Scapholunate Kinematics After Combined Palmar and Dorsal Ligament Reconstruction: A Quantitative Evaluation Using Four-Dimensional Computed Tomography.

Purpose: This observational pilot study investigated (1) carpal positioning in the neutral wrist pose, (2) the scapholunate (SL) rotation axis, (3) physiological SL motion, and (4) the SL distance after combined palmar and dorsal SL ligament reconstruction using quantitative four-dimensional computed tomography (4D-CT) imaging.

Methods: Six subjects were included, and 4D-CT images of both wrists were obtained. Kinematic parameters of the treated side were compared to those of the healthy contralateral side, which was used as the normal reference.

Patient-specific scaphoid prosthesis: surgical technique.

The scaphoid bone is essential for wrist stability, force transmission, and movement, being crucial for maintaining carpal kinematics. In cases where the scaphoid is non-reconstructable, a complete replacement can serve as a treatment option to preserve carpal alignment and motion. This approach has evolved since its first descriptions in 1945, benefiting significantly from advancements in patient-specific implant design, additive manufacturing/3D printing, and material use in recent years.

Accuracy of intertrochanteric osteotomy for patients with slipped capital femoral epiphysis operated with 3D printed patient-specific guides.

Background: Slipped Capital Femoral Epiphysis (SCFE), is one of the most common hip disorders in adolescents, and is treated surgically by performing an Imhäuser osteotomy. The use of 3D printed guides has shown promise in improving the accuracy of the osteotomy. However, misplacement of the guide may limit the improvement.

Bilateral symmetry assessment of healthy forearm kinematics using 4D-CT.

Advanced stage distal radio-ulnar joint (DRUJ) injury may warrant radius corrective osteotomy or arthroplasty. These procedures aim to restore geometry, function and kinematics and could benefit from preoperative planning where the contralateral forearm is typically used as reference. Natural variations regarding geometry and function between forearms are known but kinematic differences are not.

Complete absence of GLUT1 does not impair human terminal erythroid differentiation.

The glucose transporter 1 (GLUT1) is 1 of the most abundant proteins within the erythrocyte membrane and is required for glucose and dehydroascorbic acid (vitamin C precursor) transport. It is widely recognized as a key protein for red cell structure, function, and metabolism. Previous reports highlighted the importance of GLUT1 activity within these uniquely glycolysis-dependent cells, in particular for increasing antioxidant capacity needed to avoid irreversible damage from oxidative stress in humans.

Non-invasive quantitative assessment of induced component displacement can safely and accurately diagnose tibial component loosening in patients: A prospective diagnostic study.

Purpose: Aseptic loosening often requires major, expensive and invasive revision surgery. Current diagnostic modalities merely show indirect signs of loosening. A recent proof of concept study proposed a non-invasive technique for the quantitative and visual assessment of implant movement as a diagnostic aid for tibial component loosening.

A three-dimensional algorithm for precise measurement of human auricle parameters.

Measurement of auricle parameters for planning and post-operative evaluation presents substantial challenges due to the complex 3D structure of the human auricle. Traditional measurement methods rely on manual techniques, resulting in limited precision. This study introduces a novel automated surface-based three-dimensional measurement method for quantifying human auricle parameters.

Minimal but potentially clinically relevant anteroinferior position of the humeral head following traumatic anterior shoulder dislocations: A 3D-CT analysis.

In unstable shoulders, excessive anteroinferior position of the humeral head relative to the glenoid can lead to a dislocation. Measuring humeral head position could therefore be valuable in quantifying shoulder laxity. The aim of this study was to measure (1) position of the humeral head relative to the glenoid and (2) joint space thickness during passive motion in unstable shoulders caused by traumatic anterior dislocations and in contralateral uninjured shoulders.

Complete absence of GLUT1 does not impair human terminal erythroid differentiation.

The Glucose transporter 1 (GLUT1) is one of the most abundant proteins within the erythrocyte membrane and is required for glucose and dehydroascorbic acid (Vitamin C precursor) transport. It is widely recognized as a key protein for red cell structure, function, and metabolism. Previous reports highlighted the importance of GLUT1 activity within these uniquely glycolysis-dependent cells, in particular for increasing antioxidant capacity needed to avoid irreversible damage from oxidative stress in humans.

Primary arthrodesis versus open reduction and internal fixation following intra-articular calcaneal fractures: a weight-bearing CT analysis.

Purpose: To compare primary arthrodesis (PA) versus open reduction and internal fixation (ORIF) in displaced intra-articular calcaneal fractures (DIACFs), based on clinical outcome and 2D and 3D geometrical analyses obtained from weight-bearing (WB) cone-beam CT images.

Materials And Methods: In this prospective study, 40 patients with surgically treated calcaneal fractures were included, consisting of 20 PA and 20 ORIF patients. Weight-bearing cone-beam CT-images of the left and right hindfoot and forefoot were acquired on a Planmed Verity cone-beam CT-scanner after a minimum of 1-year follow-up.

Load-induced deformation of the tibia and its effect on implant loosening detection.

CT imaging under external valgus and varus loading conditions and consecutive image analysis can be used to detect tibial implant loosening after total knee arthroplasty. However, the applied load causes the tibia to deform, which could result in an overestimation of implant displacement. This research evaluates the extent of tibia deformation and its effect on measuring implant displacement.

Performance of the Aptis Distal Radioulnar Joint Implant: A Clinical Case Series Including Four-Dimensional Computed Tomography Kinematic Analysis.

High complication rates and surgical revision rates following Aptis implant placement have been reported in the literature. This study evaluates the performance of the Aptis implant of twelve patients using four-dimensional kinematic analysis. The (mean) follow-up was 58 months.

Promising results of an non-invasive measurement of knee implant loosening using a loading device, CT-scans and 3D image analysis.

Background: After total knee arthroplasty up to 13% requires revision surgery to address loosening. No current diagnostic modalities have a sensitivity or specificity higher than 70-80% to detect loosening, leading to 20-30% of patients undergoing unnecessary, risky and expensive revision surgery. A reliable imaging modality is required to diagnose loosening.

Quantification of the methodological error in kinematic evaluation of the DRUJ using dynamic CT.

Distal radio-ulnar joint (DRUJ) motion analysis using dynamic CT is gaining popularity. Following scanning and segmentation, 3D bone models are registered to (4D-)CT target frames. Imaging errors like low signal-to-noise ratio (SNR), limited Z-coverage and motion artefacts influence registration, causing misinterpretation of joint motion.

Metatarsophalangeal and interphalangeal joint angle measurements on weight-bearing CT images.

Background: The aim of this study was to present and evaluate methods of measuring toe joint angels using joint-surface based and inertial axes approaches.

Methods: Nine scans of one frozen human cadaveric foot were obtained using weight-bearing CT. Two observers independently segmented bones in the forefoot and measured metatarsalphalangeal joint (MTPJ) angles, proximal and distal interphalangeal joint (PIPJ and DIPJ) angles and interphalangeal angles of the hallux (IPJ) using 1) inertial axes, representing the long anatomical axes, of the bones and 2) axes determined using centroids of articular joint surfaces.

Assessment of foot deformities in individuals with cerebral palsy using weight-bearing CT.

Objective: The aims of this study were to visualize and quantify relative bone positions in the feet of individuals with cerebral palsy (CP) with a foot deformity and compare bone positions with those of typically developed (TD) controls.

Materials And Methods: Weight-bearing CT images of 14 individuals with CP scheduled for tendon transfer and/or bony surgery and of 20 TD controls were acquired on a Planmed Verity WBCT scanner. Centroids of the navicular and calcaneus with respect to the talus were used to quantify foot deformities.

Kinematic analysis of forearm rotation using four-dimensional computed tomography.

This study aimed to quantify forearm kinematics with a focus on the forearm rotation axis. Ten healthy volunteers were included in the study. One three-dimensional computed tomographic scan and two four-dimensional computed tomographic scans were done in all the arms to capture forearm joint motion.

Translation of 3D Anatomy to 2D Radiographic Angle Measurements in the Ankle Joint: Validity and Reliability.

Background: The objective consisted of 2 elements, primarily to define 2 bone geometry variations of the ankle that may be of prognostic value on ankle instability and secondly to translate these bone variations from a 3D model to a simple 2D radiographic measurement for clinical use.

Methods: The 3D tibial and talar shape differences derived from earlier studies were translated to two 2D radiographic parameters: the medial malleolar height angle (MMHA) and talar convexity angle (TCA) respectively to ensure clinical use. To assess validity, the MMHA and TCA were measured on 3D polygons derived from lower leg computed tomographic (CT) scans and 2D digitally reconstructed radiographs (DRRs) of these polygons.

Functional bracing in distal radius fractures: a cadaveric pilot study.

Background: Extra-articular distal radius fractures are often treated by circular casting. A functional brace, however, may equally support the fracture zone but allows early mobilization of the radiocarpal joint. Since the amount of fracture movement for different types of fixation is currently unknown, a study was initiated to investigate the degree of bone displacement in extra-articular distal radius fractures fixated by regular circular casting, functional bracing, or no-fixation.

Comparison of an oblique single cut rotation osteotomy with a novel 3D computer-assisted oblique double cut alignment approach.

An oblique double-cut rotation osteotomy (ODCRO) enables correcting a complex bone deformation by aligning, in 3D, the distal, middle and proximal bone segments with a target bone, without intersegmental gaps. We propose virtual preoperative planning of an ODCRO. To minimize a residual translation error, we use an optimization algorithm and optimize towards bone length, alignment in the transverse direction, or a balanced reconstruction.

Madelung Deformity: Radioscapholunate Arthrodesis With a Neo-DRUJ.

Background: Madelung deformity is a rare wrist anomaly that causes considerable pain while restricting function. In this study, we describe a radioscapholunate (RSL) arthrodesis with a neo-distal radioulnar joint (DRUJ) in Madelung deformity patients with an abnormal sigmoid notch and compare results to patients after a reverse wedge osteotomy.

Methods: Six wrists underwent RSL arthrodesis with a neo-DRUJ in a two-phase approach: (1) modified RSL arthrodesis with triquetrectomy; and (2) distal scaphoidectomy.