Repair of articular cartilage and subchondral defects in rabbit knee joints with a polyvinyl alcohol/nano-hydroxyapatite/polyamide 66 biological composite material.

BACKGROUND: This study sought to prepare a new PVA/n-HA/PA66 composite to investigate the repair of articular cartilage and subchondral defects in rabbit knee joints. METHODS: A 5 × 5 × 5 mm-sized defect was created in the patellofemoral joints of 72 healthy adult New Zealand rabbits. The rabbits were then randomly divided into three groups (n = 24): PVA/n-HA+PA66 group, polyvinyl alcohol (PVA) group, and control (untreated) group. Cylindrical PVA/n-HA+PA66, 5 × 5 mm, comprised an upper PVA layer and a lower n-HA+PA66 layer. Macroscopic and histological evaluations were performed at 4, 8, 12, and 24 weeks, postoperatively. Type II collagen was measured by immunohistochemical staining. The implant/cartilage and bone interfaces were observed by scanning electron microscopy. RESULTS: At 24 weeks postoperatively, the lower PVA/n-HA+PA66 layer became surrounded by cartilage, with no obvious degeneration. In the PVA group, an enlarged space was observed between the implant and the host tissue that had undergone degeneration. In the control group, the articular cartilage had become calcified. In the PVA/n-HA+PA66 group, positive type II collagen staining was observed between the composite and the surrounding cartilage and on the implant surface. In the PVA group, positive staining was slightly increased between the PVA and the surrounding cartilage, but reduced on the PVA surface. In the control group, reduced staining was observed throughout. Scanning electron microscopy showed increased bone tissue in the lower n-HA+PA66 layer that was in close approximation with the upper PVA layer of the composite. In the PVA group, the bone tissue around the material had receded, and in the control group, the defect was filled with bone tissue, while the superior aspect of the defect was filled with disordered, fibrous tissue. CONCLUSION: The diphase biological composite material PVA/n-HA+PA66 exhibits good histocompatibility and offers a satisfactory substitute for articular cartilage and subchondral bone.

A genome-wide association study of fetal response to type 2 porcine reproductive and respiratory syndrome virus challenge.

Control of porcine reproductive and respiratory syndrome (PRRS) is economically important for the swine industry worldwide. As current PRRS vaccines do not completely protect against heterologous challenge, alternative means of control, including enhanced genetic resilience, are needed. For reproductive PRRS, the genetic basis of fetal response to PRRS virus (PRRSV) infection is poorly understood. Genome-wide association studies (GWAS) were done here using data from 928 fetuses from pregnant gilts experimentally challenged with type 2 PRRSV. Fetuses were assessed for viral load in thymus (VLT), viral load in endometrium (VLE), fetal death (FD) and fetal viability (FV), and genotyped at a medium density. Collectively, 21 candidate genomic regions were found associated with these traits, seven of which overlap with previously reported QTLs for pig health and reproduction. A comparison with ongoing and related transcriptomic analyses of fetal response to PRRSV infection found differentially expressed genes within 18 candidate regions. Some of these genes have immune system functions, and have been reported to contribute to host response to PRRSV infection. The results provide new evidence about the genetic basis of fetal response to PRRSV challenge, and may ultimately lead to alternative control strategies to reduce the impact of reproductive PRRS.

[TREATMENT OF ACETABULAR ANTERIOR AND POSTERIOR COLUMN FRACTURES BY MODIFIED Stoppa APPROACH].

OBJECTIVE: To evaluate the surgical techniques, perioperative complications, clinical outcomes of the modified Stoppa approach in the treatment of acetabular anterior and posterior column fractures. METHODS: Between March 2008 and October 2014, 42 cases of acetabular anterior and posterior column fractures were treated by modified Stoppa approach or modified Stoppa approach combined with iliac fossa approach, and the clinical data were retrospectively analyzed. There were 20 females and 22 males with an average age of 43.2 years (range, 19-68 years). Fractures were caused by traffic accident in 21 cases, by falling from height in 16 cases, and by heavy pound in 5 cases. The time from injury to operation was 3-15 days (mean, 6 days). According to fracture classification of Letournel-Judet, there were 20 cases of both column fractures, 15 cases of anterior and posterior hemi-transverse fractures and 7 cases of T-shaped fractures. The intraoperative blood loss, the amount of blood transfusion, the operation time, the volumn of drainage, and complication were recorded. Matta radiological standard was used to evaluate the reduction quality of fracture, and Merled'Aubigné-Postel system to evaluate hip function. RESULTS: The average intraoperative blood loss was 900 mL; the average amount of blood transfusion was 400 mL; the average volume of drainage was 110 mL; and the average operation time was 165 minutes. Intraoperative complications included 4 cases of tractive injury of obturator nerve and 2 cases of the external iliac vein injury, and postoperative complications included 2 cases of lateral femoral cutaneous nerve palsies and 1 case of deep vein embolism of lower extremity, which were improved after treatment. The patients were followed up 36 months on average (range, 12-48 months). There was no infection or heterotopic ossification. According to Matta radiological evaluation system, the reduction quality of fractures was rated as excellent in 21 cases, good in 16 cases, and poor in 5 cases, with an excellent and good rate of 88.1%. The healing time of fracture was 3.5-8.0 months (mean, 5.1 months). According to Merled'Aubigné-Postel system for hip function, 20 cases were graded as excellent, 15 cases as good, 4 cases as fair, and 3 cases as poor, with an excellent and good rate of 83.3% at last follow-up. CONCLUSIONS: Modified Stoppa approach or with iliac fossa approach can get full exposure of quadrilateral area, good reduction, and firm internal fixation in the treatment of acetabular fractures associated with T-shaped fractures, both column fractures, anterior and posterior hemi-transverse fractures.

Roles of leptin in bone metabolism and bone diseases.

Adipose tissue has been more accepted as an active contributor to whole body homeostasis, rather than just a fat depot, since leptin, a 16 kDa protein, was discovered as the product of the obese gene in 1994. With more and more studies conducted on this hormone, it has been shown that there is a close relationship between adipose tissue and bone, which have important effects on each other. Bone is the source of many hormones, such as osteocalcin, that can affect energy metabolism and then the anabolism or catabolism of fat tissue. In contrast, the adipose tissue synthesizes and releases a series of adipokines, which are involved in bone metabolism through direct or indirect effects on bone formation and resorption. Interestingly, leptin, one of the most important cytokines derived from fat tissue, seems to account for the largest part of effects on bone, through direct or indirect involvement in bone remodeling and by playing a significant role in many bone diseases, such as osteoporosis, osteoarthritis, rheumatic arthritis, bone tumors and even fractures. In this review, we will discuss the progress in leptin research, particularly focusing on the roles of leptin in bone diseases.

The evaluation of patient-specific factors associated with meniscal and chondral injuries accompanying ACL rupture in young adult patients.

PURPOSE: To evaluate patient-specific factors, including the mechanism of injury, time from the injury, activity level after the initial trauma, re-injury and body mass index (BMI), as risk factors for meniscal and chondral injuries accompanying anterior cruciate ligament (ACL) rupture. METHODS: A retrospective review of young adult patients with complete ACL rupture was performed between 2007 and 2011. The presence of meniscal tears and/or chondral injury, and the mechanism of injury, time from the injury, activity level after the initial trauma, re-injury and BMI were recorded. The data were analysed for associations between patient-specific factors and the prevalence of meniscal and chondral injuries. RESULTS: A total of 293 patients were included. Increasing time from the injury, active daily life and re-injury were risk factors associated with meniscal injuries (p < 0.05). Independent risk factors associated with meniscal injuries included active daily life (OR = 4.66, 95 % CI 2.21-9.86, p < 0.0001) and re-injury (OR = 7.68, 95 % CI 3.24-18.22, p < 0.0001). Contact injury, increasing time from the injury, active daily life and re-injury were risk factors associated with chondral injuries (p < 0.05). Independent risk factors associated with chondral injuries included contact injury (OR = 2.54, 95 % CI 1.27-5.10, p < 0.01), active daily life (OR = 2.62, 95 % CI 1.35-5.08, p < 0.01) and re-injury (OR = 4.18, 95 % CI 2.09-8.35, p < 0.001). The incidence of re-injury was associated with the activity level (p < 0.001) and increased with increasing time from the injury (r = -0.698, p < 0.001). CONCLUSIONS: An increased risk of meniscal tear (especially medial meniscus) was strongly associated with an active daily life and re-injury. The combination of contact injury, active daily life and re-injury substantially increased the risk of cartilage injury. Patients with increasing time from the injury and active daily life exhibited a higher risk of re-injury, implying a higher prevalence of intra-articular damage.

[Analyzing risk factors for surgical site infection following Pilon fracture surgery].

OBJECTIVE: To study the related risk factors for surgical site infection following Pilon fracture surgery. METH ODS: The data of 561 patients with Pilon fractures treated with open reduction plate osteosynthesis at our institution's trauma centre were collected from January 2006 to December 2012. All the patients were divided into two groups: infection group and non-infection group. In the infection group, there were 23 males and 10 females, ranging in age from 21 to 69 years old, with an average of (45.50±4.40) years old. In the non-infection group, there were 296 males and 232 females, ranging in age from 16 to 76 years old, with an average of (43.50±7.19) years old. The possible risk factors such as age, gender, smoking, diabetes, alcohol abuse, open fractures, compartment syndrome and operative time were studied. The multivariate Logistic regression model was used to analyze the risk, factors. RESULTS: The infection rate of surgical site after Pilon fracture surgery was 5.88%. There were significant statistical differences between infection group and non-infection group in operative time, open fractures and compartment syndrome. However, multivariate Logistic regression analysis revealed that only operative time was significantly associated with surgical site infection (P=0.005, OR=44.92). CONCLUSION: Operation time is an independent predictor for post-operative surgical site infection of Pilon fracture treated with open reduction plate osteosynthesis. Though open fracture and compartment syndrome could increase the surgical site infection rate, they could not not be considered as independent predictors.

Comparison of three plate system for lateral malleolar fixation.

BACKGROUND: This study was to compare clinical and radiographic outcomes with three different implants and evaluate the effectiveness of minimally invasive plate osteosynthesis (MIPO) technique for the distal fibular fractures. METHODS: We performed a retrospective cohort single-surgical team single-facility study between 2000 and 2011. 147 patients receiving surgical interventions for closed, displaced distal fibular fractures were included. Based on the different implants, patients were divided into three groups: Group A: one-third tubular plate; Group B: locking compression (LCP) metaphyseal plate; Group C: LCP distal fibula plate. Clinical and radiographic outcomes were compared among the three groups. RESULTS: Totally, we found that patients in Group C had significant higher functional scores than those in Group A (p1 = 0.004; p2 = 0.002) (p1 stands for the p value for Olerud & Molandar Score, p2 stands for the p value for American Orthopaedic Foot & Ankle Society score). The healing time was significant less in Group C than that in Group A (p < 0.0001) and Group B (p < 0.0001). Subgroup analysis showed that: (1) For Weber A fracture, the functional scores of the Group C were higher than those in Group A (p1 = 0.020; p2 = 0.029) and B (p1 = 0.020; p2 = 0.034). (2) For Weber B fracture, the functional scores of the Group B (p1 = 0.033; p2 = 0.030) and C (p1 = 0.027; p2 = 0.017) were higher than those in Group A. No significant differences were observed in terms of the ankle range of motion, reduction accuracy and complication rate. CONCLUSIONS: Our study demonstrated using LCP metaphyseal plate in patients associated with lateral malleolar fracture could achieve significantly better OMS & AOFAS scores and less healing time than using one-third tubular plate. Specifically, For Weber A fracture, LCP distal fibula plate is much better than one-third tubular plate and LCP metaphyseal plate. While for Weber B fracture, LCP distal fibula plate and LCP metaphyseal plate are better than one-third tubular plate. As to the complications, using MIPO technique in patients with distal fibular fractures is at least comparable to the traditional one.

[Proteomics study on effect of basic fibroblast growth factor long circulation liposome on spinal cord traction injury in rats].

OBJECTIVE: To explore the possible active mechanism of the basic fibroblast growth factor (bFGF) long circulation liposome (LCL) (bFGF + LCL) on spinal cord traction injury in rats at the level of proteomics. METHODS: Twenty Sprague Dawly rats were randomly divided into groups A and B, 10 rats in each group. The models of spinal cord traction injury was established at T12-L3 spines. The rats were not treated in group A, and the rats were treated with bFGF + LCL (20 µg/kg) in group B. At 3 weeks after operation, the rats were sacrificed for harvesting T13-L2 spinal tissue specimens. The protein was extracted and quantified in the spinal tissue firstly. The proteins from spinal tissue were separated by two-dimensional gel electrophoresis and identified by mass spectrometry. The different expression profiling was established in each group, and the differentially expressed protein was determined by comparing the level of each spot with gel imaging software and manually. The proteins were identified by nano ultra-high performance liquid chromatography-electrospray tandem mass spectrometry (NanoUPLC-ESI-MS/MS), and the proteins were classified. RESULTS: The differentially expressed protein spots were found in 2 groups. Compared with group A, 4 spots were up-regulated and 6 were down-regulated in group B. NanoUPLC-ESI-MS/MS results showed that 18 significant proteins were identified in 26 differentially expressed proteins, including 4 apoptosis-related proteins, 3 nerve signal transduction related proteins, 7 proteins involved in metabolism, 1 unknown function protein, and 3 unnamed proteins. CONCLUSION: The differentially expressed proteins are found in spinal cord traction injury of rats treated with bFGF + LCL. bFGF + LCL can affect the proteins expression in rats with spinal cord traction injury. The possible active mechanism is that it has protective and repair effects on injured spinal cord by nerve signal transduction, and regulation of nerve cells apoptosis and metabolism.

[Locking compression plate (LCP) combined with minimally invasive percutaneous plate osteosynthesis (MIPPO) for the treatment of Pilon fracture].

OBJECTIVE: To summarize clinical outcomes of locking compression plate (LCP) combined with minimally invasive percutaneous plate osteosynthesis (MIPPO) for the treatment of Pilon fracture. METHODS: From January 2009 to December 2012, Pilon fracture patients treated by LCP with MIPPO were retrospectively analyzed. All open fractures, pathologic fractures and those who had limb vascular disease or nerve injury were excluded. Thirty-eight patients were enrolled, including 29 males and 9 females aged from 21 to 78 years old with an average of 48 years old. According to AO classification, 20 cases were type B, 18 cases were type C. Operative time, blood loss, reduction quality, time of fracture healing complications and postoperative ankle joint function were applied for evaluating clinical outcomes, AOFAS scoring were used for assessing postoperative clinical effects. RESULTS: All patients were followed up from 13 to 24 months (averaged 18 months). All patients obtained bone union without any plate failures or loss of fixation/reduction. One patient occurred superficial wound infection, and resolved with antibiotics and local wound care. Postoperative average AOFAS score was 81 (ranged 65 to 97). CONCLUSION: LCP with MIPPO for Pilon fratcure has advantages of less invasion, fewer complications and satisfactory ankle function.

Randomized, controlled trial of the modified Stoppa versus the ilioinguinal approach for acetabular fractures.

The objective of this study was to determine whether the modified Stoppa approach or the ilioinguinal approach is better for the treatment of acetabular fractures by comparing the results of those 2 approaches. A randomized trial was undertaken of 60 consecutive patients with acetabular fractures treated with either the modified Stoppa or the ilioinguinal approach. In addition to the patients' demographics, the assessed preoperative parameters included fracture pattern, associated injuries, time to surgery, and Injury Severity Score; intraoperative parameters included blood loss and operative time for each procedure; and postoperative parameters included wound drainage, blood transfusion, perioperative complications, early operative complications, late operative complications, quality of reduction, radiological results, and clinical outcomes. The study showed no significant differences in all measured preoperative variables between the 2 groups (all P>.05). In addition, no significant differences were found in the intraoperative complication rate, early operative complication rate, late operative complication rate, quality of reduction, radiological results, and clinical outcomes (all P>.05). However, compared with the ilioinguinal approach, the modified Stoppa approach reduced intraoperative blood loss-and in doing so decreased wound drainage and the need for blood transfusion-and shortened operative time (all P<.05). The authors recommend using the modified Stoppa approach rather than the classical ilioinguinal approach to treat acetabular fractures when anterior exposure of the acetabulum is required.

[Screen and identification of the relative protein expressed in the acute tractive spinal cord injury in rats].

OBJECTIVE: To screen and identify the relative protein expressed in the acute tractive spinal cord injury (TSCI) in rats. METHODS: Ten adult Sprague Dawley rats were randomly divided into Sham group and TSCI group, 5 rats in each group. Rats from Sham group and TSCI group at 1 day after surgery were sacrificed for harvesting T13-L2 spinal tissue specimens. The extraction and quantitation of protein in the spinal tissue was finished firstly. Proteins from spinal tissue were separated by two-dimensional electrophoresis (2-DE) and identified by mass spectrometry (MS). The different expression map was established in each group, and proteins express differently was determined by comparing the level of each spot with gel imaging software and manually. Proteins were identified by High performance liquid chromatography-electrospray tandem (NanoUPLC-ESI-MS/MS) and peptide sequence tag with tandem MS combining with database respectively. After that, the function of these identified proteins was known and classified. RESULTS: There were 22 differential protein expression spots were found between Sham group and TSCI group. Among them, 18 spots were up-regulated and 4 were down-regulated. 4 differential protein expression spots were newly found in TSCI group. Sixteen significant proteins were identified by NanoUPLC-ESI-MS/MS. Four kind of proteins were related to apoptosis, 3 in nerve signal transduction and 6 in metabolism, respectively. Unnamed proteins were 3. CONCLUSIONS: The differential expression proteins were found between Sham group and TSCI group. These identified proteins may play important role in the process of injury and recovery through transduction nerve signal, regulating nerve cells apoptosis and metabolism.

[Comparison of proximal femoral nail antirotation and reconstruction nail for ipsilateral fractures of hip and femoral shaft].

OBJECTIVE: To compare the effectiveness of proximal femoral nail antirotation (PFNA) and reconstruction nail with minimally invasive technique for ipsilateral femoral shaft and extracapsular hip fractures in young and middle-aged patients. METHODS: Sixty-nine young and middle-aged patients with ipsilateral femoral shaft and extracapsular hip fractures were treated between January 2000 and August 2010, and their data were analyzed retrospectively. Of them, fractures were fixed by reconstruction nail in 44 cases (reconstruction nail group) and by PFNA in 25 cases (PFNA group). There was no significant difference in gender, age, weight, injury cause, fracture type, or disease duration between 2 groups (P > 0.05). The operation time, blood loss, fracture healing time, complications, and functional outcomes were compared between 2 groups to evaluate the effectiveness. RESULTS: The operation time and blood loss in the PFNA group were significantly less than those in the reconstruction nail group (P < 0.05). The follow-up time was 12-38 months (mean, 20 months ) in the PFNA group and was 12-48 months (mean, 22 months) in the reconstruction nail group. No complication occurred as follows in 2 groups: wound infection, deep venous thrombosis, pulmonary embolism, breakage of the implants, avascular necrosis of the femoral head, or serious rotation and shortening deformity of lower limbs. In the PFNA group and the reconstruction nail group, 1 patient underwent technical difficulty in nail implant and 7 patients underwent technical difficulty in proximal locking screw, respectively; 3 patients and 6 patients had intra-operative iatrogenic fracture of femoral shaft, respectively; and delayed union of femoral shaft was observed in 1 patient and 2 patients, respectively. The complication rate was 20% (5/25) in the PFNA group and 34% (15/44) in the reconstruction nail group, showing no significant difference (chi2 = 1.538, P = 0.215). No significant difference was found in fracture healing time between 2 groups (P > 0.05). At last follow-up, there was no significant difference in Harris hip score and Evanich knee score between 2 groups (P > 0.05). CONCLUSION: PFNA or reconstruction nail with minimally invasive technique is a good method to treat ipsilateral femoral shaft and extracapsular hip fractures, but the PFNA is superior to the reconstruction nail because of simple operation.

[Correlation analysis between residual displacement and hip function after reconstruction of acetabular fractures].

OBJECTIVE: To investigate the relationships between residual displacement of weight-bearing and non weight-bearing zones (gap displacement and step displacement) and hip function by analyzing the CT images after reconstruction of acetabular fractures. METHODS: The CT measures and clinical outcome were retrospectively analyzed from 48 patients with displaced acetabular fracture between June 2004 and June 2009. All patients were treated by open reduction and internal fixation, and were followed up 24 to 72 months (mean, 36 months); all fractures healed after operation. The residual displacement involved the weight-bearing zone in 30 cases (weight-bearing group), and involved the non weight-bearing zone in 18 cases (non weight-bearing group). The clinical outcomes were evaluated by Merle d'Aubigné-Postel criteria, and the reduction of articular surface by CT images, including the maximums of two indexes (gap displacement and step displacement). All the data were analyzed in accordance with the Spearman rank correlation coefficient analysis. RESULTS: There was strong negative correlation between the hip function and the residual displacement values in weight-bearing group (r(s) = -0.722, P = 0.001). But there was no correlation between the hip function and the residual displacement values in non weight-bearing group (r(s) = 0.481, P = 0.059). The results of clinical follow-up were similar to the correlation analysis results. In weight-bearing group, the hip function had strong negative correlation with step displacement (r(s) = 0.825, P = 0.002), but it had no correlation with gap displacement (r(s) = 0.577, P = 0.134). CONCLUSION: In patients with acetabular fracture, the hip function has correlation not only with the extent of the residual displacement but also with the location of the residual displacement, so the residual displacement of weight-bearing zone is a key factor to affect the hip function. In patients with residual displacement in weight-bearing zone, the bigger the step displacement is, the worse the hip function is.

Timing of internal fixation and effect on Schatzker IV-VI tibial plateau fractures.

OBJECTIVE: To study the effect of internal fixation performed at different times on therapeutic outcomes of Schatzker IV-VI tibial plateau fractures. METHODS: The clinical data of 42 cases of Schatzker IV-VI tibial plateau fractures treated in our department were analyzed retrospectively. Among these 42 patients, 21 received surgical treatment within 12 h after injury (Group I), the other 21 were first treated by traction or plaster fixation followed by a delayed internal fixation after soft tissue swelling subsided (Group II). The surgical time, complications, length of hospital stay, cost of hospitalization, and time for fracture union, as well as functional recovery were analyzed and compared between the two groups. RESULTS: After 10-28 months follow-up (mean 16.5 months), except 5 cases who lost to follow-up, no differences were found between the two groups regarding surgical time, preoperative and postoperative complications, healing time or the Hospital for Special Surgery (HSS) score at the end of follow-up, but significant differences were found in the length of hospital stay, cost of hospitalization and HSS score at 3 months after operation (P less than 0.05). CONCLUSION: Under certain conditions, early internal fixation for Schatzker IV-VI tibial plateau fracture is feasible, which can shorten the length of hospital stay, decrease the cost of hospitalization and promote early functional rehabilitation.

A comparative study of ipsilateral intertrochanteric and femoral shaft fractures treated with long proximal femoral nail antirotation or plate combinations.

OBJECTIVE: To compare the results of long proximal femoral nail antirotation (PFNA-long) and plate combinations in the treatment of ipsilateral intertrochanteric and femoral shaft fractures. METHODS: Between March 2004 and April 2009, 23 patients with ipsilateral intertrochanteric and femoral shaft fractures were treated with PFNA-long or plate combinations. The patients were divided into two groups. Group I contained 13 patients who were treated with dynamic hip screws (DHS) combined with compression plate fixation. The 10 patients in Group II were treated with PFNA-long. RESULTS: The average follow-up was 17.8 and 16.8 months for Groups I and II, respectively. The average union time for intertrochanteric fractures was 17.4 and 16.6 weeks in Groups I and II, respectively, and for femoral shaft fracture 22.2 and 21.5 weeks, respectively. There were nine good, two fair, and two poor functional results in Group I, and eight good, one fair, and one poor in Group II. There was nonunion of two femoral shaft fractures in Group I and one in Group II. There were no significant differences between the two groups in functional outcomes or major complications. CONCLUSION: Both treatment methods achieve satisfactory functional outcomes in patients with ipsilateral intertrochanteric and femoral shaft fractures. PFNA-long is the better choice for the treatment of complex fractures, having the advantages of minimal exposure, reduced perioperative blood loss, and achievement of biological fixation of both fractures with a single implant.

Overexpression of GDF5 through an adenovirus vector stimulates osteogenesis of human mesenchymal stem cells in vitro and in vivo.

The use of stem cells combined with gene therapy could be an important way to facilitate bone regeneration. In this study, the aim was to investigate the potential of growth and differentiation factor-5 (GDF5) to genetically manipulate human mesenchymal stem cells (hMSCs) for bone regeneration. Recombinant adenovirus Ad-GDF5 and Ad-GFP were constructed and identified, and the titer of both were determined. Third-passage hMSCs were infected with adenovirus, and the expression of GDF5 was confirmed by detection of GFP-positive cells, GDF5 mRNA levels, Western blotting, and enzyme-linked immunosorbent assay (ELISA). hMSCs at passage 3 were divided into four groups: (1) an experimental group infected with Ad-GDF5, (2) a positive control group cultured with osteogenic differentiation medium, (3) a control group infected with Ad-GFP cultured with standard medium, and (4) a blank control group cultured with standard medium. Evaluation of cell morphology and proliferation, analysis of the expression of genes related to osteogenic differentiation, von Kossa staining, and immunofluorescent staining of collagen I were used to investigate the osteogenesis of cells among the groups. After culturing the cells for 2 days under each corresponding condition, the cells were detached and subcutaneously injected into the backs of nude mice to evaluate bone formation. Samples were collected for histological staining, protein Western blotting, and micro-computer tomography. When infected with Ad-GDF5, hMSCs could overexpress GDF5 for a prolonged period in vitro and reach a concentration of 160 ng/ml. Cells infected with Ad-GDF5 or cultured in osteogenic medium displayed osteogenic differentiation based on their histological and cellular properties and on their gene and protein expression patterns. Furthermore, Ad-GDF5 showed a better ability to upregulate the expression of collagen I, alkaline phosphatase, and osteocalcin mRNA than the osteogenic medium. Furthermore, Ad-GDF5 expression was associated with enhanced bone formation in vivo. Our findings suggest that hMSCs infected with Ad-GDF5 can differentiate in an osteogenic direction and may be a promising cell source for bone regeneration.

Traumatic asymmetrical bilateral hip dislocation: a case report and literature review.

Traumatic asymmetrical bilateral dislocation of the hip joint is a rare occurrence. Herein we report a case of traumatic asymmetrical bilateral dislocation of the hip caused by a falling object. A 31-year-old healthy male was injured by a falling wall of weighing approximately 100 kg from behind in the lumbosacral area. The patient sustained a pelvic fracture, posterior dislocation of the right hip joint associated with a comminuted fracture of the right acetabulum, and anterior dislocation of the left hip joint. Manual reduction of both hip dislocations was performed in the Emergency Department. The posterior wall fracture of the right acetabulum was treated with open reduction and internal fixation by plate and screw. Reduction of both hips was successful and no femur necrosis or arthrosis was found during the four-year follow-up. Heterotopic ossification was found but it did not affect joint function. Prompt reduction of hip dislocations in the Emergency Department can reduce the incidence of avascular necrosis of the femoral head.

[Effectiveness of posterior approaches for treatment of posterior coronal fracture].

OBJECTIVE: To observe the effectiveness of posterior approaches for the treatment of posterior coronal fractures of tibial plateau, and to analyze the fracture morphology, radiographic features, and the recognition of Schatzker classification. METHODS: Between June 2003 and June 2009, 23 patients with posterior coronal fractures of tibial plateau were treated surgically by posterior approaches. There were 15 males and 8 females with an average age of 38 years (range, 32-56 years). All patients had closed fractures. Fracture was caused by traffic accident in 15 cases, by sports in 3 cases, and by falling from height in 5 cases. According to Moore classification, there were 10 cases of type I, 9 cases of type II, and 4 cases of type IV. The X-ray films, CT scanning, and three-dimensional reconstruction were performed. The time from injury to operation was 3-14 days (mean, 6 days). RESULTS: After operation, 17 cases had anatomical reduction and 6 had normal reduction. Incisions healed by first intention. All cases were followed up 12 to 36 months (mean, 24 months). The average fracture healing time was 7.6 months (range, 6-9 months). No related complication occurred, such as nerve and vessel injuries, failure in internal fixation, ankylosis, traumatic osteoarthritis, and malunion. According to Rasmussen's criteria for the function of the knee, the results were excellent in 14 cases, good in 7 cases, and fair in 2 cases with an excellent and good rate of 91.3%. CONCLUSION: Posterior coronal fracture of tibial plateau is rare, which has distinctive morphological features, and Schatzker classification can not contain it totally. The advantages of posterior approach include reduction of articular surface under visualization, firm fixation, less complications, and earlier functional exercise, so it is an ideal surgical treatment plan.

[Case-control study on therapeutic effects of surgery for the treatment of complex acetabular fractures and effect of waiting time for surgery on clinical results].

OBJECTIVE: To discuss the operative effects and evaluate how the waiting time before surgery influence the outcome of complex acetabular fractures. METHODS: From January 2006 to December 2008, 33 patients, 28 males and 5 females, with complex acetabular fractures were operated in our hospital. All of them were followed up for an average 24 months (ranged, 14 to 47 months). The average age was 42 years (ranged,27 to 57 years). According to the waiting time before surgery, all patients were divided into two groups, namely preoperative waiting time of more than 14 days group and preoperative waiting time of less than 14 days group. Postoperative reduction quality and long-term radiographic results were evaluated according to the Matta radiological systems. The modified Merle d' Aubigne-postel hip scoring system was used for evaluating the functional outcomes. The Mos SF-36 was used to evaluate the quality of life. RESULTS: Anatomical reduction in 28 cases, good in 4 cases, and poor in 1 case. According to the mean Merle d'Aubigne and Postel Score, 22 patients got excellent result, 4 good, 4 fair and 3 bad. Average score of the Mos SF-36 was (70.63 +/- 17.03). When time was measured as a categorical variable, an anatomical reduction and an excellent or good functional outcome were more likely if surgery was performed within 14 days. Postoperative complications: iatrogenic injuries of sciatic nerve in 2 cases, heterotopic ossification in 6 cases,traumatic osteoarthritis in 3 cases, and femoral head necrosis in 1 case. CONCLUSION: Good image evaluation,correct approaches, appropriate time before surgery and approach, early functional rehabilitation are essential for better outcomes in the treatment of complex acetabular fractures, of which, time to surgery is a crucial and controllable prognostic factor.

[Establishment of tractive spinal cord injury model in rats with a novel spinal distractor].

OBJECTIVE: To develop a tractive spinal cord injury model in rats with a novel spinal distractor so as to supply the reliable animal model for researching the pathological mechanism and rehabilitation treatment of tractive spinal cord injury. METHODS: A novel spinal distractor was prepared based on previous study. Sixty adult Sprague Dawley rats (weighing 250-300 g) were randomly divided into 5 groups, 12 rats in each group. T12-L3 spinal structures in the rear area were exposed and then T13-L2 spinal cords were revealed via dual laminectomy and kept integrity. In group A, a novel spinal distractor was placed without distraction; in groups B, C, D, and E, the T12-L3 spines were traced with a novel spinal distractor which put on transverse process of T12-L3 vertebrae. During the tractive period, the somatosensory evoked potential (SEP) was used to monitor spinal cord function. The SEP amplitudes descended 50% and kept distracting for 5 minutes in group B and for 10 minutes in group C, and descended 70% and kept distracting for 5 minutes in group D and for 10 minutes in group E, respectively to establish the tractive spinal cord injury model of T11-L2. The improved combine behavioral score (ICBS) was recorded at 1 and 7 days after injury in 6 rats of each group. The T13-L2 spinal tissue specimens were harvested for the morphological observation by HE and Nissl's staining and for neurons counting. RESULTS: In group A, the ICBS score was 0 at 1 and 7 days after operation, showing significant difference when compared with the scores of the other groups (P < 0.05). The ICBS scores of groups D and E were significantly higher than those of groups B and C (P < 0.05). Edema and hemorrhage were observed in spinal cord surface and normal morphological structures were destroyed at different extent in groups B, C, D, and E at 1 day. There were adherence and congestion between spinal cord surface and peripheral issue without luster at 7 days, and dura depression was observed at the injury section, especially in group E. Necrosis and dissolution occurred in some neurons, and Nissl body structure dissolved or disappeared in groups B, C, D, and E. The neuron counting gradually decreased in accordance with the aggravation of injury in groups B, C, D, and E, showing significant difference when compared with group A (P < 0.05). Significant differences in neuron counting were found among groups B, C, D, and E (P < 0.05). CONCLUSION: The tractive spinal cord injury model in rats can be successfully established with novel spinal distractor, and the model established by SEP amplitude descending 70% and keeping distracting for 10 minutes is more suitable for study in tractive spinal cord injury.