To eliminate thermal stress during laser cladding and to raise the bonding strength between substrate and coating, composition gradient coatings are designed and fabricated by using wide-band laser cladding technique on a Ti alloy. The rare earth Nd2O3 was added to improve the properties of the bioceramic coating. The experimental results indicate that when the adding of Nd2O3 reaches 0.6wt%, the characteristic peaks of HA and β-TCP are the highest, which demonstrates the amount of HA and β-TCP is the largest. However, when the content of Nd2O3 is up to 0.8wt%, the peaks of HA and β-TCP conversely goes down. The biocompatibility and bioactivity are related to the amount of HA and β-TCP catalyzed by Nd2O3. When the content of Nd2O3 is 0.6wt%, the number of cells proliferated and the ALP secreted on coatings is the most, which indicate the biocompatibility and bioactivity of gradient bioceramic coating is the best.
Background
Femoral neck fractures (FNFs) comprise a large proportion of osteoporotic fractures in Asia. However, the full range of prognostic variables that affect prognosis remains unclear. Here, we aimed to determine whether the severity of bone defects at the fracture site and other variables impact the prognosis of displaced FNFs.
Methods
We evaluated the incidence of FNF internal fixation failures at regular intervals after surgery in data collected retrospectively. Digital Imaging and Communications in Medicine (DICOM) magnetic resonance imaging data of the displaced FNFs of 204 patients (> 20 years old; mean age, 52.3 years; men, 55.4%) who underwent internal fixation were used to construct three-dimensional (3D) virtual models of the femoral neck region. We calculated the position and volume of bone defect (VBD) using our independently developed algorithm and Mimics software. Each participant was followed up for at least 24 months; complications were noted and correlated with VBD and demographic and clinical variables.
Results
On the basis of VBD values calculated from virtual reduction models, 57 patients were categorized as having a mild defect, 100 as having a moderate defect, and 47 as having a severe defect. Age (
p
= 0.046) and VBD (
p
< 0.001) were significantly correlated with internal fixation failure. Multivariate analysis revealed that severe bone defects were associated with internal fixation failure (adjusted odds ratio [aOR], 23.073; 95% confidence interval [CI], 2.791–190.732) and complications (aOR, 8.945; 95% CI, 1.829–43.749). In patients with a severe defect, bone grafting was inversely associated with internal fixation failure (aOR, 0.022; 95% CI, 0.002–0.268) and complications (aOR, 0.023; 95% CI, 0.002–0.299).
Conclusions
Bone defect severity was associated with internal fixation failure and other complications. For young adults with large VBDs, bone grafting of the defect can reduce the risk of internal fixation failure. These results provide useful new quantitative information for precisely classifying displaced FNFs and guiding subsequent optimal treatments.
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