IGF-PLGA microspheres promote angiogenesis and accelerate skin flap repair and healing by inhibiting oxidative stress and regulating the Ang 1/Tie 2 signaling pathway.

Random flaps are widely used in the treatment of injuries, tumors, congenital malformations, and other diseases. However, postoperative skin flaps are prone to ischemic necrosis, leading to surgical failure. Insulin-like growth factor- 1(IGF-1) belongs to the IGF family and exerts its growth-promoting effects in various tissues through autocrine or paracrine mechanisms. Its application in skin flaps and other traumatic diseases is relatively limited. Poly (lactic-co-glycolic acid) (PLGA) is a degradable high-molecular-weight organic compound commonly used in biomaterials. This study prepared IGF-PLGA sustained-release microspheres to explore their impact on the survival rate of flaps both in vitro and in vivo, as well as the mechanisms involved. The research results demonstrate that IGF-PLGA has a good sustained-release effect. At the cellular level, it can promote 3T3 cell proliferation by inhibiting oxidative stress, inhibit apoptosis, and enhance the tube formation ability of human umbilical vein endothelial cells (HUVEC) . At the animal level, it accelerates flap healing by promoting vascularization through the inhibition of oxidative stress. Furthermore, this study reveals the role of IGF-PLGA in activating the Angiopoietin-1(Ang1)/Tie2 signaling pathway in promoting flap vascularization, providing a strong theoretical basis and therapeutic target for the application of IGF-1 in flaps and other traumatic diseases.

Suture anchors for primary deltoid ligament repair associated with acute ankle fractures.

The aim of the study is to evaluate the clinical effect of primary suture anchors repair in the treatment of deltoid ligament rupture associated with ankle fractures. 34 patients with acute deltoid ligament rupture associated with ankle fractures were selected between 2011 and 2014. Medial clear space (MCS), American Orthopaedic Foot and Ankle Society (AOFAS) scores, visual analog scale (VAS) were noted. The mean follow-up was 28.4 (range, 22-35) months. The mean AOFAS score was 92.6 (range, 90-95) and the mean VAS score was 1.06±0.65 (range 0 to 2) points at the final follow-up. The mean MCS is (9.10±4.99) mm before and (3.71±0.33) mm after surgery in radiographs. At the postoperative final follow-up, the mean MCS of injured ankle is (3.74±0.32) mm in radiographs, and (3.65±0.17) mm of uninjured contralateral ankle. Using suture anchors for the primary repair of deltoid ligament rupture during the treatment of ankle fractures can achieve satisfactory outcomes.

Direct anterior approach for mini plate fixation of Regan-Morrey type II comminuted ulnar coronoid process fracture.

BACKGROUND: The goal of this study was to evaluate the clinical effect of Regan-Morrey type II comminuted coronoid process fracture treated with mini plate through the direct anterior approach (DAA). METHODS: Ten patients who underwent open reduction and internal fixation (ORIF) with mini plate through the DAA between February 2013 and August 2016 was included. There were three women and seven men, with an average age of 34.4 ± 7.5 years. At the final follow-up, the Mayo Elbow Performance Index (MEPS), Visual Analogue Scale (VAS) score, Disability of the Arm, Shoulder, and Hand (DASH) score, and the elbow range of motion were noted. RESULTS: The mean follow-up was 26.3 ± 2.2 (range 24-31) months. The mean elbow arc of motion was 118.5° with a mean arc of extension of 4° ± 5.2° and flexion of 122.5° ± 7.2°.The mean forearm pronation was 72° ± 7.2°, and the mean supination was 68° ± 6.3° with a mean forearm rotation arc of 140°. The average postoperative score according to the MEPS was 91 ± 5.7 points (range 80-100 points), and all patients achieved satisfactory scores (8 excellent and 2 good). The final average VAS score was 0.6 ± 1 (range 0-3). The final average DASH score was 4.0 ± 1.6 (range 2.3-7.4). None of the patients complained about elbow instability that required secondary surgery. No complications of infection, joint incongruency, fracture nonunion, median nerve palsy, or implant failure were reported. CONCLUSIONS: ORIF with mini plate through the DAA for the treatment of the type II comminuted coronoid process fractures can achieve satisfactory outcomes.

Relationship Between Apoptosis of Endplate Microvasculature and Degeneration of the Intervertebral Disk.

OBJECTIVE: To explore the relationship between intervertebral disk degeneration and endplate microvasculature, and to determine the role of apoptosis in the pathophysiology underlying end plate microvasculature. METHODS: Twelve 6-month-old rabbits were randomly divided into group A (control group where animals underwent a sham operation, in which the loading device was implanted but without loading) and group B (degeneration group, where a calibrated spring within the loading device would immediately create static shear force of 50 N to the disk of L4-5). Paraffin-embedded midsagittal sections of the L4-5 disk were obtained 4 weeks after surgery in the both groups. Sections were stained with cluster of differentiation (CD) 31 immunohistochemistry to measure the blood vessel density in the endplate, with CD31 immunofluorescence and terminal dUTP nick-end labeling (TUNEL) to detect the apoptosis of vascular endothelial cells in the endplate. RESULTS: After 4 weeks, the microvasculature density was 91 ± 8 vessels/mm2 in group A and 47 ± 2 vessels/mm2 (P < 0.001) in group B, demonstrating that vessels were reduced in the endplate of intervertebral disk degeneration. CD31 immunofluorescence and TUNEL showed that apoptosis of vascular endothelial cells exists in the endplate of intervertebral disk degeneration. CONCLUSIONS: The results of this study suggest that apoptosis of vascular endothelial cells results in a decrease in endplate microvasculature density, further affecting the pathologic process of intervertebral disk degeneration.

Magnetic Resonance-Based Morphological Features of the Manubrium and the Surgeons' View Line: When to Use Manubriotomy?

OBJECTIVE: We sought to identify the morphological features of the relationship between the manubrium and vertebrae of the cervicothoracic junction for use in guidelines for the selection of the appropriate surgical approach. METHODS: We performed a review of 222 midsagittal section magnetic resonance imaging scans. The surgeons' view line was parallel to the inferior caudal vertebral endplate. Morphometric measurement of the manubrium and the cervicothoracic junction's vertebral body included the distance from the highest point of the manubrium to the surgeons' view line and the angle between that line to the horizontal line. RESULTS: A significant difference was found with regard to the distance between the groups (P < 0.001). A significant difference between males and females was also identified. The lowest level above the manubrium was the T1. Between the groups, the angles were significantly different (P ≤ 0.01). Males had a larger angle than females with respect to groups C6, C7, T1 (P < 0.001), and T2 (P = 0.007). In terms of both the distance and the angle, no significant difference was found according to age (P > 0.05). CONCLUSION: Our results have provided insight into the anatomy of the manubrium and vertebrae of the cervicothoracic junction. Furthermore, our results have shown that, for most people, the T1 forms the boundary of the manubriotomy. We found that both the distance and angle differed significantly according to sex. A better understanding of the radiological anatomy of the surgeons' view line will help in the preoperative assessment of patients and in indicating an appropriate surgical approach.

Chloroquine Promotes the Recovery of Acute Spinal Cord Injury by Inhibiting Autophagy-Associated Inflammation and Endoplasmic Reticulum Stress.

Spinal cord injury (SCI) is a severe nervous system disease that may lead to lifelong disability. Studies have shown that autophagy plays a key role in various diseases; however, the mechanisms regulating cross-talk between autophagy, inflammation, and endoplasmic reticulum (ER) stress during SCI recovery remain unclear. This study was designed to investigate the mechanism by which chloroquine (CQ) inhibits autophagy-associated inflammation and ER stress in rats during their recovery from acute SCI. We evaluated the locomotor function, level of autophagy, and levels of inflammatory cytokines and ER-stress-associated proteins and examined the degradation of the key regulator of inflammation inhibitor of kappa B alpha (I-κBα) through autophagy by analyzing the colocalization of I-κBα, p62, and microtubule-associated protein 1 light chain 3-II. In addition, overexpression of the p62 and activating transcription factor 4 (ATF4) silencing plasmids was used to verify the important roles for autophagic degradation and ER stress. In this study, locomotor function is improved, and autophagy and inflammation are significantly inhibited by, CQ treatment in the model rats. In addition, CQ significantly inhibits the degradation of ubiquitinated I-κBα and blocks the nuclear translocation of nuclear factor kappa B p65 and expression of inflammatory factors. Overexpression of p62 increases I-κBα degradation and improves inflammatory responses. Moreover, CQ treatment also inhibits the activation of ER stress in the rat SCI model, and the ATF4 signaling pathway is required for ER-stress-induced activation of autophagy. These findings reveal a novel mechanism underlying the beneficial effects of CQ on the recovery of SCI, particularly the mechanisms regulating cross-talk between autophagy, inflammation, and ER stress.

Dl-3-n-butylphthalide prevents the disruption of blood-spinal cord barrier via inhibiting endoplasmic reticulum stress following spinal cord injury.

After spinal cord injury (SCI), the destruction of blood-spinal cord barrier (BSCB) is shown to accelerate gathering of noxious blood-derived components in the nervous system, leading to secondary neurodegenerative damages. SCI activates endoplasmic reticulum stress (ER stress), which is considered to evoke secondary damages of neurons and glia. Recent evidence indicates that Dl-3-n-butylphthalide (NBP) has the neuroprotective effect in ischaemic brain injury, but whether it has protective effects on SCI or not is largely unclear. Here, we show that NBP prevented BSCB disruption after SCI via inhibition of ER stress. Following a moderate contusion injury of the T9 level of spinal cord, NBP was administered by oral gavage and further treated once a day. NBP significantly attenuated BSCB permeability and breakdown of adherens junction (AJ) and tight junction (TJ) proteins, then improved locomotion recovery following SCI. The protective role of NBP on BSCB disruption is associated with the restrain of ER stress caused by SCI. Furthermore, NBP considerably constrained the expression of ER stress-associated proteins and degradation of TJ and AJ in human brain microvascular endothelial cells (HBMECs) treated with TG. In conclusion, our results indicate that ER stress is associated with the disruption of BSCB integrity after injury, NBP attenuates BSCB disruption via inhibiting ER stress and improve functional recovery following SCI.

Dl-3-n-butylphthalide improves functional recovery in rats with spinal cord injury by inhibiting endoplasmic reticulum stress-induced apoptosis.

Endoplasmic reticulum (ER) stress-induced apoptosis occurs in the spinal cord following traumatic spinal cord injury (SCI). Dl-3-n-butylphthalide (NBP) exerts an neuroprotective effects against both ischemic brain injury and neurodegenerative diseases; however, the relationship between ER stress-induced apoptosis and the therapeutic effect of NBP in SCI remains unclear. In this study, moderate spinal cord injuries were induced in Sprague-Dawley (SD) rats with a vascular clip. NBP was administered by oral (80 mg/kg/d) gavage 2 h before injury and then once daily for 28 d thereafter. Neurological recovery was assessed using the Basso, Beattie, and Bresnahan (BBB) locomotion rating scale, the inclined plane test, and the footprint analysis. Neuronal cell death was examined by TUNEL staining at 7 days post-injury. ER stress and apoptosis-related proteins were quantified by immunofluorescence staining and western blotting both in vivo and in vitro. Our results showed that NBP significantly decreased spinal cord lesion cavity area and improved locomotor recovery in SD rats after SCI. NBP also decreased neuronal apoptosis and inhibited activation of the caspase 3 cascade. Upregulation of ER stress-related proteins, such as GRP78, ATF-6, ATF-4, PDI, XBP-1, and CHOP, was reversed by NBP treatment in SD rats with SCI. Similarly, NBP effectively ameliorated ER stress and apoptosis-related protein expression induced by incubation with thapsigargin (TG) in PC12 cells. Our findings demonstrate that NBP treatment alleviates secondary SCI by inhibiting ER stress-induced apoptosis, thereby promoting neurological and locomoter functional recovery.

The predictive potential and oncogenic effects of HOXC8 expression on osteosarcoma.

Homeobox C8 (HOXC8) has been implicated in cell growth, migration, and metastasis of various cancers, yet its role in osteosarcoma remains to be explored. In the present study, resected osteosarcoma specimens from 50 patients were enrolled to evaluate the expression of HOXC8 protein by immunohistochemistry (IHC). In vitro and in vivo assays were used to determine the effect of HOXC8 on cell growth, migration, and tumor growth. HOXC8 expression was observed in 31 (62.0 %) of the 50 primary tumors and significantly associated with poorly or un-differentiated specimens (P = 0.031) and larger tumor size (P = 0.049). Survival analysis demonstrated that HOXC8 is a candidate predictive factor in predicting patients' outcome and chemotherapeutic effect. HOXC8 knockdown led to inhibition of tumor cell proliferation and migration in vitro by inhibiting MMP-9 expression and tumor growth in vivo. Our results strongly suggest that HOXC8 is involved in the tumorigenesis of osteosarcoma and might serve as a novel predictor for patients' outcome.

Local Infiltration Analgesia Versus Regional Blockade for Postoperative Analgesia in Total Knee Arthroplasty: A Meta-analysis of Randomized Controlled Trials.

BACKGROUND: Total knee arthroplasty (TKA) is one of the most commonly performed procedures while postoperative analgesia still remains challenging. The efficacy and safety of local infiltration analgesia (LIA) versus regional blockade (RB; epidural analgesia and/or peripheral nerve block) for pain management after TKA are controversial. OBJECTIVES: The purpose of this meta-analysis was to determine whether LIA compared with RB would provide better postoperative pain control, consume less morphine, facilitate early functional recovery, entail a differential risk of side effects and complications, and allow a shorter length of stay. STUDY DESIGN: This meta-analysis pooled all data published in randomized controlled trials (RCTs) examining the efficacy and safety of LIA versus RB following TKA. SETTING: The work was performed at Affiliated Cixi Hospital, Wenzhou Medical University. METHODS: Literature in English was searched using EMBASE, Medline, Cochrane Library, CINAHL, Web of Science, and Scopus from inception to April 2015. RCTs that compared LIA and RB for postoperative analgesia following TKA were included. Methodological quality was assessed using the Cochrane Back Review Group checklist, and a sensitivity analysis was performed. Sixteen RCTs with a total of 1,206 patients were finally included in our study. RESULTS: The results of our meta-analysis indicate that patients managed by LIA showed significantly lower numeric rating scale (NRS) score at rest (WMD: -0.40 [-0.72, -0.07]; P = 0.02) when compared with those managed by RB. Difference of morphine consumption was not significant (WMD: -1.39 [-7.21, 4.44]; P = 0.64) between the 2 groups. In terms of early functional recovery, the LIA group showed more straight leg raise (RR: 2.90 [2.15, 3.93]; P < 0.00001) on the first postoperative day; better range of motion within one week (WMD: 4.33 [2.61, 6.05]; P < 0.00001), but not at 3 months (WMD: 1.98 [-0.02, 3.98]; P = 0.05); and comparable knee society score (WMD: -8.79 [-27.05, 9.48]; P = 0.35). Length of hospital stay of the LIA group was marginally shorter (WMD: -0.25 [-0.49, -0.01]; P = 0.05) than that of the RB group. Risk of side effects and complications were comparable between groups. LIMITATIONS: The lack of a standard criterion regarding the technique details of LIA and heterogeneity resulting from the various analgesic components, dosages, and different administration methods might have posed a bias on the results. CONCLUSION: Our results have indicated that LIA provided better analgesia than RB at rest and preserved quadriceps function in the immediate postoperative period, which may be beneficial to early functional recovery. And its safety profile is reliable. With the biases in our meta-analysis, a rigorous and adequately powered RCT is needed to validate our results. KEY WORDS: Local infiltration analgesia, regional block, peripheral nerve block, epidural analgesia, postoperative analgesia, total knee arthroplasty, meta-analysis, randomized controlled trial.

[Case control study on open reduction internal fixation (ORIF) and minimally invasive percutaneous plate osteosynthesis (MIPPO) for the treatment of proximal humerus fractures in aged].

OBJECTIVE: To investigate the clinical effects of close reduction and minimally invasive percutaneous plate osteosynthesis in treating proximal humerus fractures in the aged. METHODS: From February 2012 to December 2013,39 patients with proximal humerus fractures were treated with minimally invasive percutaneous plate osteosynthesis (MIPPO group, 21 cases) and open reduction internal fixation (ORIF group, 18 cases). Including 17 males and 22 females in the study, and aged from 67 to 88 years old with an average of (71.8 ± 5.2) years old. In MIPPO group, there were 11 males and 10 females with an average age of (70.0 ± 5.3) years old;and in ORIF group, there were 10 males and 8 females with an average age of (72.0 ± 4.2) years old. Operation time, blood loss during operation, fracture healing time and postoperative complications were recorded. The functions of the shoulder joints were assessed according to Constant-Murley score at final follow-up. RESULTS: All the patients were followed up from 11 to 27 months with an average of 18.1 months. The mean blood loss of the MIPPO group was (176.0 ± 57.4) ml,while the ORIF group was (356.0 ± 66.9) ml (t = 7.22,P = 0.01). The operation time of the MIPPO group was (47.4 ± 14.9) min, while the ORIF group was (92.7 ± 15.8) min (t = 0.79, P = 0.03). Fracture healing time in the MIPPO group and ORIF group was (17.6 ± 5.8), ( 21.7 ± 4.9) weeks, respectively (P < 0.05). The mean Constant-Murley score at final follow-up was 89.7 ± 14.5 in MIPPO group, and 81.8 ± 13.2 in ORIF group (P < 0.05). CONCLUSION: MIPPO has advantages of little trauma, less blood loss, rapid recovery, less vascular damage and so on and can effectively treat the proximal humerus fracture in the aged.

[Myogenic elephant skin cream combined with Vacuum sealing drainage (VSD) for the treatment of bedsores].

OBJECTIVE: To discuss the efficacy of the myogenic elephant skin cream combining with VSD for treating severe bedsores. METHODS: Twenty-nine cases of III and IV degree bedsores were treated from June 2009 to June 2013. Among them, 15 cases were treated by myogenic elephant skin cream combined with VSD (VSD group) including 7 males and 8 females with an average age of (69.0±5.3) years old ranging from 17 to 96 years;other 14 cases were treated by the treatment of conventional dressing change (control group) including 6 males and 8 females with an average age of (71.0±4.2) years old ranging from 40 to 86 years. At 7, 14, 21, 28 d after treatments, specimens of wound two groups were respectively taken to examine immunohistochemical CD34 adopted SABC, the number of wild vascular cross were observed as capillary density value under high magnification microscope. It was used to assess the hyperplasia of granulation tissue of wound. The capillary density value and the visual wound observation were indicators for evaluation of clinical efficacy. RESULTS: Seventeen of 19 cases got complete data of specimens of wound at 7, 14, 21, 28 d,included 9 cases of VSD group,8 of control group. In the microscope view, the capillary density of VSD group was higher than that of control group significantly (P<0.05), it showed the application of VSD technology improved hyperplasia of granulation tissue much faster than conventional dressing change. In VSD group, 13 cases with 15 wounds healed, 2 cases with 3 wounds improved; in control group,3 cases with 3 wounds healed,7 cases with 9 wounds improved, 4 cases with 5 wounds were unhealed. CONCLUSION: Using the VSD technology with continuous high pressure suction to clean the drainage of wound and lacuna thoroughly can effectively control infection,promote the growth of granulation tissue, and then applying myogenic elephant skin cream to improve partial blood supply while prompting rapid growth of new granulation tissue and epithelial cell. The risk of this treatment is low,and the course of treatment is short, this provides a safe and effective method for treating bedsores.

Operative versus non-operative treatment for clavicle fracture: a meta-analysis.

PURPOSE: The purpose of this study was to assess the effects of operative and non-operative treatment on clavicle fractures. METHOD: Relevant clinical trials on the operative and non-operative treatment for clavicle fractures were retrieved through searching the databases MEDLINE, Embase, OVID and the Cochrane Central Register of Controlled Trials up to December 2011. The quality of the included studies was assessed by two authors. A meta-analysis was carried out on homogeneous studies. Five studies involving 633 clavicle fractures were included. RESULTS: The differences in nonunion [risk ratio (RR) 0.12, 95 % confidence interval (CI) 0.05-0.29], malunion (RR 0.11, 95 % CI 0.04-0.29) and neurological complications (RR 0.45, 95 % CI 0.25-0.81) were statistically significant between operative and non-operative treatment. There was no statistically significant difference in delayed union (RR 0.78, 95 % CI 0.31-1.95). CONCLUSION: Operative treatment is better than non-operative treatment, but decisions should be made in accordance with specific conditions for clinical application.

Patelloplasty versus traditional total knee arthroplasty for osteoarthritis.

The purpose of this study was to compare the clinical effects of patelloplasty and traditional patellar management in total knee arthroplasty (TKA) for osteoarthritis. A total of 152 patients with osteoarthritis treated with TKA between January 2004 and December 2005 were retrospectively studied. The patients were randomly divided into 2 groups: the patelloplasty group (group A; n=76) and the traditional treatment group (group B; n=76). Knee Society Score (KSS), Feller patellar score, Lonner patellar score, patient satisfaction, joint range of motion (ROM), and incidence of postoperative anterior knee pain were compared between the groups. Mean follow-up was 55 months (range, 48-71 months) for 132 patients, including 68 patients in group A and 64 in group B. Significant differences were found in KSS functional score, Feller patellar score, Lonner patellar score, and patient satisfaction, but no significant differences were found in ROM and total KSS score between the groups postoperatively. Group A obtained higher KSS scores and patient satisfaction than group B, with no significant difference in postoperative anterior knee pain. Postoperative radiographs revealed a significant difference in patellofemoral congruence between the groups. Patelloplasty relieves pain, enhances patient satisfaction, and improves function better than traditional patellar management in TKA with patellar nonresurfacing.

[A study on individual internal fixation with steel plate according to 3D reconstruction of CT images and Ugnx, Pro/E machining method].

PURPOSE: Discuss the new method of individual internal fixation with steel plate customization. METHOD: Customize individual internal fixation with steel plate according to 3D reconstruction of CT images and Ugnx. Pro/E machining method. RESULT: Success in customization about the first individual internal fixation with clavicular hook plate for the treatment of multisegmental fracture of clavicle. CONCLUSION: The new method of individual internal fixation with steel plate customization according to 3D reconstruction of CT images and Ugnx, Pro/E machining technique is a good news for patients of orthopaedic trauma. We are fully confident of the future development of the method of individual internal fixation with steel plate customization.

[Treatment of Bennett's fracture with closed reduction and percutaneous Kirschner wire fixation].

OBJECTIVE: To evaluate clinical effect of new method of percutaneous Kirschner wire fixation in treating Bennett's fracture. METHODS: Thirteen patients with Bennett's fracture were treated with close reduction and percutaneous Kirschner wire fixation. There were male 8 cases and female 5 cases with an average age of 32 years (range from 20 to 45 years). The mean time from injury to operation was 4.3 days (range from 2 to 7 days). External fixation with plaster slab was applied after operation with an average of 35 days (range from 30 to 41 days). The reduction of articular surface, symptom of ache and function of thumb after operation were evaluated. RESULTS: All the patients were followed up with an average of 6.4 months (range from 4 to 9 months). All fractures united and the articular surfaces were reduced well. Only 1 case has mild pain when activity. The grasp force decreased in all patients. CONCLUSION: Close reduction and percutaneous Kirschner wire fixation has advantage such as simply operation, precisely fixation, high potency ratio. The method especially fits Bennett's fracture with small triangular fragment.

[Stress test and clinical application of the minimal-invasive dynamic hip screw].

OBJECTIVE: To recognize the effect of minimal-invasive dynamic hip screw (MIDHS) on the treatment of intertrochanteric fracture of the hip by biomechanical test and preliminary clinical application. METHODS: Ten artifical made intertrochanteric fractures of femoral specimen from five cadavers were divided into two groups randomly. The fractures in first group were fixed by MIDHS and other group were fixed by dynamic hip (DHS). Biomechanical characteristics of two different devices were compared with the biomechanical character of load-straining, load-displacing, rigidity and strength of femur by statistic analysis. According to the Harris evaluation, healing effect of intertrochanteric fractures was evaluated clinically on the 15 cases. RESULTS: Straining changes of MIDHS were 14% and 11% less than that of DHS on the tensile side and the pressure side respectively; Sinking and horizontal displacement, were 19% and 22% less than that of DHS respectivly. But external and internal stress intensity,axial and bending rigidity were all higher than that of DHS, they were 12%, 11%, 19% and 37%. Maximal destroyed twisting moment (15%) and average twisting rigidity (15%) were both higher than that of DHS, but twisting angle was 18% less. Under the force, of 1 800 N, the open angle of the fracture on transverse section was 2.28 degrees,while the DHS's was 3.60 degrees . The data above were significant differences statistically (P < 0.01). The average Harris score of the 15 cases with intertrochanteric fractures treated by MIDHS was 91, excellent and good rate was 92.7%, without complications of internal fixation failure,postoperative infection and so on. CONCLUSION: The design of minimal-invasive dynamic hip screw is reasonable and effective against rotating, shearing and varus stress force of the fracture, and it provides possibility of implanting the internal fixation with minimal incision. So it is an ideal internal fixation device for the treatment of intertrochanteric fractures.