[Objective]To study the influence of hydroxypropyl methyl cellulose(HPMC) on injectability of calcium phosphate cements(CPC).[Method]Calcium phosphate cement(ICPC) with different content of HPMC(0～4%) was prepared.Injectability coefficient and consistency were tested to evaluate the injectability of the cements.[Result]Injectability increased as HPMC content increased.CPC injectability coefficient reached to 95% with lowest consistency when HPMC increased to 2%.CPC with 2% HPMC could be injected from syringe completely.Injectability began decrease when HPMC beyond 3%.Injectability decreased to 90% as HPMC increased to 4%,2% HPMC increased the injectability and decreased the consistency significantly,without any influence of setting time.[Conclusion]Rheology and injectability of CPC can be improved by HPMC significantly,Injection of CPC with 2% HPMC can be used for mini-invasive orthopedic surgery.

Great and extensive progress has been made in joint surgery in the last decade. With the evolution of surgical concepts and the development of operational technique and equipment, indications, selective range for surgica l operation and management in the period of perioperation have been surveyed in new perspectives and with deeper insights. This article introduces the situation of joint surgery of China in these years, briefly reviews the latest progresses in the fields of the arthroscopy, the arthroplasty and the joint cartilage repa ration, and thus suggests developmental strategies for Chinese joint surgery in the future.

Objective In order to explore the possibility of bone ingrowth into a hollow prosthesis at the bone-implant interface, and the promoting effects induced by rhBMP-2/carrier compound as well. Methods Bone harvest chamber (BHC) modified form Albrektsson designation, was implanted into meta-physis of tibia of New Zealand rabbit to establish an animal model. 10 ?l rhBMP-2 and rhBMP-2/Healon GV compound, each of which contained 1mg rhBMP-2, were loaded into BHC respectively. The same vol-ume of Healon GV and injection water was also loaded into as control. The tissues in the BHC were harvest- ed at 2, 4 and 6 weeks after implantation respectively. Histological observation with non-decalcified slicing technique was adopted, and bone histomorphometry was analyzed by computerized image analysis system to calculate TBV (trabecular bone volume). The data was compared among the different groups. Results At two weeks after loading, there were woven bone formation in groups of rhBMP-2/Healon GV compound and rhBMP-2, and mature bone trabeculae with marrow-like tissue were observed at 4 weeks; At 6 weeks, new bone formation in the BHC became more intensive. However, the tissues in BHC of Healon GV and injection water at 4 weeks were just like those of the former two groups at 2 weeks, and mature bone trabeculae with marrow-like tissue could only been found until 6 weeks. Conclusion Bone at the interface can grow into the contained space of hollow prosthesis through holes at the wall, and form mature bone. rhBMP-2 loaded in the hollow space can obviously promote this effect and the carrier Healon GV has no negative influence but can increase bone inductive effect.

Objective To report the experience of the revision procedure with morselized bone grafting and a special design of acetabular prosthesis with three wings for loosened acetabular component in our hospital. Methods Since December 1989 to Junanry 1999, 23 cases with loosened acetabular component and bone defect were revised by morselized bone auto/allografting. There were 12 males and 11 females, the average age of the patients was 54.2 years old (range from 38 to 71 years old). The prosthesis of primary THA was double cup in 4 cases, the conventional THA in 19 cases, cemented in 22 cases and cementless in 1 cases. The severity of acetabular component loosening was classified into four types according to Gustillo: Type II in 3 cases, type III in 9 cases and type IV in 11 cases. The morselized bone autografting and allografting with size 4－ 6 mm were used in 6 cases and in 17 cases respectively. Different acetabular components had been used, the thread metal acetabular cup in 2 cases, screw fixed conventional metal acetabular cup in 10 cases and special design acetabular prosthesis with three wings in 11 cases. The latter prosthesis consists of an conventional acetabular component with pearl porous surface and three wings with different length and sharp edge distributed centrally in the superior lateral quadrant on the surface, the liner is made of UHMPE. Results No infection of the wound occurred in this group. The mean time of follow- up was 3 years and 8 months. Except 3 cases, all of the bone grafts was healed well and X－ ray showed that the containing of acetabular component was good, no translucent line between donor bone bed and prosthesis, and the bone defect had been repaired. The average Harris score was 47 before revision, and 86 after revision. The successful rate of revision was 86.9％ . There were 3 loosening cases postoperatively, 2 cases were due to incorrect position of prostheses and insufficient bone graft, another case was due to the screw being too short to fix the acetabular component. However, all of the three cases have partial bone growth in the original loosening acetabular. Conclusion 1. Direct contact between the morselized bone auto/allograft and the surface of metal acetabular component and the firm fixation of the prosthesis have showed good result of bone defect reconstruction. 2. The special design of acetabular prosthesis with three wings could be selected as an alternative method for huge bone loss of acetabulum (ranged from 64 to 79 mm), because it was able to enlarge the volume of the acetabular component.

Objective Experimental and clinical data suggest that fixed element knee designs a re not able to both supply adequate mobility and eliminate unnecessary constra int forces,as well as provide low contact stresses compatible with pr olonged life of UHMWPE bearing components.The present study investi-gated the preliminary clinical outc ome of TACK(Total Articulating Cementless Knee)system,a new design of mobile-bearing knee prosthesis.Methods Eighty-eight knees in 61patients underwent total knee replace-ment by using TACK were reviewed.Forty-five knees of 31patients were followed-up at least one year.The HSS knee rating score system as well a s X-ray films were used to evaluate th e clinical results with the mean follow-up period of 25.4months.Results At the latest follow-up examination,the rate of good to excellent clinical results was 96.4%.The range of motion was improved from 0-6.5-68.3degrees preoperatively to0-2-88.4degrees at the latest follo w-up.The complications such as oste olysis around the prosthesis,prosthetic loosening and dislocation of meniscus bearings were not found.Conclusion The TACK Knee is a third generation knee system design ed to introduce movable bearings between the metal tibial and femoral components that would reduce the sur face and subsurface stress states at the bearing surfaces and at the bone-implant interfaces by maximiz ing the conformity of the tibial and f emoral components and allowing mo-bility of the bearing surface.In an a verage of more than two years experie nce,it was observed that there was no aseptic loosening of the componen ts.A long term follow-up is obviously necessary to make more precise statement about this knee replaceme nt system.

Objective To compare the results of one-stage bilateral total hip arthroplasty (THA) and staged bilateral THA, and to determine the safety and efficacy of one-stage simultaneous bilateral THA. Methods The patients who were indicated for with bilateral THA were divided into 2 groups. Gourp A included 87 patients with one-stage simultaneous bilateral THA, and Group B included 31 patients with staged bilateral THA. The operating time, the amount of blood loss, the amount of blood transfusion necessary, post-operation functional scores, and perioperative complications were compared between group A and group B. Result There was no significant difference between group A and group B. Conclusion One-stage simultaneous bilateral total hip arthroplasty was a safe and efficacious procedure.

BACKGROUND:The main factors that influence revision of acetabular bone defects include evaluation of acetabular bone defects,reconstruction of acetabulum and appropriate acetabular cups used in revision.OBJECTIVE:The review from the three aspects will help to choose an appropriate cup in revision and to formulate the best revision protocols.METHODS:A computer-based online search of PubMed was performed for English articles published from January 1900 to June 2009 with the key words of acetabulum,revision,bone defect,in English and Chinese.Clinical studies published in core periodicals of the latest twenty years were reviewed.Articles regarding primary joint replacement,femoral prosthesis revision and animal experiments were excluded.RESULTS AND CONCLUSION:A total of 61 articles were analyzed,31 were excluded,and 30 mainly published in 5 years,were included.Reconstruction of acetabular bone structure,restoration of original rotation center of hip joint are key factors for repair.Moreover,appropriate prosthesis further benefits the repair effect.Bone transplantation for bone defect and cementedless prosthesis have become favorable methods for revision of acetabular bone defects.

Objective\ Treatment of spondylolisthesis using freeze dried femoral ring allografts plus morselled cancellous autografts (called as composite cortical ring) by anterior lumbar interbody fusion (ALIF). Methods\ Fourteen patients were treated by this procedure, there were six males and eight females. The age of the patients range from 40 to 56(average 46). Ten segments were of grade Ⅱspondylolisthesis, five segments were of gradeⅠ. Ten patients were treated with RF as internal fixation, four patients with short Harrington rod as internal fixation. Results\ The fusion rate and clinical results of ALIF were analyzed by comparing the findings on the X-ray films taken preoperatively and 6 months postoperatively as well as by JOA score. The fusion rate of 15 segments of 14 patients(two segments of 1 patient was fused) is 85.7%, the average improvement rate of JOA score is 73.3%at an average follow up of 26.6 months. Conclusion\ ALIF with composite cortical ring could successfully restore the spinal structure, maintain the interspace height distracted intraoperatively, obtain high fusion rate and excellent clinical results.\;

Objective To compare the expression of osteolysis and osteogenesis cytokines in the interface membrane around aseptically loosened prosthesis for the elucidation of the biological mechanism of osteolysis caused by wear particles at bone-implant interface. Methods Reverse transcription polymerase chain reaction(RT-PCR) and computerized image processing were adopted to determine the mRNA expression of PDGF-B and BMP-7 respectively in the interface membrane(IM) at osteolysis region(with wear particles) and non-osteolysis region. Normal synovial membrane(NSM), OA synovial membrane(OASM) and normal cancellous bone(NCB) were obtained as negative or positive control. Results Expression of PDGF-B mRNA from high to low was OASM, IM at osteolysis region, NCB, IM at non-osteolysis region and NSM(P

Objective To study the orientation of tissue differentiation at bone implant interface by comparing PDGF－? and BMP－ 7 receptor distribution on histiocytes of interface membranes around aseptic loosened prosthesis. Methods Interface membrane tissues of osteolysis and non- osteolysis regions around aseptic loosened prostheses of 10 cases were immunohistochemically stained by PDGFR－? and ActR－Ⅰ (ALK－ 2) multiclonal antibodies. The relative grey values of 100 positive cells of each factors from every case were determined by computerized image analysis system and were compared between different groups and cells. Results No specificity of PDGFR－? distribution on different kinds of cells of interface membrane. PDGFR－? expression on macrophages and fibroblasts of the membranes at osteolysis regions was significantly higher than that at non- osteolysis regions (P