Lumbar intervertebrae disc protrusion is a term for the description of morphology, with different pathological changes, pathogenesis and clinical characteristics. We propose a new pathologoical classification including damage-hernia?tion, degeneration-protrusion, posterior vertebral osteochondrosis with disc protrusion, and disc cyst. The appropriate treat?ment including surgical option should be selected according to pathological changes.

BACKGROUND:It is crucial to determine the location of the rotation center of the hip joint using X-ray.Ranawat's triangle is commonly used to define the hip rotational center in bilateral developmental dysplasia of the hip and revision hip surgery especialy in cases with bone stock deficiency,but there are rare articles about its value in normal hip.OBJECTIVE:To compare the difference between Ranawat's triangle method and Mose circle method in determining the healthy hip joint rotational center.METHODS: We selected 30 patients with normal traumatic femoral neck fracture,who underwent unilateral total hip arthroplasty.Ranawat's triangle method and Mose circle method were applied to measure the anteroposterior radiographs of the pelvis after arthroplasty and to compare the distance between the hip rotational center and the reference lines (X-axis: teardrop line; Y-axis: a line perpendicular to the X-axis,drawn from the intersection of theKohler line and the teardrop line.The distance from the hip joint rotational center to X-axis is dx1,dx2 and the distance to Y-axis is dy1,dy2 in Ranawat's triangle and Mose circle respectively.).We also compared the ratios (dx1/H,dy1/W; dx2/H,dy2/W) in the pelvic height (H: the distance between the highest point on the iliac wing and the lowest point on the ischial tuberosity) and width (W: the distance between the most lateral points on the iliac crests).RESULTS AND CONCLUSION:When the values were compared with both methods,highly significant differences were observed for both X and Y,Ranawat's triangle method dx1=(19.52±3.03) mm,dy1=(24.43±2.26) mm; and Mose circle method dx2=(11.90±3.55) mm,dy2=(34.29±3.79) mm (P＜0.001) and these ratios (dx1/H=0.0992±0.0133,dy1/W=0.0855±0.0069; dx2/H=0.0611±0.0194,dy2/W=0.1201±0.0178) in pelvic height and width (P＜ 0.001).Scatterplot results demonstrated that the hip rotational center identified by Ranawat's triangle method is near to the proximal end and medial end,which may affect mechanical environment surrounding the joint.For cases of bilateral hip dysplasia and joint revision,because of the changes in structure surrounding the acetabulum,Ranawat's triangle method can be a feasible method to identify the hip rotational center.For cases of unilateral lesion,Mose circle method can exactly identify the hip rotational center taking healthy side as a control.

BACKGROUND:Femoral head necrosis induced by glucocorticoid is typical under mechanics load.OBJECTIVE:To create the rat models of the femoral head necrosis by long-term glucocorticoid treatment,and to Observe the changes of femoral head necrosis induced by glucocorticoid under mechanics load.METHODS:Wistar rats with 4-month old were randomly divided into the experimental and control groups.After the buttocks injection of dexamethasone 20mg/kg weakly for 8 weeks,rats in the experimental group were made to run on the running machine at a speed of 1 km/h to forme the hyper-weight model;at the same time those in the control group were with the normal physiological weight.Rats in both groups were sacrificed at weeks 2,4,6 and 8.The left legs were taken for the biomechanics test on the EnduraTEC ELF3200,the biggest vertical deformation and stiftness were calculated,the number of empty osteocyte lacunas was calculated,and the cumulative absorbance value was compared between two groups.RESULTS AND CONCLUSION:The femoral head presented with necrosis at 8 weeks in the experimental group.and the width of bone trabecula,and the stiffness of which were smaller than that of the control group.but the biggest vertical deformation was greater the concurrent control group(P＜0.05).The Bcl-2 cumulative absorbance value of 2 groups had significant differences at 4 weeks(P＜0.05),which was increased with time prolonged in the experimental group(P＜0.05).The results demonstrated that:in glucocorticoid-induced osteonecrosis of the femoral head,mechanics Ioad induces the obviously osteocyte necrosis.more cartilage repair,and trabeculae rupture,which is considered as the direct reason of the necrosis of the femoral head The typical femoral head necrosis is presented.

BACKGROUND:The main change of knee osteoarthritis is cartilaginous degeneration and secondary bone hyperplasia. The mechanism of these pathological changes is unclear, but some experiments have proved that the onset of knees osteoarthritis is closely related to inflammatory substances.
OBJECTIVE:To discuss the role of inflammatory substances in the pathogenesis of knee osteoarthritis.
METHODS:According to diagnostic criteria set by the American Colege of Rheumatology, we selected 60 knee osteoarthritis patients as experimental group, and another 60 patients undergoing the operative treatment of traumatic amputation or meniscus injury (except knee injury) as control group. After extracting synovial fluid samples from two groups, ELISA assay method was used to detect the levels of interleukin-1β, interleukin-6, interleukin-8, interleukin-10, tumor necrosis factor α, basic fibroblast growth factor, and osteopontin. The nitric oxide level in the synovial fluid was detected with nitric oxide detection kit. The content of lipid peroxidase was detected using TBA fluorescence method.
RESULTS AND CONCLUSION:We found higher levels of interleukin-1β, interleukin-6, interleukin-8, interleukin-10, tumor necrosis factor α, basic fibroblast growth factor, osteopontin, nitric oxide, and lipid peroxidase in knee osteoarthritis patients, and these levels were positively correlated with knee osteoarthritis. These inflammatory substances are realy involved in the inflammation process of knees osteoarthritis.

BACKGROUND:Discitis is an inflammatory lesion of the intervertebral disc.However,it attracts more attention on autoimmune factors.OBJECTIVE:To construct discitis animal model by destroying the fibrous ring and the cartilage lamina through the surgery,in addition,to explore the changes of autoimmune reaction.DESIGN,TIME AND SETTING:Randomized controlled animal experiment was performed at the Orthpeadic Laboratory of General Hospital of Tianjin Medical University from June to December 2007.MATERIALS:Fifty healthy,adult,New Zealand rabbits,irrespective of gender,were randomly divided into the model(n=30),sham operation(n=10)and control(n=10)groups.METHODS:Thirty rabbits were randomly selected after anesthetized,L3-4,L4-5,L5-6 intervertebral discs were exposed,discitis models were created by destroying the fibrous ring and the cartilage lamina with self-made transfixion pin.Animals in the sham operation group were exposed intervertebral discs without damage.Rabbits in the model and sham operation were executed to get the intervertebral disc specimens at weeks 1,2,4,8,and 12 after operation.MAIN OUTCOME MEASURES:①Hematoxylin-eosin staining,immunocytochemical comparison and lymphocytic expression.②The positive CD4 cells,CD8 positive T cells,as well as the expression of IgG,IgM were detected by immunohistochemistry and immunofluorescence technique.③Bacteriological cultivation.RESULTS:Under light microscope,the internal and external layer fibrous rings could be seen disordered,with inflammatory reaction and fibrosis in the model group.However,there was no same appearance in the sham operation and control group.Immunohistochemistry showed that there was more CD4 positive lymphocyte expressed at weeks 1 and 2 after operation,and the CD8 positive lymphocyte expressed more at 2 and 4 after operation.There was a few lymphocyte expressions in the sham operation group,and no expressed in the control group.Immunofluorescence demonstrated that immune globulin IgG,IgM was positive,a little expression was found in the model group at 1 week,which increased at the 2,4,and 8 weeks after operation.Only a little of IgG expression could be found in the sham operation and control groups.The bacteriological cultivation was negative.CONCLUSION:①Discitis animal model can be established by using the anterior external surgery to destroy the fibrous ring and the cartilage lamina.②After destroying the fibrous ring and the cartilage lamina,the contact between the autoantigen of the nucleus pulposus and blood circulation will provocate autoimmune reaction,which display in both cellular immunity and humoral immunity.③Autoimmune reaction plays a vital role in pathogenesy,pathological change and symptom generating of discitis.

Low back pain has a serious impact on people's lives in t he world.With the approaching of aging society in China,the number of low back pain increased rapidly.Though many of the pathological factors in spine might lead to low back pain,Modic changes (MCs) was one of the most important factors.Therefore,to get familiar with MCs in the etiology and pathology has a positive practical significance.Although a large number of studies have analyzed the epidemiological and imaging characteristics of MCs,there are relatively few studies on the histological and pathological fields of MCs.In recent years,researchers have gradually shed some light on etiology of MCs and found that low toxic bacterial infection and autoimmune reaction may play a vital role in the development of MCs.The damage of vertebral body or endplate is closely related to the etiopathogenesis of MCs.In addition,to reveal the pathological characteristic of MCs is also a good attempt for better understanding of MCs.There are various imaging changes in MCs,however,what is the pathological basis behind it.It is also unclear that why different types of MCs are capable of transformation? When MCs occur,the activation of some cytokines (such as IL-6,RANKL,etc.) and certain receptors (TLR,PPARγ,etc.) can interfere with the formation and metabolism of the nearby bone marrow cells,break the balance of formation and absorption in trabecular beam and further change their microstructures through various pathways.During this dynamic balance process,the different types of MCs can be transformed into each other.The specific type may not only depend on the intensity and duration of inflammatory stimulus,but also rely on the composition and metabolic status of the bone marrow.Although the study of animal models has made some progress,some limitations still exist in practical course.Due to the unclear mechanism of MCs,the study on etiology and pathology of MCs may play a great important role in clarifying this issue.

Peripheral nerve injury is very common in clinics. It has brought the patients with high rate of disability and huge economic burden and become one of serious health problems in the world. Nowadays, with the development of nerve tissue engineering, it provides new method for surgical procedures of nerve defects repair.The nerve scaffold plays a vital role in repairing nerve defects. It can provide temporary support for nerve cells to grow,adhere and to form structures. This review aims at introducing classification, properties and the applications of the nerve scaffolds for tissue engineering. Future development of the nerve scaffolds and remaining problems are discussed as well.

Objective To evaluate the surgical techniques of open reduction and internal fixation and its clinical results of trimalleolar fractures retrospectively. Methods Between March 1996 and October 2002, 48 consecutive patients, including 27 males and 21 females with an average age of 42.8 years, were treated for trimalleolar fractures. According to the system of Lauge-Hansen, the fractures were classified as pronation-external rotation(grade Ⅳ) injury in 20 cases, and supination-external rotation(grade Ⅳ) in 28 cases. The time from injury to operation was from 2 hours to 21 days. The operation was delayed due to associated injury, skin conditions and so on, and then the patients were manipulated primarily and immobilized with a posterior plaster splint. The medial, lateral and posterior malleolus were exposed by anteromedial and Gatellier-Chastang approaches. The reduction and internal fixation started with the posterior, then the medial and the lateral malleolus and distal tibiofibular syndesmosis in sequence. The ankles were immobilized with plaster in neutral position and elevated. All patients were assessed with Baird and Jackson ankle scoring system based on pain, instability, walking ability, movement and radiological manifestations. Results The follow-up period varied from 6 to 36 months with an average of 13 months. The rates of clinical result were excellent in 26, good in 15, fair in 5 and poor in 2 respectively. The total rate of good to excellent results was 85.4%. There were no local complication, malunion and nonunion of the fractures and the deformity of the ankle. However, the inserted screw to distal tibiofibular syndesmosis was broken in one case. Conclusion Trimalleolar fractures require open reduction and internal fixation more often, especially while the fragment of posterior malleous is so large that it should be anatomically reduced and immobilized with internal fixation. It can ensure anatomical joint restoration and union for the ankle trimalleolar fractures, only by achieving most satisfied kinematics of the ankle joint.

Objective To introduce laminar shelling decompression technique and to discuss its benefit for decompression of thoracic ossification of ligamentum flavum. Methods 102 patients were diagnosed as thoracic ossification of ligamentum flavum, 63 males and 39 females with an average age of 49.7 years (range, 33 to 71 years). 99 cases suffered with sensation disturbance, 73 cases with constriction on trunk or lower limbs, 77 cases with sphincter dysfunction. The IMSOP Standard Neurological Classification of Spinal Cord Injury was applied for localized the level of thoracic spondylopathy. The JOA lower limb motor function standard and sphincter function standard were used to evaluate the ability of lower limb motion and sphincter function respectively. In the decompression the dorsal cortex of lamina was the first layer to resect, the facet joint surface indicate the depth for removing the second layer, then thinning the ossified tissue by shaving with the motor bur until it was somewhat lucent. Finally decompress the spinal canal by moth eaten manner. Results The mean decompression length was 2.8 lamina(2 to 4 lamina). The mean follow-up duration was 18.9 months (3 to 41 months). Among 99 sensation disturbance 69 totally recovered, 30 relived. 73 cases with the feel of constriction of trunk or lower limbs were completely recovered. Postoperative JOA sphincter function score was 2.632?0.407, comparing with the preoperation score, and the difference was significant (t=15.93, P

Objective To treat complex fractures of the proximal tibia with the hybrid external fixation and internal fixation and to evaluate their efficiency. Methods During January 2000 to January 2005, 69 patients with complex proximal tibia fractures received operation in our hospital, which included Schatzker types Ⅳ(17 cases), Ⅴ(14 cases) and Ⅵ(9 cases) and AO A3 type 27 cases, and 2 amputation. The average age was 39 years(range from 18 to 74 years). Among them, 19 open fractures and 21 closed fractures were operated with hybrid external skeleton fixation(HESF) combined limited internal fixation, the others were treated by open reduction and internal fixation (ORIF). Results All the patients were followed from 6 months to 5 years(mean, 25 months), in the HESF group the average time of operation was 2.66 h, the bleeding in operation was 170.50 ml, while ORIF group was 3.33 h and 285.19 ml, the amount healing time of HESF group was 16.40 weeks, while the ORIF groups was 12.37 weeks; there were no deep infectious and skin necrosis patients in the HESF group. According to the HSS score system, there were excellent 31, good 5, fair 3 and bad 1 case, the rate of excellent and good was 90%. In the ORIF group, there were 1 deep infectious and 2 skin necrosis patients, 6 cases were malunion, 2 cases were nonunion. There were excellent 5, good 12, fair 7, bad 3 cases, the rate of excellent and good was 63%; and there were significantly difference between the two groups(u=219, P