Objective To explore the effects of co-culture of chondrocytes and bone mesenchymal stem cells (BMSCs) on constructing engineered cartilages, and confirm the most suitable ratio of chondrocytes to BMSCs. Methods Chondrocytes and BMSCs were isolated from articulars cartilages of rabbit (1 month old)cells (40 μl 4×107/ml) were seeded into a poly(lactic-co-glycolic acid) (PLGA) scaffold and cultured statically for 2 days. They were transferred into the cyclic pressures system, and cultured under cyclic pressures for 3 weeks. The engineered cartilages were harvested and examined by gross observation, histological staining, immunohistochemisty of collagen Ⅱ, the content of glyeosaminoglycans, GAGs, DNA and the percentage of collagen Ⅱ dyeing area. Results The engineered cartilages of the co-cultured groups grew bigger than those of the chondrocytes alone group, and their surfaces were smooth and glossy. The distributions of cartilaginous extracellular matrices in the co-cultured groups were more homogenous than those of the chondrocytes alone group.gen Ⅱ dyeing area of the co-cultured groups were higher than those of the chondrocytes alone group. The conConclusion Co-culture of chondrocytes and BMSCs could improve the quality of engineered cartilages. The

Objective To evaluate effect of two-stage exchange total hip arthroplasty (THA) using an antibiotic-loaded cement spacer in the treatment of hip infection secondary to hip surgery.Methods From January 2005 to January 2010,6 consecutive patients with infected hip secondary to hip surgery,including 2 males and 4 females,aged from 43 to 68 years (average,59.7±9.2 years) were treated with two-stage exchange THA.There were 3 cases of femoral neck fracture treated with compression screws fixation,1 case of femoral head necrosis treated with bone graft,and 2 cases of early stage femoral head necrosis treated with core decompression and local interventional therapy respectively.Debridement and insertion of antibioticloaded cement spacer was performed in the first stage.After eradication of infection,it was converted to THA in the second stage.All patients were followed up regularly.Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were tested.Harris score was used to evaluate the function of the hips.Results All patients were followed up for an average of 46 months (range,24 to 81 mouths).Five of 6 patients were successfully converted to THA after an average of 14 weeks.One patient accepted the second debridement and reinsertion of a spacer owing to the abnormal values of ESR and CRP; this case was converted to THA successfully 12 weeks after the second debridement.Harris hip score improved from preoperative 35.6±3.3 to 57.8±5.4 between the two stages and 92.3±5.7 at final follow-up.One patient suffered deep vein thrombosis in the infected extremity and pulmonary embolism.There was no reinfection after THA.Conclusion Twostage exchange THA using an antibiotic-loaded cement spacer can obtain satisfactory results for the treatment of hip infection secondary to the hip surgery.

Objective To investigate the method and efficacy in treating acetabular bone defects by the use of titanium wire mesh and impact bone allograft in revision total hip arthroplasty.Methods Twenty-two patients (22 hips) with acetabular bone defects in revision total hip arthroplasty were treated with wire mesh and impact bone allograft from January 2008 to December 2013.There were 7 males and 15 females in the present study.The average age of the patients at the surgery was 64.8 (37-78) years.According to Paprosky classification,there were 9 cases of type ⅡA,4 cases of ⅡB,7 cases of ⅡC and 2 cases of ⅢB.Twenty cases with aseptic loosen and 2 with periprosthetic infection were underwent revision surgery.Deep frozen cancellous bone allograft was sterilized and morselized to particles with the size of 7 to 10 mm.After removal of loosed acetabular component,the bone grafts were impacted into the acetabular defects area to restore the bone quantity.Titanium wire mesh with appropriate diameter was chosen to fix on impacted bone graft and fixed acetabulum with screws.Polyethylene cup was cemented in the mesh wire with proper position.Harris hip score system was used to evaluate the hip joint function.The AP pelvis X-ray was taken at 1 week,3 months,12 months and annually thereafter postoperatively to evaluate the rotation center,fusion of the bone graft and loosening of cup.Results All patients were followed up with the average period 5.1 years (3-7 years).The average Harris hip score before revision was 43.75±13.45,while the score was 85.33±7.84 at last follow-up (t=7.930,P=0.000).The average height of hip rotation center of surgical side was 3.49±0.77 cm before surgery,while its height at last follow-up was 2.22±0.22 cm (t=4.390,P=0.005).The distance between hip rotation center and the base of acetabulum was 3.54±0.45 cm before surgery,while its value was 3.52± 0.76 cm at last follow-up.All the bone grafts came to infusion with the average time 12 months (9-15 months).There was no case with cup migration more than 4 mm or rotation greater than 5° at last follow-up.One patient had the symptom of sciatic nerve injury.No case was with infection or dislocation.Conclusion In the treatment of acetabular bone defects,wire mesh and impact bone allograft with cemented cup in revision total hip arthroplasty can reconstruct hip rotation center and the acetabular bone quantity effectively.Satisfied early-midterm curative effects could be acquired by using this method.

Objective To evaluate mortality associated with simultaneous bilateral or staged bilateral TKA, and better understand the risks involved in the simultaneous versus staged bilateral procedures.Methods A systematic review was conducted, following an a priori protocol, according to the methods recommended by the Cochrane Musculoskeletal Group in the Cochrane Collaboration. Eligible studies were identified in PubMed (1990-2010), OVID MEDLINE (1990-2010), and the Cochrane library, concerning postoperative complications of bilateral or staged bilateral total knee arthroplasty. All of the English-language abstracts were obtained, and retrieval words including bilateral total knee arthroplasty, staged total knee arthroplasty, and total knee arthroplasty, etc. An extensive analysis was then performed to identify articles fulfilling the inclusion criteria for the study. The details of the reported data were extracted and evaluated by two reviewers independently. Data analyses were conducted with Stata 10.0. Results Six studies met our inclusion criteria for review. The combined results showed that the prevalence of mortality[OR=2.925, 95% CI (2.352, 3.638)], mortality 30 days postoperatively[OR=5.078, 95% CI (2.192, 1 1.763)]and mortality in 70 years or older patients[OR=4.087, 95% CI (1.947, 8.582)]were statistically higher in the population that had undergone simultaneous TKA compared with staged TKA. Conclusion Compared with staged bilateral TKA, simultaneous bilateral TKA might carries a higher potential risk of postoperative mortality. Patients should be aware of this information when deciding whether to proceed with simultaneous bilateral TKA. Further well-designed and large-scale randomized controlled trials are required to confirm these findings.

Objective To determine the incidence of avascular necrosis after closed reduction and cannulated compression screws fixation of intra-capsular femoral neck fracture and to investigate the multiple factors correlated to avascular femoral head necrosis.Methods All the patients of intra-capsular femoral neck fracture who accepted closed reduction and cannulated compression screws fixation between 2001 and 2010 in Jiangsu Province were reviewed in multi-centers retrospectively.The multiple factors were analyzed including age,gender,affected side,mechanism of injury,fracture classification,procedure delay,quality of reduction,time of full-weight-bearing,configuration of the screws and removal of the screws.Multiple correlation factors were analyzed with SPSS 13.0 statistic system.Results Complete case records were documented in 1849 cases who were followed up for an average 6.5±2.7 years (range,2-10 years).Avascular necrosis occurred in 246 cases (13.3％).The average time of diagnosis of avascular necrosis was 17±4.6months (range,8-72 months) after injury.The average Harris score of the hips which didn't develop to avascular necrosis was 93.8±8.9 (range,78～100) at the last follow up.Multiple correlation factors analysis indicated that displacement degrees of fracture and the quality of reduction were significantly correlated to the incidence of avascular necrosis (OR=2.078,3.423).Conclusion Closed reduction and cannulated compression screws fixation after the intra-capsular femoral neck fracture can get satisfactory results.Displacement degrees of fracture and the quality of reduction are significantly correlated to the incidence of avascular femoral head necrosis.