bluuebunny/crossref_metadata_2025 huggingface dataset:
Oficinas de Habilidades Sociais com alunos de grêmios do Ensino Médio para promoção de saúde mental e prevenção ao suicídio
Authors: Leme Vanessa Barbosa Romera , Alves Ana Júlia de Carvalho Pereira , Carvalho Damares Moreira de , Rosa Victor de Lima , Teixeira Bruna Silva de Araujo , Gomes Taynara Maria da Silva , França Fernanda de Azevedo , Silveira Priscila Sá da , Serqueira Adriana Pinheiro , Fernandes Luana de Mendonça , Leopoldino Letícia Costa , Calabar Fernanda Pereira , Penna-de-Carvalho Aline
Published: November 2024

Pesquisas indicam que as habilidades sociais podem ajudar a melhorar a relação entre pares e com seus professores, proporcionando um ambiente mais positivo e acolhedor, configurando-se como um fator de proteção ao suicídio e outros transtornos mentais nesse momento da trajetória escolar. Contudo, há poucos estudos sobre intervenções com foco nas habilidades sociais visando a prevenção do suicídio, o que sinaliza uma área aberta para investigação. A partir de uma abordagem qualitativa e exploratória, este estudo teve como objetivo descrever oficinas de habilidades sociais, realizadas no âmbito de um projeto de extensão com estudantes do Ensino Médio (EM), na campanha do setembro amarelo. Participaram 96 alunos do primeiro ao terceiro ano do EM, com idade entre 15 e 26 anos, sendo 64 do sexo feminino (66,66%), que frequentavam grêmios estudantis em duas escolas públicas estaduais na cidade do Rio de Janeiro. Os resultados evidenciaram a valorização do debate promovido pelas oficinas em torno de temas classificados como tabus, como sofrimento mental e suicídio. Quanto aos sentimentos evocados pelas atividades, destacam-se os de conforto, acolhimento e felicidade. Foi observado, também, que reflexões acerca da empatia nas relações interpessoais, do estímulo à solidariedade e à construção de plano de vida foram favorecidos com as oficinas. Conclui-se sobre a importância da promoção de habilidades sociais com alunos de grêmios do EM, de modo a torná-los multiplicadores no contexto escolar, utilizando uma comunicação mais efetiva, a resolução de conflitos de maneira construtiva e o estabelecimento de relacionamentos saudáveis e duradouros
Cord prolapse
Authors: Yarrington Aimee
Published: November 2024

This fourth and final maternity CPD article focuses on that of the extremely rare, but often fatal for the foetus, complication of cord prolapse. The current JRCALC guidance has just been reviewed and there are, as you will see from this article, a couple of major alterations to this guidance. Rapid recognition and removal to definitive care is the only potential life-saving intervention that is required – and the quicker that the woman reaches definitive care, the better chance her baby has of survival.
The number of spanning trees of the bipartite complement of a semiregular bipartite graph
Authors: Gong Helin , Yao Jutian , Zhang Hailiang
Published: November 2024

For a bipartite graph $G$ on parts of cardinality $m$ and $n$, the bipartite complement of $G$ is defined as the graph obtained from the complete bipartite graph $K_{m,n}$ by removing the edges of an isomorph of $G$. In this paper, based on the matrix-tree theorem and the Schur complement technique, we give a determinant expression for the number of spanning trees of the bipartite complement of a semiregular bipartite graph. As by-products, we show that the corresponding result can generalize some previous results on the problem of enumerating spanning trees and obtain an explicit formula for the number of spanning trees of the bipartite complement of the subdivison of a regular circulant graph.
EVALUATING THE BIOMECHANICAL EFFICACY OF 2.5-MM AND 2.0-MM DOUBLE PLATING AGAINST 3.5-MM SINGLE PLATING IN ULNAR SHAFT FRACTURE FIXATION: A CADAVERIC STUDY
Authors: Zderic I. , Kraus M. , Rossenberg L. v. , Puls L. , Pastor T. , Gueorguiev B. , Richards G. , Pape H. C. , Pastor T.
Published: November 2024

Introduction

The main postoperative complications in fixation of ulna shaft fractures are non-union and implant irritation using currently recommended 3.5-mm locking compression plates. An alternative approach using a combination of two smaller plates in orthogonal configuration has been proposed. The aim of this study was to compare the biomechanical properties of a single 3.5-mm locking compression plate versus double plating using one 2.5-mm and one 2.0-mm mandible plate in a human ulna shaft fracture model.

Method

Eight pairs human ulnar specimens with a standardized 10-mm fracture gap were pairwise assigned for instrumentation with either a single 3.5-mm plate placed posteriorly, or for double plating using a 2.5-mm and a 2.0-mm mandible plate placed posteriorly under the flexor muscles and laterally under the extensor muscles. All constructs were initially non-destructively biomechanically tested in axial compression, torsion, and bending, which was followed by cyclic torsional loading to failure. Interfragmentary movements were monitored by means of optical motion tracking.

Result

There were no significant differences between the two plating techniques for axial stiffness (p=0.335), torsional stiffness in supination (p=0.462), torsional stiffness in pronation (p=0.307), medio-lateral bending stiffness (p=0.522), and antero-posterior bending stiffness (p=0.143). During cyclic torsional loading over the first 3000 cycles, there were no significant differences between the two plating techniques for shear displacement across the fracture gap, p=0.324. The numbers of cycles until clinically relevant failure of 5° angular deformation were 1366±685 for double plating and 2024±958 for single plating, which was statistically non-significantly different, p>0.05. The constructs treated with both plating techniques failed due to bone breakage at the most distal screw.

Conclusion

From a biomechanical perspective double plating of ulna shaft fractures using a 2.5-mm and a 2.0-mm locking mandible plate demonstrated equivalent fixation strength as conventional plating using a single 3.5-mm locking compression plate.
BONE-IMPLANT PRIMARY STABILITY PREDICTION BY CBCT-BASED FINITE ELEMENT SIMULATIONS
Authors: Vautrin A. , Thierrin R. , Wili P. , Voumard B. , Rauber C. , Klingler S. , Chapuis V. , Varga P. , Zysset P.
Published: November 2024

Introduction

Achieving an appropriate primary stability after implantation is a prerequisite for the long-term viability of a dental implant. Virtual testing of the bone-implant construct can be performed with finite element (FE) simulation to predict primary stability prior to implantation. In order to be translated to clinical practice, such FE modeling must be based on clinically available imaging methods. The aim of this study was to validate an FE model of dental implant primary stability using cone beam computed tomography (CBCT) with ex vivo mechanical testing.

Method

Three cadaveric mandibles (male donors, 87-97 years old) were scanned by CBCT. Twenty-three bone samples were extracted from the bones and conventional dental implants (Ø4.0mm, 9.5mm length) were inserted in each. The implanted specimens were tested under quasi-static bending-compression load (cf. ISO 14801).

Sample-specific homogenized FE (hFE) models were created from the CBCT images and meshed with hexahedral elements. A non-linear constitutive model with element-wise density-based material properties was used to simulate bone and the implant was considered rigid. The experimental loading conditions were replicated in the FE model and the ultimate force was evaluated.

Result

The experimental ultimate force ranged between 67 N and 789 N. The simulated ultimate force correlated better with the experimental ultimate force (R2=0.71) than the peri-implant bone density (R2=0.30).

Conclusion

The developed hFE model was demonstrated to provide stronger prediction of primary stability than peri-implant bone density. Therefore, hFE Simulations based on this clinically available low-radiation imaging modality, is a promising technology that could be used in future as a surgery planning tool to assist the clinician in evaluating the load-bearing capacity of an implantation site.

Acknowledgements

Funding: EU's Horizon 2020 grant No: 953128 (I-SMarD).

Dental implants: THOMMEN Medical AG
INCIDENCE AND TREATMENT TRENDS OF TROCHANTERIC FRACTURES IN GERMANY: A COHORT STUDY COVERING 1.16 MILLION FRACTURES IN 15 YEARS
Authors: Rau Y. , Amtsfeld J. , Reimers N. , Behrends L. , Hinz N. , Schulz A. P.
Published: November 2024

Introduction

Hip fractures, with a global age-standardised incidence rate (per 100,000 population) of 187.2 (2019), are a major public health problem. With a 7.71 billion population worldwide in 2019, hip fractures, in general, are affecting around 14.43 million people per year globally.

We aim to provide a nationwide epidemiological analysis of trochanteric fractures and their respective surgical treatments. In this study we research the epidemiology of trochanteric and subtrochanteric fractures, as well as their most common kinds of osteosynthesis, on a nationwide scale in Germany.

Method

Data was retrieved from the national database of the German Ministry of Interior. ICD-10-GM and OPS-data from the period of 2006-2020 were analyzed, all patients with trochanteric/subtrochanteric fractures were included. Patients were grouped by age/gender and linear-regression was performed to calculate statistically significant correlations between variables/incidences.

Result

985,104 trochanteric and 178,810 subtrochanteric-fractures were reported during the analyzed period. This calculates to a mean incidence of 80.08±6.34 for pertrochanteric and 14.53±1.50 for subtrochanteric fractures per-million-inhabitants. In both fracture-types, a distinct dependence of incidence on age can be seen. Incidence rates equally rise in both sexes through the age groups with an increase of about 288-fold from those under 60 to those over the age of 90 in pertrochanteric fractures. Intramedullary nailing was the most common kind of treatment for both fracture types with augmentative cerclages on the rise throughout the whole period. Dynamic compression screws were decreasing in frequency.

Conclusion

We found an ongoing increase of incidence among the elderly and an increase in intramedullary nailing as well as augmentative cerclages. Not only could we show an age-dependence of the incidences, but also a sex-dependence that seems to remain consistent in its development. While younger males (<60 years) are at a higher risk than their female peers, older females are at significantly higher risk than their male peers.
DEVELOPING A SMALL ANIMAL TRAUMA MODEL FOR FEMORAL HEAD OSTEONECROSIS
Authors: Bal Z. , Takakura N.
Published: November 2024

Introduction

Femoral head osteonecrosis (FHO) is a condition in which the inadequate blood supply disrupts osteogenic-angiogenic coupling that results in diminishment of femoral perfusion and ends up with FHO. The insufficient knowledge on molecular background and progression pattern of FHO and the restrictions in obtaining human samples bring out the need for a small animal trauma model to research FHO aetiology. Hence, this study aims to develop a mouse trauma model to elucidate the molecular mechanisms behind FHO.

Method

Left femoral head was dislocated from the hip joint, ligamentum teres was cut, and a slight circular incision was done around the femoral neck of 8-week-old male C57BL/6J mice to disrupt the blood supply to femoral head. Right hip joint was left unoperated as control. Animals (n=5 per time point) were sacrificed on 2-3-4-6-8-10-12 weeks, and ex-vivo µCT was taken to assess bone structural parameters. Haematoxylin/eosin (HE)- and immunohistochemical-staining (IHCS) for CD31 and EMCN were done to observe histology and marrow-specific H-type vascular structures, respectively.

Result

μCT assessment showed trabecular bone loss and decreased BV/TV from 2 to 8 weeks in FHO side. HE staining displayed the increased number of empty lacunae was observed in FHO side as early as 24h after operation. By 4th week, IHCS results displayed the invasion of the epiphyseal plate by H-type blood vessels in FHO side, while the epiphyseal plate was observed intact in control side. Also, by 6th week the HE-staining showed the presence of bone marrow necrosis and bone fat accumulation in FHO side.

Conclusion

Trabecular bone loss, increased number of empty lacunae, bone fat imbalance and bone marrow necrosis are reported as the signs of osteonecrosis. Thus, our results are coherent with the literature and indicated that we were able to effectively generate a trauma model for FHO in mice for the first time in literature.
ASSESSING ROTATOR CUFF COMPENSATIONS: EFFECTS OF SUPERIOR CAPSULAR RECONSTRUCTION (SCR) AND LOWER TRAPEZIUS TRANSFER (LTT) ON TERES MINOR AND SUBSCAPULARIS FORCES IN CADAVERIC SHOULDER MODELS
Authors: Mungalpara N. , Kim S. , Baker H. , Lee C. , Shakya Aa , Chen K. , Athiviraham A. , Koh J. , Elhassan B. , Maassen N. H. , Amirouche F.
Published: November 2024

Introduction

Supraspinatus and infraspinatus tears (Massive Rotator Cuff Tear- MRCT) cause compensatory activation of the teres minor (TM) and subscapularis (SubS) to maintain humeral head alignment. This study measures force changes in TM and SubS using a dynamic shoulder testing setup. We hypothesize that combining superior capsule reconstruction (SCR) and lower trapezius tendon (LTT) transfer will correct rotator cuff forces.

Methods

Eight fresh-frozen human shoulder specimens from donors aged 55-75 (mean = 63.75 years), balanced for gender, averaging 219.5 lbs, were used. Rotator cuff and deltoid tendons were connected to force sensors through a pulley system, with the deltoid linked to a servohydraulic motor for dynamic force measurement. The system allowed unrestricted humeral abduction from 0 to 90 degrees.

Results

Teres Minor (TM):

Control: 7.43 N (SD = 1.66)

SS tear: 5.46 N (SD = 1.45)

MRCT: 3.94 N (SD = 1.43)

LTT post-MRCT: 5.85 N (SD = 1.13)

SCR post-MRCT: 4.68 N (SD = 0.71)

Combined LTT+SCR: 6.43 N (SD = 1.24)

TM force reduction: 26.51% post-SS tear, 46.97% from intact to MRCT, 63.20% increase with LTT+SCR.

Subscapularis (SubS):

Control: -0.73 N (SD = 0.43)

SS tear: -0.46 N (SD = 0.36), 36.99% increase

MRCT: 0.96 N (SD = 0.47), 31.51% increase

LTT post-MRCT: -0.32 N (SD = 0.47), 66.67% reduction

SCR post-MRCT: -0.28 N (SD = 0.16), 70.83% reduction

Combined LTT+SCR: -0.66 N (SD = 0.32), 31.25% reduction

Non-parametric Friedman's ANOVA showed overall statistical significance for TM (P = 1.083×10-6) and SubS (P = 4.77×10-4).

Conclusion

The cadaveric model assesses rotator cuff compensations, showing significant TM force reductions following rotator cuff tears and improvements with LTT and SCR, particularly when combined. SubS exhibited negative force during normal abduction but compensated during MRCT, returning to normal values post-LTT and SCR.
THE UTILITY OF EXTENDED BACTERIAL CULTURES AND NEXT-GENERATION SEQUENCING IN IDENTIFYING PATHOGENS IN ‘CULTURE NEGATIVE’ FRACTURE-RELATED INFECTIONS
Authors: Menon J. , Murugan T. , Biswas R. , K Prashanth
Published: November 2024

Introduction

Identification of the causative pathogen in musculoskeletal infection is critical as it directs further treatment. Fracture-related infection is often associated with ‘no growth’ in standard culture. We investigated the efficiency of two alternate methods to identify the causative pathogen, namely extended bacterial culture and 16Sr RNA gene sequence analysis with next generation sequencing (NGS) in ‘culture negative’ fracture related infections.

Method

Patients were diagnosed as having fracture related infection based on the MSIS criteria (n=120). All patients had samples taken for culture and sensitivity. All samples which were culture negative by standard culture methods formed the study group. These samples were subjected to further extended culture in both aerobic and anaerobic medium for 14 days to improve recovery of pathogens. Further, DNA isolated from implants from a sub-group of these culture negative patients were subjected to 16SrRNA gene amplification followed by Sanger sequencing. Subsequent sequencing analysis was performed using the Illumina NGS platform which identified and detected the most abundant genera/species present in those samples more precisely.

Result

57 culture negative samples formed the study group. Eight samples (14%) converted to positivity after 14 days of culture. Bacteroides fragilis was the commonest yield. 14 samples underwent 16SrRNA gene amplification followed by Sanger sequencing. Acinetobacter baumannii, Enterococcus faecalis, Pseudomonas aeruginosa were identified as common pathogens. Next generation sequencing (n=12) not only identified common pathogens like as Staphylococcus, Acinetobacter baumannii, but also many uncultivable species.

Conclusion

Positive results from extended bacterial culture are about 15%. The delay in definite identification of pathogens in extended culture may be critical in certain clinical situations. Molecular methods are quicker and have additional yield in culture negative infections. The exact role of all microorganisms identified by molecular methods in the pathogenesis of infection is unknown.
BIOMECHANICAL ASSESSMENT OF NOVEL DYNAMIC VERSUS CONVENTIONAL HIGH-STRENGTH SUTURES IN DISTAL BICEPS TENDON REPAIR
Authors: Zderic I. , Kraus M. , Rossenberg L. V. , Gueorguiev B. , Richards G. , Pape H. C. , Pastor T. , Pastor T.
Published: November 2024

Introduction

Tendon ruptures are a common injury and often require surgical intervention to heal. A refixation is commonly performed with high-strength suture material. However, slipping of the thread is unavoidable even at 7 knots potentially leading to reduced compression of the sutured tendon at its footprint. This study aimed to evaluate the biomechanical properties and effectiveness of a novel dynamic high-strength suture, featuring self-tightening properties.

Method

Distal biceps tendon rupture tenotomies and subsequent repairs were performed in sixteen paired human forearms using either conventional or the novel dynamic high-strength sutures in a paired design. Each tendon repair utilized an intramedullary biceps button for radial fixation. Biomechanical testing aimed to simulate an aggressive postoperative rehabilitation protocol stressing the repaired constructs. For that purpose, each specimen underwent in nine sequential days a daily mobilization over 300 cycles under 0-50 N loading, followed by a final destructive test.

Result

After the ninth day of cyclic loading, specimens treated with the dynamic suture exhibited significantly less tendon elongation at both proximal and distal measurement sites (-0.569±2.734 mm and 0.681±1.871 mm) compared to the conventional suture group (4.506±2.169 mm and 3.575±1.716 mm), p=0.003/p<0.002. Gap formation at the bone-tendon interface was significantly lower following suturing using dynamic suture (2.0±1.6 mm) compared to conventional suture (4.5±2.2 mm), p=0.04. The maximum load at failure was similar in both treatment groups (dynamic suture: 374± 159 N; conventional suture: 379± 154 N), p=0.925. The predominant failure mechanism was breakout of the button from the bone (dynamic suture: 5/8; conventional suture: 6/8), followed by suture rupturing, suture unraveling and tendon cut-through.

Conclusion

From a biomechanical perspective, the novel dynamic high-strength suture demonstrated higher resistance against gap formation at the bone tendon interface compared to the conventional suture, which may contribute to better postoperative tendon integrity and potentially quicker functional recovery in the clinical setting.
REDUCED HEART RATE VARIABILITY AND INCREASED STRESS HORMONE LEVELS INDICATE AN AUTONOMIC DYSFUNCTION IN OSTEOARTHRITIS PATIENTS
Authors: Sohn R. , Assar T. , Kaufhold I. , Brenneis M. , Braun S. , Junker M. , Zaucke F. , Pongratz G. , Jenei-Lanzl Z.
Published: November 2024

Introduction

Recent studies suggested that the progression of osteoarthritis (OA), a chronic degenerative joint disease, may be affected by the autonomic nervous system (ANS). Under healthy conditions, the sympathetic (SNS) and parasympathetic (PNS) branches of the ANS are well coordinated to maintain homeostasis. However, pathological conditions are frequently associated with a disturbance of this fine-tuned balance. Therefore, we analyzed whether an autonomic dysfunction occurs in OA patients.

Method

225 participants with early- or late-stage knee OA as well as 40 healthy age-matched probands were included in this study. Autonomic activity was investigated by analyzing heart rate variability (HRV), which decreases under chronic sympathetic overactivity. Time- and frequency-domain HRV indices SDRR, RMSSD, pRR50 and LF were examined. Linear regression analysis was performed to adjust for clinical characteristics, such as age, sex, BMI, or medication. Moreover, perceived chronic stress (PSQ) and pain (WOMAC) were assessed via questionnaires. In addition, the serum stress hormones cortisol, DHEA-S and IL-6 were analyzed via ELISA.

Result

SDRR, RMSSD, and pRR50 were slightly reduced in the early stage of OA and showed significant decrease in the later stage of the disease. Also LF decreased significantly with OA progression. HRV was significantly influenced by the grade of OA, but not other patient characteristics. Moreover, late-stage OA patients demonstrated significantly higher PSQ and WOMAC levels compared to healthy controls. In addition, cortisol/DHEA-S ratio and IL-6 serum concentrations were significantly higher in late-stage than in early-stage OA patients and healthy controls.

Conclusion

Reduced HRV, increased cortisol/DHEA-S ratio and PSQ level as well as elevated systemic IL-6 concentration indicated an autonomic shift towards a more pronounced SNS activity due to PNS deficiency in OA patients, particularly in the late-stage of the disease. Therefore, modulation of the ANS, for example by vagus nerve stimulation, might be a potential treatment strategy for of knee OA patients.
DEVIATION FROM PREOPERATIVE PLANNING AND ACCURACY OF TRANSPEDICULAR SCREW FIXATION USING INTRAOPERATIVE 3D NAVIGATION FOR LUMBAR SPONDYLOLISTHESIS
Authors: Vadalà G. , Papalia G. F. , Russo F. , Nardi N. , Ambrosio L. , Papalia R. , Denaro V.
Published: November 2024

Introduction

Intraoperative navigation systems for lumbar spine surgery allow to perform preoperative planning and visualize the real-time trajectory of pedicle screws. The aim of this study was to evaluate the deviation from preoperative planning and the correlations between screw deviation and accuracy.

Method

Patients affected by degenerative spondylolisthesis who underwent posterior lumbar interbody fusion using intraoperative 3D navigation since April 2022 were included. Intraoperative cone-beam computed tomography (CBCT) was performed before screw planning and following implantation. The deviation from planning was calculated as linear, angular, and 3D discrepancies between planned and implanted screws. Accuracy and facet joint violation (FJV) were evaluated using Gertzbein-Robbins system (GRS) and Yson classification, respectively. Statistical analysis was performed using SPSS version28. One-way ANOVA followed by Bonferroni post-hoc tests were performed to evaluate the association between GRS, screw deviation and vertebral level. Statistical significance was set at p<0.05.

Result

This study involved 34 patients, for a total of 154 pedicle screws. Mean age was 62.6±8.9 years. The mean two-dimensional screw tip deviation in mediolateral (ML), craniocaudal (CC), and anteroposterior (AP) was 2.6±2.45mm, 1.6±1.7mm, and 3.07±2.9mm, respectively. The mean screw tip 3D deviation was 5±3.3mm. The mean two-dimensional screw head deviation in ML, CC and AP was 1.83±1.8mm, 1.7±1.67mm and 3.6±3.1mm, respectively. The mean screw head 3D deviation was 4.94±3.2mm. 98% of screws were clinically acceptable (grade A+B), and grade 0 for FJV. Significant results were found between GRS and ML (p=0.005), AP (p=0.01) and 3D (p=0.003) tip deviations, and between GRS and AP and 3D head deviations (both p=0). Moreover, a significant correlation was found between GRS and vertebral level (p=0).

Conclusion

Our results showed a reasonable rate of discrepancy between planned and positioned screws. However, accuracy was clinically acceptable in almost all cases. Therefore, pedicle screw fixation using intraoperative CBCT, 3D navigation and screw planning is safe and accurate.
IMPLANT DETECTION AND CLASSIFICATION FROM A SMALL DATASET OF LOWER LIMB RADIOGRAPHS: PERFORMANCE OF DEEP LEARNING MODELS PRE-TRAINED ON LARGER DATASETS
Authors: Birkholtz F. , Eken M. , Swanevelder M. , Engelbrecht A.
Published: November 2024

Introduction

Inaccurate identification of implants on X-rays may lead to prolonged surgical duration as well as increased complexity and costs during implant removal. Deep learning models may help to address this problem, although they typically require large datasets to effectively train models in detecting and classifying objects, e.g. implants. This can limit applicability for instances when only smaller datasets are available. Transfer learning can be used to overcome this limitation by leveraging large, publicly available datasets to pre-train detection and classification models. The aim of this study was to assess the effectiveness of deep learning models in implant localisation and classification on a lower limb X-ray dataset.

Method

Firstly, detection models were evaluated on their ability to localise four categories of implants, e.g. plates, screws, pins, and intramedullary nails. Detection models (Faster R-CNN, YOLOv5, EfficientDet) were pre-trained on the large, freely available COCO dataset (330000 images). Secondly, classification models (DenseNet121, Inception V3, ResNet18, ResNet101) were evaluated on their ability to classify five types of intramedullary nails. Localisation and classification accuracy were evaluated on a smaller image dataset (204 images).

Result

The YOLOv5s model showed the best capacity to detect and distinguish between different types of implants (accuracy: plate=82.1%, screw=72.3%, intramedullary nail=86.9%, pin=79.9%). Screw implants were the most difficult implant to detect, likely due to overlapping screw implants visible in the image dataset. The DenseNet121 classification model showed the best performance in classifying different types of intramedullary nails (accuracy=73.7%). Therefore, a deep learning model pipeline with the YOLOv5s and DenseNet121 was proposed for the most optimal performance of automating implants localisation and classification for a relatively small dataset.

Conclusion

These findings support the potential of deep learning techniques in enhancing implant detection accuracy. With further development, AI-based implant identification may benefit patients, surgeons and hospitals through improved surgical planning and efficient use of theatre time.
WEARABLE INERTIAL SENSORS AND DEEP LEARNING TO DETECT CLINICALLY MEANINGFUL REAL-WORLD WALKING SURFACE CHARACTERISTICS
Authors: Vinco G. , Ley C. , Dixon P. , Grimm B.
Published: November 2024

Introduction

The ability to walk over various surfaces such as cobblestones, slopes or stairs is a very patient centric and clinically meaningful mobility outcome. Current wearable sensors only measure step counts or walking speed regardless of such context relevant for assessing gait function. This study aims to improve deep learning (DL) models to classify surfaces of walking by altering and comparing model features and sensor configurations.

Method

Using a public dataset, signals from 6 IMUs (Movella DOT) worn on various body locations (trunk, wrist, right/left thigh, right/left shank) of 30 subjects walking on 9 surfaces were analyzed (flat ground, ramps (up/down), stairs (up/down), cobblestones (irregular), grass (soft), banked (left/right)). Two variations of a CNN Bi-directional LSTM model, with different Batch Normalization layer placement (beginning vs end) as well as data reduction to individual sensors (versus combined) were explored and model performance compared in-between and with previous models using F1 scores.

Result

The Bi-LSTM architecture improved performance over previous models, especially for subject-wise data splitting and when combining the 6 sensor locations (e.g. F1=0.94 versus 0.77). Placement of the Batch Normalization layer at the beginning, prior to the convolutional layer, enhanced model understanding of participant gait variations across surfaces. Single sensor performance was best on the right shank (F1=0.88).

Conclusion

Walking surface detection using wearable IMUs and DL models shows promise for clinically relevant real-world applications, achieving high F1 levels (>0.9) even for subject-wise data splitting enhancing the model applicability in real-world scenarios. Normalization techniques, such as Batch Normalization, seem crucial for optimizing model performance across diverse participant data. Also single-sensor set-ups can give acceptable performance, in particular for specific surface types of potentially high clinical relevance (e.g. stairs, ramps), offering practical and cost-effective solutions with high usability. Future research will focus on collecting ground-truth labeled data to investigate system performance in real-world settings.
FRACTURE DETECTION IN WRIST TRAUMA RADIOGRAPH: OPTIMIZING ALGORITHM PERFORMANCE USING TRANSFER LEARNING
Authors: Birkholtz F. , Eken M. , Boyes A. , Engelbrecht A.
Published: November 2024

Introduction

With advances in artificial intelligence, the use of computer-aided detection and diagnosis in clinical imaging is gaining traction. Typically, very large datasets are required to train machine-learning models, potentially limiting use of this technology when only small datasets are available. This study investigated whether pretraining of fracture detection models on large, existing datasets could improve the performance of the model when locating and classifying wrist fractures in a small X-ray image dataset. This concept is termed “transfer learning”.

Method

Firstly, three detection models, namely, the faster region-based convolutional neural network (faster R-CNN), you only look once version eight (YOLOv8), and RetinaNet, were pretrained using the large, freely available dataset, common objects in context (COCO) (330000 images). Secondly, these models were pretrained using an open-source wrist X-ray dataset called “Graz Paediatric Wrist Digital X-rays” (GRAZPEDWRI-DX) on a (1) fracture detection dataset (20327 images) and (2) fracture location and classification dataset (14390 images). An orthopaedic surgeon classified the small available dataset of 776 distal radius X-rays (Arbeidsgmeischaft für Osteosynthesefragen Foundation / Orthopaedic Trauma Association; AO/OTA), on which the models were tested.

Result

Detection models without pre-training on the large datasets were the least precise when tested on the small distal radius dataset. The model with the best accuracy to detect and classify wrist fractures was the YOLOv8 model pretrained on the GRAZPEDWRI-DX fracture detection dataset (mean average precision at intersection over union of 50=59.7%). This model showed up to 33.6% improved detection precision compared to the same models with no pre-training.

Conclusion

Optimisation of machine-learning models can be challenging when only relatively small datasets are available. The findings of this study support the potential of transfer learning from large datasets to improve model performance in smaller datasets. This is encouraging for wider application of machine-learning technology in medical imaging evaluation, including less common orthopaedic pathologies.
ANALYSIS OF REOPERATIONS FOLLOWING POSTERIOR PEDICLE FIXATION IN SPINAL SURGERY
Authors: Bulut H. , Maestre M. , Tomey D.
Published: November 2024

Introduction

Unplanned reoperations (UROs) following corrective surgery for adult spinal deformity (ASD) present significant challenges for both patients and surgeons. Understanding the specific UROs types is crucial for improving patient outcomes and refining surgical strategies in ASD correction.

Method

This retrospective analysis utilized data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database spanning from 2017 to 2021. Patient information was extracted using specific CPT codes related to posterior pedicle fixation.

Result

In a cohort of 1088 patients undergoing posterior spinal deformity corrections, we examined various preoperative factors to discern their correlation with reoperation prevalence. Our analysis revealed no statistically significant differences in reoperation prevalence concerning gender (male: 4.0%, p=0.131) or ethnicity (Hispanic: 4.2%, p=0.192). Similarly, no notable associations were identified for diabetes mellitus, smoking status, dyspnea, history of severe COPD, hypertension, ASA classification, or functional health status before surgery, with reoperation prevalences ranging from 3.2% to 8.8% and p-values spanning from 0.146 to 0.744. Overall, the reoperation prevalence within the entire cohort stood at 5.2% (55 cases). In terms of the types of reoperations investigated, spinal-related procedures emerged as the most prevalent, accounting for 43.7% (24 cases), followed closely by wound site revisions at 23.6% (13 cases). Additionally, gastrointestinal-related procedures and various other miscellaneous interventions, such as uroscopy, demonstrated reoperation prevalences of 7.2% (4 cases) and 25.5% (14 cases), respectively.

Conclusion

our findings highlight the diverse spectrum of reoperation procedures encountered following posterior spinal deformity corrections, with wound site revisions and spinal-related interventions being the most prevalent categories. These results emphasize the complexity of managing UROs in spinal surgery and the need for tailored approaches and infection/incision protocols to address the specific challenges associated with each type of reoperation.
AUTOMATIC MULTI-CLASS SEGMENTATION OF HIP JOINT SPACE USING 3D DEEP LEARNING ALGORITHMS
Authors: Sawant S. , Borotikar B. , Raghu V. , Audenaert E. , Khanduja V.
Published: November 2024

Introduction

Three-dimensional (3D) morphological understanding of the hip joint, specifically the joint space and surrounding anatomy, including the proximal femur and the pelvis bone, is crucial for a range of orthopedic diagnoses and surgical planning. While deep learning algorithms can provide higher accuracy for segmenting bony structures, delineating hip joint space formed by cartilage layers is often left for subjective manual evaluation. This study compared the performance of two state-of-the-art 3D deep learning architectures (3D UNET and 3D UNETR) for automated segmentation of proximal femur bone, pelvis bone, and hip joint space with single and multi-class label segmentation strategies.

Method

A dataset of 56 3D CT images covering the hip joint was used for the study. Two bones and hip joint space were manually segmented for training and evaluation. Deep learning models were trained and evaluated for a single-class approach for each label (proximal femur, pelvis, and the joint space) separately, and for a multi-class approach to segment all three labels simultaneously. A consistent training configuration of hyperparameters was used across all models by implementing the AdamW optimizer and Dice Loss as the primary loss function. Dice score, Root Mean Squared Error, and Mean Absolute Error were utilized as evaluation metrics.

Results

Both the models performed at excellent levels for single-label segmentations in bones (dice > 0.95), but single-label joint space performance remained considerably lower (dice < 0.87). Multi-class segmentations remained at lower performance (dice < 0.88) for both models. Combining bone and joint space labels may have introduced a class imbalance problem in multi-class models, leading to lower performance.

Conclusion

It is not clear if 3D UNETR provides better performance as the selection of hyperparameters was the same across the models and was not optimized. Further evaluations will be needed with baseline UNET and nnUNET modeling architectures.
PATIENT-SPECIFIC TIBIAL IMPLANTS: ALGORITHMIC DESIGN PROCESSES FOR CLINICAL CASES
Authors: Kühl J. , Grocholl J. , Seekamp A. , Klüter T. , Fuchs S.
Published: November 2024

Introduction

The surgical treatment of critical-sized bone defects with complex three-dimensional (3D) geometries is a challenge for the treating surgeon. Additive manufacturing such as 3D printing enables the production of highly individualized bone implants meeting the shape of the patient's bone defect and including a tunable internal structure. In this study, we showcase the design process for patient-specific implants with critical-sized tibia defects.

Methods

Two clinical cases of patients with critical tibia defects (size 63×20×21 mm and 50×24×17 mm) were chosen. Brainlab software was used for segmentation of CT data generating 3D models of the defects. The implant construction involves multiple stages. Initially, the outer shell is precisely defined. Subsequently, the specified volume is populated with internal structures using Voronoi, Gyroid, and NaCl crystal structures. Variation in pore size (1.6 mm and 1.0 mm) was accomplished by adjusting scaffold size and material thickness.

Results

An algorithmic design process in Rhino and Grasshopper was successfully applied to generate model implants for the tibia from Ct data. By integrating a precise mesh into an outer shell, a scaffold with controlled porosity was designed. In terms of the internal design, both Voronoi and Gyroid form macroscopically homogeneous properties, while NaCl, exhibits irregularities in density and consequently, in the strength of the structure. Data implied that Voronoi and Gyroid structures adapt more precisely to complex and irregular outer shapes of the implants.

Conclusion

In proof-of-principle studies customized tibia implants were successfully generated and printed as model implants based on resin. Further studies will include more patient data sets to refine the workflows and digital tools for a broader spectrum of bone defects. The algorithm-based design might offer a tremendous potential in terms of an automated design process for 3D printed implants which is essential for clinical application.
DEVELOPMENT OF TISSUE-ENGINEERED SUBSTITUTES FOR THE REGENERATION OF TENDON TOTAL RUPTURES
Authors: Llucia A. , Espinosa S. C.
Published: November 2024

Introduction

Tendon ruptures represent one of the most common acute tendon injuries in adults worldwide, affecting millions of people anually and becoming more prevalent due to longer life expectancies and sports activities. Current clinical treatments for full tears are unable to completely restore the torn tendons to their native composition, structure and mechanical properties.

To address this clinical challenge, tissue-engineered substitutes will be developed to serve as functional replacements for total tendon ruptures that closely resemble the original tissue, restoring functionality.

Method

Water borne polyurethanes (WBPU) containing acrylate groups, specifically polyethylene glycol methacrylate (PEGMA) or 2-hydroxyethyl methacrylate (HEMA), were combined with mouse mesenchymal stem cells (MoMSCs) and heparin sodium to formulate bioinks for the fabrication of scaffolds via extrusion-based 3D bioprinting.

Result

The biocompatibility of acrylated-WBPUs was confirmed in 2D with MoMSCs using lactate dehydrogenase assay, DNA assay and live/dead assays. Cell-laden scaffolds were 3D-bioprinted by encapsulating MoMSCs at varying cell densities within the acrylated WBPUs. The resulting 3D structures support cell viability and proliferation within the scaffolds, as confirmed by live/dead assay, lactate dehydrogenase assay and DNA assays. Differentiation studies in the 3D-bioprinted scaffolds demonstrated the phenotype transition of MoMSCs toward tenocytes through gene expression and protein deposition analysis. The inclusion of sodium heparin in the bioinks revealed increased synthesis of matrix assembly proteins within the 3D-bioprinted constructs.

Conclusion

The developed bioinks were biocompatible and printable, supporting cell viability within the 3D-bioprinted scaffold. The fabricated cell-laden constructs sustained cell proliferation, differentiation, and tissue formation. The addition of heparin sodium enhanced tissue formation and organization, showing promising results for the regeneration of tendon total ruptures.

Principio del formularioThis work was supported by the Spanish State Research Agency (AEI) under grant No CPP2021-008754. The authors would like to thank their partners in the project, which are in charge of the synthesis of heparin sodium and acrylated-WBPUs.
ANISOTROPIC COLLAGEN/HYALURONAN 3D-PRINTED HYDROGELS AS NOVEL IN VITRO MODEL OF ANNULUS FIBROSUS
Authors: Oliveira S. D. , Miklosic G. , Guicheux J. , Visage C. L. , D'este M. , Helary C.
Published: November 2024

INTRODUCTION

Intervertebral disc (IVD) degeneration is not completely understood because of the lack of relevant models. In vivo models are inappropriate because animals are quadrupeds. IVD is composed of the Nucleus Pulposus (NP) and the Annulus Fibrosus (AF), an elastic tissue that surrounds NP. AF consists of concentric lamellae made of collagen I and glycosaminoglycans with fibroblast-like cells located between layers. In this study, we aimed to develop a novel 3D in vitro model of Annulus Fibrosus to study its degeneration. For this purpose, we reproduced the microenvironment of AF cells using 3D printing.

METHOD

An ink consisting of dense collagen (30 mg.mL-1) and tyramine-functionalized hyaluronic acid (THA) at 7.5 mg.mL-1 was first designed by modulating pH and [NaCl] in order to inhibit the formation of polyionic complexes between collagen and THA. Then, composite inks were printed in different gelling baths to form collagen hydrogels. Last, THA photocrosslinking using eosin and green light was performed to strengthen hydrogels. Selected 3D printed constructs were then cellularized with fibroblasts.

RESULTS

The physicochemical study revealed that collagen/THA solutions (4:1 ratio) used at pH 5 with 200 mM NaCl were homogenous. In addition, collagen fibrils were observed in these solutions. The dense composite collagen/THA inks printed in a 2X PBS bath rapidly gelled and the photo-crosslinking increased the mechanical properties by 2 to reach 25 kPa (Young's modulus). Then, 3D printing parameters were optimized (85 kPa, extrusion, 4.5 mm/s speed and 80% fill-in percentage) to generate flat and anisotropic lamellae observed by polarized light microscopy. For the in vitro study, several anisotropic layers were printed and fibroblasts seeded between them. Cells adhered to layers, spread, proliferate and aligned along the axis of printed layers.

CONCLUSION

Taken together, these results show it is possible to reproduce in vitro the main AF's biochemical and physical properties.
IMPACT OF ANNULUS FIBROSUS STIFFNESS ON THE FRACTURE LOAD OF FUNCTIONAL SPINE UNITS
Authors: Strack D. , Mesbah M. , Rayudu N. M. , Baum T. , Kirschke J. , Subburaj K.
Published: November 2024

Introduction

Functional Spine Units (FSUs) play a vital role in understanding biomechanical characteristics of the spine, particularly bone fracture risk assessment. While established models focus on simulating axial compression of individual bones to assess fracture load, recent models underscore the importance of understanding fracture load within FSUs, offering a better representation of physiological conditions. Despite the limited number of FSU fracture studies, they predominantly rely on a linear material model with an annulus fibrosus Young's modulus set at 500 MPa, significantly higher than stiffness values (ca. 4 MPa) utilized in other FSU and spine section biomechanical models. Thus, this study aims to study the effect of varying annulus fibrosus stiffness on FSU fracture load, aiming to identify physiologically relevant biomechanical parameters.

Method

Subject-specific geometry and material properties of bones were derived from computed tomography (CT) image data of five human cadaveric FSU specimens. The annulus fibrosus and nucleus pulposus were manually recreated and assigned linear elastic material properties. By subjecting the model to axial compression, the fracture load of the FSU was deduced from the peak of the force-displacement graph. To explore the effect of stiffness of the annulus fibrosus on simulated fracture load, we conducted a parameter study, varying stiffness values from the high 500 MPa to a more physiologically relevant 25 MPa, aiming to approximate values applied in FSU kinematic models while achieving bone fracture.

Result

Significant reductions in fracture load were observed, ranging from 23% to 46%, as annulus stiffness decreased from 500MPa to 25MPa. Additionally, a discernible, gradual decline in fracture load was observed with a decrease in stiffness values.

Conclusion

The stiffness of the annulus fibrosus significantly influences the simulated fracture load of an FSU. Future investigations should prioritize biomechanically accurate modeling of the intervertebral disc, ensuring alignment with experimental findings regarding FSU fracture load while maintaining biomechanical fidelity.
POLYACRYLAMIDE HYDROGEL FOR KNEE OSTEOARTHRITIS: FOUR-YEAR RESULTS FROM A PROSPECTIVE STUDY
Authors: Bliddal H. , Beier J. , Hartkopp A. , Conaghan P. , Henriksen M.
Published: November 2024

Introduction

Polyacrylamide hydrogel (iPAAG1), is CE marked for treating symptomatic knee osteoarthritis (OA), meeting the need for an effective, long-lasting, and safe non-surgical option. This study evaluates the efficacy and safety of a single 6 ml intra-articular injection of iPAAG in participants with moderate to severe knee OA over a 5-year post-treatment period, presenting data from the 4-year follow up.

Method

This prospective multicentre study (3 sites in Denmark) involved 49 participants (31 females) with an average age of 70 (range 44 – 86 years). They received a single 6 mL iPAAG injection. All participants provided informed consent and re-consented to continue after 1 year. The study followed GCP principles and was approved by Danish health authorities and local Health Research Ethics committees. Twenty-seven participants completed the 4-year follow-up.

The study evaluated WOMAC pain, stiffness, function, and Patient Global Assessment (PGA) of disease impact. Changes from baseline were analysed using a mixed model for repeated measurement (MMRM). Sensitivity analyses were applied on the extension data, where the MMRM analysis was repeated only including patients in the extension phase and an ANCOVA model was used, replacing missing values at 4-years with baseline values (BOCF).

Results

The planned MMRM analysis (n=49) revealed a statistically significant decrease in WOMAC pain subscale scores (-22.0; 95%CI: -29.5; -14.4) from baseline to 4-years. Analysis of the extension phase (n=27) showed similar results (-21.8; 95%CI: -29.0; -14.6) compared to the initial analysis. Furthermore, BOCF analysis indicated a statistically significant reduction in WOMAC pain subscale scores from baseline (-13.0 units). Four new adverse events were reported between the 3-year and 4-year visits; none were related to treatment.

Conclusions

This study shows that single injections of 6 ml intra-articular iPAAG were well tolerated and continued to provide clinically important effectiveness at 4-years after treatment.

Acknowledgements

The study was sponsored by Contura International A/S.