Objective The application of intraoperative evoked EMG monitoring during lumbar pedicle screw fixation and to find new stimulus threshold criterion.Methods The validity of the evoked EMG monitoring in detecting the malposition of the pedicle screws was tested again by animal experiment.Nineteen patients was inserted pedicle screws with persistent evoked EMG monitoring via tap stimulator,and the electric current was set at 30% of bone threshold of the same pedicle,all patients were ohecked by CT scan to prove the outcome.Results Thirty-two pedicles of six dogs were inserted Kirchner wires.The stimulate thresholds of mal-position wires had significant difference with those of normal-position wires.During clinical trial,122 screws were inserted in to nineteen patients.Four screws were positive during intraoperative evoked EMG monitoring.Of which one screw was confirmed as mal-position during operation and was then adjusted;another screw was found to be mal-positioned by CT scan post-operation;the other two screws were found normal by CT scan.The sensitivity of this technique was 100% and the specificity was 98%.Conclusion Intraoperative evoked EMG monitoring during lumbar pedicle screw fixation can detect the mal-positioned screws and to protect the nerve roots.The stimulate current may set at 30% of the bone threshold of the relevant pedicle.

Objective Establishment of two experimental models for osteoclast differentiation from monocyte in vitro,and to study the potential of osteoclast differentiation induced by cytokines.Methods Direct model of osteoclast differentiation: CD14+ monocyte fraction of peripheral blood mononuclear cell(PBMC) stimulated by(25 ?g/L) M-CSF+(10~(-8)mol/L) LTB4 for two weeks.Indirect model of osteoclast differentiation: Utilize the coculture model of RAFLs and monocyte that were stimulated in the presence of 25 g/L M-CSF+(10~(-8)mol/L) LTB4 for three weeks.In TRAP staining the multinucleated TRAP staining positive osteoclast-like cells were counted as marker of as differentiation effect of each group.Results Osteoclast-like cells can be induced by both direct and indirect models.Conclusion Two experimental models for osteoclast differentiation can be separately used to study the effect of various cytokines for direct and indirect OC differentiation.

Objective To determine whether LTB4 could indirectly stimulate human osteoclast differentiation in RA through increasing RANKL expression of RAFLs. Methods We utilize the coculture model of RAFLs and monocyte which were stimulated in the presence of 2.5 ng/ml M-CSF in the control group, 2.5 ng/ml M-CSF +10-8 mol/L LTB4 in the experimental group A, 2.5 ng/ml M-CSF+10-8 mol/L LTB4+100 ng/ml OPG in the experimental group B. After culture for 3 weeks, through TRAP staining we counted the number of multinucleated TRAP staining positive osteoclast-like cells stained with TRAP to evaluate the differentiation effect in each group. Results There was almost no osteoclast-like cell in the control group and the experimental group B. Whereas there were many osteoclast-like cells in the experimental group A. Conclusion LTB4 can indirectly stimulate human osteoclast differentiation in RA through increasing RANKL expression of RAFLs.

OBJECTIVETo confirm the role of HLA-B2704 and hbeta(2)m gene in the pathogenesis of spontaneous inflammatory diseases by establishing HLA-B2704 and hbeta(2)m double transgenic mice model of ankylosing spondylitis. It will provide a powerful animal model for exploring the etiology, prevention and treatment of B27-relevant diseases.

METHODSThe screening, identification and expression of HLA-B2704 and hbeta(2)m gene were determined by PCR, dot blot, Southern blot hybridization, RT-PCR, flow cytometry and immunohistochemistry. HE staining was performed for the diseased mice.

RESULTSEight double transgenic mice bearing high copy developed spontaneous dermatosis, arthritis and nail changes in the rear paw. The results of flow cytometry in normal mice, B27 single transgenic mice, and HLA-B27/hbeta(2)m double transgenic mice were 0.63%, 7.87% and 35.87% respectively. HLA-B2704 antigen was high expressed on the cell surface, but not evident on those of B27 single transgenic mice.

CONCLUSIONSHLA-B2704 heavy chain can induce spontaneous inflammatory diseases in the transgenic mice. Hbeta(2)m can form a stable complex with HLA-B27 and may stabilize and enhance the expression of HLA-B2704 on the cell surface.

Animals ; Disease Models, Animal ; HLA-B27 Antigen ; genetics ; Inflammation ; etiology ; Mice ; Mice, Transgenic ; Reverse Transcriptase Polymerase Chain Reaction ; Spondylitis, Ankylosing ; genetics ; physiopathology

Objective To report the method and outcomes ot arthroscopic examination and removal of the.loose bodies from the posterior compartments of the knee. Methods Four mm 30? arthroscope was used to examine the patients with osteoarthritic loose body in the politeal fossa on the preoperative roentgenograms via posterolateral and posteromedial portals. An assistant portal at 1 - 1.5 cm in front of the standard portals was made, and loose bodies were removed arthroscopically. Postoperative algesia on the leg and foot, active flexion and extension of the malleolus, toe and phalanxes, and the lateral stress test of the knee were observed. Results Of the three hundred and sixty-four cases undergone knee arthroscopy during January 1999 to December 2000, 17 case had osteoarthritis and loose bodies in the posterior compartment on the roentgenograms. Loose bodies were found in the posterolateral portal in 9 cases, which were removed arthroscopically. Howerver, no loose body was found via the posteromedial portal. The mean duration of follow-up was 14. 88 months. Except one case with subcutaneous loose body was overlooked and one patient developed hematoma, there was no neurovascular or ligamentous complications. Conclusion It is safe and possible to use 4 mm 30? arthroscope to examine the posterior compartments of the knee and to remove loose bodies.

Objective To analyze the composition of hospital cost for total knee replacement (TKR)in recent years in order to improve the effectiveness of TKR,reduce its complications and extend the TKR more widely in China.Methods The data was obtained for primary unilateral TKA performed in2001,1998,1995compared with that performed in1992in Peking University People's Hospital.There were no postoperative complications and other surgical treatments during the hospitalization period.Results From1992through2001,prosthetic and physical therapy cost were predominantly increased214.2%and318.0%respectively in1998;219.8%and291.4%respectively in2001.The least cost was hospital room and blood transfusion fee.Among all the hospital costs in these four individual years,the most expensive was at-tributed to prosthesis cost,reached as54.7%,56.1%,56.0%and63.3%of total costs respectively.The influ-enced factors of the increasing hospital costs for TKR were as following:1)The using of imported knee im-plants increased in achieving better post-operative function of knee;2)The expensive imported antibiotic was widely used because of high drug-resistance due to the abuse of antibiotics;3)The anti-coagulative drugs on account of reducing the incidence of post-operative DVT was widely accepted;4)The emphasis on physical therapy was more considered.The possible factors of the decreasing hospital costs for TKR were using less expensive home-made antibiotics in short time just to prevent infections,reducing the length of hospital stay by enough preparation before operation,improving surgical technique and adopting preoperative blood salvage and re-transfusion to reduce the blood transfusion cost.Conclusion Through the analysis of total hospi tal cost of TKR in recent ten years,the prosthesis cost accounted for the most proportion,and the in crease of the hospital cost was attributed to prosthesis,anti-coagulative drugs,antibiotics and physical ther-apy.At same time,the average postoperative ROM of knee increased from93.6?to112.3?,and the in ci-dence of compli cations decreased from10.3%to5.3%.The better result of TKR,satisfactory knee function and the life quality of patient were obtained.

Objective To investigate the effect of medialization of the patella component on patel-lar-femoral track and clinic result in patellar resurfacing arthroplasty in Chinese adults.Methods From September2001to March2002,patellar-femoral track of medialized patella component in total75consecu-tive total knee arthroplasties were checked with"no thumb test"sign during patellar resurfacing as well as af-ter patellar resurfacing.The patients consisted of 8males(14knees)and40females(61knees).The average age of the patients was66.2years old(ranging from62to79years old).The preoperative diagnosis of the knees were osteoarthritis96%,rheumatoid arthritis4%.There were65varus knees,9nomal knees and1val-gus knee.Eight knees had patellar subluxation or bad patellar-femoral track before arthroplasty.Results Patellar-femoral track were checked with"no thumb test"sign after putting femoral and tibial tray before patellar resurfacing,69of 75knees could reach"no thumb test".After resurfacing and medialization of patella com ponent by2to5mm,all69knees could still reach"no thumb test".But 6knees were ineffectual.After resur facing and medialization of patella component by4to8mm,5of the6knees could reach"no thumb test",the remained one reached"no thumb test"and was of 15?valgus after lateral release.Average flexion of total75knees was108.6?(from90?to115?)two weeks after operation,and increased to116.5?(from95?to125?)after an average follow-up of 15months,ranging from12to18months.No case had patellar fracture insta bility and patellar subluxation.Conclusion Medialization of the patella component in total knee arthro plasty can improve patellar-femoral track,reduce requirement of release of patellar lateral retinac-ulum,decrease patellar-femoral joint complication and increase survival ship of prosthesis.

Objective Bone defect in proximal tibia was common problem needed to manage in serious genu varum during total knee arthroplasty. In order to introduce measures and experiences to reconstruct slope bone defects in proximal tibia with autograft of tibial plateau in total knee arthroplasty, 29 knees of 22 cases treated in our hospital were reviewed retrospectively. Methods From November 1992 to September 2000, 22 cases with slope bone defects in proximal tibia underwent total knee arthroplasty, there were 5 males with 5 knees and 17 females with 24 knees, the average age of the patients was 61.2 years ranging from 43 to 78 years. The diagnosis of the patients was osteoarthritis in 13 cases (14 knees) which were associated with genu varum in 12 cases (13 knees) and genu valgum in 1 case (1 knee), rheumatoid arthritis in 7 cases (12 knees), synovial chondromatosis in 1 case (1 knee), and Kaschin-Beck disease in 1 case (1 knee). All of the knee prostheses were fixed by antibiotic cement. During operation, the slope bone defect of the proximal tibia was repaired into steping bone defect by osteotomy, and then the defect was restored with the resected tibial plateau autograft. Results Three days after operation, functional excise of the knee was begun, the wound healed in one stage in all the patients. The patients were followed up 1 to 9 years with the average of 4.2 years. Knee pain and deformity of the patients disappeared. The HSS knee score improved from preoperative 10-26 to postoperative 76-94. One patient was revised with ⅠB-Ⅱwedge prosthesis because of late infection, absorption of the autograft bone and loosening of the prosthesis. Nonunion, displacement, bone absorption of the autograft or loosening of the prostheses were not found in the other cases at final follow-up. Conclusion In total knee arthroplasty with slope bone defects in proximal tibia, the autograft of resected tibial plateau may reconstruct its integrity and prevent collapse of the tibia plateau. These procedures will markedly provide the initial stability of the prostheses and improve the success rate of the surgery.

Objective The purpose was focused on discussing the causes of sciatic nerve injury following total hip replacement in order to introduce the methods for protecting sciatic nerve during operation by reviewing 655 consecutive total hip replacement and total hip revision. Methods From January 1998 to December 2001, 655 total hip replacement and total hip revision cases were performed in our hospital, 9 cases of which occurred as sciatic nerve injury postoperatively. There were 8 cases in 587 primary total hip replacements and one case in 68 total hip revisions. The 9 patients included 3 males with 3 hips and 6 females with 6 hips with an average age of 51 years ranging from 35 to 67 years old. In the group, 4 cases were diagnosed as avascular necrosis of femoral head, 2 cases as congenital acetabular dysplasia accompanied with osteoarthritis, 1 case as ankylosing spondylitis, 1 case as rheumatoid arthritis and 1 case as loosening of prosthesis. 8 prosthetic components of the hip were fixed by uncement, and the other one was fixed by cement. Results All of the 9 patients experienced sciatic nerve palsy sooner after operation, 8 cases of which suggested simple injury of common peroneal nerve, and 1 case a combined injury of common peroneal nerve and tibial nerve. Of the 9 cases, 7 cases underwent leg lengthening or soft tissue release because of hip joint stiffness during operation. After six to forty-eight months follow-up, the function of sciatic nerve was recovered completely in eight cases after half a year. The other one received total hip revision was not recovered from sciatic never palsy in six months, and the operation of never incision and exploration was performed. During operation, part of the sciatic nerve was found to become thinner without marked compression and other injury. Then release soft tissue around the injured never, the function of sciatic nerve was partly recovered one year after operation. Conclusion It is concluded that sciatic nerve injury associated with total hip arthroplasty is most commonly caused by over-lengthening the low extremity and mechanical compression. The function of sciatic nerve may be recovered in most patients with incomplete injury.

Objective To study the erythrocytic morphological changes in unwashed autologous drainage blood after total knee arthroplasty (TKA), on account of the postoperative anemia status that was poorly improved after reinfusion. Methods 20 patients (34 knees) underwent TKA from November 2000 to March 2001. There were 6 males and 14 females, whose average age was 66 years (range, 32-79 years). TKA was performed unilaterally in 6 patients, and bilaterally in 14 patients. The disorders were diagnosed as OA in 17, RA in 2 and AS in 1 respectively. All of them received unwashed autologous drainage blood reinfusion, using CBCⅡ Consta VacTM blood salvage system. Blood routine tests were performed preoperatively and on the second and seventh day postoperatively. Blood routine and blood smear tests were also performed on the preoperative blood samples, the postoperative venous blood and drainage blood samples at the first and sixth hour respectively. Erythrocytic morphological changes in these samples were observed under light and electric microscope. Results In the unilateral TKA group, the blood loss in the operation was 208.3 ml, the mean volume of drainage blood was 910 ml,of which 708.3 ml was reinfused; One patient received 800 ml of allogenic bank blood due to postoperative anemia. In the bilateral TKA group, the blood loss, the mean volume of the drainage blood and reinfused volume of blood were 296.4 ml, 1718.2 ml and 1370 ml respectively; Five patients received a total amount of 2200 ml of allogenic bank blood, the average volume was 440 ml. Anemia of different degrees was found at the 2nd and 7th day postoperatively. Compared to venous blood, the levels of hemoglobin and hematocrit were lower in shed blood, and more erythrocytes were deformed. Conclusion The relatively large number of deformed erythrocytes is one of the important reasons that the anemia status is poorly improved postoperatively after reinfusion.