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Objective To compare the biomechanical stability of different fixation methods for unstable pelvic fractures, so as to provide references for clinical treatment. Methods An unstable pelvic fracture model (Tile C) with the sacroiliac joint dislocation at one side and the pubic rami fracture was constructed via three-dimensional finite element method. In the front of the pelvis, the fracture models were fixed with anterior pelvic Stoppa approach (ASA),subcutaneous anterior pelvic approach (APA), anterior pelvic ilioinguinal approach (AIA) and anterior pelvic external fixation (AEF),and the rear was fixed with sacroiliac joint screw (SIJS）and posterior tension-band plate (PTP). The Von Mises stress and strain distributions of fracture models fixed by different combinations of fixation approaches were analyzed under simulated standing conditions. Results After the models were applied with 500 N vertical load, the maximum stresses at the fracture sites were all reduced, which were smaller than 10 MPa in the front of the pelvis. The maximum stress at the anterior and posterior part of implants in sequence was ASA＜AIA＜AEF＜APA, and the average displacement under the same stress in sequence was ASA＜AIA＜AEF＜APA. Meanwhile, the maximum stresses at the sacroiliac joint and the posterior part of implants in PTP group were significant smaller than those in SIJS group, and the maximum total displacement and vertical displacement in PTP group were also smaller than those in SIJS group. Conclusions Unstable pelvic fractures could be significantly improved when the fracture was fixed by implants in eight combined methods. However, the overall biomechanical properties of the AIA groups were superior to those of the AEF groups and the APA groups. The stability of PTP groups in the treatment of posterior injury was better than that of SIJS groups.
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Objective To investigate the effect of Calcium Dobesilate Capsules in the treatment of diabetic retinopathy ( DR ) and its effect on hemorheology, vascular endothelial function and thrombin.Methods According to the random number table the 80 cases of DR patients admitted in our hospital from September 2014 to August 2016 were divided into observation group and control group, 40 cases in each group, two groups of patients were treated with conventional therapy, the observation group was treated with Calcium Dobesilate capsules.Two groups of treatment were three months.Compared of the therapeutic effects, the before and after treatment changes of visual acuity, hemorheology, vascular endothelial function and thrombin index.Results The total efficiency of the observation group 92.50% was higher than the control group 72.50% (P<0.05);After treatment, two groups visual acuity increased, and the observation group after treatment higher than the control group (P<0.05); Plasma viscosity, whole blood viscosity at high shear and low shear whole blood viscosity, erythrocyte aggregation index in two groups were decreased, and observation group lower than the control group (P<0.05);Plasma NO and ET-1 levels in two groups were reduce, and observation lower than the control group after treatment (P<0.05); After treatment, two groups PT, TT and APTT increased, and observation group PT, TT and APTT higher than the control group (P<0.05) .There were no obvious adverse reactions in the two groups during the treatment period.Conclusion The effect of calcium dobesilate capsules in the treatment of patients with DR is obvious, and it can improve hemorheology.
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Objective To compare the clinical effects of open kinetic chain (OKC) exercises with those of closed kinetic chain (CKC) exercises and limited open kinetic chain combined with closed kinetic chain exercises on rehabilitation after the anterior cruciate ligament reconstruction.Methods Ninety-four patients recovering from single-bundle anterior ligament reconstructions were enrolled and randomly divided into an OKC group (n =33),a CKC group (n =30) or a limited open kinetic chain combined with closed kinetic chain group (combined group) (n =31).Lysholm score,International Knee Documentation Committee (IKDC) score,KT-1000,and active and passive range of motion were evaluated for the 3 groups three and six months after the surgery.Results Three months after surgery,significant differences were found among the 3 groups in Lysholm scores [(87.00±4.79),(83.67± 3.55) and (86.71±3.62) respectively],IKDC scores [(89.45±4.79),(86.40±3.76) and (88.58±3.60) respectively],KT-1000[(1.99±0.30),(1.05±0.26) and (1.02±0.24) mm],as well as active and passive range of motion [(10.06±2.06),(7.73±1.41) and (8.10±1.35) mm;(9.76±2.26),(7.87±1.89) and (8.39±1.62) mm] (P＜ 0.05).Six months after surgery,no significant differences were found in Lysholm scores and IKDC scores(P＞0.05),but significant differences were found in KT-1000,and active and passive range of motion(P＜0.05) compared to those at 3 months after surgery.Moreover,there were no significant differences between the OKC and combined groups in Lysholm scores and IKDC scores(P＞0.05),but significant differences between them in active and passive range of motion (P＜0.05).There were no significant differences between the CKC and combined groups in Lysholm scores,IKDC scores,KT-1000,and active and passive range of motion(P＜0.05).Conclusion Combining limited open kinetic chain exercise with closed kinetic chain exercise is safe and reliable in the rehabilitation after anterior cruciate ligament reconstruction.
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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.
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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.
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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).
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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.
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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.
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[Objective]To discuss the method and effectiveness of arthroscopically assisted mini-incision arthrolysis for the stiff knee.[Method]A small lateral suprapatellar incision was made in all 26 patients suffered from stiff knee,and the scissors were introduced the joint to release the adhesive tissues of patellofemoral joint.All adhesive tissues between the medial,lateral retinaculum and the femur,and the between vastus intermedius and femur were released subsequently.After the release of the adherence between the fat pad and femoral condyle,the lateral retinaculum was dissected 1 cm lateral to the patellae,and the dissection of medial retinaculum was applied at the insertion of the vastus medialis.Eventually,arthroscopic debridement and hemostasis combined with manipulative release was applied to remove all remanent adhesive bundles and scar tissues.[Result]Follow-ups were maintained for an average of 19 months(range,from 8-32 months).An increase in the average range of motion of the knee was attained from 32 degrees preoperatively to 113 degrees postoperatively.No complications such as skin necrosis,wound dehiscence,tendon rupture and fracture had occurred during the follow-up period.[Conclusion]The advantages of arthroscopically assisted mini-incision arthrolysis for the stiff knee include simple procedure,minimal trauma,and quick rehabilitation.Otherwise,reservation of the insertion of vastus medialis is of great importance not only for the maintenance of extensive strength and stability of the knee,but also for the functional recovery and the reduction of complications.