A new bone substitute developed from 3D-prints of polylactide (PLA) loaded with collagen I : an in vitro study

Although a lot of research has been performed, large segmental bone defects caused by trauma, infection, bone tumors or revision surgeries still represent big challenges for trauma surgeons. New and innovative bone substitutes are needed. Three-dimensional (3D) printing is a novel procedure to create 3D porous scaffolds that can be used for bone tissue engineering. In the present study, solid discs as well as porous cage-like 3D prints made of polylactide (PLA) are coated or filled with collagen, respectively, and tested for biocompatibility and endotoxin contamination. Microscopic analyses as well as proliferation assays were performed using various cell types on PLA discs. Stromal-derived factor (SDF-1) release from cages filled with collagen was analyzed and the effect on endothelial cells tested. This study confirms the biocompatibility of PLA and demonstrates an endotoxin contamination clearly below the FDA (Food and Drug Administration) limit. Cells of various cell types (osteoblasts, osteoblast-like cells, fibroblasts and endothelial cells) grow, spread and proliferate on PLA-printed discs. PLA cages loaded with SDF-1 collagen display a steady SDF-1 release, support cell growth of endothelial cells and induce neo-vessel formation. These results demonstrate the potential for PLA scaffolds printed with an inexpensive desktop printer in medical applications, for example, in bone tissue engineering

Traumatic brain injury enhances the formation of heterotopic ossification around the hip : an animal model study

Introduction: The incidence of heterotopic ossification (HO) is at its highest when trauma of the hip or pelvis concurs with traumatic brain injury (TBI). The pathogenic mechanisms underlying the neurogenic enhancement of the formation of HO remain, however, poorly understood. Hence, the goal of the present study was to develop a novel small animal model that combines hip and brain trauma that can prove the enhancement of HO around the hip after TBI. Materials and methods: Forty male Wistar rats were divided into four groups, to undergo hip surgery alone (group 1), hip surgery + moderate TBI (group 2), hip surgery + severe TBI (group 3) and only severe TBI (group 4). The femoral canal was reamed up to 2 mm and a muscle lesion was made to simulate hip surgery. An established controlled cortical impact model was used to create a TBI. Twelve weeks after surgery, the hip with the proximal half of the femur and the pelvic bone was removed and subjected to micro-computed tomography (µCT) analysis. A quantitative analysis using a modified Brooker score as well as a quantitative analysis using a bone-to-tissue ratio was used. Results: No HO could be found in all the ten animals that did not undergo hip surgery (group 4). In the animals that did undergo surgery to the hip, no HO was found in only one animal (group 1). All the other animals developed HO. In this study, significantly more HO was found in animals that underwent an additional severe TBI. Conclusion: The newly developed rat model, with a combined hip and brain trauma, showed an enhancement of the HO formation around the hip after severe TBI

Evaluation of bone sialoprotein coating of three-dimensional printed calcium phosphate scaffolds in a calvarial defect model in mice

The bioactive coating of calcium phosphate cement (CPC) is a promising approach to enhance the bone-healing properties of bone substitutes. The purpose of this study was to evaluate whether coating CPCs with bone sialoprotein (BSP) results in increased bone formation. Forty-five female C57BL/6NRj mice with an average age of six weeks were divided into three groups. Either a BSP-coated or an uncoated three-dimensional plotted scaffold was implanted into a drilled 2.7-mm diameter calvarial defect, or the defect was left empty (control group; no CPC). Histological analyses revealed that BSP-coated scaffolds were better integrated into the local bone stock eight weeks after implantation. Bone volume/total volume (BV/TV) ratios and bone thickness at the bone-implant contact were analyzed via micro computed tomography (µCT) after eight weeks. BSP-coated scaffolds and uncoated CPC scaffolds increased bone thickness in comparison to the control (CPC + BSP: 691.1 ± 253.5 µm, CPC: 603.1 ± 164.4 µm, no CPC: 261.7 ± 37.8 µm, p < 0.01). Accordingly, BV/TV was enhanced in both scaffold groups (CPC + BSP: 1.3 ± 0.5%, CPC: 0.9 ± 0.5%, no CPC: 0.2 ± 0.3%, p < 0.01). The BSP coating showed a tendency towards an increased bone thickness (p = 0.18) and BV/TV (p = 0.18) in comparison to uncoated CPC scaffolds. However, a significant increase in bone formation through BSP coating was not found

A Bibliometric Analysis of Fragility Fractures: Top 50.

Background and Objectives: The population is aging and fragility fractures are a research topic of steadily growing importance. Therefore, a systematic bibliometric review was performed to identify the 50 most cited articles in the field of fragility fractures analyzing their qualities and characteristics. Materials and Methods: From the Core Collection database in the Thomson Reuters Web of Knowledge, the most influential original articles with reference to fragility fractures were identified in February 2021 using a multistep approach. Year of publication, total number of citations, average number of citations per year since year of publication, affiliation of first and senior author, geographic origin of study population, keywords, and level of evidence were of interest. Results: Articles were published in 26 different journals between 1997 and 2020. The number of total citations per article ranged from 12 to 129 citations. In the majority of publications, orthopedic surgeons and traumatologists (66%) accounted for the first authorship, articles mostly originated from Europe (58%) and the keyword mostly used was "hip fracture". In total, 38% of the articles were therapeutic studies level III followed by prognostic studies level I. Only two therapeutic studies with level I could be identified. Conclusions: This bibliometric review shows the growing interest in fragility fractures and raises awareness that more high quality and interdisciplinary studies are needed

Misdiagnosis of Thoracolumbar Posterior Ligamentous Complex Injuries and Use of Radiographic Parameter Correlations to Improve Detection Accuracy

Study Design Retrospective study. Purpose To evaluate radiological parameters as indicators for posterior ligamentous complex (PLC) injuries in the case of limited availability of magnetic resonance imaging. Overview of Literature Traumatic thoracolumbar spinal fractures with PLC injuries can be misdiagnosed on X-rays or computed tomography scans. This study aimed to retrospectively assess unrecognized PLC injuries and evaluate radiographic parameters as indicators of PLC injuries requiring surgery. Methods In total, 314 patients with type A and type B2 fractures who underwent surgical treatment between 2001 and 2010 were included. The frequency of misdiagnosis was reassessed, and radiographic parameters were evaluated and correlated. Results The average age of the patients was 51.8 years. There were 225 type A3/A4 and 89 type B2 fractures; 39 of the type B2 fractures (43.8%) had been misdiagnosed as type A fractures. Type B fractures presented with a significantly higher kyphotic wedge angle and Cobb angle and a lower sagittal index (SI) than type A fractures. In addition, the normalized interspinous distance was higher in type B2 fractures. The significant mathematical indicators for PLC injuries were as follows: Cobb angle+kyphotic wedge angle >29°; Cobb angle2 >170°; and vertebral angle/SI >25. Conclusions The results demonstrated that PLC injuries are frequently misdiagnosed. Correlations between certain radiological parameters associated with PLC injuries can be useful indicators of the presence of such injuries requiring surgery

Focus on fragility fractures of the pelvis

Introduction!#!In fragility fractures of the pelvis (FFP), fractures of the posterior pelvic ring are nearly always combined with fractures of the anterior pelvic ring. When a surgical stabilization of the posterior pelvis is performed, a stabilization of the anterior pelvis is recommended as well. In this study, we aim at finding out whether conventional plate osteosynthesis is a valid option in patients with osteoporotic bone.!##!Materials and methods!#!We retrospectively reviewed medical charts and radiographs of all patients with a FFP, who underwent a plate osteosynthesis of the anterior pelvic ring between 2009 and 2019. Patient demographics, fracture characteristics, properties of the osteosynthesis, complications and revision surgeries were documented. Single plate osteosynthesis (SPO) at the pelvic brim was compared with double plate osteosynthesis (DPO) with one plate at the pelvic brim and one plate anteriorly. We hypothesized that the number and severity of screw loosening (SL) or plate breakage in DPO are lower than in SPO.!##!Results!#!48 patients with a mean age of 76.8 years were reviewed. In 37 cases, SPO was performed, in 11 cases DPO. Eight out of 11 DPO were performed in patients with FFP type III or FFP type IV. We performed significantly more DPO when the instability was located at the level of the pubic symphysis (p = 0.025). More patients with a chronic FFP (surgery more than one month after diagnosis) were treated with DPO (p = 0.07). Infra-acetabular screws were more often inserted in DPO (p = 0.056). Screw loosening (SL) was seen in the superior plate in 45% of patients. There was no SL in the anterior plate. There was SL in 19 of 37 patients with SPO and in 3 of 11 patients with DPO (p = 0.16). SL was localized near to the pubic symphysis in 19 of 22 patients after SPO and in all three patients after DPO. There was no SL in DPO within the first month postoperatively. We performed revision osteosynthesis in six patients (6/48), all belonged to the SPO group (6/37). The presence of a bone defect, unilateral or bilateral anterior pelvic ring fracture, post-operative weight-bearing restrictions, osteosynthesis of the posterior pelvic ring, and the presence of infra- or supra-acetabular screws did not significantly influence screw loosening in SPO or DPO.!##!Conclusion!#!There is a high rate of SL in plate fixation of the anterior pelvic ring in FFP. In the vast majority, SL is located near to the pubic symphysis. DPO is associated with a lower rate of SL, less severe SL and a later onset of SL. Revision surgery is less likely in DPO. In FFP, we recommend DPO instead of SPO for fixation of fractures of the anterior pelvic ring, which are located in or near to the pubic symphysis

Focus on pelvic trauma

Purpose!#!Decompressive hemicraniectomy (DC) has been established as a standard therapeutical procedure for raised intracranial pressure. However, the size of the DC remains unspecified. The aim of this study was to analyze size related complications following DC.!##!Methods!#!Between 2013 and 2019, 306 patients underwent DC for elevated intracranial pressure at author´s institution. Anteroposterior and craniocaudal DC size was measured according to the postoperative CT scans. Patients were divided into two groups with (1) exposed superior sagittal sinus (SE) and (2) without superior sagittal sinus exposure (SC). DC related complications e.g. shear-bleeding at the margins of craniectomy and secondary hydrocephalus were evaluated and compared.!##!Results!#!Craniectomy size according to anteroposterior diameter and surface was larger in the SE group; 14.1 ± 1 cm vs. 13.7 ± 1.2 cm, p = 0.003, resp. 222.5 ± 40 cm!##!Conclusions!#!Complete hemispheric exposure in terms of DC with SE was associated with significantly lower levels of iatrogenic shear-bleedings compared to a SC-surgical regime. Although we did not find significant outcome difference, our findings suggest aggressive craniectomy regimes including SE to constitute the surgical treatment strategy of choice for malignant intracranial pressure

Single stage reconstruction of a neglected open book pelvic injury with bladder herniation into the upper thigh: a case-report

When open-book injuries are neglected and result into a pelvic malunion or nonunion, long-term problems, such as chronic pain, gait abnormalities, sitting discomfort, neurological symptoms and urogenital symptoms can occur. In this case report, we describe the repair of a neglected pelvic disruption with the dislocation of the urinary bladder in a one-stage procedure. The clinical image with which the patient presented could be split into unique sub-problems, for which separate solutions needed to be chosen: large symphysis diastasis, instability and pain in both SI joints, malunion of the superior and inferior pubic rami fractures; and urinary bladder herniation into the upper thigh. In a single-stage procedure, the pelvic ring was reconstructed and the bladder reduced. The patient was thereafter continent for urine and could walk independently. A complex clinical problem was divided into its sub-problems, for which specific solutions were found