In vivo dynamic intrusion and extrusion of the menisci in varus and valgus load within a healthy population.

Purpose: Axial loading, varus and valgus stress lead to meniscal motion towards the joint periphery, defined as meniscal extrusion. Direction and amount of extrusion is unknown as this is a dynamic process within a 3D environment dependent on joint loading as well as individual anatomy. We propose that there is motion in all compartments of the medial and lateral meniscus during valgus and varus stress.

Predicting the Hamstring Graft Size for ACL Reconstruction Using a 3D Tendon Model in Preoperative MRI.

Rupture of the ACL is a common injury among men and women athletes. While planning the surgical ACL reconstruction procedure, the eventual graft's diameter is extremely important. Many parameters are therefore evaluated pre-surgery to ensure access to reliable data for estimating the graft diameter.

ETL: From the German Health Data Lab data formats to the OMOP Common Data Model.

Objective: The German Health Data Lab is going to provide access to German statutory health insurance claims data ranging from 2009 to the present for research purposes. Due to evolving data formats within the German Health Data Lab, there is a need to standardize this data into a Common Data Model to facilitate collaborative health research and minimize the need for researchers to adapt to multiple data formats. For this purpose we selected transforming the data to the Observational Medical Outcomes Partnership Common Data Model.

Medial patellofemoral ligament reconstruction normalizes patellar kinematics but fails to predict cartilage contact area: A prospective 3D MRI study.

Introduction: The medial patellofemoral ligament (MPFL) is the main patellar stabilizer in low knee flexion degrees (0-30°). Isolated MPFL reconstruction (MPFLr) is therefore considered the gold standard of surgical procedures for low flexion patellofemoral instabilities (PFIs). Despite excellent clinical results, little is known about the effect of MPFLr on kinematic parameters (KPs) of the patellofemoral joint in vivo.

The transepicondylar distance is a reliable and easily measured parameter for estimating femoral cartilage surface area using MRI.

Purpose: Different cartilage repair techniques are widely used to regenerate cartilage, such as autologous chondrocyte implantation (ACI), osteochondral autograft transfer, microfracturing and minced cartilage. Defect size is a key parameter for selecting the best procedure to repair cartilage. However, the defect's size is not related to the patient's total cartilage surface.

Prediction of the Hamstring Graft Size for ACL Reconstruction Using Different Axial Layers in Preoperative MRI.

Background: In ACL reconstruction, it is desirable to assess preoperatively whether a sufficient graft diameter can be achieved with the planned tendon graft. The present study investigated the effect of the location of the cross-sectional area (CSA) measurement of the hamstring tendons in preoperative MRI on the correlation of the CSA with the intraoperative graft diameter. In addition, we analyzed whether the measurement results of examiners with different skill levels were comparable.

Time-Resolved Quantification of Patellofemoral Cartilage Deformation in Response to Loading and Unloading via Dynamic MRI With Prospective Motion Correction.

Background: In vivo cartilage deformation has been studied by static magnetic resonance imaging (MRI) with in situ loading, but knowledge about strain dynamics after load onset and release is scarce.

Purpose: To measure the dynamics of patellofemoral cartilage deformation and recovery in response to in situ loading and unloading by using MRI with prospective motion correction.

Study Type: Prospective.

Change in Descriptive Kinematic Parameters of Patients with Patellofemoral Instability When Compared to Individuals with Healthy Knees-A 3D MRI In Vivo Analysis.

Background: Patellofemoral instability (PFI) leads to chronic knee pain, reduced performance and chondromalacia patellae with consecutive osteoarthritis. Therefore, determining the exact patellofemoral contact mechanism, as well as the factors leading to PFI, is of great importance. The present study compares in vivo patellofemoral kinematic parameters and the contact mechanism of volunteers with healthy knees and patients with low flexion patellofemoral instability (PFI).

Individual Influence of Trochlear Dysplasia on Patellofemoral Kinematics after Isolated MPFL Reconstruction.

Introduction: The influence of the MPFL graft in cases of patella instability with dysplastic trochlea is a controversial topic. The effect of the MPFL reconstruction as single therapy is under investigation, especially with severely dysplastic trochlea (Dejour types C and D). The purpose of this study was to evaluate the impact of trochlear dysplasia on patellar kinematics in patients suffering from low flexion patellar instability under weight-bearing conditions after isolated MPFL reconstruction.

Patchy Alopecia in a Patient with Rheumatoid Arthritis: A Practical Application of Trichoscopy.

Trichoscopy is an efficient, convenient, and accurate diagnostic dermatological procedure which is widely used in the examination of patients with skin diseases. Herein, we report a 56-year-old woman with a long-term history of rheumatoid arthritis complaining of pruritic patchy alopecia on her scalp who was referred for biopsy to exclude cutaneous lupus erythematosus. Taking advantage of trichoscopy, we were able to quickly diagnose tinea capitis.

Deep learning for the rapid automatic quantification and characterization of rotator cuff muscle degeneration from shoulder CT datasets.

Objectives: This study aimed at developing a convolutional neural network (CNN) able to automatically quantify and characterize the level of degeneration of rotator cuff (RC) muscles from shoulder CT images including muscle atrophy and fatty infiltration.

Methods: One hundred three shoulder CT scans from 95 patients with primary glenohumeral osteoarthritis undergoing anatomical total shoulder arthroplasty were retrospectively retrieved. Three independent radiologists manually segmented the premorbid boundaries of all four RC muscles on standardized sagittal-oblique CT sections.

Automated CT bone segmentation using statistical shape modelling and local template matching.

Accurate CT bone segmentation is essential to develop chair-side manufacturing of implants based on additive manufacturing. We herewith present an automated method able to accurately segment challenging bone regions, while simultaneously providing anatomical correspondences. The method was evaluated on demanding regions: normal and osteoarthritic scapulae, healthy and atrophied mandibles, and orbital bones.

Patellar bone strain after total knee arthroplasty is correlated with bone mineral density and body mass index.

Patella-related complications after total knee arthroplasty (TKA) remain a major clinical concern. Previous studies have suggested that increased postoperative patellar bone strain could be related to such complications, but there is limited knowledge on patellar strain after TKA. The objective of this study was to predict patellar bone strain after TKA and evaluate correlations with various preoperative data.

Quantification of patellofemoral cartilage deformation and contact area changes in response to static loading via high-resolution MRI with prospective motion correction.

Background: Higher-resolution MRI of the patellofemoral cartilage under loading is hampered by subject motion since knee flexion is required during the scan.

Purpose: To demonstrate robust quantification of cartilage compression and contact area changes in response to in situ loading by means of MRI with prospective motion correction and regularized image postprocessing.

Study Type: Cohort study.

How Symmetrical Are Bony Orbits in Humans?

Purpose: Establishing the symmetry of intraindividual orbital volumes is crucial for radiologic assessment, preoperative planning, and postoperative outcome evaluation. However, no reliable method exists to measure orbital volume because of problems in defining the bony boundaries of the orbit. Therefore, the purpose of this study was to propose a new approach to analyze human orbits and determine its application for quantifying bony symmetry in a cohort of patients.

Statistical analysis of the inter-individual variations of the bone shape, volume fraction and fabric and their correlations in the proximal femur.

Including structural information of trabecular bone improves the prediction of bone strength and fracture risk. However, this information is available in clinical CT scans, only for peripheral bones. We hypothesized that a correlation exists between the shape of the bone, its volume fraction (BV/TV) and fabric, which could be characterized using statistical modeling.

Biomechanical Role of Bone Anisotropy Estimated on Clinical CT Scans by Image Registration.

Image-based modeling is a popular approach to perform patient-specific biomechanical simulations. Accurate modeling is critical for orthopedic application to evaluate implant design and surgical planning. It has been shown that bone strength can be estimated from the bone mineral density (BMD) and trabecular bone architecture.