BACKGROUND: Thermosensitive hydrogel has made great progresses in drug carrier and tissue engineering. However, its phase-transition temperature is lower than human body temperature, so it has not been used as implants. OBJECTIVE: To prepare and evaluate the biocompatibility of a thermosensitive hydrogel poly-(N-isopropylacrylamide-co-N-hydroxymethylacrylamide)[P(NIPAAm-co-NHMPA)] In vitro so as to assess its safety as a medical implant.DESIGN, TIME AND SETTING: Material experiment was performed at the Central Laboratory of Union Hospital of Tongji Medical College, Huazhong University of Science & Technology and Key Laboratory of Biomedical Polymers, Ministry of Education, Wuhan University Chemical Department from January to October 2007.MATERIALS: L929 mice fibroblast line was provided by Professor Chen, Stomatology Hospital of Wuhan University. N-isopropylacrylamide and N-hydroxymethylacrylamide were purchased from Aldrich.METHODS: Using ammonium persulfate and tetramethylethylenediamine as oxidateion-reduction initiation system and N, N'-methylene bisacrylamide as crosslinking agent, mass fraction 8.5% N-hydroxymethylacrylamide was added to the reaction system. The N-isopropylacrylamide and N-hydroxymethylacrylamide were dissolved in deionized water and reacted with N, N'-methylene bisacrylamide, ammonium persulfate and tetramethylethylenediamine at room temperature for 3 hours. The colorless transparent cylinder gel was obtained, soaked in deionized water and dried.MAIN OUTCOME MEASURES: Biocompatibility in vitro of the material was validated by cytotoxicity test, cells/scaffolds interaction test, hemolysis test and pyrogen test in vitro.RESULTS: Synthesized hydrogel showed thermosensitive character as expected and the lower critical solution temperature was 38 ℃. The toxicity rate was grade 0-1. Through the scanning electron microscopy, cells and scaffolds were tightly attached, producing a perfect interface, and the shape of cells was all right. Hemolysis rate was 2.54%. No pyrogen reaction was found. CONCLUSION: P(NIPAAm-co-NHMPA) has been successfully prepared with good biocompatibility in vitro and might become a good medical implant for clinical use.

Objective To evaluate the clinical outcome associated with the core decompression in combination with the nano-hydroxyapatite/collagen composite rod combined with decalcified bone matrix in a consecutive series of patients with osteonecrosis of femoral head,especially the prevention of collapse of femoral head and its predisposing factors.Methods From August,2012 to May,2013,46 pationts (50 hips) who had undergone core decompression in combination with nano-hydroxyapatite/collagen composite rod insertion in corporated with decalcified bone matrix in our hospital were involved in this study.Postoperative care consisted of prophylactic intravenous antibiotic and anticoagulation therapy.Patients were instructed to be non-weight-bearing for 3 weeks,to partial weight-bear for the next 3 weeks,and to weight bear as tolerated thereafter.All patients were evaluated both clinically and radiographically.The primary clinical outcome of this study was functional improvement assessed with the Harris hip score.Serial radiograms of the pelvis were taken at 1,3,6,12 months post-operatively to analyze the process of osteonecrosis.Results All patients followed up for 12 months,no one suffer complications.The mean Harris score pre-operation was 65.6 ± 10.6,post-operation score was 87.5 ± 15.3,with a mean improvement of 21.8 ± 13.2 (P ＜ 0.05).According to Harris hip score system,excellent for 30 hips,good for 14 hips,fair for 2 hip and poor for 4 hips.Refer to the Kaplan-Meier survivorship curve,the success rate at 12 months post-operatively was 92％.Radiological changes coincided with clinical changes.Conclusion Core decompressionin combination with nano-hydroxyapatite/ collagen composite rod insertion in corporated with decalcified bone matrix provided a minimally invasive surgical treatment option to treat early stage osteonecrotic hips(stage Ⅰ and Ⅱ) and to prevent femoral heads from collapsing,with clinical outcomes and success rates priorto other commonly used surgical procedures.

Objective To retrospectively analyze the methods and clinical outcome to treat Crowe type Ⅳ developmental dysplasia of the hip (DDH) in young adults with total hip arthroplasty (THA) after limb-lengthing with external fixator.Methods From October 2007 to January 2012,12 patients with unilateral Crowe type Ⅳ DDH were treated with two-staged surgical method in our department.There were 2 males and 10 females with an average age of 25.7 years (range,18-35 years).In the first stage,the patients underwent soft tissue relaxation and iliofemoral distraction with use of an external fixator for 10-17 days.There were 1-2 cm distraction at the first time and 3-5 mm daily distraction.When the femoral head was distracted to the level of anatomical position,the second stage-THA was performed.All patients underwent uncemented prosthesis with bulk femoral head autograft for acetabular reconstruction.The acetabular cup was placed in the anatomical position in every patient.Shortening femoral osteotomies were not required.Results The mean time of first operation was 35.2±3.6 min,and hospital stay was 13.3±1.6 days.The mean time of second operation was 77.3±12.4 min,and hospital stay was 9.2±2.5 days.The average follow-up was 13.6±3.2 months,limb-length discrepancy was 5.6±1.5 cm on average preoperatively and 0.5±0.2 cm on average postoperatively.The Harris hip score was increased from 45.7±2.6 preoperatively to 92.3±3.3 postoperatively.All of the cases had acquired good hip and knee function.No patient suffered pin-site infection,hip joint infection,prosthesis loosening or deep vein thrombosis in our research.Transient nerve palsy occurred during the leg limb lengthening in 3 cases; calf skin numbness after THA occurred in 5 cases.Conclusion For the Crowe type Ⅳ DDH in young adults,normal limb length can be restored nearly and avoid nerve injury via continuously limb-lengthing with external fixator before THA.This method can get precise results,improve limb function significantly and have fewer complications.

[Objective]To introduce the surgical technique and its rationale and to evaluate the early and mid-term clinical outcome of routine core decompression and insertion of a biomaterial loaded allograft threaded cage(ATC)in the treatment of necrotic femoral head．[Methods]Seventy-six patients(78 hips)with femoral head necrosis were allocated to a program of either core decompression or core decompression and implantation of ATC．[Results]At review all patients had a minimum follow-up of 24-months(24 to 68 months)．In the control group，no significant improvement in Harris hip score(HHS)was found，and 13 of the 22 hips had deteriorated to stageⅢ．In the treatment group．the mean HHS was improved from 62．8 to 81．6．Collapse was seen in 1 hip，and this collapse Was progressive in 3 hips．[Conclusion]It，s thus evident that the technique is attractive as a salvage procedure．which shows encouraging Success rates and early clinical results.

Objective To evaluate the clinical efficacy of total hip arthroplasty with subtrochanteric femoral shortening osteotomy for Crowe Ⅳ developmental dysplasia of the hip.Methods From September 2003 to September 2012,21 patients (24 hips) underwent total hip arthroplasty with subtrochanteric femoral shortening osteotomy for Crowe Ⅳ developmental dysplasia of the hip in our hospital.There were 3 males and 18 females,aged from 28 to 71 years (average,54±10 years).The ceramicpolyethylene articulation was used in 17 patients (20 hips),and metal-polyethylene articulation in 4 patients (4 hips).The osteotomy site was treated with autologous bone graft in 18 patients (21 hips) and allogeneic bone graft in 3 patients (3 hips).The Harris hip score was used to assess the clinical results.Results A total of 18 patients were followed up for 0.5 to 9 years (average,3.5 years).The Harris hip score was improved from preoperative 47.9±9.1 to 88.4±3.5 at 6 months postoperatively.For most patients,hip pain relieved significantly; range of motion of the hip was improved,and the gait returned to normal.Sciatic nerve palsy occurred in 1 patient.There was no wound infection.X-rays 6 months after operation showed that the position of prostheses was satisfactory,without loosening of prostheses and bone block resorption.Conclusion Total hip arthroplasty with subtrochanteric femoral shortening osteotomy can achieve good clinical effect in Crowe Ⅳ developmental dysplasia of the hip.Moreover,it can improve leg length discrepancy and decrease the risk of sciatic nerve injury.

Objective To evaluate the clinical effects and experiences of short stem ceramic-on-ceramic total hip arthroplasty in the treatment of young and middle-aged patients with femoral head necrosis.Methods From December 2009 to March 2011,40 patients with femoral head necrosis were treated primarily with short stem ceramic-on-ceramic hip arthroplasty (43 hips) through posterior-lateral or anterior-lateral approach.There were 23 males,17 females； with the mean age of 40.5 years (range,27-55 years).All cases were stage Ⅳ or more according Steinberg stage.The patients were followed up at the 3,6,12 months after operation,and then once each year.Standard X-ray films were taken at the follow-ups.Femoral prosthesis subsidence was assessed through X-ray films.Harris scores system and WOMAC Osteoarthritis Index were recorded before and after operation to evaluate clinical effects of surgery.Results Thirty-eight patients (41 hips) were followed up for 21-36 months,with an average of 31.3 months.The femoral stem subsided 0.68±2.90 mm at the last follow-up.After operation,hip pain of patients was relieved obviously.The Harris score improved from 38.7±12.1 (15-66) preoperatively to 95.2±4.49 (83-100) postoperatively,WOMAC Index from 66.7±12.0 (49-94) to 12.8±5.6 (0-24).During follow-up period,there was no serious complication such as femoral neck fracture,infection of wound,pulmonary embolism,et al.No dislocation,implant prosthesis failure and infection were observed.Conclusion The short stem hip arthroplasty preserves bone stock to a great extent.The short stem implant showed a good stability and osseous integration.The wear rate of ceramic-on-ceramic bearing surface is extremely low.Short stem hip arthroplasty plus ceramic-on-ceramic bearing surface might be a good option for the young and middle-aged patients with femoral head necrosis.

Objective To evaluate the clinical indications and outcomes of dynesys neutralization system in the treatment of degenerative lumbar diseases.Methods From January 2007 to December 2011,102 consecutive patients with degenerative lumbar spine diseases underwent posterior decompression and internal fixation with the Dynesys dynamic neutralization system.Among them,69 patients were followed up,including 39 males and 30 females,aged from 30 to 62 years (average,44 years).The series of cases were composed of 24 cases of lumber disc herniation,35 cases of degenerative spinal stenosis,10 cases of degenerative changes of lumbar discs.Results The mean follow-up period was 35 months (range,6-44 months).The visual analogue scale (VAS) score decreased from preoperative 8.6 (range,6-9) to postoperative 2.8 (range,0-5),and the Oswestry disability index (ODI) improved from preoperative 73％ (range,30％-91％) to postoperative 30％ (range,0-61％).There were no implant failure or infection.According to the evaluation criteria of surgical treatment for low back pain,which was established by the Chinese Orthopaedic Association,the result was excellent in 53 patients,good in 12 patients,fair in 4 patients and poor in 1 patient.Conclusion The Dynesys dynamic neutralization system is effective in the treatment of degenerative lumbar spine disease,which can reserve the range of motion of stabilized segments,prevent degeneration of adjacent segments and improve clinical outcomes.

By co-culturing humm mesenchymal stem cells (hMSCs) and human umbilical rein endothelial cells (HUVECs) under hypoxia and creating a microenvironment similar to that of transplanted hMSCs for the treatment of avascular ni ANFH, the effect of hMSCs on survival, apoptosis, migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) under the hypoxic condition were investigated in vitro. hMSCs and HUVECs were cultured and identified in vitro. Three kinds of conditioned media, CdM-CdM(NOR), CdM-CdM(HYP) and HUVEC-CdM(HYP) were prepared. HUVECs were cultured with these conditioned media under hypoxia. The survival rate, apoptosis rate, migration and angiogenesis of HUVECs were respectively detected by CCK-8, flow cytometry, Transwell and tube formation assay. The content of SDF-1α, VEGF and IL-6 in CdM was determined by ELISA. Our results showed that hMSCs and HUVECs were cultured and identified successfully. Compared with MSC-CdM(NOR) and HUVEC-CdM(HYP) groups, the survival rate, migration and angiogenesis of HUVECs in MSC-CdM(HYP) group were significantly increased while the apoptosis rate was declined (P<0.05). Moreover, the expression of SDF-1α, VEGF and IL-6 in MSC-CdM(HYP) group was up-regulated. Under hypoxia, the apoptosis of HUVECs was inhibited while survival, migration and angiogenesis were improved by co-culture of hMSCs and HUVECs. The underlying mechanism may be that hMSCs could secrete a number of cytokines and improve niche, which might be helpful in the treatment of femoral head necrosis.

The present study examined the role of Wnt/β-catenin signaling pathway in the degeneration of nucleus pulposus cells and the protective effect of DKK1 on nucleus pulposus cells. The model of nucleus pulposus cell degeneration was induced by intra-disc injection of TNF-α, and the expression of β-catenin protein was detected by Western blotting. The cultured rabbit nucleus pulposus cells were divided into 4 groups. In group A, the cells were cultured with normal medium and served as control group. In group B, the cells were cultured with TNF-α and acted as degeneration group. In group C, the cells were cultured with TNF-α and transfected with Adv-eGFP and was used as fluorescence control group. In group D, the cells were cultured with TNF-α and transfected with Adv-hDKK1-eGFP, serving as intervention group. The expression of type II collagen, proteoglycan, β-catenin, and MMP-13 in each group was detected by immunocytochemistry and RT-PCR. The result showed that TNF-α increased the expression of β-catenin and MMP-13, and significantly inhibited the synthesis of type II collagen and proteoglycan, which resulted in the degeneration of nucleus pulposus cells. This effect could be obviously reversed by DKK1. We are led to concluded that TNF-α could activate the Wnt/β-catenin signaling pathway, and increase the expression of MMP-13, thereby resulting in disc degeneration. Specifically blocking Wnt/β-catenin signaling pathway by DKK-1 could protect the normal metabolism of intervertebral disc tissue. The Wnt pathway plays an important role in the progression of the intervertebral disc degeneration.

Osteoarthritis is a common cause of functional deterioration in older adults and is an immense burden on the aging population. Altered chondrogenesis is the most important pathophysiological process involved in the development of osteoarthritis. However, the molecular mechanism underlying the regulation of chondrogenesis in patients with osteoarthritis requires further elucidation, particularly with respect to the role of microRNAs. MiR-21 expression in cartilage specimens was examined in 10 patients with knee osteoarthritis and 10 traumatic amputees. The effect of miR-21 on chondrogenesis was also investigated in a chondrocyte cell line. The effect of miR-21 on the expression of growth differentiation factor 5 (GDF-5) was further assessed by luciferase reporter assay and western blot. We found that endogenous miR-21 is upregulated in osteoarthritis patients, and overexpression of miR-21 could attenuate the process of chondrogenesis. Furthermore, we identified GDF-5 as the direct target of miR-21 during the regulation of chondrogenesis. Our data suggest that miR-21 has an important role in the pathogenesis of osteoarthritis and is a potential therapeutic target.
Cartilage/metabolism/pathology ; Case-Control Studies ; Cell Line ; Chondrocytes/*metabolism/pathology ; Growth Differentiation Factor 5/genetics/*metabolism ; Humans ; MicroRNAs/genetics/*metabolism ; Osteoarthritis/*metabolism/pathology ; Up-Regulation