Resolving Multielement Semiconductor Nanocrystals at the Atomic Level: Complete Deciphering of Domains and Order in Complex CuαZnßSnγSeδ (CZTSe) Tetrapods.

Semiconductor nanocrystals (NCs) with high elemental and structural complexity can be engineered to tailor for electronic, photovoltaic, thermoelectric, and battery applications etc. However, this greater complexity causes ambiguity in the atomic structure understanding. This in turn hinders the mechanistic studies of nucleation and growth, the theoretical calculations of functional properties, and the capability to extend functional design across complementary semiconductor nanocrystals. Herein, we successfully deciphered the atomic arrangements of 4 different nanocrystal domains in CuαZnßSnγSeδ (CZTSe) nanocrystals using crucial zone axis analysis on multiple crystals in different orientations. The results show that the essence of crystallographic progression from binary to multielemental semiconductors is actually the change of theoretical periodicity. This transition is caused by decreased symmetry in the crystal instead of previously assumed crystal deformation. We further reveal that these highly complex crystalline entities have highly ordered element arrangements as opposed to the previous understanding that their elemental orderings are random.

Campylobacter majalis sp. nov. and Campylobacter suis sp. nov., novel Campylobacter species isolated from porcine gastrointestinal mucosa.

Strains LMG 7974T and LMG 8286T represent single, novel Campylobacter lineages with Campylobacter pinnipediorum and Campylobacter mucosalis as nearest phylogenomic neighbours, respectively. The results of average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) analyses of LMG 7974T, LMG 8286T and type strains of species of the genus Campylobacter confirmed that these strains represent novel species of the genus Campylobacter. The 16S rRNA gene sequences of both strains showed highest identity towards C. mucosalis (97.84 and 98.74 %, respectively). Strains LMG 7974T and LMG 8286T shared 72.5 and 73.7% ANI, respectively, with their nearest phylogenomic neighbours and less than 21 % dDDH. The draft genome sizes of LMG 7974T and LMG 8286T are 1 945429 bp and 1 708214 bp in length with percentage DNA G+C contents of 33.8 and 37.2 %, respectively. Anomalous biochemical characteristics and low MALDI-TOF mass spectrometry log scores supported their designation as representing novel species of the genus Campylobacte. We therefore propose to classify strain LMG 7974T (=CCUG 20705T) as the type strain of the novel species Campylobacter majalis sp. nov. and strain LMG 8286T (=CCUG 24193T, NCTC 11879T) as the type strain of the novel species Campylobacter suis sp. nov.

Semi-automated Tracing of Hamstring Muscle Architecture for B-mode Ultrasound Images.

Hamstring strains are the most prevalent injury sustained by field-sport athletes. Insufficiencies in the architectural characteristics of the hamstring muscles can heighten an athlete's risk of incurring a hamstring strain. To evaluate the influence of hamstring muscle architectural characteristics (i. e., fascicle length, pennation angle, muscle thickness) on injury risk, it is necessary to precisely evaluate these characteristics. Considering this, our aim was to develop and evaluate the precision of a novel semi-automated tracing software to measure the architectural characteristics of the biceps femoris long head (the most commonly injured hamstring muscle) in B-mode ultrasound images. We acquired static sonograms of the biceps femoris long head from ten healthy male field-sport athletes. The architectural characteristics (fascicle length, pennation angle, and muscle thickness) of participants' biceps femoris long head were evaluated 10 times using the tracing software, with the specific purpose of determining its measurement precision. The tracing software precisely measured the architectural characteristics of the participants' biceps femoris long head: fascicle length (% CV: 0.64-1.12), pennation angle (% CV: 2.58-10.70), muscle thickness (% CV: 0.48-2.04) Our semi-automated skeletal muscle tracing algorithm precisely measures fascicle length, pennation angles, and muscle thickness of the biceps femoris long head in static B-mode ultrasound images.

An Anatomic Study of the Proximal Tibial Epiphysis With Relevance to Percutaneous Epiphysiodesis Using Transphyseal Screws (PETS).

BACKGROUND: Percutaneous epiphysiodesis using transphyseal screws (PETS) is a common procedure to correct lower extremity limb-length discrepancies in the pediatric population. A potential complication of this procedure is development of tibial valgus deformity, which may occur secondary to decreased screw purchase in the thinner medial proximal tibial epiphysis. The thickness of the proximal tibial epiphysis has not yet been well quantified, which was the aim of this study. METHODS: Three-dimensional surface scans of 32 cadaveric proximal tibial epiphyses in specimens aged 3 to 17 years old were obtained and computer modeling software was utilized to measure the thickness of the proximal tibial epiphysis at 20 standardized potential screw insertion points according to a generated 5×4 map. RESULTS: When normalized to the total width of the proximal tibial epiphysis, the lateral side is thicker compared with the medial side. The positions with the greatest thickness are located at the midline in the sagittal plane and 33% of the total physeal width away from the medial and lateral edges in the coronal plane (0.265 and 0.261 normalized thickness, respectively). The proximal tibial epiphysis is particularly thin 25% from the medial edge (normalized thickness range: 0.196 to 0.221). Multiple regression analysis revealed a significant relationship between increasing age and female sex with thinner normalized medial and lateral heights. CONCLUSIONS: During PETS, areas for greater screw purchase are located centrally in the sagittal plane and 33% of the total width away from the medial and lateral edges of the proximal tibial epiphysis in the coronal plane. Caution should be taken when inserting screws in the medial 25% of the proximal tibial epiphysis as it is thinner relative to the lateral edge, particularly in females. CLINICAL RELEVANCE: This study provides quantitative, anatomic data on the thickness of the proximal tibial epiphysis, which can direct screw placement during PETS for correcting limb-length discrepancies. These data may help lessen the risk of developing tibial valgus deformity although future clinical studies are necessary to fully evaluate this possibility.

The Development of a Digital Twin Framework for an Industrial Robotic Drilling Process.

A digital twin is a digital representation of a physical entity that is updated in real-time by transfer of data between physical and digital (virtual) entities. In this manuscript we aim to introduce a digital twin framework for robotic drilling. Initially, a generic reference model is proposed to highlight elements of the digital twin relevant to robotic drilling. Then, a precise reference digital twin architecture model is developed, based on available standards and technologies. Finally, real-time visualisation of drilling process parameters is demonstrated as an initial step towards implementing a digital twin of a robotic drilling process.

Internal tibial torsion is related to syndesmosis injury in a large osteological collection.

BACKGROUND: The long-term consequences of tibial torsion remain unclear. This study evaluated whether syndesmotic injuries are associated with tibial torsion. METHODS: A collection of over 3000 cadaveric skeletons was screened for irregular bony prominence along the lateral distal tibia, consistent with previous syndesmosis injury. Tibial torsion was measured and compared to 1034 control cadaveric tibiae. RESULTS: Mean torsion of 236 specimens with syndesmotic injury was 6.2±8.9 degrees, while that of control specimens was 7.9±8.8 degrees (P = 0.008). Multiple regression analysis showed a non-statistically significant trend toward internal torsion and syndesmotic injury (standardized beta=-0.051, P=0.059). Syndesmosis injury was present in 48/200 specimens (24.0%) with internal torsion and 31/199 specimens (15.6%) with external torsion (P=0.035). CONCLUSION: This association between internal tibial torsion and syndesmotic injury suggests that internal tibial torsion might not be an entirely benign condition and merits further study.

Developmental Patterns of the Greater Trochanter in Skeletally Immature Patients.

BACKGROUND: Trochanteric entry femoral nailing in immature patients is controversial. Although it has become increasingly accepted in pediatric patients aged 8 years and older, complications related to physeal violation have been reported. To date, the appropriate minimum age for safe antegrade nailing in skeletally immature patients remains to be unknown. The purpose of this investigation was to determine the degree of trochanteric bony and cartilage growth with increasing age to provide normative growth values. METHODS: A total of 408 serial digitized radiographs of the left hip in 45 healthy children (n=26 female individuals, n=19 male individuals) between the ages of 6 and 14 were retrospectively reviewed by 2 independent authors. Radiographs were examined to measure the changing height of the bony greater trochanter with increasing age. Magnetic resonance imaging (MRI) scans of 55 (n=29 male individuals, n=26 female individuals) contemporary children between the ages of 6 and 14 were evaluated to measure bony greater trochanteric and the overlying cartilage cap height. RESULTS: Intraclass correlation coefficient values for both radiographic and MRI measurements were excellent. Longitudinal radiographs demonstrated that the bony growth was largely complete by age 11 in male and female individuals. MRI measurements demonstrated that bony trochanteric and overlying cartilage cap height was maximal by age 7 in female individuals and age 8 in male individuals, while no significant difference in bony and cartilage height was appreciated with increasing age in male, female individuals or male+female individuals. CONCLUSIONS: Combined bony and cartilaginous trochanteric growth is largely complete by age 7 in female individuals and age 8 in male individuals, with increases in the height of the trochanter beyond this age likely coming from ossification of the cartilaginous portions. As such, antegrade intramedullary nailing for closed femoral shaft fractures is reasonable in male and female individuals aged 8 years and older. LEVEL OF EVIDENCE: Level II-retrospective study.

Analyzing Pelvic Asymmetry by Sex and Ancestry: Insights From an Osteological Collection.

INTRODUCTION: Pelvic asymmetry has been noted in pelvic imaging, and might influence the development of various spinal pathologies, most notably scoliosis. There is a limited understanding of the relationship between pelvic asymmetry and sex and ancestry, and limited use of 3D modeling. The purpose of this study was to identify pelvic asymmetry and morphology differences between sex and ancestry utilizing 3D modeling on young adults in an osteological collection. METHODS: Thirty-three osteological pelvic specimens aged 18-25 years (average age 21.4 ± 2.0 years) were scanned to create virtual 3D models for analysis. Pelvic asymmetry and morphology were measured and compared across sex (male and female) and ancestry (European American and African American). Multivariate regression analysis was performed to examine the relationship between the variables measured. RESULTS: Multivariate regression analysis demonstrated statistically significant relationships between innominate-pelvic ring ratio and both sex (p < 0.001) and ancestry (p= 0.003) with larger ratios in male and African American specimens respectively. There was also a statistically significant relationship of greater sacral 1 coronal tilt in European American specimens (p= 0.042). There were no statistically significant differences with sex or ancestry in terms of innominate or sacral asymmetry. CONCLUSION: Although there are differences in overall pelvic shape between sex and ancestry, there is no relationship between these two variables versus pelvic asymmetry in the axial or sagittal planes in young adult osteological specimens.

Cutaneous burn injury represents a major risk factor for the development of traumatic ectopic bone formation following blast-related extremity injury.

Blast-related traumatic heterotopic ossification (tHO) impacts clinical outcomes in combat-injured patients, leading to delayed wound healing, inflammatory complications, and reduced quality of life. Blast injured patients often have significant burns. This study investigated whether a partial thickness thermal burn injury exacerbates blast-related tHO in a clinically relevant polytrauma animal model. Adult male Sprague Dawley rats were subjected to an established model involving a whole-body blast overpressure exposure (BOP), complex extremity trauma followed by hind limb amputation (CET) followed by the addition of a 10 % total body surface area (TBSA) second degree thermal burn (BU). Micro-CT scans on post-operative day 56 showed a significant increase in HO volume in the CET + BU as compared to the CET alone injury group (p < .0001; 22.83 ± 3.41 mm3 vs 4.84 ± 5.77 mm3). Additionally, CET + BU concomitant with BOP significantly increased HO (p < .0001; 34.95 ± 7.71 mm3) as compared to CET + BU alone, confirming BOP has a further synergistic effect. No HO was detectable in rats in the absence of CET. Serum analysis revealed similar significant elevated (p < .0001) levels of pro-inflammatory markers (Cxcl1 and Il6) at 6 h post-injury (hpi) in the CET + BU and BOP + CET + BU injury groups as compared to naïve baseline values. Real-time qPCR demonstrated similar levels of chondrogenic and osteogenic gene expression in muscle tissue at the site of injury at 168 hpi in both the CET + BU and BOP+CET + BU injury groups. These results support the hypothesis that a 10 % TBSA thermal burn markedly enhances tHO following acute musculoskeletal extremity injury in the presence and absence of blast overpressure. Furthermore, the influence of BOP on tHO cannot be accounted for either in regards to systemic inflammation induced from remote injury or inflammatory-osteo-chondrogenic expression changes local to the musculoskeletal trauma, suggesting that another mechanism beyond BOP and BU synergistic effects are at play. Therefore, these findings warrant future investigations to explore other mechanisms by which blast and burn influence tHO, and testing prophylactic measures to mitigate the local and systemic inflammatory effects of these injuries on development of HO.

Plasma fibrinogen is an accurate marker of disease activity in patients with polymyalgia rheumatica.

OBJECTIVE: The overall aim of this study was to establish whether plasma fibrinogen was a superior biomarker of disease activity in active PMR than the standard biomarkers, ESR and CRP. METHODS: Sixty patients with PMR were divided into active (n = 25) or inactive (n = 35) disease groups based on symptoms, physician assessment and biomarkers ESR and CRP. Plasma fibrinogen was assayed. Groups underwent assessment at baseline and 6 weeks. Disease activity as per the PMR activity score (PMR-AS) was recorded at all visits. Receiver operator curves (ROCs), predictive values and likelihood ratios were calculated for all biomarkers. RESULTS: Disease activity measures improved significantly in the active group between weeks 1 and 6 (P < 0.001). There was no significant difference between the activity scores at week 6 in the active group and the inactive group. Mean fibrinogen decreased from 5.2 to 3.5 g/l (normal <4 g/l) between weeks 1 and 6 in the active group. Mean ESR and CRP decreased from 59.6 to 24.3 mm/h (normal <30 mm/h) and 45.9 to 12.66 mg/l (normal <5 mg/l), respectively. Receiver operator curve analysis revealed fibrinogen to be more specific than either ESR or CRP for the detection of response to treatment in active PMR, with an overall sensitivity and specificity of 92% and 96%, respectively. Values above the upper limit of normal for fibrinogen, CRP and ESR were associated with likelihood ratios for active disease of 20.53, 2.9 and 2.8, respectively (P < 0.001). CONCLUSION: Plasma fibrinogen is at least as useful as CRP and ESR for the diagnosis of active PMR and more specific for confirmation of response to treatment than either ESR or CRP.

Bilateral Chronic Quadriceps Tendon Ruptures Treated with Hamstring Autograft Reconstruction: A Case Report.

CASE: A 30-year-old semiprofessional football player presented with chronic bilateral quadriceps tendon ruptures. Both quadriceps tendon ruptures were unsuitable for isolated primary repair because of tendon retraction and immobility. A novel reconstruction technique using semitendinosus and gracilis tendon autografts was performed to restore both lower extremities' disrupted extensor mechanisms. At the final follow-up, the patient regained excellent motion of both knees and returned to high-intensity activity. CONCLUSION: Chronic quadriceps tendon ruptures present challenges related to tendon quality and mobilization. Reconstruction with hamstring autograft using a Pulvertaft weave through the retracted quadriceps tendon in a high-demand athletic patient represents a novel approach for treating this injury.

Bone Homeostasis and Physiology in Normal and Orthopaedic Disease Conditions.

Some of the most common human systemic diseases-both benign and malignant-affect bone regulation, formation, and homeostasis (the cellular balance regulated by osteocytes, osteoblasts, and osteoclasts). This review discusses our current understanding of the molecular components and mechanisms that are responsible for homeostasis and interactions resulting in dysregulation (dysfunction due to the loss of the dynamic equilibrium of bone homeostasis). Knowledge of key pathways in bone biology can improve surgeon understanding, clinical recognition, and treatment of bone homeostasis-related diseases.

Investigation of Thermal, Mechanical and Shape Memory Properties of 3D-Printed Functionally Graded Nanocomposite Materials.

In this study, a 3D-printed photocurable resin was developed by incorporating graphene nanoplatelets functionalised with melamine to investigate the thermal, mechanical, fracture and shape memory behaviours. The objective of this work was to produce a printed functionally graded nanocomposite material that has a smart temperature-responsive structure; presents good thermal stability, strength and fracture toughness; and can demonstrate shape-changing motions, such as sequential transformations, over time. The functionalised graphene nanoplatelets were examined via thermogravimetric analysis, Fourier transform infrared spectroscopy, Raman spectroscopy and ultraviolet-visible spectroscopy. Thermogravimetric analysis showed that the degradation temperature of the nanocomposite containing 0.1 wt% of functionalised graphene nanoplatelets at the weight loss of 5% was 304 °C, greater than that of the neat one by 29%. Dynamic mechanical analysis results showed property enhancements of the storage modulus and glass transition temperature. Fracture toughness, tensile strength and impact resistance were improved by 18%, 35% and 78%, respectively. The shape memory tests were performed to obtain the temperature-time recovery behaviour of the 3D-printed structures. The addition of functionalised graphene nanoplatelets demonstrated an enhancement in the shape recovery ratios. Generally, the five subsequent cycles were notably stable with a high recovery ratio of 97-100% for the flat shape and circular shape of the M-GNP specimens. On the other hand, these values were between 91% and 94% for the corresponding neat specimens.

Repair of Impacted Thermoplastic Composite Laminates Using Induction Welding.

The lack of well-developed repair techniques limits the use of thermoplastic composites in commercial aircraft, although trends show increased adoption of composite materials. In this study, high-performance thermoplastic composites, viz., carbon fibre (CF) reinforced Polyetherketoneketone (PEKK) and Polyether ether ketone (PEEK), were subjected to low-velocity impact tests at 20 J. Post-impact, the damaged panels were repaired using an induction welder by applying two different methods: induction welding of a circular patch to the impacted area of the laminate (RT-1); and induction welding of the impacted laminates under the application of heat and pressure (RT-2). The panels were subjected to compression-after-impact and repair (CAI-R), and the results are compared with those from the compression-after-impact (CAI) tests. For CF/PEKK, the RT-1 and RT-2 resulted in a 13% and 7% higher strength, respectively, than the value for CAI. For CF/PEEK, the corresponding values for RT-1 and RT-2 were higher by 13% and 17%, respectively. Further analysis of the damage and repair techniques using ultrasonic C-scans and CAI-R tests indicated that induction welding can be used as a repair technique for industrial applications. The findings of this study are promising for use in aerospace and automotive applications.

Preventing biological waste: Effective use of viable tissue in traumatized lower extremities.

Severe open lower extremity trauma requires debridement to remove contamination and devitalized tissues. Aggressive debridement should be balanced with preservation of viable tissue. These often damaged but preserved viable tissues are "spare parts" that augment the options available for reconstruction. The long-term goal of reconstruction should be functional limb restoration and optimization. Injury patterns, levels, and patient factors will determine whether this endeavor is better accomplished with limb salvage or amputation. This article reviews the rationale and strategies for preserving spare parts throughout debridement and then incorporating them as opportunistic grafts in the ultimate reconstruction to facilitate healing and maximize extremity function. Level of Evidence: 5.

Inhibition of focal adhesion kinase 2 results in a macrophage polarization shift to M2 which attenuates local and systemic inflammation and reduces heterotopic ossification after polysystem extremity trauma.

Introduction: Heterotopic ossification (HO) is a complex pathology often observed in combat injured casualties who have sustained severe, high energy polytraumatic extremity injuries. Once HO has developed, prophylactic therapies are limited outside of surgical excision. Tourniquet-induced ischemia injury (IR) exacerbates trauma-mediated musculoskeletal tissue injury, inflammation, osteogenic progenitor cell development and HO formation. Others have shown that focal adhesion kinase-2 (FAK2) plays a key role in regulating early inflammatory signaling events. Therefore, we hypothesized that targeting FAK2 prophylactically would mitigate extremity trauma induced IR inflammation and HO formation. Methods: We tested whether the continuous infusion of a FAK2 inhibitor (Defactinib, PF-573228; 6.94 µg/kg/min for 14 days) can mitigate ectopic bone formation (HO) using an established blast-related extremity injury model involving femoral fracture, quadriceps crush injury, three hours of tourniquet-induced limb ischemia, and hindlimb amputation through the fracture site. Tissue inflammation, infiltrating cells, osteogenic progenitor cell content were assessed at POD-7. Micro-computed tomography imaging was used to quantify mature HO at POD-56. Results: In comparison to vehicle control-treated rats, FAK2 administration resulted in no marked wound healing complications or weight loss. FAK2 treatment decreased HO by 43%. At POD-7, marked reductions in tissue proinflammatory gene expression and assayable osteogenic progenitor cells were measured, albeit no significant changes in expression patterns of angiogenic, chondrogenic and osteogenic genes. At the same timepoint, injured tissue from FAK-treated rats had fewer infiltrating cells. Additionally, gene expression analyses of tissue infiltrating cells resulted in a more measurable shift from an M1 inflammatory to an M2 anti-inflammatory macrophage phenotype in the FAK2 inhibitor-treated group. Discussion: Our findings suggest that FAK2 inhibition may be a novel strategy to dampen trauma-induced inflammation and attenuate HO in patients at high risk as a consequence of severe musculoskeletal polytrauma.

Optimal Fluoroscopic Angulation to Determine Intercondylar Notch Violation during Pediatric Medial Patellofemoral Ligament Reconstruction.

Previous anatomic data has suggested that during pediatric medial patellofemoral ligament (MPFL) reconstruction, the femoral tunnel must be angled distally and anteriorly to avoid damage to the distal femoral physis and then intercondylar notch. The purpose of this study was to determine the optimal degree of fluoroscopic angulation necessary to radiographically determine the presence of intercondylar notch violation. Fourteen adult cadaveric human femora were disarticulated and under fluoroscopic guidance, Schöttle's point was identified. A 0.62-mm Kirschner wire was then drilled through the condyle to create minimal notch violation. The femur was then placed on a level radiolucent table and coronal plane radiographs angled from -15 to 60 degrees were obtained in 5-degree increments to determine the fluoroscopic angle at which intercondylar notch violation was most evident. Grading of optimal fluoroscopic angle between two authors found that violation of the notch was the best appreciated at a mean angle of 43 ± 15 degrees from neutral. Results from this study emphasize the importance of angling the beam to essentially obtain a notch view to assess for a breech.

Multi-objective optimisation of ultrasonically welded dissimilar joints through machine learning.

The use of composite materials is increasing in industry sectors such as renewable energy generation and storage, transport (including automotive, aerospace and agri-machinery) and construction. This is a result of the various advantages of composite materials over their monolithic counterparts, such as high strength-to-weight ratio, corrosion resistance, and superior fatigue performance. However, there is a lack of detailed knowledge in relation to fusion joining techniques for composite materials. In this work, ultrasonic welding is carried out on a carbon fibre/PEKK composite material bonded to carbon fibre/epoxy composite to investigate the influence of weld process parameters on the joint's lap shear strength (LSS), the process repeatability, and the process induced defects. A 33 parametric study is carried out and a robust machine learning model is developed using a hybrid genetic algorithm-artificial neural network (GA-ANN) trained on the experimental data. Bayesian optimisation is employed to determine the most suitable GA-ANN hyperparameters and the resulting GA-ANN surrogate model is exploited to optimise the welding process, where the process performance metrics are LSS, repeatability and joint visual quality. The prediction for the optimal LSS was subsequently validated through a further set of experiments, which resulted in a prediction error of just 3%.

Phenotypic and genetic analyses of two Campylobacter fetus isolates from a patient with relapsed prosthetic valve endocarditis.

Campylobacter fetus can cause intestinal and systemic disease in humans and are well-established veterinary and economic pathogens. We report the complete genomic sequences of two C. fetus subsp. fetus (Cff) isolates recovered in 2017 (CITCf01) and 2018 (CITCf02) from a case of recurrent prosthetic valve endocarditis. Both were capable of growth aerobically. Their genomes were found to be highly conserved and syntenic with 99.97% average nucleotide identity (ANI) while differences in their respective sap loci defined the temporal separation of their genomes. Based on core genome phylogeny and ANI of 83 Cff genomes belonging to the previously described human-associated Cff lineage, CITCf01 and CITCf02 grouped in a clade of 11 sequence type (ST)3 Cff (including the Cff type strain NCTC 10842T). CITCf01 and CITCf02 were marked for their lack of unique genomic features when compared to isolates within the subspecies and the type strain in particular. We identified point mutations in oxidative stress response genes, among others, that may contribute to aerobiosis. We report a case of Cff causing relapsed prosthetic valve endocarditis and we highlight the sap island as a polymorphic site within the genetically stable ST3 lineage, central to pathogenicity.

Three-Dimensional Printing of Medical Devices Used Directly to Treat Patients: A Systematic Review.

Until recently, three-dimensional (3D) printing/additive manufacturing has not been used extensively to create medical devices intended for actual clinical use, primarily on patient safety and regulatory grounds. However, in recent years there have been advances in materials, printers, and experience, leading to increased clinical use. The aim of this study was to perform a structured systematic review of 3D-printed medical devices used directly in patient treatment. A search of 13 databases was performed to identify studies of 3D-printed medical devices, detailing fabrication technology and materials employed, clinical application, and clinical outcome. One hundred and ten papers describing one hundred and forty medical devices were identified and analyzed. A considerable increase was identified in the use of 3D printing to produce medical devices directly for clinical use in the past 3 years. This is dominated by printing of patient-specific implants and surgical guides for use in orthopedics and orthopedic oncology, but there is a trend of increased use across other clinical specialties. The prevailing material/3D-printing technology used were titanium alloy/electron beam melting for implants, and polyamide/selective laser sintering or polylactic acid/fused deposition modeling for surgical guides and instruments. A detailed analysis across medical applications by technology and materials is provided, as well as a commentary regarding regulatory aspects. In general, there is growing familiarity with, and acceptance of, 3D printing in clinical use.