miR-181b promotes angiogenesis and neurological function recovery after ischemic stroke.

Promotion of new blood vessel formation is a new strategy for treating ischemic stroke. Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke. miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model, while its effect on ischemic stroke remains elusive. In this study, we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell proliferation and enhanced angiogenesis. In rat models of focal cerebral ischemia, overexpression of miR-181b reduced infarction volume, promoted angiogenesis in ischemic penumbra, and improved neurological function. We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3'-UTR of phosphatase and tensin homolog (PTEN) mRNA to induce PTEN downregulation, leading to activation of the protein kinase B (Akt) pathway, upregulated expression of vascular endothelial growth factors, down-regulated expression of endostatin, and promoted angiogenesis. Taken together, these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stroke through activating the PTEN/Akt signal pathway and promoting angiogenesis.

Biomechanical evaluation of compression buttress screw and medial plate fixation for the treatment of vertical femoral neck fractures.

OBJECTIVE: To compare the biomechanical properties of compression buttress screw (CBS) fixation with three plate fixation methods for the treatment of vertical femoral neck fractures (FNFs). METHODS: A total of forty synthetic femoral models with simulated Pauwels type III fractures (angle of 70°) were equally assigned to one of four fixation groups: CBS fixation, anteromedial plate fixation (AMP), medial buttress plate fixation (MBP) and medial buttress plate fixation without proximal screw (MBPw). Within each group, half of the specimens were randomly assigned to two loading settings, an axial compression loading test and a hip-flexion torsion test. RESULTS: There were no significant differences in axial load to failure, axial stiffness, torsional strength, or torsional stiffness when comparing CBS with MBP (p>0.05). In the axial compression loading test, both CBS and MBP showed higher load to failure and axial stiffness than MBPw (p<0.05). In torsional testing, AMP exhibited superior torsional strength and torsional stiffness than both MBPw and MBP (all p<0.05) and a higher torsional strength than CBS fixation (p<0.05). There were no significant differences in torsional stiffness between the CBS and AMP fixation groups (p>0.05). CONCLUSION: The biomechanical parameters of CBS fixation are comparable to that of AMP and MBP, and demonstrate superior axial stiffness than MBPw fixation. Although the CBS method for surgical fixation of vertical FNF holds promise as a less invasive surgical technique than plate fixation with similar biomechanical assessments, further clinical evaluation is warranted.

Decreased complications but a distinctive fixation loosening mechanism of fully threaded headless cannulated screw fixation for femoral neck fractures in young adults.

BACKGROUND: Despite being a commonly encountered injury in orthopedic practice, controversy surrounds the methods of optimal internal fixation for femoral neck fractures (FNF) in young patients. The objective of the present study is to compare complication rates and failure mechanisms for surgical fixation of FNF using fully threaded headless cannulated screws (FTHCS) versus partial threaded cannulated screws (PTS) in young adults. METHODS: A total of 75 patients (18-65 years old) with FNF were prospectively treated with close reduction and internal fixation using three parallel FTHCS and compared to a historical control case-matched group (75 patients) with FNF treated by PTS fixation. After 2 years follow-up, rates of fixation failure (including varus collapse, fracture displacement, and femoral neck shortening), nonunion, and avascular necrosis of the femoral head (ANFH) were compared between the two cohorts. The demographic, follow-up information, and radiological images were assessed by independent blinded investigators. RESULTS: Patient demographics and fracture patterns were similar in the two patient groups. The overall fixation failure rates were 8% (6/75) in the FTHCS cohort, which was significantly lower than the 25.3% (19/75) seen in the PTS group. Rates of nonunion and ANFH were significantly lower in the FTHCS group when compared to the PTS control group. When stratified by injury severity (high-energy vs. low-energy fractures), the rate of fixation failure was significant lower with the use of FTHCS when compared with PTS for high-energy fractures while there was no difference in the rates of nonunion or ANFH for high or low-energy fracture patterns. Unique to the FTHCS cohort was an atypical screw migration pattern with varus collapse (6/75, 8%). CONCLUSIONS: The results show that FTHCS fixation could significantly reduce the complication rate of young patients with FNF, especially in high-energy fracture patterns (Garden III-IV, Pauwels III, or vertical of the neck axis (VN) angle ≥ 15°). There was also confirmation that the modes of fixation loosening in the FTCHS group, including screw "medial migration" and superior cutout, were different from the screw withdrawal pattern seen in the PTS cohort. TRIAL REGISTRATION: The study was retrospectively registered at www.Chictr.org.cn ( ChiCTR-IPR-1900025851 ) on September 11, 2019.

Tibial plateau fractures in elderly people: an institutional retrospective study.

BACKGROUND: Tibial plateau fractures are the most common intra-articular fractures, which require careful evaluation and preoperative planning. The treatment of tibial plateau fractures in elderly patients is challenging, and the comprehension of epidemiology and morphology can be helpful. This study described the characteristics of geriatric tibial plateau fractures. METHODS: A total of 327 (23.24%) patients aged ≥60 years were reviewed in our level one trauma center over a 4-year period (from January 2013 to November 2016). The following parameters were collected and evaluated: (1) demographic data, (2) injury mechanisms and (3) fracture classifications. RESULTS: Females accounted for 60.86% in all included elderly patients. Electric-bike accidents were the cause of 32.42% of all these injuries, and 39.62% of these led to high-energy injuries. The most common type of fracture was Schatzker II (54.74%). According to the three-column classification, single lateral column fracture (28.75%) and four-quadrant fracture (involving lateral, medial, posterolateral and posteromedial fractures) (23.24%) were the two most frequent patterns. In all cases, 67.58% involved the posterior column, and the prevalence of posterolateral and posteromedial fractures were 62.69% and 37.92% respectively. Isolated posterior column fractures accounted for 12.54% of patients in total, which mostly consisted of posterolateral fracture in older females (85.37%). CONCLUSIONS: The majority of elderly patients with tibial plateau fractures are females, and Electric-bike accidents are an important cause of injury. Geriatric tibial plateau fractures have unique distribution in classification.

Reinforcement strategy for lateral rafting plate fixation in posterolateral column fractures of the tibial plateau: The magic screw technique.

BACKGROUND: A posterolateral column fracture of the tibial plateau (PLCF) is not uncommon, especially lateral and bicondylar tibial plateau fractures. Currently, there is no consensus on the methods of surgical treatment for PLCF, including the surgical approach or the fixation strategy. Though various posterior approaches have been explored and can allow posterior buttress plate fixation, the necessity of a posterior approach with fixation for PLCFs is increasingly questioned. Meanwhile, there is no literature to analyse the morphological features of PLCFs. None of the available surgical techniques can solve all of the problems of PLCFs. METHODS: From February 2016 to June 2016, an inconsecutive series of 16 patients who suffered Schatzker type II tibial plateau fractures involving the posterolateral column were selected based on an analysis of the morphological characteristics of PLCFs. The patients were all treated by lateral rafting plate fixation with magic screw implantation through the extended lateral approach. RESULTS: According to PLCF morphology, 4 patients had mild slope-type depression fractures (MSDF) of the articular surface, and the other 12 patients had block-type splitting fractures (BSF). After a 12-month follow-up period, there were no complications related to the fixation technique and no significant changes in limb alignment. At the final follow-up, the average range of motion (ROM) of the affected knees was 2.3°-125°, and the average HSS score was 94.2. CONCLUSIONS: The selected patients who suffered Schatzker type II fractures involving the posterolateral column could be successfully treated via lateral rafting plate fixation with the magic screw technique. For PLCF treatment, magic screw fixation is a valuable technique that may reduce the utilization of posterior approaches and posterior fixations.

Application of avidin-biotin technology to improve cell adhesion on nanofibrous matrices.

BACKGROUND: Electrospinning is an easy and effective technique to produce submicron fibers possessing a range of attractive characteristics such as interconnected porous structures similar to natural ECM and good resilience to movement. Rapid and efficient cell attachment to nanofibrous matrices is a necessary prerequisite in tissue engineering. Thus, the aim of this study is to evaluate poly(ε-caprolactone-co-lactide)/Pluronic (PLCL/Pluronic) nanofibrous matrices with avidin-biotin technology for improving cell adhesion for the first time. RESULTS: PLCL/Pluronic nanofibers had relatively homogeneous fibers and interconnected porous structures. Pluronic significantly modified the hydrophilicity of nanofibrous matrices and PLCL/Pluronic nanofibrous matrices had better performance on maintaining cell proliferation. Avidin-biotin technology had no negative effect on the hydrophilic property, mechanical property and cell proliferation. Meanwhile, the attachment and spreading of adipose-derived stem cells (ADSCs) onto PLCL/Pluronic nanofibrous matrices with avidin-biotin technology was promoted obviously. CONCLUSIONS: PLCL/Pluronic nanofibrous matrices inheriting the excellent characteristics of both PLCL and Pluronic have the better cell adhesion ability through avidin-biotin technology, implying a promising application in skin care, tissue regeneration and other related area.