Digital smart internal fixation surgery for coronal process basal fracture with normal joint spaces or radius-shortening: Occult factor of radius-ulna load sharing.

BACKGROUND: Reasonable postoperative humeroradial and humeroulnar joint spaces maybe an important indicator in biomechanical stability of smart internal fixation surgery for coronoid process basal fractures (CPBF). The aim of this study is to compare elbow articular stresses and elbow-forearm stability under smart internal fixations for the CPBF between normal elbow joint spaces and radius-shortening, and to determine the occult factor of radius-ulna load sharing. METHODS: CT images of 70 volunteers with intact elbow joints were retrospectively collected for accurate three-dimensional reconstruction to measure the longitudinal and transverse joint spaces. Two groups of ten finite element (FE) models were established prospectively between normal joint space and radius-shortening with 2.0 mm, including intact elbow joint and forearm, elbow-forearm with CPBF trauma, anterior or posterior double screws-cancellous bone fixation, mini-plate-cancellous bone fixation. Three sets of physiological loads (compression, valgus, varus) were used for FE intelligent calculation, FE model verification, and biomechanical and motion analysis. RESULTS: The stress distribution between coronoid process and radial head, compression displacements and valgus angles of elbow-forearm in the three smart fixation models of the normal joint spaces were close to those of corresponding intact elbow model, but were significantly different from those of preoperative CPBF models and fixed radius-shortening models. The maximum stresses of three smart fixation instrument models of normal joint spaces were significantly smaller than those of the corresponding fixed radius-shortening models. CONCLUSIONS: On the basis of the existing trauma of the elbow-forearm system in clinical practice, which is a dominant factor affecting radius-ulna load sharing, the elbow joint longitudinal space has been found to be the occult factor affecting radius-ulna load sharing. The stability and load sharing of radius and ulna after three kinds of smart fixations of the CPBF is not only related to the anatomical and biomechanical stability principles of smart internal fixations, but also closely related to postoperative elbow joint longitudinal space.

Anatomical and Biomechanical Stability of Single/Double Screw-Cancellous Bone Fixations of Regan-Morry Type III Ulnar Coronoid Fractures in Adults: CT Measurement and Finite Element Analysis.

OBJECTIVE: At present, it is still uncertain whether single screw has the same stability as double screws in the treatment of ulnar coronal process basal fracture (Regan-Morry type III). So, we aimed to compare the pull-out force and anti-rotation torque of anterior single/double screw-cancellous bone fixation (aSSBF, aDSBF) in this fracture, and further study the influencing factors on anatomical and biomechanical stability of smart screw internal fixations. METHODS: A total of 63 adult volunteers with no history of elbow injury underwent elbow CT scanning with associated three-dimensional reconstruction that enabled the measurements of bone density and fixed length of the proximal ulna and coronoid. The models of coronal process basal fracture, aSSBF and aDSBF, were developed and validated. Using the finite element model test, the sensitivity analysis of pull-out force and rotational torque was carried out. RESULTS: The pull-out force of aSSBF model was positively correlated with the density of the cancellous bone and linearly related to the fixed depth of the screw. The load pattern of pull-out force of aDSBF model was similar to that of aSSBF model. The ultimate torque of aDSBF model was higher than that of aSSBF model, but the load pattern of ultimate torque of both models was similar to each other when the fracture reset was satisfactory, and the screw nut attaches closely to coronoid process. Moreover, with enhancement of initial pre-tightening force, the increase of ultimate torque of both models was small. CONCLUSIONS: In addition to three pull-out stability factors of smart screw fixations, fracture surface fitting degree and nut fitting degree are the other two important anatomical and biomechanical stability factors of smart screw fixations both for rotational stability. When all pull-out stability and rotational stability factors meet reasonable conditions simultaneously, single or double screw fixation methods are stable for the treatments of ulnar coronoid basal fractures.

Specific Detection of Carcinoembryonic Antigen Based on Fluorescence Quenching of Hollow Porous Gold Nanoshells with Roughened Surface.

The detection of tumor biomarkers in the early stage is highly desirable for the therapy of cancer. However, rapid, low-cost, sensitive, and selective detection of biomarkers remains a challenge owing to the sequence homology, short length, and low abundance. This Research Article describes the synthesis of a novel carcinoembryonic antigen (CEA) probe using hollow porous gold nanoparticles (HPGNPs) with roughened surface based on fluorescence quenching. For specific detection of CEA, the surface of HPGNP is modified by carboxyl modification, carboxyl activation, and antibody conjugation. Furthermore, to enhance the detection performance, we have systematically optimized the parameters, such as particle size, surfactants, surface roughness, surface hole size, and the molecule-particle distance (MPD). The results demonstrate that the fluorescence quenching efficiency would be enhanced with a larger particle size and surface hole size, roughened surface and a greater MPD. Also, with careful inspection of different surfactants of CTAB and PVP, we find that PVP has the optimal performance on fluorescence quenching. Under these optimized conditions, CEA could be detected with an ultralow detection limit of 1.5 pg/mL, and the probe shows a linear range from 2 to 100 pg/mL. The limit of detection is an order of intensity lower than related methods. Interference experiment results have shown that the influence of the interfering proteins could be neglected in the detection procedure.