PGC-1α regulates the expression and activity of IRF-1.

Interferon regulatory transcription factor 1 (IRF-1) regulates downstream signals of tumor necrosis factor α (TNF-α). The activity of IRF-1 is mediated by Jak/Stat signaling pathway. In this study, we found that PPAR γ coactivator-1α (PGC-1α) is able to suppress the induction of IRF-1. Treatment with TNF-α in MC3T3 cells leads to a sustainable increase in the expression of IRF-1 and its target gene cyclooxygenase 2 (COX-2). In contrast, TNF-α treatment led to a sustainable reduction in expression of PGC-1α. Interestingly, we found that overexpression of PGC-1α attenuated the induction of IRF-1 and COX-2. However, silence of PGC-1α exacerbated the induction of IRF-1 and COX-2. Importantly, we found that the effect of PGC-1α on repressing IRF-1 expression and activity is facilitated by the reduction in phosphorylation of STAT1 at position 727 (S727P), an essential transcriptional activator of IRF-1. Finally, we found that calyculin A, a pharmacological inhibitor of protein phosphatase 2A (PP2A) and PP1 abolishes the repression of STAT1 phosphorylation mediated by PGC-1α, suggesting a new mechanism of PGC-1α in regulating STAT1/IRF-1 pathway.

Genetic variations in the PRKCG gene and osteosarcoma risk in a Chinese population: a case-control study.

Osteosarcoma is a common malignant tumor, which exists widely in the bone of children and adolescents. Protein kinase C gamma (PRKCG) gene, which encodes γPKC, plays important roles in tumor promotion, cell proliferation, differentiation, and migration. The objective of the present study was to investigate the relationship between PRKCG polymorphisms and the risk of osteosarcoma. Five tag single nucleotide polymorphisms (SNPs) of PRKCG were retrieved from the HapMap database and genotyped by the method of SNapShot in a hospital-based study containing 388 patients and 388 healthy individuals. Odds ratios (ORs) and their 95 % confidence intervals (CIs) were used to evaluate the association SPSS 20.0 statistical software package was used to analyze statistical data. Our results suggested that the T/C variant of rs454006 located in the intron 3 region of PRKCG gene was significantly associated with an increased risk of osteosarcoma (CC vs. TT, OR = 1.91; 95 % CI 1.29-2.85; P = 0.001; CC vs. TT+TC, OR = 2.14, 95 % CI = 1.48-3.09, P = 0.001; C vs. T, OR = 1.32, 95 % CI = 1.08-1.62, P = 0.008). Similarly, the rs3745406 T/C variant can also elevate the risk of osteosarcoma in the dominant model (OR = 1.45, 95 % CI = 1.08-1.96, P = 0.014), homozygous model (OR = 1.68, 95 % CI = 1.10-2.59, P = 0.002), and allelic model (OR = 1.31, 95 % CI = 1.07-1.61, P = 0.009). However, there were no significant differences in genotypes and allele frequencies of rs2547362 (T>C), rs8103851 (C>G), and rs2242245 (T>C) SNPs between osteosarcoma patients and healthy controls. The results showed that carrier of rs454006*C allele and rs3745406*C might elevate the risk of osteosarcoma. Further studies are needed to validate the coalition between PRKCG gene polymorphisms and risk of osteosarcoma relying on a larger population that included the participants in different ethnicity and hospital.

Whole meniscus regeneration using polymer scaffolds loaded with fibrochondrocytes.

OBJECTIVE: To study the feasibility of regenerating a whole menisci using poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffolds loaded with meniscal cells in rabbits undergoing total meniscectomy, and to explore its protective effect on cartilage degeneration. METHODS: A solvent casting and particulate leaching technique was employed to fabricate biodegradable PHBV scaffolds into a meniscal shape. The proliferated meniscal cells were seeded onto the polymer scaffolds, transplanted into rabbit knee joints whose lateral menisci had been removed. Eight to 18 weeks after transplantation, the rege- nerated neomenisci were evaluated by gross and histological observations. Cartilage degeneration was assessed by Mankin score. RESULTS: Eighteen weeks after transplantation, the implants formed neomenisci. Hematoxylin and eosin (HE) staining of the neomenisci sections revealed regeneration of fibrocartilage. Type I collagen in the neomenisci was also proved similar to normal meniscal tissue by immunohistochemical analysis and Sirius scarlet trinitrophenol staining. Articular cartilage degeneration was observed 8 weeks after implantation. It was less severe as compared with that in total meniscectomy controls and no further degeneration was observed at 18 weeks. At that time, the regenerated neomenisci strongly resembled normal meniscal fibrocartilage in gross and histological appearance, and its mechanical property was also close to that of normal meniscus. CONCLUSIONS: The present study demonstrates the feasibility of tissue-engineering a whole meniscal structure in total meniscectomy rabbit models using biodegradable PHBV scaffolds together with cultured allogeneic meniscal cells. Cartilage degeneration is decreased. But long-term in vivo investigations on the histological structure and cartilage degeneration of the neomenisci regenerated by this method are still necessary to determine the clinical potential of this tissue engineering avenue.

Fingertip replantation at or beyond the nail base in children.

Although success of digital replantations in children has been reported by many authors, the very distal fingertip replantation remains technically demanding. The aim of this article is to review our experience with fingertip replantations at or distal to the nail base in pediatric patients and evaluate the clinical outcomes. From October 2000 to May 2007, 12 pediatric fingertips amputated at or distal to the nail base were replanted. Only one artery was anastomosed for revascularization with or without nerve repair; vein drainage was provided by the controlled bleeding technique. Eleven of the 12 replants (91%) survived; one replant of crushed digit failed. An average of 26 month (range, 6 to 36 months) follow-up revealed excellent restoration of finger motion and appearance. The regained static 2-point discrimination (S2PD) sensation was from 3.2 to 5.0 mm (mean, 4.2 mm). Both the parents and the children were satisfied with the final results. In conclusion, fingertip replantation in children allows good functional and esthetical recovery and should be attempted if technically feasible.

Post-arthroscopic osteonecrosis of the knee: A case report and literature review.

Post-arthroscopic osteonecrosis is a rare complication of arthroscopic surgery. The present study reported on a case of knee osteonecrosis after arthroscopic surgery. The patient, an 81-year-old male, presented with left knee pain and limited range of motion without any history of trauma. MRI revealed medial meniscus tear. Medial partial meniscectomy was performed using arthroscopy. The pain was found to be relieved due to the operation. However, there was an aggravation of pain after two months post-operatively. X-ray revealed that the subchondral bone in the medial femoral condyle (MFC) had collapsed. MRI revealed a large area of bone marrow edema in the MFC with cartilage delamination and subchondral flattening. Considering the age of the patient and the large area of bone necrosis, total knee arthroplasty was performed. At the 1-year follow-up, the Knee Society Knee Score improved from 44 points pre-operatively to 90 points and the Knee Society Functional Score was elevated from 35 to 90 points. Patient-reported outcome measures were assessed in the form of the Oxford Knee Score, which was 16. Furthermore, previous case reports of post-arthroscopic osteonecrosis were reviewed and the clinical and radiographic features, as well as the treatment, were summarized. If the patient complains of persistent and worsening pain after arthroscopy, particularly in elderly osteoporotic patients with meniscal tears or chondral lesions, the possibility of post-arthroscopic knee osteonecrosis should be considered. Diagnosis and treatment at the early stages are likely to be beneficial for the outcome.

Lumican promotes joint fibrosis through TGF-ß signaling.

Joint contracture (also known as arthrofibrosis) is a fibrotic joint disorder characterized by excessive collagen production to form fibrotic scar tissue and adhesions within joint capsules. This can severely affect day-to-day activities and quality of life because of a restricted range of motion in affected joints. The precise pathogenic mechanism underlying joint contractures is not fully understood. Lumican belongs to the class II small leucine-rich repeat proteoglycan superfamily, which makes up collagen fibrils in the extracellular matrix. Lumican is ubiquitously expressed in the skin, liver, heart, uterus and articular cartilage and has reported roles in cell migration, proliferation, angiogenesis and Toll-like receptor 4 signaling. Previous research has suggested that lumican is involved in the pathogenesis of several fibrotic diseases. Because joint contracture resembles a fibrotic disease, we aimed to investigate the role of lumican in the development of joint contracture in vitro. Here, we showed that protein levels were up-regulated in the fibrotic joint capsule versus control. We observed that lumican significantly enhanced the proliferation, migration and fibroblast-myofibroblast transition of synovial fibroblasts. Moreover, lumican led to increased transcription of alpha-smooth muscle actin, matrix metallopeptidase 9, Collagen I, plasminogen activator inhibitor 1 and transforming growth factor-ß in vitro. Lumican treatment promoted collagen lattice contraction in a dose-dependent manner as early as 24 h after treatment. Thus, our studies reveal that lumican could promote fibroblast-myofibroblast transition and joint contracture.

TIMP-1 inhibits proliferation and osteogenic differentiation of hBMSCs through Wnt/ß-catenin signaling.

The present study aimed to evaluate the effect of tissue inhibitor of metalloproteinase-1 (TIMP-1) on the proliferation and osteogenic differentiation potential of human bone marrow-derived MSCs (hBMSCs). hBMSCs with stable TIMP-1 overexpression or TIMP-1 knockdown were generated. Osteogenic differentiation was assessed by Alizarin Red S staining, alkaline phosphatase (ALP) activity and expression of specific markers. Compared with the vehicle controls, TIMP-1 knockdown significantly promoted the growth of hBMSCs. TIMP-1 knockdown up-regulated ß-catenin and cyclin D1 proteins. During osteogenic differentiation, TIMP-1 knockdown elevated the deposition of calcium nodules, ALP activity and the mRNA levels of the osteogenic markers sex determining region Y-box 9 (Sox9), CCAAT-enhancer-binding protein and peroxisome proliferator-activated receptor γ. During osteogenic differentiation, TIMP-1 knockdown significantly enhanced the up-regulation of osteocalcin proteins. Meanwhile, TIMP-1 overexpression attenuated the Wnt/activator Wnt3a-induced up-regulation cyclin D1 and Runt-related transcription factor 2 (RUNX-2) (during osteogenic differentiation) proteins, while TIMP-1 knockdown restored the inhibitor Dickkopf 1-induced inhibition effect on the expression of ß-catenin, cyclin D1 and RUNX-2. TIMP-1 plays a negative regulatory role in the proliferation and osteogenesis of hBMSCs, at least partially, through Wnt/ß-catenin signaling.

Central Tendon-Splitting Approach and Double Row Suturing for the Treatment of Insertional Achilles Tendinopathy.

BACKGROUND: To assess the clinical outcomes of central tendon-splitting approach and double row anchor suturing for the treatment of insertional Achilles tendinopathy. METHODS: 28 patients (28 feet) diagnosed with insertional Achilles tendinopathy were included in this study. The inclusions were symptom of hindfoot pain around the insertion of the Achilles tendon, radiographic demonstration of calcification, or degeneration of the Achilles tendon, showing no symptom improvement even after standard nonsurgical treatment for more than six months. The X-ray revealed that patients had obvious posterior superior calcaneal exostosis with the possibility of friction with the Achilles tendon or intratendinous calcification. Surgical correction by the central tendon-splitting approach and double row Achilles tendon suturing was performed. The ankles were immobilized with plaster for four weeks postoperatively. The American Orthopaedic Foot and Ankle Society (AOFAS) score and visual analogue score (VAS) were assessed preoperatively and at 2 years postoperatively. At final follow-up, the Manchester-Oxford Foot Questionnaire (MOXFQ) as patient-reported outcome measures (PROMs) was also evaluated. RESULTS: No complication, including postoperative wound infection and tendon rupture, was not found. All the patients resumed their daily activities with no high level of daily activities, such as jumping and jogging after 6 weeks postoperatively. 27 patients were available for follow-up for at least 2 years, while only one patient was lost to follow-up. At postoperative 2 years, the postoperative AOFAS score increased significantly, while the VAS score decreased statistically when compared with preoperative values. At final follow-up, 24 patients had complete alleviation of pain, whereas the remaining 3 patients complained of mild heel pain after walking for a long time. The MOXFQ score showed obvious relief of previous symptoms for all included cases. CONCLUSIONS: Central tendon-splitting approach and double row Achilles tendon suture provide excellent intraoperative visual field, larger tendon-bone contact area, and stronger pullout strength and, thus, facilitate early rehabilitation. It can be a safe and effective method for the treatment of insertional Achilles tendinopathy.

Spinal surgeons' learning curve for lumbar microendoscopic discectomy: a prospective study of our first 50 and latest 10 cases.

BACKGROUND: Microendoscopic discectomy (MED) is a minimally invasive operation that allows rapid recovery from surgery for lumbar disc herniation, but has replaced traditional open surgery in few hospitals because most surgeons avoid its long learning curve. We evaluated the effectiveness and safety of lumbar MED at stages of spinal surgeons' learning curve. METHODS: Fifty patients receiving MED from June 2002 to February 2003 were divided into chronological groups of ten each: A - E. The control group F was ten MED patients treated later by the same medical team (September - October 2006). All operations were performed by the same team of spinal surgeons with no MED experience before June 2002. We compared groups by operation time, blood loss, complications and need for open surgery after MED failure. RESULTS: Operation times by group were: A, (107 +/- 14) minutes; B, (85 +/- 13) minutes; C, (55 +/- 19) minutes; D, (52 +/- 12) minutes; E, (51 +/- 13) minutes; and F, (49+/- 15) minutes. Blood loss were: A, (131 +/- 73) ml; B, (75 +/- 20) ml; C, (48 +/- 16) ml; D, (44 +/- 17) ml; E, (45 +/- 18) ml; and F, (45 +/- 16) ml. Both operation time and blood loss in groups C, D, E and F were smaller and more stable compared with groups A and B. Japanese Orthopedic Association assessment (JOA) score of each group in improvement rate immediately and one year after operation were as follows (in percentage): A, (79.8 +/- 8.8)/(89.8 +/- 7.7); B, (78.6 +/- 8.5)/(88.5 +/- 7.8); C, (80.8 +/- 11.3)/(90.8 +/- 6.7); D, (77.7 +/- 11.4)/(88.9 +/- 9.3); E, (84.0 +/- 8.7)/(89.6 +/- 9.0); and F, (77.8 +/- 11.6)/(86.9 +/- 8.4). Groups showed no statistical difference in improvement rates. Complications developed in three patients in group A, two in group B, and none in the other groups. CONCLUSIONS: Spinal surgeons performing MED become proficient after 10 - 20 operations, when their skill becomes fairly sophisticated. Patients' improvement rate is the same regardless of surgeons' phase of learning curve.

Concurrent arthroscopic bicruciate ligament reconstruction using Achilles tendon-bone allografts: experience with 15 cases.

OBJECTIVE: To evaluate the clinical outcome of arthroscopically assisted combined anterior and posterior cruciate ligament (ACL/PCL) reconstructions using Achilles tendon-bone allografts. METHODS: Associated meniscus injuries were treated according to established methods prior to ligament reconstructions during arthroscopic surgery. Thirty Achilles tendon-bone allografts were used to reconstruct torn ACL and PCL in 15 knees. At postoperative follow-up, all knees were graded using the modified IKDC and the Lysholm scoring systems just as done preoperatively. RESULTS: were analyzed compared with the contralateral healthy knees. Results: Eleven men and 4 women with a minimum of 3-year follow-up (mean 38 months) were included in the study. Preoperatively, the group ratings by the modified IKDC standards were all severely abnormal. Twelve bicruciate reconstructions were performed in subacute or chronic stage (larger than 3-8 weeks), 3 for acute ligamentous deficiencies (less than or equal to 3 weeks). The noticeable early complication was transitory local fever combined with joint effusion in one case. At postoperative follow-up, 9 knees were normal, 5 nearly normal and 1 abnormal. On Lysholm score the difference was statistically significant (t- test, P less than 0.001) before and after operation. CONCLUSIONS: Achilles tendon-bone allograft offers an alternative for simultaneous arthroscopic ACL/PCL reconstructions. However, further investigation is needed to eradicate its potential immunogenicity for better use.

Arthroscopic partial capsulotomy for exposure and treatment of hip disease.

Hip arthroscopy is an effective method for the diagnosis and treatment of hip joint pathologies. However, gaining access to the central and peripheral compartments is challenging. The present study aimed to assess the advantages of using an arthroscopic extra-capsular approach and partial capsulotomy for access and subsequent management of hip diseases. Patients subjected to hip arthroscopy by partial capsulotomy for exposure and treatment of hip diseases between February 2012 and February 2016 were retrospectively analyzed. A total of 32 patients, including 19 males and 13 females, aged 19-48 years (median age, 36 years), had undergone the procedure. Firstly, the distal anterior lateral and anterolateral arthroscopic approach with blunt dissection was performed. Subsequently, a T-shaped partial capsulotomy was established to achieve adequate exposure. The shaver, radiofrequency probe and tissue penetrating suture grasper were then inserted to perform procedures including debridement of the synovium, suturing of the glenoid labrum. During surgery, a probe hook was used to push the capsule section limbs or pull the sutures placed on the capsule section limbs to improve exposure. For patients with pre-operative anterior instability, ligamentous laxity or acetabular dysplasia capsules were sutured to finish capsule closure. The pre-operative and post-operative Visual Analogue Scale (VAS) score and modified Harris hip score (MHHS) were used to assess the effectiveness of the procedure. No obvious post-operative complications were encountered. The mean follow-up time was 22.4 months (range, 18-32 months) and 31 patients completed the follow-up, while 1 patient was lost to follow-up. Compared with the pre-operative score, the MHHS was significantly increased (66.2±6.0 vs. 82.6±5.2; P<0.05) and the VAS score was significantly decreased (6.5±1.1 vs. 1.2±0.7; P<0.05) at the end of the follow-up. In conclusion, arthroscopic partial capsulotomy provides access to the peripheral and central compartments of the hip and is a relatively simple technique that is easy to master for surgeons with limited experience in hip surgery.

Coculture of endothelial progenitor cells and mesenchymal stem cells enhanced their proliferation and angiogenesis through PDGF and Notch signaling.

The beneficial effects of combined use of mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs) on tissue repair and regeneration after injury have been demonstrated, but the underlying mechanism remains incompletely understood. This study aimed to investigate the effects of direct contact coculture of human bone marrow-derived EPCs (hEPCs)/human bone marrow-derived MSCs (hMSCs) on their proliferation and angiogenic capacities and the underlying mechanism. hEPCs and hMSCs were cocultured in a 2D mixed monolayer or a 3D transwell membrane cell-to-cell coculture system. Cell proliferation was determined by Cell Counting Kit-8. Angiogenic capacity was evaluated by in vitro angiogenesis assay. Platelet-derived growth factor-BB (PDGF-BB), PDGF receptor neutralizing antibody (AB-PDGFR), and DAPT (a γ-secretase inhibitor) were used to investigate PDGF and Notch signaling. Cell proliferation was significantly enhanced by hEPCs/hMSCs 3D-coculture and PDGF-BB treatment, but inhibited by AB-PDGFR. Expression of cyclin D1, PDGFR, Notch1, and Hes1 was markedly enhanced by PDGF-BB but inhibited by DAPT. In vitro angiogenesis assay showed that hEPCs/hMSCs coculture and PDGF-BB significantly enhanced angiogenic capacity, whereas AB-PDGFR significantly reduced the angiogenic capacity. PDGF-BB increased the expression of kinase insert domain receptor (KDR, an endothelial marker) and activated Notch1 signaling in cocultured cells, while DAPT attenuated the promoting effect of PDGF-BB on KDR expression of hEPCs/hMSCs coculture. hEPCs/hMSCs coculture enhanced their proliferation and angiogenic capacities. PDGF and Notch signaling pathways participated in the promoting effects of hEPCs/hMSCs coculture, and there was crosstalk between these two signaling pathways. Our findings should aid understanding of the mechanism of beneficial effects of hEPCs/hMSCs coculture.

[Ankle arthroscopy for ankle impingement syndrome through anterior and posterior passage].

OBJECTIVE: To analyze clinical efficiency and intraoperative considerations of ankle arthroscopy for ankle impingement syndrome through anterior and posterior passage. METHODS: From April 2011 to April 2015, the clinical data of 17 patients diagnosed as ankle impingement syndrome were performed arthroscopy, including 12 males and 5 females, with an average age of 32.4 years (ranging from 22 to 47). Ankle arthroscopy cleaning were carried out according to clinical symptoms and radiological imaging, crashed part were cleaned too. Non steroidal anti-inflammatory drugs and intra-articular injection of sodium hyaluronate were used as conventional postoperatively treatment. AOFAS score and Ogilvie-Harris score were used to assess preoperative situation and postoperative situation. RESULTS: Intra-operative conditions showed 8 cases with anterior lateral impingement syndromes, 2 cases with anterior medial impingement syndromes, 2 cases with posterior impingement syndromes and 3 cases combined with anterior and posterior impingement syndromes. Distal bundle of anterior tibiofibular ligament, anterior talusfibular ligament and synovial tissue and scar tissue were cleared up during operation. Four patients were combined with concomitant articular cartilage injury, and damage area were about 1 mm×3 mm to 1.5 mm×4 mm. Microfracture treatment were performed by 1.2 mm diameter Kirschner wire. All patients were followed up from 8 to 24 months with an average of 14.3 months. AOFAS score increased from 62.3±5.20 preoperatively to 87.6±5.40 postoperatively, Ogilvie-Harris ankle score increased from 6.70±0.98 preoperatively to 12.80±1.21 postoperatively. No neurovascular damage, wound infection or wound healing problem occurred. Ankle swelling were appeared with different degrees, but disappeared at 4 to 8 weeks postoperatively. CONCLUSIONS: For ankle impingement syndrome patients, ankle arthroscopy through anterior with posterior passage could effectively clear up bone and soft tissue impingement. Postoperatively non-steroidal anti-inflammatory drugs and intra-articular injection of sodium hyaluronate could effectively relieve ankle pain and swollen and achieve good therapeutic effect.

Development and potential of a biomimetic chitosan/type II collagen scaffold for cartilage tissue engineering.

BACKGROUND: Damaged articular cartilage has very limited capacity for spontaneous healing. Tissue engineering provides a new hope for functional cartilage repair. Creation of an appropriate cell carrier is one of the critical steps for successful tissue engineering. With the supposition that a biomimetic construct might promise to generate better effects, we developed a novel composite scaffold and investigated its potential for cartilage tissue engineering. METHODS: Chitosan of 88% deacetylation was prepared via a modified base reaction procedure. A freeze-drying process was employed to fabricate a three-dimensional composite scaffold consisting of chitosan and type II collagen. The scaffold was treated with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide. Ultrastructure and tensile strength of the matrix were carried out to assess its physico-chemical properties. After subcutaneous implantation in rabbits, its in vivo biocompatibility and degradability of the scaffold were determined. Its capacity to sustain chondrocyte growth and biosynthesis was evaluated through cell-scaffold co-culture in vitro. RESULTS: The fabricated composite matrix was porous and sponge-like with interconnected pores measuring from 100-250 microm in diameter. After cross-linking, the scaffold displayed enhanced tensile strength. Subcutaneous implantation results indicated the composite matrix was biocompatible and biodegradable. In intro cell-scaffold culture showed the scaffold sustained chondrocyte proliferation and differentiation, and maintained the spheric chondrocytic phenotype. As indicated by immunohistochemical staining, the chondrocytes synthesized type II collagen. CONCLUSIONS: Chitosan and type II collagen can be well blended and developed into a porous 3-D biomimetic matrix. Results of physico-chemical and biological tests suggest the composite matrix satisfies the constraints specified for a tissue-engineered construct and may be used as a chondrocyte carrier for cartilage tissue engineering.

Hepcidin promotes osteogenic differentiation through the bone morphogenetic protein 2/small mothers against decapentaplegic and mitogen-activated protein kinase/P38 signaling pathways in mesenchymal stem cells.

The ability of mesenchymal stem cells (MSCs) to differentiate into osteogenic lineages requires management for their future use in treating bone destruction and osteoporosis. Hepcidin is closely associated with bone metabolism, however, it remains to be elucidated whether hepcidin affects osteogenic differentiation in MSCs. The present study demonstrated that hepcidin enhanced osteoblastic differentiation and mineralization, which was manifested by an upregulation in the differentiation markers alkaline phosphatase and osteogenic genes. Furthermore, the expression levels of bone morphogenetic proteins and small mothers against decapentaplegic homologs were concomitantly increased following hepcidin treatment. In addition, the p38 mitogen-activated protein kinase may be an upstream kinase for osteoblastic differentiation. Thus, hepcidin may be important in the osteogenic differentiation of MSCs and may be considered as a target in the development of therapies for pathological bone loss.

[Analysis of therapeutic effects of cannulated compression screws for the treatment of femoral neck fractures].

OBJECTIVE: To evaluate the therapeutic effects of cannulated compression screws for the treatment of femoral neck fractures, and to investigate the related factors influencing the avascular necrosis of femoral head after surgery. METHODS: A retrospective review was done for 96 patients with femoral neck fractures treated with cannulated compression screws from January 2003 to June 2009. Among them, there were 44 males and 52 females with 21 to 88 years old (averaged 56.3 years old). According to Garden classification, 4 patients were type I, 34 patients were type II, 37 patients were type III and 21 patients were type IV. Factors such as patients' age, gender, fracture type, duration from injury to surgery and fracture reduction quality were statistically analysed to find correlations with nonunion and avascular necrosis of femoral head. RESULTS: Eighty-four patients were followed up ranging from 9 to 60 months and the mean time was 25.4 months. Postoperative complications included deep venous thrombosis of lower extremity in 2 cases, bone nonunion in 8 cases and avascular necrosis of femoral head in 11 cases. According to Harris criterion, the total postoperative Harris score was 86.20 +/- 11.00, and 40 patients got an excellent result, 32 good, 7 fair and 5 poor. The incidence of avascular necrosis of femoral head in nondisplaced fracture group and displaced fractures group were 3.22% and 18.87% respectively;and there were significant difference between the two groups (P = 0.037). The incidence of avascular necrosis of femoral head in anatomical reduction group and non-anatomical reduction group were 5.00% and 20.45% respectively; also,significant difference was existed between the two groups (P = 0.036). However, there was no statistically significant difference of the incidence of avascular necrosis of femoral head according to different age, sex, operative time. CONCLUSION: The therapeutic effect of cannulated compression screws for non-displaced femoral neck fractures is good. The fracture type and reduction quality are found to be main factors correlated with avascular necrosis of femoral head statistically. For young patients with a displaced femoral neck fracture,in order to avoid incidence of avascular necrosis of femoral head, anatomical reduction should be ensured. For elder patients with a severe displaced femoral neck fracture, the total hip replacement should be recommended.

[Culture of chondrocytes using collagen-hydroxyapatite composite scaffolds in vitro].

OBJECTIVE: To evaluate the feasibility and the value of the layered cylindric collagen-hydroxyapatite composite as a scaffold for the cartilage tissue engineering after an observation of how it absorbs the chondrocytes and affects the cell behaviors. METHODS: The chondrocytes were isolated and multiplied in vitro, and then the chondrocytes were seeded onto the porous collagen/hydroxyapatite composite scaffold and were cultured in a three-dimensional environment for 3 weeks. The effects of the composite scaffold on the cell adhesivity, proliferation, morphological changes, and synthesis of the extracellular matrix were observed by the phase-contrast microscopy, histology, scanning electron microscopy, and immunohistochemistry. RESULTS: The pore diameter of the upper layer of the collagen-hydroxyapatite composite scaffold was about 147 microm, and the porosity was 89%; the pore diameter of the bottom layer was about 85 microm and the porosity was 85%. The layered cylindric collagen-hydroxyapatite composite scaffold had good hydrophilia. The chondrocytes that adhered to the surface of the scaffold, proliferated and migrated into the scaffold after 24 hours. The chondrocytes attached to the wall of the microholes of the scaffold maintained a rounded morphology and could secrete the extracellular matrix on the porous scaffold. CONCLUSION: The layered cylindric collagen-hydroxyapatite composite scaffold has a good cellular compatibility, and it is stronger in the mechanical property than the pure collagen. It will be an ideal scaffold for the cartilage tissue engineering.

[Fabrication and properties of a composite chitosan/type II collagen scaffold for tissue engineering cartilage].

OBJECTIVE: To develop a novel porous three-dimensional scaffold and to investigate its physico-chemical properties for tissue engineering cartilage. METHODS: Refined 88% deacetylation degree chitosan was prepared and dissolved in 0.2 mol/L acetate acid and fully mixed with highly purified porcine type II collagen in 0.5 mol/L acetate acid solution in a ratio of 4 to 1 (wt/wt). Freeze-drying process was employed to fabricate the composite scaffold. The construct was cross-linked by use of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). A mechanical tester was utilized to determine the tensile strength change before and after cross-linking. The microstructure was observed via scanning electron microscopy (SEM). The lysozyme degradation was performed to evaluate the degradability of the scaffold in vitro. RESULTS: A bulk scaffold with desired configuration was obtained. The mechanical test showed that the cross-linking treatment could enhance the mechanical strength of the scaffold. The SEM results revealed that the two constituents evenly distributed in the scaffold and that the matrix was porous, sponge-like with interconnected pore sizing 100-250 microm. In vitro lysozyme degradation indicated that cross-linked or uncross-linked composite scaffolds had faster degradation rate than the chitosan matrix. CONCLUSION: Chitosan and type II collagen can be developed into a porous three-dimensional scaffold. The related physico-chemical tests suggest that the composite scaffold meets requirements for tissue engineered scaffold and may serve as an alternative cell-carrier for tissue engineering cartilage.