A structured framework for standardized 3D leg alignment analysis: An international Delphi consensus study

Background: Increased attention has been directed toward the acetabular morphology in the management of patients with femoroacetabular impingement syndrome (FAIS). Whether acetabular version influences patient-reported outcomes remains poorly understood. Purpose: To use computed tomography (CT)–based 3-dimensional (3D) bone models to (1) quantify acetabular version in patients with FAIS, (2) compare acetabular version on 3D bone models with current plain radiographic parameters, and (3) explore the relationship between the magnitude of acetabular version and minimum 2-year clinical outcomes after hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: Three-dimensional models of the pelvis and femur were generated by semiautomated segmentation and aligned to a standard coordinate system. Acetabular version was quantified at the 3-o’clock position, and 3 groups were identified: acetabular retroversion (AR; <15°), normal acetabular version (NV; 15°-25°), and acetabular anteversion (AA; >25°). Patient demographic characteristics, plain radiographic parameters, and clinical outcomes were analyzed, including the Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, modified Harris Hip Score (mHHS), International Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain and satisfaction. Results: Preoperative CT scans were acquired in 105 consecutive patients before hip arthroscopy for FAIS, of which 84 (80.0%) completed minimum 2-year patient-reported outcomes. The mean ± SD age and body mass index of patients were 33.9 ± 12.6 years and 26.0 ± 5.4, respectively; 70.2% were female. The number of patients and the mean central acetabular version within each group were as follows: AR (n = 12; 11.3°± 2.7°), NV (n = 56; 20.7°± 2.9°), and AA (n = 16; 28.5°± 2.7°). Posterior wall sign was the only plain radiographic parameter that was significantly more observed in the AR group than in the other 2 groups. At minimum 2-year follow-up, significant between-group differences in the mHHS, iHOT-12, and VAS for pain and satisfaction (P < .05) were appreciated, while post hoc analysis with Bonferroni correction (P < .0167) found lower scores on the mHHS, iHOT-12, and VAS for pain and satisfaction in patients with AR as compared with NV. Lower scores on the VAS for satisfaction were reported in patients with AR when compared with AA (P = .006) but not on the mHHS (P = .023), iHOT-12 (P = .032), or VAS for pain (P = .072). Conclusion: Traditional plain radiographic indices to describe AR, including crossover sign and ischial spine sign, were not reliable in defining AR according to 3D models derived from CT scans. Only the posterior wall sign was observed in a higher proportion in the AR group. Patients with AR demonstrated inferior outcomes when compared with patients with NV and AA after hip arthroscopy for FAIS.

Many of the 2D/3D registration for joint use 3D bone model obtained by MRI and CT. Making a bone model only use the X-ray image (lateral view) contribute to reducing the cost and exposure dose of X-ray. We have developed the reconstruction methods of subject's 3D bone model from X-ray lateral image and prepared 3D bone model that consists of voxels. In this study, the proposal method was adopted to the cervical spine. Using the 3D bone models made from CT and 3D bone model that was reconstructed the proposed method, template pattern matching was carried out, and the accuracy of pose estimation was compared. Estimation accuracy of the proposed method was θ_x=2.60±2.00deg, θ_y=1.68±1.43deg. Estimation accuracy of the conventional method was θ_x=0.36±0.13deg, θ_y=0.83±0.44deg. Because the present method is to modify the prepared 3D bone model based on only lateral X-ray image, bone shape, especially about the depth direction, cannot exactly reflect subject's bone shape. The method can't reproduction the bone shape with a recessed shape, such as bottom of vertebral body. These problems affect the estimation accuracy.

Motion capture systems estimate underlying bone movements by tracking trajectories of skin-mounted markers. However, the reliability of the kinematics parameters derived from the skin markers has often questioned due to skin movement artefact. The objective of this study was to evaluate skin movement artefact associated with dorsiflexion and plantar flexion of the foot using 3D bone models and bi-plane radiography. Four healthy subjects participated in this study. The subject underwent CT scan to reconstruct 3D tibial, the first metatarsal bone, and the fifth metatarsal bone models. Sixteen polymeric markers with radio-opaque beads in its center were attached to the shank and foot. To quantify the skin marker movement with respect to the tibia, the first metatarsal bone, and fifth metatarsal bone, bi- plane radiographic images were collected during neutral, plantar flexion, and dorsiflexion of the foot. The positions of the tibia, the first metatarsal bone, and the fifth metatarsal bone were recovered by a 2D to 3D image registration method. Then the positions of the markers were determined with respect to the relevant coordinate system embedded in the 3D bone models. The mean values ± SD of the translations in the corresponding markers with plantar flexion were 3.1 ± 1.8 mm for the tibia, 8.2 ± 4.2 mm for the first metatarsal bone, and 14.0 ± 6.3 mm for the fifth metatarsal bone. With dorsiflexion, the translations were 6.0 ± 3.1 mm for the tibia, 18.1 ±6.4 mm for the first metatarsal bone, and 36.0 ±12.8 mm for the fifth metatarsal bone.

Volumetric information about the patient’s anatomy is quite valuable for medical diagnosis. Computed tomography (CT) is the common imaging modality for 3D visualization of bone tissue but rising costs in health care system demand for new approaches. A promising one is to use a 3D model being deformable under the constraint of statistical plausibility. The model is adapted to the patient’s anatomy by extracting the specific bone features from several conventional radiographs (2D–3D registration). These have to be acquired under different angles thus providing the features’ 3D position by means of which the model is deformed. The resulting bone representation may then be used for medical diagnosis instead of using CT data. Present work validates accuracy of the resulting bone shape and thus of the diagnosis relying thereon. Results are starting point for further implementations and modifications in order to reduce remaining errors.

Correcting the knee joint to accommodate the pre-existing soft tissue structures is a major aim in total knee arthroplasty. 3D-to-2D registration of segmented boney geometry obtained from computer tomography (CT) scans to functionally stressed positions in X-Ray (XR) imaging can be a more accurate method of obtaining the laxity envelop. From which, a more patient specific limit for the correctability of the knee joint can be found. Supine CT scans were segmented, and 3D bone models and anatomical landmarks were registered to 2D functional stressed XR imaging. The functional position of the patient femoral and tibial bone is then used to calculate the varus and valgus extent of the patient’s knee joint laxity. 103 preoperative knees undergoing primary total knee arthroplasty identified from six different surgeons. The range of patients who are correctable back to within 3 degrees when a force is applied is 52%. 65% of patients who were within 3 degrees varus/valgus for tibia varus were correctable, while 41% of patients who were within 3 degrees varus/valgus for femoral valgus were correctable. 26% of patients were correctable when the LDFA is outside the threshold and MPTA is not, while 56% of patients were correctable when the MPTA is outside the threshold and LDFA is not. This study demonstrates the complexity of soft tissue structures of the knee joint. The main finding of this study is that correctability is more sensitive to the proximal tibial than the distal and posterior femoral articulating geometry. A lack of dependency between correctability of the knee joint and anatomical measures specific to flexion of the knee is seen. Careful consideration should be made intraoperatively when balancing the knee joint flexion gaps surrounding the soft tissue structures.

<sec> <title>BACKGROUND</title> Alongside expected benefits, several ethical concerns arise from Artificial Intelligence (AI) based models. From the design to the implementation and subsequent evaluation, it is crucial to map potential ethical concerns regarding the use of AI models in healthcare. Patient-Reported Outcomes (PROs) and Digital Biomarkers (DBs) are being increasingly collected to improve patient-centered healthcare systems. However, due to the sensitive nature of this data, its processing into AI models may raise ethical concerns that should be considered. While general AI ethics frameworks exist, no international consensus has specifically addressed the unique ethical challenges of integrating PROs and DBs in AI healthcare models. </sec> <sec> <title>OBJECTIVE</title> This study aims to fill this critical gap by establishing the first international expert consensus on ethical, legal, and social considerations specifically for PROs and DBs integration in AI-based healthcare models. </sec> <sec> <title>METHODS</title> A mixed-method study was performed. Initially, a narrative review was performed to identify the main ethical considerations regarding integrating PROs and DBs in AI-based models in healthcare. Then, a modified two-round online Delphi study was conducted to reach a consensus on the recommendations for integrating PROs and DBs in AI-based models, among selected international experts. </sec> <sec> <title>RESULTS</title> The findings of the two complementary components of this study (narrative review and modified Delphi study) were organized around five core ethical principles: autonomy, beneficence, non-maleficence, justice, and transparency and accountability. The modified Delphi study achieved high consensus (≥80%) on 57 specific recommendations across these principles. Key recommendations included implementing dynamic consent models, establishing continuous model validation protocols, conducting regular impact assessments, ensuring diverse stakeholder engagement to mitigate biases, and maintaining human oversight within AI systems. </sec> <sec> <title>CONCLUSIONS</title> This study provides the first comprehensive, internationally validated ethical framework specifically designed for PROs and DBs integration in AI healthcare systems, filling a critical gap in the literature that has primarily focused on general AI ethics rather than the unique challenges posed by patient-generated health data. </sec>

Geoscience modellers develop numerical models where constraints are placed on how the model domain and sampling relates to location in the modelled world and the real world. The shape of the model domain is a significant factor for numerical algorithms and computational solvers. This leads to a number of interesting definitions of coordinate reference systems. I will summarise some requirements the modelling community have for specifying and working with coordinate reference systems. Post processing and presentation of analyses are important factors; archiving for future use is a crucial consideration. I will present examples of horizontal and vertical coordinate system definitions in common use in the meteorology and oceanography domains and the challenges they may bring. The conclusion will be a discussion how specifications and tools for defining, interpreting and transforming coordinate reference systems, such as Well Known Text (WKT), European Petroleum Survey Group (EPSG) and PROJ.4 are able or unable to meet the requirements of a geosciences modeller.

SummaryBackgroundRandomized controlled trials (RCTs) in gastrointestinal surgery often lack standardized approaches to Surgical Quality Assurance (SQA), which threatens both internal and external validity. The technical complexity and inherent inter-surgeon variability in gastrointestinal procedures pose significant challenges for standardizing interventions and ensuring reproducible outcomes. SQA involves credentialing of surgeons, standardization of surgical techniques, and monitoring of performance, but consensus on essential components has been missing. To address this gap, we conducted a four-round Delphi consensus process with 40 international experts in gastrointestinal surgery and clinical trials.MethodsExperts from 15 countries were invited to rate the relevance of potential SQA items using a 5-point Likert scale from December 2023 to December 2024. The checklist was structured into three domains: credentialing, standardization of surgical techniques, and performance monitoring. Items rated as 4 (‘important’) or 5 (‘very important’) by at least 80% of experts were included in the final SQA checklist.FindingsConsensus was reached on 13 essential SQA items including a minimum annual case volume per center, a minimum surgeon case volume (overall and annually), standardized reporting guidelines, pretrial education (written materials and videos), standardization of surgical approach, standardized extent of lymphadenectomy, proctoring surgeons (without and with limited experience), periodic pathological assessment, and performance monitoring through Case Report Forms or patient file data.InterpretationThis Delphi study establishes an international expert consensus framework of 13 items for Surgical Quality Assurance in RCTs in gastrointestinal surgery. This framework is expected to be widely utilized to enhance the quality of surgical trials by improving the internal and external validity. Adoption of these standards may help strengthen the credibility, comparability, and clinical relevance of future surgical RCTs.FundingThis study received no funding.

Optical motion capture (OMC) is the current gold standard for motion analysis, however measuring patellofemoral kinematics is not possible using the technique. One approach to measuring in-vivo kinematics is to use biplane video X-ray (BVX) and 3D models generated from MRI to track the movement of the patellar. Understanding how the patellar is moving during different loaded dynamic activities can help with understanding the effects of different interventions when treating disease or injury. Objective To develop a protocol and compare patellofemoral kinematics for different activities using biplane video X-ray (BVX) Methods Two healthy volunteers performed level walk, lunge, and stair ascent activities while simultaneous capturing BVX and synchronised OMC. Participants undertook MR imaging (Magnetom 3T Prisma, Siemens) which was manually segmented into 3D bone models (Simpleware Scan IP, Synopsis). Bone position and orientation for the patellar and femur were calculated by manual matching of 3D Bone models to X-Rays (DSX Suite, C-Motion, Inc.). Patellofemoral kinematics were calculated using Visual 3D (C-Motion, Inc.). Results Initial results show that patellar flexion(+) (PF) was greatest during lunge (52.1o) compared with stair ascent (49.4o) and stance phase of gait (5.4o), however stair ascent had the largest PF range of motion (ROM) of 48.8o. The lunge activity had the greatest ROM for patellar lateral rotation (12.8o) compared with stair ascent (8.7o) and gait (3.7o). Patellar lateral (+) tilt was found to be greatest during gait (8.4o) compared with stair ascent (6.7o) and lunge (6.8o). Conclusions These results highlight the variability of patellofemoral kinematics between different loaded dynamic activities. When considering the influence and efficacy of patellofemoral interventions it is important to investigate different activities to fully understand their effects. Future work will look at more dynamic activities and to investigate further the effect of different activities on patellofemoral tracking. Declaration of Interest (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Using 3D models of bones can highly improve accuracy and reliability of orthopaedic evaluation. However, it may impose excessive computational load. This article proposes a fully automatic method for extracting a compact model of the femur from its 3D model. The proposed method works by extracting a 3D skeleton based on the clinical parameters of the femur. Therefore, in addition to summarizing a 3D model of the bone, the extracted skeleton would preserve important clinical and anatomical information. The proposed method has been applied on 3D models of 10 femurs and the results have been evaluated for different resolutions of data.

Category: Midfoot/Forefoot Introduction/Purpose: Proximal fifth metatarsal fractures (PFMF) are among the most common fractures in the foot and can be categorized into three fracture zones [1]. To investigate the fracture mechanism of PFMF in different zones, a better understanding of the anatomy of the bone and its surrounding soft tissues is required. Both the plantar fascia (PF) and the peroneus brevis (PB) tendon insertions are at the base of the fifth metatarsal, and may contribute to the pathophysiology of PFMF. However, the role of the PB and PF insertions in the pathogenesis of PFMF remains unclear. The purpose of this study was to accurately define the footprint of the PB and PF insertions of the base of the 5th metatarsal in relation to the different zones of PFMF. Methods: 21 cadaveric fifth metatarsal bones were harvested from cadaveric feet. All bones were freed of any remaining soft tissue adherence, except for the PB and the PF insertions. Three reference screws with a diameter of 1 mm were placed and secured on each bone with 2 screws distally and 1 screw proximally for registration. All bones were CT scanned to create a 3D bone reconstruction. Next, the insertions of the PB and PF and the reference screws of each bone were digitized and then mapped to its corresponding 3D bone model. In order to describe the three different fracture zones of the 5th metatarsal, an established coordinate system was made for each bone to simulate separate fracture zones (Figure a) based on Lawrence guideline [1]. The shape, location and surface areas of both insertions and their relation to the different fractures zones were determined (Figure b). Results: The insertion of the PB was oval shaped and located on the dorsal side of the base, with a mean surface area of 88.1 ± 46.4 mm2. The PF was oval shaped and situated around the tip of tuberosity, with a mean surface area of 150.7±53.5 mm2. The PB insertion was present in zone 1 fractures in 100% (21/21) of the 5th metatarsal models and 29% (6/21) of the models for zone 2 fractures. The PF insertion was involved in 100% (21/21) of the 5th metatarsal models for zone 1 fractures and 43% (9/21) of the models for zone 2 fractures. Conclusion: Results of this study demonstrate that the insertion of both the PB and PF are involved in all zone 1 PFMF and a significant percentage of zone 2 PFMF. The location of tendon insertions affect the forces exerted on the bone, which may indicate a relation of the insertions of both the PB and the PF with the fracture mechanism of many zone 1 and 2 PFMF. Moreover, in the treatment of these fractures, care should be taken to maintain or restore the anatomy of these insertions to maximize functional outcomes.

Establishment of standards for the referral of large nonpedunculated colorectal polyps: an international expert consensus using a modified Delphi process

Both in radiology and in surgery, numerous applications are emerging that enable 3D visualization of data from various imaging modalities. In clinical practice, the patient's images are analyzed on work stations in the Radiology Department. For specific preclinical and educational applications, however, data from single patients are insufficient. Instead, similar scans from a number of individuals within a collective must be compiled. The definition of standardized acquisition procedures and archiving formats are prerequisite for subsequent analysis of multiple data sets. Focusing on bone morphology, we describe our concept of a computer database of 3D human bone models obtained from computed tomography (CT) scans. We further discuss and illustrate deployment areas ranging from prosthesis design, over virtual operation simulation up to 3D anatomy atlases. The database of 3D bone models described in this work, created and maintained by the AO Development Institute, may be accessible to research institutes on request.

Recurrence is a key outcome measure of treatment for differentiated thyroid carcinoma (DTC). In international guidelines and current literature, a consistent definition is lacking, which hinders comparison of treatment-related oncological outcomes. Therefore, the aim of this study was to reach international consensus among experts from all medical specialties involved in the care of patients with DTC on the essential elements minimally required for a universal definition of recurrence-serving as a first step toward developing a new, universally accepted definition of DTC recurrence. We conducted an international Delphi study. A steering committee provided advice on the study protocol and Delphi rounds. Experts were identified through various scientific associations, international guidelines, ClinicalTrials.gov, our systematic review on definitions of DTC recurrence, and suggestions from the steering committee. A 3-round Delphi process was conducted to reach consensus on the minimally essential components of the definition of DTC recurrence. The initial list of components was derived from our systematic review. In total, 127 experts from all medical specialties involved in the diagnosis and treatment of DTC, representing 35 countries across 4 continents, completed 3 Delphi rounds. Thirteen key components critical for defining complete remission and recurrence of DTC were identified, following treatment with total thyroidectomy and postoperative radioiodine therapy (RIT), total thyroidectomy without RIT, and less-than-total thyroidectomy. The components identified through this international Delphi consensus can serve as the foundation for the further development of universal definitions of DTC recurrence.

Dynamic foraminal dimensions during neck extension and rotation in fusion and artificial disc replacement: an observational study