Dominant PURA variants (encoding purine-rich element-binding protein A) cause a neurodevelopmental disorder with hypotonia, cognitive impairment, and variable neuromuscular symptoms. Clinical presentations and response to pyridostigmine, moreover, highlighted neuromuscular junction (NMJ) involvement. However, NMJ architecture, underlying molecular mechanisms, and potential minimally invasive biomarkers in PURA syndrome remain poorly characterized. This study aimed to profile PURA-related disease using integrated clinical, histological, ultrastructural, transcriptional, and protein analyses of skeletal muscle and blood. Ten genetically confirmed patients underwent detailed phenotyping with emphasis on congenital myasthenic syndrome (CMS)-like features. Quadriceps biopsy from one patient was analyzed by histology, immunohistochemistry, and electron microscopy. Protein profiling of muscle, serum, and extracellular vesicles (EVs) was performed by ELISA and mass spectrometry, with validation by qPCR. In line with the recognized classification of PURA syndrome as a CMS subtype, our patients exhibited hypotonia, ptosis, ocular weakness, and myopathic facies, reflecting impaired neuromuscular transmission. Subtle vesicle accumulation and minor NMJ alterations suggest possible neuromuscular involvement in PURA syndrome. Muscle proteomics showed reduced PURA protein and dysregulation of transcriptional regulation, vesicle transport, extracellular matrix remodeling, and complement activation. qPCR confirmed POSTN and PHGDH upregulation among others. Serum analyses demonstrated elevated TSP4, identifying a promising candidate blood biomarker for PURA-associated NMJ dysfunction. EV proteomics revealed dysregulated immunoglobulins, complement components, and novel candidates including NOTCH2, TARSH, and PON1. Pathogenic PURA variants may impair NMJ structure and vesicle homeostasis, potentially linking molecular and ultrastructural defects with clinical myasthenic features and pyridostigmine responsiveness. Proteomic analysis of skeletal muscle provides initial molecular insights into the consequences of dominant PURA variants in muscle tissue. The identification of TSP4 and extracellular vesicle-associated proteins as potential minimally invasive biomarkers provides a framework for biochemical monitoring of PURA syndrome.
Wrist implant arthroplasty represents a function-preserving alternative to joint arthrodesis in cases of advanced arthritis, osteonecrosis, and rheumatoid arthritis. Although fourth-generation implants have been available in Germany since the early 2000s, they still remain in limited use among hand surgeons in Germany.Using a combined approach, we performed a narrative review of the literature on the development of wrist implant arthroplasty, associated complications, and implant models. Additionally, an online survey was conducted to assess the current practice of wrist implant arthroplasty in Germany, supplemented by the results of a prospective data collection from our own patients with wrist prostheses. Subjective hand function and symptoms were evaluated using the DASH and PRHWE scores. Grip strength was measured, and the range of motion was assessed according to the neutral-zero-method. Complications and special cases were documented.Of the surveyed hand surgeons, 38% reported implanting wrist prostheses. The implantation of prostheses was primarily performed in older patients (>40 years) with rheumatoid arthritis, advanced post-traumatic and idiopathic arthritis, and osteonecrosis. During the study period from December 2022 to August 2025, 52 implanted MOTEC® prostheses with a follow-up period of at least one year were recorded. There was a significant improvement in hand function, a reduction in load-dependent pain, and an improvement in mobility (extension/flexion, radial/ulnar deviation). In addition, a trend towards improved grip strength was noted, although statistical significance has not yet been reached. A total of 14 complications were observed, most of which were mechanically induced and partly infectious, and could be resolved through surgical revision.In summary, satisfactory functional results can be achieved with the implantation of wrist prostheses even in patients with high functional demands, such as younger and manually active individuals. However, the procedure is associated with a relatively steep learning curve and an increased complication rate, particularly in the context of the first prosthesis implantations.
Zusammenfassung Die Endoprothetik des Handgelenkes stellt eine funktionserhaltende Alternative zur Arthrodese des Gelenkes bei fortgeschrittener Arthrose, Osteonekrose und rheumatoider Arthritis dar. Obwohl seit Anfang der 2000er Jahre Prothesen der vierten Generation in Deutschland verfügbar sind, hat sich ihre Anwendung unter Handchirurginnen und -chirurgen bislang nur in begrenztem Umfang etabliert. Durch eine kombinierte Vorgehensweise wird zum einen eine Literaturübersicht über die Entwicklung der Endoprothetik des Handgelenkes, Komplikationen und Prothesenmodelle gegeben. Zum anderen wurde anhand einer online Umfrage die aktuelle Praxis der Handgelenksendoprothetik in Deutschland erhoben und durch die Ergebnisse einer prospektiven Datenerhebung von eigenen Patientinnen und Patienten mit Handgelenksprothesen ergänzt. Hierfür wurden die subjektive Handfunktion und Beschwerden anhand des DASH- und PRHWE-Scores, die Grobkraft und die Bewegungsausmaße nach Neutral-0-Methode ermittelt sowie Komplikationen und Sonderfälle dargestellt. Von den befragten Handchirurginnen und -chirurgen gaben 38% an, Handgelenksprothesen zu implantieren. Größtenteils wurde die Implantation von Prothesen bei älteren Patienten (>40 Jahre) mit rheumatoider Arthritis, fortgeschrittenen posttraumatischen und idiopathischen Arthrosen sowie Osteonekrosen angewandt. Im Untersuchungszeitraum von Dezember 2022 bis August 2025 wurden 52 implantierte MOTEC®-Prothesen mit einem Nachuntersuchungszeitraum von mindestens einem Jahr erfasst. Es zeigte sich eine signifikante Verbesserung der Handfunktion, eine Reduktion von belastungsabhängigen Schmerzen und eine Verbesserung der Beweglichkeit (Extension/Flexion, Radial-/Ulnarduktion). Außerdem stellte sich ein Trend zur Verbesserung der Grobkraft dar, welcher jedoch bisher nicht das Signifikanzniveau erreichte. Es ließen sich 14 Komplikationen beobachten, die größtenteils mechanisch sowie zum Teil infektiös bedingt waren und durch eine chirurgische Revision behoben werden konnten. Zusammenfassend lassen sich auch bei Patientinnen und Patienten mit einem hohen funktionellen Anspruch, wie jüngere und handwerklich tätige, zufriedenstellende funktionelle Ergebnisse nach Implantation von Handgelenksprothesen erzielen. Es besteht eine vergleichsweise hohe Lernkurve und eine erhöhte Komplikationsrate, insbesondere im Rahmen der ersten Prothesenimplantationen.
Objective Surgical decision-making during arthroscopic procedures often relies on the subjective visual assessment of tissue morphology, particularly the redness of the long head of the biceps tendon (LHB), which serves as an indicator for potential surgical intervention. This subjectivity introduces variability across clinicians, underscoring the need for objective, data-driven methods. The present study aimed to evaluate the feasibility of applying the MASKRCNN_RESNET50_FPN deep learning model for automated segmentation of the LHB in arthroscopic images, thereby converting subjective visual assessments into quantifiable, reproducible measurements. Methods This original research article is a retrospective cohort analysis of arthroscopic images obtained from 124 participants (84 male, 40 female) who underwent arthroscopic procedures between March 2015 and May 2019 at a single institution. From a comprehensive database of 130,000 arthroscopic images, 15,000 images featuring the LHB were identified, and 200 were selected for manual annotation by an experienced physician. The MASKRCNN_RESNET50_FPN model, combining a ResNet50 backbone with a Feature Pyramid Network and a mask prediction branch, was trained for 10,000 iterations using the AdamW optimizer (learning rate 1×10 -5 ) with transfer learning from COCO-pretrained weights. Model performance was assessed through expert evaluation on 400 randomly selected validation images and through automated pixel-level evaluation computing Precision, Recall, F1-score (Dice coefficient), and Intersection over Union (IoU). A baseline comparison with a U-Net (ResNet34 encoder) and three classical segmentation methods was performed. The reporting of this study conforms to the STROBE guidelines. Results Expert evaluation of 400 validation images yielded a precision of 0.88. The automated pixel-level evaluation on the same 400 images yielded a mean precision of 0.83, recall of 0.86, F1-score of 0.83, and IoU of 0.76 (median IoU: 0.90). The model demonstrated consistent performance across varying tendon orientations and background conditions, and effectively assigned low relevance scores (0.1–0.3) to imaging artifacts. In the baseline comparison, a U-Net achieved a higher mean IoU of 0.91 (Wilcoxon p < 0.001). The combined training loss converged to 0.0809 after 10,000 iterations. Conclusions The MASKRCNN_RESNET50_FPN model may serve as a tool for objective and reproducible segmentation of the LHB in arthroscopic images, with performance corroborated by both expert assessment and automated pixel-level evaluation. These findings suggest that deep learning-based image segmentation has the potential to reduce subjectivity in surgical decision-making. Limitations include the single-center design, limited demographic diversity, and the relatively small training dataset. Multi-center validation with a more diverse patient cohort is recommended.
Background Myotonic dystrophy type 2 (DM2) is a frequent yet underdiagnosed muscle disorder. Although muscle MRI is increasingly used in neuromuscular disorders, there is an overt lack of evidence regarding its role in DM2. This study aimed to characterise whole-body muscle involvement using semiquantitative and quantitative MRI (qMRI) and to determine its relationship with clinical disease severity. Methods In this prospective study, 27 genetically confirmed DM2 patients and 26 age-matched and sex-matched healthy controls underwent whole-body MRI. Semiquantitative muscle involvement was assessed using Fischer grading, while qMRI included fat fraction, T2 and diffusion tensor imaging metrics. Imaging findings were correlated with clinical measures including 6-minute walk test (6MWT), Medical Research Council (MRC) sum score, hip flexion strength, pulmonary function, laboratory parameters and CCTG repeat length. Results DM2 patients demonstrated significantly higher muscular degeneration than controls, predominantly involving proximal muscles. Semiquantitative whole-body MRI correlated with MRC sum score, 6MWT and CCTG repeat length. Importantly, the average involvement of the most severely affected muscles closely reflected overall disease burden, indicating that a focused set of muscles adequately captures global muscle involvement. QMRI confirmed these findings, demonstrating increased fat fraction and T2 values, both of which correlated with clinical performance. Conclusions Whole-body qMRI provides a robust, objective biomarker for DM2 severity. The close agreement between focused and whole-body assessment enables efficient disease stratification, with potential applications in clinical trials and personalised patient management. QMRI may provide a standardised imaging outcome measure for future clinical studies in DM2, warranting longitudinal validation.
