In vivo high-resolution peripheral quantitative computed tomography (HR-pQCT) studies on bone characteristics are limited, partly due to the lack of standardized and objective techniques to describe motion artifacts responsible for lower-quality images. This study investigates the ability of such deep-learning techniques to assess image quality in HR-pQCT datasets of human scaphoids. In total, 1451 stacks of 482 scaphoid images from 53 patients, each with up to six follow-ups within one year, and each with one non-displaced fractured and one contralateral intact scaphoid, were independently graded by three observers using a visual grading scale for motion artifacts. A 3D-CNN was used to assess image quality. The accuracy of the 3D-CNN to assess the image quality compared to the mean results of three skilled operators was between 92% and 96%. The 3D-CNN classifier reached an ROC-AUC score of 0.94. The average assessment time for one scaphoid was 2.5 s. This study demonstrates that a deep-learning approach for rating radiological image quality provides objective assessments of motion grading for the scaphoid with a high accuracy and a short assessment time. In the future, such a 3D-CNN approach can be used as a resource-saving and cost-effective tool to classify the image quality of HR-pQCT datasets in a reliable, reproducible and objective way.

INTRODUCTION:The exact mechanisms of bone remodelling after scaphoid fractures are not fully understood. Blood supply may lead to delayed consolidation and non-unions as challenging long-term problems. The aim of this study was to follow-up the microstructure during the scaphoid bone remodelling process using High Resolution peripheral Quantitative Computed Tomography (HR-pQCT) and compare the results with clinical and laboratory data. PATIENTS AND METHODS:In this monocentric, prospective, controlled, clinical trial 39 patients with an unilateral conservatively treated scaphoid fracture at the level of the waist or the distal pole were followed up over one year (2, 4, 6, 12, 26 and 52 weeks after trauma). Fracture healing was monitored by clinical examination, blood bone remodelling markers and HR-pQCT. RESULTS:The HR-pQCT showed significant changes in trabecular number, trabecular thickness, trabecular separation and bone mineral density until the 52 week follow-up. Complete bony consolidation on HR-pQCT was evident in half of the fractures at 12 weeks and in all fractures at 52 weeks after trauma. None of the patients developed a non-union. Carboxy-terminal collagen crosslinks as resorption marker showed significant changes until the 52 week follow-up. CONCLUSION:This study shows detailed clinical, laboratory and radiologic changes during follow-up of uncomplicated fracture healing of conservative scaphoids. Bony consolidation is highly variable and can take up to one year after fracture. Larger studies are warranted, as HR-pQCT might provide detailed microstructural information to better predict fracture healing processes, thus acting as a high-resolution and low-radiation alternative to standard conventional CT.

Fehlstellungen am Unterarm als Folge einer fehlverheilten Fraktur können schwerwiegende Funktionseinschränkungen, Schmerzen und posttraumatische Arthrosen verursachen. Je nach Ausmaß und individueller Situation besteht eine Indikation zu Korrektureingriffen. Die häufigsten Fehlheilungen finden sich am distalen Radius, seltener am Unterarmschaft und im proximalen Drittel. Bei der Korrektur von Fehlstellungen ist beim wachsenden Skelett das Korrekturpotenzial des kindlichen Knochens zu berücksichtigen. Korrektureingriffe stellen aufgrund der komplexen Anatomie und Biomechanik des Unterarms eine Herausforderung in der Behandlung dar. Um das Ziel der Wiederherstellung der normalen Anatomie und Funktion zu erreichen, ist eine exakte präoperative Planung notwendig. Die Fortschritte in der 3D-Technik ermöglichen es, Fehlstellungen auf Grundlage von Schnittbildern in der Computertomographie (CT) dreidimensional darzustellen und zu analysieren sowie die Korrekturosteotomie exakt zu planen und durchzuführen. In diesem Übersichtartikel werden die verschiedenen Arten der Fehlstellungen sowie ihre Ursachen und Behandlungsmöglichkeiten beschrieben. Ein Schwerpunkt dabei ist die 3D-Technologie und ihre Anwendung bei der Planung und Durchführung der Korrekturosteotomien am Unterarm.

Malalignment of the forearm as a sequel to an incorrectly healed fracture can cause severe functional limitations, pain and posttraumatic arthritis. Depending on the extent of the deformity and patient-specific factors, there is an indication for corrective surgery. The most frequent forms of incorrect healing are found at the distal radius, less frequently on the forearm shaft and in the proximal third. When correcting pediatric deformities, the correction potential of the growing skeleton must be taken into account. Corrective surgery represents a challenge in the treatment due to the complex anatomy and biomechanics of the forearm. An accurate preoperative planning is necessary to achieve the goal of restoring normal anatomy and function. Advances in 3D techniques make it possible to visualize and analyze deformities in three dimensions based on computed tomography (CT) cross-sectional imaging and to accurately plan and perform the corrective osteotomy. This overview article describes the different types of forearm malalignment as well as the causes and treatment options. A special focus is placed on 3D techniques and the implementation in the planning and performance of corrective osteotomy of the forearm.

Summary The study shows a high incidence of motion artefacts in a central European population and a significant increase of those artefacts with higher age. These findings may impact on the design and conduct of future in vivo HR-pQCT studies or at least help to estimate the potential number of drop outs due to unusable image quality. Purpose Motion artefacts in high-resolution peripheral quantitative computed tomography (HR-pQCT) are challenging, as they introduce error into the resulting measurement data. The aim of this study was to assess the general occurrence of motion artefacts in healthy distal radius and to evaluate the influence of demographic factors. Methods The retrospective study is based on 525 distal radius second-generation HR-pQCT scans of 95 patients. All stacks were evaluated by two experienced observers and graded according to the visual grading scale recommended by the manufacturer, ranging from grade 1 (no visible motion artefacts) to grade 5 (severe motion artefacts). Correlations between demographic factors and image quality were evaluated using a linear mixed effects model analysis. Results The average visual grading was 2.7 (SD ± 0.7). Age and severity of motion artefacts significantly correlated ( p = 0.026). Patients aged 65 years or above had an average image quality between grades 1 and 3 in 72.7% of cases, while patients younger than 65 had an average image quality between grades 1 and 3 in 91.9% of cases. Gender, smoking behaviour, and handedness had no significant influence on motion artefacts. Conclusion This study showed a high incidence of motion artefacts in a representative central European population, but also a significant increase of motion artefacts with higher age. This could impact further study designs by planning for a sufficiently large and if possible a more selective study population to gain a representative amount of high-quality image data.

Background In-vivo high-resolution peripheral quantitative computed tomography (HR-pQCT) has high potential in scaphoid bone pathologies’ scientific and clinical fields. The manufacturer’s visual grading scale (VGS) classifies motion artifacts and divides scans into five quality grades ranging from grade 1 (good quality) to grade 5 (poor quality). This prospective study aimed to investigate the feasibility of the VGS and the influence of image quality on bone density and microarchitecture parameters for the scaphoid bone. Methods Within one year, twenty-two patients with scaphoid fractures received up to six scans of their fractured and contralateral wrist (each consisting of three stacks) using second-generation HR-pQCT (total 256 scans). Three experienced observers graded each stack following the visual grading system, and inter- and intraobserver variability were assessed. The contralateral uninjured scaphoids were then compared pairwise within each patient to high-quality grade 1 scans to determine the influence of image quality on density and microarchitecture parameters. Results Inter- and intraobserver variability among the three observers significantly revealed fair to moderate agreement, P<0.001 and P<0.05, respectively. Bone volume (BV) fraction tended to increase with poorer image quality but did not exceed four percent. Trabecular bone mineral density (Tb.BMD) decreased with poorer image quality but did not exceed five percent. Trabecular number and trabecular thickness significantly increased by 15.5% and 6.8% at grade five (P<0.001), respectively, and trabecular separation significantly decreased by 13.7% at grade five (P<0.001). Conclusions This study revealed a considerable influence of motion on bone morphometry parameters of the scaphoid. Therefore, high image quality must be a central point in studies focusing on the histomorphometry of small objects. The high inter- and intraobserver variability limit the VGS. Future research may focus on other grading systems or automated techniques leading to more consistent and reproducible results. Currently, the use of microarchitectural analysis should be limited to cases without motion artefacts or, at most low graded motion artefacts.

ABSTRACT Clinical evaluation of fracture healing is often limited to an assessment of fracture bridging from radiographic images, without consideration for other aspects of bone quality. However, recent advances in HRpQCT offer methods to accurately monitor microstructural bone remodeling throughout the healing process. In this study, local bone formation and resorption were investigated during the first year post fracture in both the fractured (n = 22) and contralateral (n = 19) radii of 34 conservatively treated patients (24 female, 10 male) who presented with a unilateral radius fracture at the Innsbruck University Hospital, Austria. HRpQCT images and clinical metrics were acquired at six time points for each patient. The standard HRpQCT image acquisition was captured for all radii, with additional distal and proximal image acquisitions for the fractured radii. Measured radial bone densities were isolated with a voxel‐based mask and images were rigidly registered to images from the previous imaging session using a pyramid‐based approach. From the registered images, bone formation and resorption volume fractions were quantified for multiple density‐based thresholds and compared between the fractured and contralateral radius and relative to demographics, bone morphometrics, and fracture metrics using regression. Compared with the contralateral radius, both bone formation and resorption were significantly increased in the fractured radius throughout the study for nearly all evaluated thresholds. Higher density cortical bone formation continually increased throughout the duration of the study and was significantly greater than resorption during late‐stage healing in both the fractured and intact regions of the radius. With the small and diverse study population, only weak relationships between fracture remodeling and patient‐specific parameters were unveiled. However this study provides methods for the analysis of local bone remodeling during fracture healing and highlights relevant considerations for future studies, specifically that remodeling postfracture is likely to continue beyond 12‐months postfracture. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

gerne antworten wir auf den Leserbrief von Herrn Prof. Dr. med. Günter Germann bezüglich der oben genannten Publikation und möchten uns vorweg für diese Möglichkeit bedanken.

Zusammenfassung Die Behandlung von Kahnbeinpseudarthrosen ist nach wie vor eine Herausforderung fur den behandelnden Handchirurgen - im Speziellen bei avaskularen, proximalen Kahnbeinpseudarthrosen oder vorangegangenen fehlgeschlagenen Operationen. Unterschiedliche operative Verfahren wurden etabliert und basieren auf der Rekonstruktion der korrekten Anatomie des Kahnbeins, welche einerseits Stabilitat bietet und andererseits eine ausreichende Durchblutung wiederherstellt. Das Behandlungsspektrum reicht von avaskularen bis hin zu freien, gefa ss gestielten Spaninterponaten. Die beiden am haufigsten verwendeten freien vaskularisierten Knochenspane stammen vom Beckenkamm und vom medialen Femurkondyl. Der Femurkondylenspan zeigt eine konstantere Gefa ss anatomie, geringere Hebemorbiditat und hoherer Heilungsrate im Vergleich zum Beckenkammspan. Zudem ist der Span technisch einfacher zu heben und kann sowohl als kortikospongioser, wie auch osteochondraler Span gehoben werden. In Summe der Vorteile kommen wir zu dem Schluss, dass die Versorgung der Kahnbeinpseudarthrose bei avaskularem proximalen Pol mittels gefa ss gestieltem Femurkondylenspan die Methode unserer Wahl ist. Abstract Treatment of scaphoid non-unions is still challenging for responsible hand surgeons, especially in cases of avascular proximal pole non-unions or failed prior surgeries. Several surgical procedures treating scaphoid non-unions have been established. These aim to restore correct anatomy to provide stability and adequate blood flow. Treatment options range from avascular to free, vascularized bone grafts. The two most used free vascularized bone grafts derive from the iliac crest and the medial femoral condyle. The vascular anatomy of the medial femoral condyle graft is more constant, the donor site morbidity lower and the healing rate higher in comparison to the iliac crest graft. It is easier to harvest the femoral condyle graft and additionally, it can be harvested as a cortico-cancellous or osteochondral graft. Looking at all advantage, we come to the conclusion that the free vascularized medial femoral condyle graft is our method of choice for the treatment of a avascular proximal pole non-union of the scaphoid.

ZusammenfassungDie Behandlung von Kahnbeinpseudarthrosen ist nach wie vor eine Herausforderung für den behandelnden Handchirurgen – im Speziellen bei avaskulären, proximalen Kahnbeinpseudarthrosen oder vorangegangenen fehlgeschlagenen Operationen. Unterschiedliche operative Verfahren wurden etabliert und basieren auf der Rekonstruktion der korrekten Anatomie des Kahnbeins, welche einerseits Stabilität bietet und andererseits eine ausreichende Durchblutung wiederherstellt. Das Behandlungsspektrum reicht von avaskulären bis hin zu freien, gefäßgestielten Spaninterponaten. Die beiden am häufigsten verwendeten freien vaskularisierten Knochenspäne stammen vom Beckenkamm und vom medialen Femurkondyl. Der Femurkondylenspan zeigt eine konstantere Gefäßanatomie, geringere Hebemorbidität und höherer Heilungsrate im Vergleich zum Beckenkammspan. Zudem ist der Span technisch einfacher zu heben und kann sowohl als kortikospongiöser, wie auch osteochondraler Span gehoben werden. In Summe der Vorteile kommen wir zu dem Schluss, dass die Versorgung der Kahnbeinpseudarthrose bei avaskulärem proximalen Pol mittels gefäßgestieltem Femurkondylenspan die Methode unserer Wahl ist.

Background: The aim of the current biomechanical study was to investigate a newly developed surgical technique for mallet fingers. The new method is based on the Ishiguro method which requires a K-wire through the distal interphalangeal joint for temporary fixation. The new technique avoids the joint trans fixation using a specially designed finger nail holder. This method was compared to the established Ishiguro's technique. Methods: For biomechanical testing, 32 paired, fresh-frozen human fingers (Digit II-V) of 4 donors (ages 60 to 71 years) were used. The paired fingers were assigned to either the new method or Ishiguro's technique. The biomechanical testing consisted of a cyclic cantilever bending (2000 cycles, 1-7N) followed by a load to failure test. The groups were evaluated for plastic deformation, stiffness, change in stiffness during cyclic loading, subluxation and failure load by analysing force-deflect data and fluoroscopic images. Findings: The nail fixation group showed significantly higher failure loads and stiffness than the trans fixation group. The values of plastic deformation were significantly lower in the nail fixation group. No differences were found in the change of stiffness. No subluxation was found in both groups. Interpretation In the current biomechanical study, nail fixation performed at least as good as Ishiguro's trans fixation technique. The results and ease of implementation indicate that the newly developed nail fixation technique might be a useful treatment method in daily clinical practice without the need of temporary joint trans-fixation avoiding possible associated problems. To establish this method, clinical trials will be necessary.