Jing-xin Zhao

Outcome of posterior cruciate ligament reconstruction using the single- versus double bundle technique: A meta-analysis

Objective To test the hypothesis that double bundle posterior cruciate ligament (PCL) reconstruction yields better improvement in stability and functional recovery of the knee than the single bundle technique. Methods PubMed®, Embase®, the Cochrane Library, CNKI, Wanfang and CBM disc databases were searched for comparative trials of PCL reconstruction using the single- versus double bundle technique. Data were extracted and meta-analysis was performed for stability improvement and functional recovery. Results The meta-analysis included 435 patients in three randomized controlled trials (RCTs) and eight non-RCTs. Double bundle reconstruction provided significantly better 90° posterior stability than the single bundle technique (weighted mean difference 0.81, 95% confidence interval, [CI] 0.2, 1.42). Double bundle reconstruction resulted in a significantly higher likelihood of International Knee Documentation Committee (IKDC) examination grade A than the single bundle technique (odds ratio 0.41, 95% CI 0.24, 0.72). Conclusions The small amount of data available indicates that double bundle reconstruction is superior to the single bundle technique after isolated PCL injury. These findings should be interpreted with caution due to the low quality and limited sample size of the studies concerned.

Chitosan–plasmid DNA nanoparticles encoding small hairpin RNA targeting MMP-3 and -13 to inhibit the expression of dedifferentiation related genes in expanded chondrocytes

Overexpression of matrix metalloproteinase (MMP)-3 and -13 can lead to the dedifferentiation of expanded chondrocytes. After implanting dedifferentiated cells for cartilage defect repair, graft failure may occur. Short hairpin RNA (shRNA) is a powerful genetic tool to reduce the expression of target genes. This study investigated the effects of chitosan-plasmid DNA (pDNA) nanoparticles encoding shRNA targeting MMP-3 and -13 on the dedifferentiation of expanded chondrocytes. The objective was to optimize the parameters of chitosan-pDNA formulation for achieving higher efficiency of pDNA delivery and gene silencing. The chitosan-pDNA nanoparticles were prepared using a complex coacervation process. Then the characteristics including size, shape, stability, and transfection efficiency were compared in different groups. The results indicated that chitosan of 800 kDa at N/P ratio of 4 and pH 7.0 was optimal to prepare chitosan-pDNA nanoparticles. These nanoparticles showed high DNA loading efficiency (95.8 ± 1.5%) and high gene transfection efficiency (24.5 ± 1.6%). After the expanded chondrocytes were transfected by chitosan-pDNA nanoparticles, MMP-3-610 and MMP-13-2024 groups showed greater suppression in mRNA and protein levels. The results indicated that chitosan-pDNA nanoparticles encoding shRNA targeting MMP-3 and -13 had great potential in silencing the dedifferentiation-related genes for regenerating prolonged and endurable cartilage.

Three-Dimensional Analysis of the Curvature of the Femoral Canal in 426 Chinese Femurs.

Purpose. The human femur has long been considered to have an anatomical anterior curvature in the sagittal plane. We established a new method to evaluate the femoral curvature in three-dimensional (3D) space and reveal its influencing factors in Chinese population. Methods. 3D models of 426 femurs and the medullary canal were constructed using Mimics software. We standardized the positions of all femurs using 3ds Max software. After measuring the anatomical parameters, including the radius of femoral curvature (RFC) and banking angle, of the femurs using the established femur-specific coordinate system, we analyzed and determined the relationships between the anatomical parameters of the femur and the general characteristics of the population. Results. Pearsons correlation analyses showed that there were positive correlations between the RFC and height (r = 0.339, p < 0.001) and the femoral length and RFC (r = 0.369, p < 0.001) and a negative correlation between the femoral length and banking angle (r = −0.223, p < 0.001). Stepwise linear regression analyses showed that the most relevant factors for the RFC and banking angle were the femoral length and gender, respectively. Conclusions. This study concluded that the banking angle of the femur was significantly larger in female than in male.

A mathematical method for precisely calculating the radiographic angles of the cup after total hip arthroplasty.

We established a mathematical method to precisely calculate the radiographic anteversion (RA) and radiographic inclination (RI) angles of the acetabular cup based on anterior-posterior (AP) pelvic radiographs after total hip arthroplasty. Using Mathematica software, a mathematical model for an oblique cone was established to simulate how AP pelvic radiographs are obtained and to address the relationship between the two-dimensional and three-dimensional geometry of the opening circle of the cup. In this model, the vertex was the X-ray beam source, and the generatrix was the ellipse in radiographs projected from the opening circle of the acetabular cup. Using this model, we established a series of mathematical formulas to reveal the differences between the true RA and RI cup angles and the measurements results achieved using traditional methods and AP pelvic radiographs and to precisely calculate the RA and RI cup angles based on post-operative AP pelvic radiographs. Statistical analysis indicated that traditional methods should be used with caution if traditional measurements methods are used to calculate the RA and RI cup angles with AP pelvic radiograph. The entire calculation process could be performed by an orthopedic surgeon with mathematical knowledge of basic matrix and vector equations.

Predicting the optimal entry point for femoral antegrade nailing using a new measurement approach.

PurposeTo establish a new reliable approach for measuring proximal femoral anatomical parameters and determining the optimal entry point of the antegrade intramedullary (IM) nailing.MethodsA new method for measuring the proximal femoral anatomy and locating the optimal entry point for the antegrade nailing was developed using Mimics and 3-Matic softwares (Materialise, Haasrode, Belgium). After verifying the reliability of the measurement method using 15 pairs of the femoral models by the intraclass correlation coefficient, the anatomical parameters of 200 Chinese femurs were measured, and statistical analyses were performed to compare the proximal femoral anatomical parameters between different genders or lateralities and determine the most relevant factors of the optimal entry point.ResultsReliability study showed that both intraobserver reliability and interobserver reliability of the current measurement approach were excellent. After independent samples

A computer aided measurement method for unstable pelvic fractures based on standardized radiographs

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Computer aided pelvic reduction frame for anatomical closed reduction of unstable pelvic fractures

T-test, the proximal femoral anatomical parameters were shown significant difference between genders. Stepwise regression statistical analyses showed that the most relevant factors of the distances between the optimal entry point and the femoral head centre, the femoral neck axis and the tip of the greater trochanter were the 3D femoral neck-shaft angle (Pearson’s