Objective To provide an anatomic evidence for the double-bundle posterior cruciate ligament (PCL) reconstruction, the sizes and locations of the attachments of the PCL to the tibia and the femur were measured. Methods We studied 30 cadaveric knees. PCLs were divided into anterolateral and posteromedial bundles to the insertion footprint, and those locations were measured and described. Results The distances from the center of the femoral insertions of the anterolateral and posteromedial bundles to the anterior margin of the medial femoral condyle were (8.52±1.81)mm and (11.63±1.81)mm. The vertical distances from the center of the femoral insertions of the double-bundle to the intercondylar roof were (4.67±0.55)mm and (10.32±1.23) mm. The vertical distances from the tibial insertion of the center of the double-bundle to the plane of the tibial articular surface were (8.43±1.21)mm and (14.52±2.31)mm. The distances from the medial margin of the articular cartilage of the tibial plateau to the center of the tibial insertions of double-bundle were (47.44±6.23)mm and (45.95±6.32)mm. The areas of the insertions of the anterolateral and posteromedial bundles on the femur were (107.12±15.25)mm~2 and (65.35±10.27)mm~2. The areas of the insertions of the double-bundle on the tibia were (50.07±11.33)mm~2and (51.08±10.22)mm~2. Conclusion The anatomic characteristic of the attachment of the anterolateral and posteromedial bundles was revealed, providing anatomical bases for surgery.

ObjectiveTo study the anatomic characteristic of the attachment of medial patellofemoral ligament and its function in patellar stability. MethodsThirty adult cadaver knees were used for anatomic study, and the attachments of medial patellofemoral ligament were observed and measured. Results The femoral attachment of medial patellofemoral ligament was anchored to the bone between the medial femoral epicondyle and the adductor tubercle. The fibers here were thin and narrow, and became thick and wide to the anterior. The patellar attachment was in the superior two-thirds of the medial margin of the patella. The fiber here were the thickest and the widest. Conclusion The anatomic characteristic of the attachment of medial patellofemoral ligament was revealed, providing anatomical bases for surgery.

Objective To explore the isometry of grafts in PCL(posterior cruciate ligament)double-bundle re-construction under femoral tunnel shifting condition.Method Knee specimens from ten fresh frozen cadavers were used.PCL were divided into anterolateral bundles(ALB)and posteromedial bundles(PMB)to the inser-tion footorint.The anterior,postedor,proximal,distal and central points of the two bundles'femoral attachment site were respectivelyanchored to the middle of the PCL's tibial attachment site by the trial wires.Changes in length of the intra-articular part of the wires were recorded while the knee was flexed from 0°to 120°.Result The length changes in every point were compared.All of the maximal length changes of ALB's proximal,pos-todor points and PMB's proximal points were not greater than 2mm.No significant difference between the length changes of ALB's proximal point and posterior(P=0.864>0.05)was found.Conclusions The femo-ral tunnel for the PCL double-bundle reconstruction should be located as follows:ALB should be at the middle point of upper edge of femoral attachment site(proximal point),while PIVIB at the middle point of femoral attachment site(proximal point).

Objective To study the optimum combination of orientation parameter of total hip prosthesis and acetabular safe zone on condition that the range of motion for activities of daily living (ADL) is fulfilled.Methods A three-dimensional generic parametric and visually kinematic simulation module of THA was developed.Range of motion ( ROM ) of hip flexion ≥ 110°,internal-rotation ≥30° at 90° flexion,extension ≥30° and external rotation ≥40° were defined as the normal criteria for ADL.ROM of hip flexion ≥ 120°,internal-rotation ≥45° at 90° flexion,extension ≥30° and external rotation ≥40° were as the severe criteria.The ranges of changes in general ratios (GRs) of head-neck,femoral neck antevemion ( FNA ),operative inclination (OI) and anteversion (OA) of acetabulur components were 2.0-2.92,0°-30°,10°-60°,and 0°-70° respectively.Within the limits of the upper two activity criteria,the synchronous OA of acetabulur components was calculated with every 5°change in OI of the cup,and the collodiaphyseal angle ( CDD ) was set as 135°.The safe-zone of combination of acetabulur operative anteversion (OA) and inclination (OI) was defined as the area that fulfilled the two mentioned criteria of ROM without cup-neck impingement.All parameters were analyzed by using SAS 6.12 software.Results The safe zone of acetabdar angle rose with the increase of GRs of head-neck and the safe zone of severe criteria was smaller than that of normal criteria.When the CDD angle was 135°,the sum of average aeetabular OA and acetahular OI plus 0.816 times of the FNA equaled to 84.76° innormal criteria; and the sum of average acetabular OA and acetabular OI plus 0.873 times of the FNA equaled to 92.04° in severe criteria.Conclusions A high GR of head-neck greatly increases the size of safe-zone of acetabular angle.The higher demand of ROM of hip joint requires the smaller safe zone of acetabular angle,as can be corrected by increasing the GR of head-neck.The optimum combination between the sum of average acetabular OA and acetabular OI ( Y) plus FA (X)in the normal criteria and severe criteria can be estimated by using the following formulae:Y1 =-0.816X1 + 84.76 (R2 =0.993 ),Y2 =-0.873X2 + 92.04( R2 =0.999) respectively.

Objective To discuss biomechanical mechanism of reconstructed joint capsule ligament stabilizing hip joint by means of three-dimensional finite element analysis.Methods A finite element model of total hip arthroplasty(THA)including ischiofemoral ligament reconstruction was construtted by using finite element analysis software Unigraphics NX 2.0 and SolidWorks 2006 to simulate seated leg crossing and obtain peak resisting moment and range of motion prior to impingement.Results The current form of finite element model was characterized by large deformation multi-body contact,large interfacial sliding and high elasticity and could clearly reflect real anatomy and biomechanical behavior of ischiofemoral ligaments.Compared with model with only metal,model of ischiofemoral ligament reconstruction could reduce the peak polyethylene stress at the impingement site and at the head egress site by typically 17%and 31%respectively,increase peak resisting moment by nearly 57%and provide 2.29-fold stability.Conclusions As a discrete structure within the posterior capsule of the hip joint,the ischiofemoral ligament may be the most important contributor to the mechanical integrity of the posterior stability structure.The joint capsule ligament must be reconstructed in hip arthroplasty.

It is very important to obtain high yield mutant strains on the base of metabolic flux analysis of Actinobacillus succinogenes S.JST for the industrial bioconversion of succinic acid. The metabolic pathway was analized at first and the flux of the metabolic networks was calculated by matrix. In order to decrease acetic acid flux, the strains mutated by soft X-ray of synchronous radiation were screened on the plates with high concentration of fluoroacetic acid. For decreasing the metabolic flux of ethanol the site-directed mutagenesis was carried out for the reduction of alcohol dehydrogenase(Adh) specific activity. Then the enzyme activity determination and the gene sequence analysis of the mutant strain was compared with those of the parent strain. Metabolic flux analysis of the parent strain indicated that the flux of succinic acid was 1.78(mmol/g/h) and that the flux of acetic acid and ethanol were 0.60 (mmol/g/h) and 1.04( mmol/g/h), respectively. Meanwhile the metabolic pathway analysis showed that the ethanol metabolism enhanced the lacking of H electron donor during the synthesis of succinic acid and that the succinic acid flux was weakened by the metabolism of byproducts ethanol and acetic acid. Compared with the parent strain, the acetic acid flux of anti-fluoroacetic mutant strain S.JST1 was 0.024 (mmol/g/h), decreasing by 96%. Then the enzyme determination showed that the specific activity unit of phosphotransacetylase(Pta) decreased from 602 to 74 and a mutated site was founded in the pta gene of the mutant strain S.JST1. Compared with that of the parent strain S.JST1 the ethanol flux of adh-site-directed mutant strain S.JST2 was 0.020 (mmol/g/h), decreasing by 98%. Then the enzyme determination showed that the specific activity unit of Adh decreased from 585 to 62 and the yield of end product succinic acid was 65.7 (g/L). The interdiction of Adh and Pta decreased the metabolism of byproducts and the H electron donor was well balanced, thus the succinic acid flux was strengthened by the redundant carbon flux from these byproducts. The mutant strain S.JST2 obtained in this paper deserves being extended to application of industrial fermentation.
Actinobacillus ; enzymology ; genetics ; growth & development ; Alcohol Dehydrogenase ; metabolism ; Metabolic Networks and Pathways ; genetics ; Mutagenesis, Site-Directed ; Mutation ; Phosphate Acetyltransferase ; metabolism ; Succinic Acid ; metabolism

Objective To evaluate the value of dynamic contrast-enhanced MRI (DCE-MRI)in diagnosing benign and malignant solitary pulmonary nodule (SPN)with Meta-analysis.Methods The databases including PubMed,EBSCO,Cochrane Library,Ovid, CBM,VIP,Wan Fang Database and CNKI were searched to select the literatures about the diagnosis of SPN with DCE-MRI.Inclusion criteria were established,according to the validity criteria for diagnostic research published by the Cochrane Methods Group on Screening and Diagnostic Tests .Methodological quality was assessed by using the quality assessment of diagnostic studies (QUADAS-2)instrument.Meta-analysis was performed by Stata 12.0 and Meta-Disc 1.4.According to the results of heterogeneity of the included articles,proper effect model was selected to calculate the pooled sensitivity,specificity,positive likelihood ration,negative likelihood ration,and diagnostic odds ratio.Summary receiver operating characteristic (SROC)curve was drawed and the area under the curve (AUC)was calculated.Results A total of 17 studies involving 1255 lesions were included.The results of Meta-analysis showed the pooled sensitivity,specificity,positive likelihood ration,negative likelihood ration,and diagnostic odds ratio were 0.95,0.81,4.9,0.06 and 85,respectively.The AUC of SROC was 0.97.Conclusion DCE-MRI has relatively high sensitivity and specificity in the differential diagnosis of benign and malignant SPN.