with an additively manufactured medical-grade polycaprolactone/tricalcium phosphate (mPCL-TCP) scaffold. The qualitative dataset was based on osteoimmunological findings gained from IHC analyses of over 350 sheep surgeries over the past two decades. Our systematic and standardized IHC protocols enabled us to gain further insight into the complex and long-drawn-out bone regeneration processes, which ultimately proved to be a critical element for successful translational research.

The Concept of Scaffold-Guided Bone Regeneration for the Treatment of Long Bone Defects: Current Clinical Application and Future Perspective.

The treatment of bone defects remains a challenging clinical problem with high reintervention rates, morbidity, and resulting significant healthcare costs. Surgical techniques are constantly evolving, but outcomes can be influenced by several parameters, including the patient's age, comorbidities, systemic disorders, the anatomical location of the defect, and the surgeon's preference and experience. The most used therapeutic modalities for the regeneration of long bone defects include distraction osteogenesis (bone transport), free vascularized fibular grafts, the Masquelet technique, allograft, and (arthroplasty with) mega-prostheses. Over the past 25 years, three-dimensional (3D) printing, a breakthrough layer-by-layer manufacturing technology that produces final parts directly from 3D model data, has taken off and transformed the treatment of bone defects by enabling personalized therapies with highly porous 3D-printed implants tailored to the patient. Therefore, to reduce the morbidities and complications associated with current treatment regimens, efforts have been made in translational research toward 3D-printed scaffolds to facilitate bone regeneration. Three-dimensional printed scaffolds should not only provide osteoconductive surfaces for cell attachment and subsequent bone formation but also provide physical support and containment of bone graft material during the regeneration process, enhancing bone ingrowth, while simultaneously, orthopaedic implants supply mechanical strength with rigid, stable external and/or internal fixation. In this perspective review, we focus on elaborating on the history of bone defect treatment methods and assessing current treatment approaches as well as recent developments, including existing evidence on the advantages and disadvantages of 3D-printed scaffolds for bone defect regeneration. Furthermore, it is evident that the regulatory framework and organization and financing of evidence-based clinical trials remains very complex, and new challenges for non-biodegradable and biodegradable 3D-printed scaffolds for bone regeneration are emerging that have not yet been sufficiently addressed, such as guideline development for specific surgical indications, clinically feasible design concepts for needed multicentre international preclinical and clinical trials, the current medico-legal status, and reimbursement. These challenges underscore the need for intensive exchange and open and honest debate among leaders in the field. This goal can be addressed in a well-planned and focused stakeholder workshop on the topic of patient-specific 3D-printed scaffolds for long bone defect regeneration, as proposed in this perspective review.

In vivo characterization of 3D-printed polycaprolactone-hydroxyapatite scaffolds with Voronoi design to advance the concept of scaffold-guided bone regeneration.

Three-dimensional (3D)-printed medical-grade polycaprolactone (mPCL) composite scaffolds have been the first to enable the concept of scaffold-guided bone regeneration (SGBR) from bench to bedside. However, advances in 3D printing technologies now promise next-generation scaffolds such as those with Voronoi tessellation. We hypothesized that the combination of a Voronoi design, applied for the first time to 3D-printed mPCL and ceramic fillers (here hydroxyapatite, HA), would allow slow degradation and high osteogenicity needed to regenerate bone tissue and enhance regenerative properties when mixed with xenograft material. We tested this hypothesis in vitro and in vivo using 3D-printed composite mPCL-HA scaffolds (wt 96%:4%) with the Voronoi design using an ISO 13485 certified additive manufacturing platform. The resulting scaffold porosity was 73% and minimal in vitro degradation (mass loss <1%) was observed over the period of 6 months. After loading the scaffolds with different types of fresh sheep xenograft and ectopic implantation in rats for 8 weeks, highly vascularized tissue without extensive fibrous encapsulation was found in all mPCL-HA Voronoi scaffolds and endochondral bone formation was observed, with no adverse host-tissue reactions. This study supports the use of mPCL-HA Voronoi scaffolds for further testing in future large preclinical animal studies prior to clinical trials to ultimately successfully advance the SGBR concept.

An in vivo study to investigate an original intramedullary bone graft harvesting technology.

BACKGROUND: Harvesting bone graft (BG) from the intramedullary canal to treat bone defects is largely conducted using the Reamer-Irrigator-Aspirator (RIA) system. The RIA system uses irrigation fluid during harvesting, which may result in washout of osteoinductive factors. Here, we propose a new harvesting technology dedicated to improving BG collection without the potential washout effect of osteoinductive factors associated with irrigation fluid. This novel technology involves the conceptual approach of first aspirating the bone marrow (BM) with a novel aspirator prototype, followed by reaming with standard reamers and collecting the bone chips with the aspirator (reaming-aspiration method, R-A method). The aim of this study was to assess the harvesting efficacy and osteoinductive profile of the BG harvested with RIA 2 system (RIA 2 group) compared to the novel harvesting concept (aspirator + R-A method, ARA group). METHODS: Pre-planning computed tomography (CT) imaging was conducted on 16 sheep to determine the femoral isthmus canal diameter. In this non-recovery study, sheep were divided into two groups: RIA 2 group (n = 8) and ARA group (n = 8). We measured BG weight collected from left femur and determined femoral cortical bone volume reduction in postoperative CT imaging. Growth factor and inflammatory cytokine amounts of the BGs were quantified using enzyme-linked immunosorbent assay (ELISA) methods. RESULTS: The use of the stand-alone novel aspirator in BM collection, and in harvesting BG when the aspirator is used in conjunction with sequential reaming (R-A method) was proven feasible. ELISA results showed that the collected BG contained relevant amounts of growth factors and inflammatory cytokines in both the RIA 2 and the ARA group. CONCLUSIONS: Here, we present the first results of an innovative concept for harvesting intramedullary BG. It is a prototype of a novel aspirator technology that enables the stepwise harvesting of first BM and subsequent bone chips from the intramedullary canal of long bones. Both the BG collected with the RIA 2 system and the aspirator prototype had the capacity to preserve the BG's osteoinductive microenvironment. Future in vivo studies are required to confirm the bone regenerative capacity of BG harvested with the innovative harvesting technology.

Biodegradable interbody cages for lumbar spine fusion: Current concepts and future directions.

Lumbar fusion often remains the last treatment option for various acute and chronic spinal conditions, including infectious and degenerative diseases. Placement of a cage in the intervertebral space has become a routine clinical treatment for spinal fusion surgery to provide sufficient biomechanical stability, which is required to achieve bony ingrowth of the implant. Routinely used cages for clinical application are made of titanium (Ti) or polyetheretherketone (PEEK). Ti has been used since the 1980s; however, its shortcomings, such as impaired radiographical opacity and higher elastic modulus compared to bone, have led to the development of PEEK cages, which are associated with reduced stress shielding as well as no radiographical artefacts. Since PEEK is bioinert, its osteointegration capacity is limited, which in turn enhances fibrotic tissue formation and peri-implant infections. To address shortcomings of both of these biomaterials, interdisciplinary teams have developed biodegradable cages. Rooted in promising preclinical large animal studies, a hollow cylindrical cage (Hydrosorb™) made of 70:30 poly-l-lactide-co-d, l-lactide acid (PLDLLA) was clinically studied. However, reduced bony integration and unfavourable long-term clinical outcomes prohibited its routine clinical application. More recently, scaffold-guided bone regeneration (SGBR) with application of highly porous biodegradable constructs is emerging. Advancements in additive manufacturing technology now allow the cage designs that match requirements, such as stiffness of surrounding tissues, while providing long-term biomechanical stability. A favourable clinical outcome has been observed in the treatment of various bone defects, particularly for 3D-printed composite scaffolds made of medical-grade polycaprolactone (mPCL) in combination with a ceramic filler material. Therefore, advanced cage design made of mPCL and ceramic may also carry initial high spinal forces up to the time of bony fusion and subsequently resorb without clinical side effects. Furthermore, surface modification of implants is an effective approach to simultaneously reduce microbial infection and improve tissue integration. We present a design concept for a scaffold surface which result in osteoconductive and antimicrobial properties that have the potential to achieve higher rates of fusion and less clinical complications. In this review, we explore the preclinical and clinical studies which used bioresorbable cages. Furthermore, we critically discuss the need for a cutting-edge research program that includes comprehensive preclinical in vitro and in vivo studies to enable successful translation from bench to bedside. We develop such a conceptual framework by examining the state-of-the-art literature and posing the questions that will guide this field in the coming years.

Internal fixation versus hip arthroplasty in patients with nondisplaced femoral neck fractures: short-term results from a geriatric trauma registry.

PURPOSE: To determine whether internal fixation (IF) or hip arthroplasty (HA) is associated with superior outcomes in geriatric nondisplaced femoral neck fracture (FNF) patients. METHODS: Data from the Registry for Geriatric Trauma of the German Trauma Society (ATR-DGU) were analyzed (IF Group 449 and HA Group 1278 patients). In-hospital care and a 120-day postoperative follow-up were conducted. Primary outcomes, including mobility, residential status, reoperation rate, and a generic health status measure (EQ-5D score), and the secondary outcome of mortality were compared between groups. Multivariable analyses were performed to assess independent treatment group associations (odds ratios, ORs) with the primary and secondary end points. RESULTS: Patients in the HA group were older (83 vs. 81 years, p < 0.001) and scored higher on the Identification of Seniors at Risk screening (3 vs. 2, p < 0.001). We observed no differences in residential status, reoperation rate, EQ-5D score, or mortality between groups. After adjusting for key covariates, including prefracture ambulatory capacity, the mobility of patients in the HA group was more frequently impaired at the 120-day follow-up (OR 2.28, 95% confidence interval = 1.11-4.74). CONCLUSION: Treatment with HA compared to treatment with IF led to a more than twofold increase in the adjusted odds of impaired ambulation at the short-term follow-up, while no significant associations with residential status, reoperation rate, EQ-5D index score, or mortality were observed. Thus, IF for geriatric nondisplaced FNFs was associated with superior mobility 120 days after surgery. However, before definitive treatment recommendations can be made, prospective, randomized, long-term studies must be performed to confirm our findings.

Interobserver reliability of the Gehweiler classification and treatment strategies of isolated atlas fractures: an internet-based multicenter survey among spine surgeons.

PURPOSE: Atlas (C1) fractures are commonly rated according to the Gehweiler classification, but literature on its reliability is scarce. In addition, evaluation of fracture stability and choosing the most appropriate treatment regime for C1-injuries are challenging. This study aimed to investigate the interobserver reliability of the Gehweiler classification and to identify whether evaluation of fracture stability as well as the treatment of C1-fractures are consistent among spine surgeons. METHODS: Computed tomography images of 34 C1-fractures and case-specific information were presented to six experienced spine surgeons. C1-fractures were graded according to the Gehweiler classification, and the suggested treatment regime was recorded in a questionnaire. For data analyses, SPSS was used, and interobserver reliability was calculated using Fleiss' kappa (κ) statistics. RESULTS: We observed a moderate reliability for the Gehweiler classification (κ = 0.50), the evaluation of fracture stability (κ = 0.50), and whether a surgical or non-surgical therapy was indicated (κ = 0.53). Type 1, 2, 3a, and 5 fractures were rated stable and treated non-surgically. Type 3b fractures were rated unstable in 86.7% of cases and treated by surgery in 90% of cases. Atlas osteosynthesis was most frequently recommended (65.4%). Overall, 25.8% of type 4 fractures were rated unstable, and surgery was favoured in 25.8%. CONCLUSION: We found a moderate reliability for the Gehweiler classification and for the evaluation of fracture stability. In particular, diverging treatment strategies for type 3b fractures emphasise the necessity of further clinical and biomechanical investigations to determine the optimal treatment of unstable C1-fractures.

Clinical translation of a patient-specific scaffold-guided bone regeneration concept in four cases with large long bone defects.

Background: Bone defects after trauma, infection, or tumour resection present a challenge for patients and clinicians. To date, autologous bone graft (ABG) is the gold standard for bone regeneration. To address the limitations of ABG such as limited harvest volume as well as overly fast remodelling and resorption, a new treatment strategy of scaffold-guided bone regeneration (SGBR) was developed. In a well-characterized sheep model of large to extra-large tibial segmental defects, three-dimensional (3D) printed composite scaffolds have shown clinically relevant biocompatibility and osteoconductive capacity in SGBR strategies. Here, we report four challenging clinical cases with large complex posttraumatic long bone defects using patient-specific SGBR as a successful treatment. Methods: After giving informed consent computed tomography (CT) images were used to design patient-specific biodegradable medical-grade polycaprolactone-tricalcium phosphate (mPCL-TCP, 80:20 â€‹wt%) scaffolds. The CT scans were segmented using Materialise Mimics to produce a defect model and the scaffold parts were designed with Autodesk Meshmixer. Scaffold prototypes were 3D-printed to validate robust clinical handling and bone defect fit. The final scaffold design was additively manufactured under Food and Drug Administration (FDA) guidelines for patient-specific and custom-made implants by Osteopore International Pte Ltd. Results: Four patients (age: 23-42 years) with posttraumatic lower extremity large long bone defects (case 1: 4 â€‹cm distal femur, case 2: 10 â€‹cm tibia shaft, case 3: complex malunion femur, case 4: irregularly shaped defect distal tibia) are presented. After giving informed consent, the patients were treated surgically by implanting a custom-made mPCL-TCP scaffold loaded with ABG (case 2: additional application of recombinant human bone morphogenetic protein-2) harvested with the Reamer-Irrigator-Aspirator system (RIA, Synthes®). In all cases, the scaffolds matched the actual anatomical defect well and no perioperative adverse events were observed. Cases 1, 3 and 4 showed evidence of bony ingrowth into the large honeycomb pores (pores >2 â€‹mm) and fully interconnected scaffold architecture with indicative osseous bridges at the bony ends on the last radiographic follow-up (8-9 months after implantation). Comprehensive bone regeneration and full weight bearing were achieved in case 2 â€‹at follow-up 23 months after implantation. Conclusion: This study shows the bench to bedside translation of guided bone regeneration principles into scaffold-based bone tissue engineering. The scaffold design in SGBR should have a tissue-specific morphological signature which stimulates and directs the stages from the initial host response towards the full regeneration. Thereby, the scaffolds provide a physical niche with morphology and biomaterial properties that allow cell migration, proliferation, and formation of vascularized tissue in the first one to two months, followed by functional bone formation and the capacity for physiological bone remodelling. Great design flexibility of composite scaffolds to support the one to three-year bone regeneration was observed in four patients with complex long bone defects. The translational potential of this article: This study reports on the clinical efficacy of SGBR in the treatment of long bone defects. Moreover, it presents a comprehensive narrative of the rationale of this technology, highlighting its potential for bone regeneration treatment regimens in patients with any type of large and complex osseous defects.

An experimental-numerical method for the calibration of finite element models of the lumbar spine.

We present a systematic and automated stepwise method to calibrate computational models of the spine. For that purpose, a sequential resection study on one lumbar specimen (L2-L5) was performed to obtain the individual contribution of the IVD, the facet joints and the ligaments to the kinematics of the spine. The experimental data was prepared for the calibration procedure in such manner that the FE model could reproduce the average motion of the 10 native spines from former cadaveric studies as well as replicate the proportional change in ROM after removal of a spinal structure obtained in this resection study. A Genetic Algorithm was developed to calibrate the properties of the intervertebral discs and facet joints. The calibration of each ligament was performed by a simple and novel technique that requires only one simulation to obtain its mechanical property. After calibration, the model was capable of reproducing the experimental results in all loading directions and resections.

Strategies for the treatment of femoral fractures in severely injured patients: trends in over two decades from the TraumaRegister DGU®.

PURPOSE: Treatment strategies for femoral fracture stabilisation are well known to have a significant impact on the patient's outcome. Therefore, the optimal choices for both the type of initial fracture stabilisation (external fixation/EF, early total care/ETC, conservative treatment/TC) and the best time point for conversion from temporary to definitive fixation are challenging factors. PATIENTS: Patients aged ≥ 16 years with moderate and severe trauma documented in the TraumaRegister DGU® between 2002 and 2018 were retrospectively analysed. Demographics, ISS, surgical treatment strategy (ETC vs. EF vs. TC), time for conversion to definitive care, complication (MOF, sepsis) and survival rates were analysed. RESULTS: In total, 13,091 trauma patients were included. EF patients more often sustained high-energy trauma (car: 43.1 vs. 29.5%, p < 0.001), were younger (40.6 vs. 48.1 years, p < 0.001), were more severely injured (ISS 25.4 vs. 19.1 pts., p < 0.001), and had higher sepsis (11.8 vs. 5.4%, p < 0.001) and MOF rates (33.1 vs. 16.0%, p < 0.001) compared to ETC patients. A shift from ETC to EF was observed. The time until conversion decreased for femoral fractures from 9 to 8 days within the observation period. Sepsis incidences decreased in EF (20.3 to 12.3%, p < 0.001) and ETC (9.1-4.8%, p < 0.001) patients. CONCLUSIONS: Our results show the changes in the surgical treatment of severely injured patients with femur fractures over a period of almost two decades caused by the introduction of modern surgical strategies (e.g., Safe Definitive Surgery). It remains unclear which subgroups of trauma patients benefit most from these strategies.

Impact of anticoagulation and antiplatelet drugs on surgery rates and mortality in trauma patients.

Preinjury anticoagulation therapy (AT) is associated with a higher risk for major bleeding. We aimed to evaluated the influence of preinjury anticoagulant medication on the clinical course after moderate and severe trauma. Patients in the TraumaRegister DGU ≥ 55 years who received AT were matched with patients not receiving AT. Pairs were grouped according to the drug used: Antiplatelet drugs (APD), vitamin K antagonists (VKA) and direct oral anticoagulants (DOAC). The primary end points were early (< 24 h) and total in-hospital mortality. Secondary endpoints included emergency surgical procedure rates and surgery rates. The APD group matched 1759 pairs, the VKA group 677 pairs, and the DOAC group 437 pairs. Surgery rates were statistically significant higher in the AT groups compared to controls (APD group: 51.8% vs. 47.8%, p = 0.015; VKA group: 52.4% vs. 44.8%, p = 0.005; DOAC group: 52.6% vs. 41.0%, p = 0.001). Patients on VKA had higher total in-hospital mortality (23.9% vs. 19.5%, p = 0.026), whereas APD patients showed a significantly higher early mortality compared to controls (5.3% vs. 3.5%, p = 0.011). Standard operating procedures should be developed to avoid lethal under-triage. Further studies should focus on detailed information about complications, secondary surgical procedures and preventable risk factors in relation to mortality.