Positive medial cortical support versus anatomical reduction for trochanteric hip fractures: Finite element analysis and biomechanical testing.

BACKGROUND AND OBJECTIVES: The anatomical reduction (AR) is usually considered the best option for fractures. Nevertheless, in unstable trochanteric hip fractures (UTHF), previous clinical reports found that the positive medial cortical support (PMCS, an over-reduction technique) attained higher mechanical stability, but this challenging clinical finding still needs experimental validation. METHODS: This study constructed in-silico and biomechanical PMCS and AR models, with the use of the most clinically-representative geometry design of fracture models, the multi-directional design in FE analysis, and the subject-specific (osteoporotic) bone material properties, to make the models better mimic the actual condition in clinical settings. Then multiple performance variables (von-Mises stress, strain, integral axial stiffness, displacement, structural changes, etc.) were assessed to uncover details of integral and regional stability. RESULTS: Among in-silico comparison, PMCS models showed significantly lower maximum displacement than AR models, and the maximum von Mises stress of implants (MVMS-I) was significantly lower in PMCS models than in AR models (highest MVMS-I in -30°-A3-AR of 1055.80 ± 93.37 MPa). Besides, PMCS models had significantly lower maximum von Mises stress along fracture surfaces (MVMS-F) (highest MVMS-F in 30°-A2-AR of 416.40 ± 38.01 MPa). Among biomechanical testing comparison, PMCS models showed significantly lower axial displacement. Significantly lower change of neck-shaft angle (CNSA) was observed in A2-PMCS models. A fair amount of AR models converted into the obvious negative medial cortical support (NMCS) condition, whereas all PMCS models kept the PMCS condition. The results were also validated through comparison to previous clinical data. CONCLUSIONS: The PMCS is superior to the AR in the UTHF surgery. The current study opens up the second thought of the role of over-reduction technique in bone surgery.

[Study on the Fixation Effect of Plate in the Middle Tibial Fracture Based on Finite Element Analysis].

In this study, tibial shaft fracture has been treated with implants as numerically to investigate the stress behavior and the effect of plate material, position and length under pressure load. Plates of stainless steel, titanium alloy(Ti6Al4V), or CF-PEEK(CF50) were used to fix the tibial shaft comminuted fracture in different location and different working length. The maximum stress, the maximum micromotion of fracture and the stress shielding of cortex bone were analyzed. CF50 is more ideal biomechanical fixation material than traditional metal material for the treatment of tibial shaft comminuted fractures. In the treatment of tibial shaft comminuted fracture, lateral position and with relatively long working length of the plate have the advantages in micromotion, stress and stress shielding rate of the fracture end.

Atrial fibrillation and concomitant left subclavian, axillary and brachial artery embolism after fiberoptic bronchoscopy: A case report.

BACKGROUND: Fiberoptic bronchoscopy has been widely used in the diagnosis and treatment of respiratory diseases. Numerous major and minor complications have been reported following this procedure. The incidence of major postoperative complications is approximately 0.5% and includes respiratory depression, pneumothorax, pulmonary edema, pneumonia, airway obstruction and cardiorespiratory arrest. Minor complications include vasovagal reactions, cardiac arrhythmias, hemorrhage, pneumothorax, aphonia, nausea, vomiting and fever. However, to our knowledge, a case of atrial fibrillation (AF) concomitant with fatal arterial embolism in the upper extremities following diagnostic bronchoscopy has never been reported. CASE SUMMARY: A 70-year-old female patient presented with a history of rheumatic heart disease beginning at 10 years of age and an approximately 10-year history of hypertension. The patient was transferred from the cardiology department to the respiratory department due to recurrent coughing, pneumonia, and fever. She underwent fiberoptic bronchoscopy in the respiratory department. Approximately 2 h after completion of bronchoscopy, she complained of left arm numbness and weakness. Physical examination detected cyanosis of the left upper extremity, grade III weakened limb muscle strength, and undetectable left brachial artery pulsation. Auscultation indicated AF. B-mode ultrasound examination of the blood vessels showed hyperechoic material in the left subclavian, axillary and brachial arteries, and parallel veins. As our hospital has no vascular surgery capability, the patient was transferred to a specialized hospital for emergency thrombectomy that day. A tracking investigation found that the patient's conditions improved after successful thrombectomy. CONCLUSION: Thromboembolism following bronchoscopy is rare, and only a few cases of cerebral air embolism after bronchoscopy have been reported.

The characteristics of screening and confirmatory test results for HIV in Xi'an, China.

OBJECTIVES: Individuals with recent or acute HIV infection are more infectious than those with established infection. Our objective was to analyze the characteristics of detection among HIV infections in Xi'an. METHODS: A 4th-generation kit (Architect HIV Ag/Ab Combo) and three 3rd-generationEIA kits (WanTai, XinChuang and Livzon) were used for HIV screening. Overall, 665 individuals were identified as positive and were tested by western blotting (WB). The characteristics of the screening and confirmatory tests were analyzed, including the band patterns, the early detection performance and the false-positive rates. RESULTS: In total, 561 of the 665 patients were confirmed as having HIV-1 infection, and no HIV-2 specific band was observed. Among these 561 WB-positive cases, reactivity to greater than or equal to 9 antigens was the most commonly observed pattern (83.18%), and the absence of reactivity to p17, p31 and gp41 was detected in 6.44%, 5.9% and 2.86% of the cases, respectively. Two cases were positive by the 4th-generation assay but negative by the 3rd-generation assay for HIV screening and had seroconversion. The false-positive rate of the Architect HIV Ag/Ab Combo (22.01%) was significantly higher than those of WanTai (9.88%), XinChuang (10.87%) and Livzon (8.93%), p<0.05. CONCLUSION: HIV infection in Xi'an is mainly caused by HIV-1, and individuals are rarely identified at the early phase. Although the false-positive rate of the 4th-generation assay was higher than that of the 3rd-generation assay, it is still recommended for use as the initial HIV screening test for high-risk individuals. In Xi'an, a 3rd-generation assay for screening could be considered.

Locking versus Non-locking Neutralization Plates with Limited Excision and Internal Fixation for Treatment of Extra-articular Type a Distal Tibial Fractures.

PURPOSE: This study aimed to compare the clinical, radiologic, and cost-effectiveness results between locking and non-locking plates for the treatment of extra-articular type A distal tibial fractures. METHODS: We performed a retrospective review of AO/OTA 42-A1, A2 distal tibial fractures treated by plates from January 2011 to June 2013. Patients were divided to the locking plate group or the non-locking plate group. Clinical outcomes, radiographic outcomes, and hospitalization fee were compared between the two plates groups. RESULTS: 28 patients were treated with a locking plate and 23 patients were treated with a non-locking plate. The mean follow-up was 18.8 months (12-23 months). There were no significant differences between the groups in surgical time, bleeding, bone union time, or AOFAS scores. The cost of the locking plate was ¥24,648.41 ± 6,812.95 and the cost of the non-locking plate was ¥11,642 ± 3,162.57, p < 0.001. Each group had one patient that experienced superficial infection these wounds were readily healed by oral antibiotics and dressing changes. To date, five patients in the locking group and ten patients in the non-locking group had sensations of metal stimulation or other discomfort (X2 = 3.99, p < 0.05) Until the last follow-up, 14 patients in the locking plate group and 18 patients in the non-locking plate group had their plates removed or wanted to remove their plates (X2 = 4.31, p < 0.05). CONCLUSION: The use of locking or non-locking plates provides a similar outcome in the treatment of distal fractures. However the locking plate is much more expensive than the non-locking plate.

In Situ Release of VEGF Enhances Osteogenesis in 3D Porous Scaffolds Engineered with Osterix-Modified Adipose-Derived Stem Cells.

Adipose-derived stem cells (ADSCs) can differentiate into various cell types and thus have great potential for regenerative medicine. Herein, rat ADSCs were isolated; transduced with lentiviruses expressing Osterix (Osx), a transcriptional factor essential for osteogenesis. Osx overexpression upregulated key osteogenesis-related genes, such as special AT-rich binding protein 2, alkaline phosphatase, osteocalcin, and osteopontin, at both mRNA and protein levels. In addition, mineral nodule formation and alkaline phosphatase activity were enhanced in Osx-overexpressing ADSCs. The expression of dickkopf-related protein 1, a potent Wnt signaling pathway inhibitor, was also increased, whereas that of ß-catenin, an intracellular signal transducer in the Wnt pathway, was decreased. ß-catenin expression was partially recovered by treatment with lithium chloride, a canonical Wnt pathway activator. The Osx-expressing ADSCs were then combined with 3D gelatin-coated porous poly(ɛ-caprolactone) scaffolds with a unique release prolife of entrapped recombinant human vascular endothelial growth factor (VEGF). The controlled release of VEGF promoted osteogenic differentiation capacity in vitro. When the scaffold-ADSC complexes were transplanted into rat calvarial critical-sized defects, more bone formed on the gelatin/VEGF-coated scaffolds than on other scaffold types. Taken together, the results indicate that, Osx-overexpression promotes ADSCs' osteogenesis both in vitro and in vivo, which could be enhanced by release of VEGF.

Minimally invasive surgery under fluoro-navigation for anterior pelvic ring fractures.

BACKGROUND: The incidence of pelvic fractures in trauma patients is reported to be 3-8.2%, with roughly half of these fractures being caused by high energy injuries with a potential for catastrophic hemorrhage and death. Indications for internal fixation of anterior pelvic ring are controversial. Because of fears of disturbing the pelvic hematoma and causing additional hemorrhage, open reduction and internal fixation of pelvic ring disruption is routinely delayed. In contrast to conventional surgery, percutaneous screw fixation is gaining popularity in the treatment of pelvic and acetabular fractures mainly because of minimal soft tissue damage, less operative blood loss, early surgical intervention and comfortable mobilization of the patient. Fluoro-navigation is a new surgical technique in orthopedic trauma surgery. This study is to investigate clinical results of fluoro-navigation surgery in anterior pelvic ring fractures. MATERIALS AND METHODS: From January 2006 to October 2011, 23 patients with anterior pelvic ring fractures were treated with percutaneous cannulated screw under fluoro-navigation. There were 14 men and 9 women, with a mean age of 40.1 years (range 25-55). According to the AO and Orthopedic Trauma Association classification, there were seven A 2.1, two A 2.2, one A 2.3, six B 1.2, one B 2.1: 1, one B 2.2, one C 1.2, two C 1.3 and two C 2.3 types of fractures. Amongst these patients, 13 had posterior pelvic ring injuries, 8 had other injuries including urethral, lumbar vertebrae fractures and femoral fractures. All patients were operated when their general condition stabilized after emergency management. The mean time from injury to percutaneous screw fixation of the anterior pelvic ring fracture was 12 days (3-15 days). All the anterior ring fractures were fixed with cannulated screws by two senior surgeons. They were familiar with the navigation system and had gained much experience in the computer-assisted percutaneous placement of screws. RESULTS: A total of 32 screws were inserted, including 19 in the pubic ramis and 13 in the anterior acetabular columns. The average surgical time was 23.3 min/screw. The average time of X-ray exposure was 19.1 ± 2.5 s/screw. The virtual images of fluoro-navigation were compared with real-time X-rays during and after the surgery. Compared to the final position of the screw, the average deviated distance was 3.11 mm and the average trajectory difference was 2.81°. Blood loss during the operation was minimal (22.3 ml/screw). One screw (3.1%) deviated out of the fracture site during the operation. No superficial or deep infection occurred. No patient sustained recognized neurologic, vascular, or urologic injury as a result of the percutaneous screw fixation. All fractures united at the last followup. CONCLUSIONS: Fluoro-navigation technique could become a safe, accurate, and fairly quick method for the treatment of anterior pelvic ring fractures. Standardization of the operative procedure and training are mandatory for the success of this procedure.

[Minimally invasive surgery of pelvic-acetabular fractures with fluoro-navigation].

OBJECTIVE: To investigate the clinical application of fluoro-navigation in the surgery for pelvic fractures. METHODS: A fluoro-navigation system was used to guide the placement of screws for the fixation of pelvic and acetabular fractures in 22 patients, 14 males and 8 females, aged 39.4. Totally 41 screws were inserted, 15 in pubic ramus, 13 in acetabulums, and 13 in sacroiliac joints. The images of fluoro-navigation were compared with those of the real X rays during and after surgery. RESULTS: The average time for operation was 22.7 minutes/screw, and the average time of X rays exposure was 20.2 seconds/screw. The mean deviated distance was 2.9 +/- 1.2 mm and the mean deviated angle was (2.2 +/- 0.3) degrees in the post operational verification. The blood loss during the operation was minimal (< 21.7 ml/screw). One screw (2.4%) was deviated out of the fracture during the operation. No complication was recorded after surgery. CONCLUSION: Fluoro-navigation-assisted operation for the pelvic and acetabular fracture makes the surgery more precise, safer, and time-saving with less X-ray exposure.