A new medical-instrumenta-tion of orthopedic surgery traction and fixation by using bone- fracture of limb reset instrument-is described.In this paper,the clinical mechanical test with 30cases for human long-bone has been measured.It is that an effective internal- external,fixation method which has been proved clinically,we found it was simple,safe and the end result was quite satisfactory.From the mechanical point of view,it can be she wn that new mechanical of design,this method of traction completely conforms to the principle of biomechanics.Better clinical results have heen made from above studies and mechanical design which agree with the mechanical experimental,fractures healing and clinic al statistics.

Objective To describe the design and application of a new fork interlocking in-tramedullary nail(FLN).Methods The anti-compression,anti-bendin g,anti-torsion and rigidity of the FLN were compared with those of recta ngle nail(RN),plum blossom nail(PBN),Ender nail(EN),GK nail(GK)and 8-hole plate biomechanically an d 169case of tibial fractures treate d with the FLN from September1998to May 2001were reviewed.Results The anti-compression,anti-bendin g,anti-torsion and rigidity of the FLN were similar to those of GK and significantly stronger than those o f RN,PBN,EN and 8-hole plate.Of 169cases,147were followed up for more than 3months.Among them,97nails have been removed.The average healing period was 19.6week s(11-31weeks)and the complications include 5exte rnal rotation deformities(from 10?to 15?),4valgus deformities,2varus deform ities,6shortening-displacements,16pain at the nail-entry points,1common peroneal nerve injury(healed 3months later)and 3delayed postoperative infection(1case one month later,2cases five mo nths later).The infection rate was 1.6%.Based o n Johner and Wruhs standard,the excellent ra te was 96.5%,fair 1.3%and failure 2.2%respectively.Conclusion1)FLN is an effective and convenient im plant to treat tibial fracture.2)In severely comminuted fractures an d distal shaft fractures,the distal h ole could be inserted with two transv erse screws similar to GK,which can widen its indication.[

Objective To investigate relationship between the level of serum high sensitive C-reactive protein (hs-CRP) and severity extent,risk factors of acute cerebral infarction. Methods The serum hs-CRP was measured in 186 patients with atherothrobotic cerebral infarction(ACI), in 155 patients with lacunar infarction (LI) and in 329 normal controls by automatic analyzer, levels of blood glucose and blood lipid were detected at the same time. The relationship between hs-CRP and the degree of nerve damage in patients with acute cerebral infarction observed and analyzed. Results The levels of hs-CRP in patients with ACI and LI were higher significantly than that in the normal controls(all P

Objective To discuss the necessity of cervical spinal plating after single-level anterior decompression and fusion on mono-segmental cervical disc herniation and cervical spondylosis without obvious kyphotic deformity and segmental lability. Methods The ranges of motion of the two groups with and without plating were tested under the load of 2.0 Nm on cervical spine specimens taken from 16 fresh cadavers. Finite element method was used to calculate the strength of bony callus and the average stress of the parts adjacent to the fused segments at various time intervals. 45 cases after single-level anterior decompression and fusion with and without cervical plating were followed-up at least 3 years, and 33 ones without cervical plating, more than 10 years. Results The test of specimens showed a higher stability of the group with plating just after operation (P

Objective To explore the effects of hypoxia on the growth,mitochondria distribution and function of mouse embryonic fibroblasts(MEFs).Methods MEFs were sub-cultured in the hypoxia group containing 5％ oxygen and normal oxygen group containing 20％ oxygen,every 24 hours,living MEFs were counted by using trypan blue staining.Mito-Tracker Green was used to stain mitochondria,then cells were observed by using laser confocal microscope.The ATP kit was used to detect ATP synthesis.Results During the logarithmic phase,the numbers of living cells in the hypoxia group were higher than those in the normal oxygen group,the differences were statistically significant (P＜0.05).The percentages of perinuclear mitochondrial in the hypoxia group were higher than those in the normal oxygen group,the differences were statistically significant (P＜0.05).Meanwhile,the significant difference was found in the ATP level between the two groups (P＜0.05).Conclusion The distribution of mitochondria in MEFs and energy synthesis are influenced by the hypoxic culture condition,which could be better for promoting cell growth compared with normal oxygen culture condition.

Objective To discuss morphology and biomechanics of the sacrum fractures so as to provide scientific basis for corresponding clinical treatment. Methods A total of 10 fresh pelvis specimens were collected for dynamic impact test and static destruction test, in the former one of which, the dynamic parameters were measured to make sure the dynamic characters of the fractures. Meanwhile, the fractures of the sacrum wing, the sacral foramina and the sacrum edge were made decalcification, slice of paraffin wax and staining (Masson, Mallory, HE) in order to make a cytological observation of the tissue. Results (1) The form of sacrum fracture or acetabulum fracture, crista iliaceis fracture was relevant to the impact energy. Low impact energy usually caused fractures of the ilium, acetabulum or sacroiliac crest. High impact energy resulted in following three kinds of fractures, just as the classification of Denis: sacral ala fractures belonged to typeⅠfractures, sacral hiatus fractures to type Ⅱ fractures and central vertebral canal fractures to type Ⅲ fractures. All three types of fractures might involve lateral or bilateral nerve roots. (2) There was a significant mechanic difference in regard of the mechanism of both dynamic destruction and static destruction of pelvis, ie, not only the limit pressure differed but also the former increased rapidly with the higher rate of the strain. The clash energy beyond 25 J would beget the cleft fractures of the sacrum via sacrum hiatus and even involve the nerve roots. The clash energy under 20 J usually resulted in fractures of the ilium and the sacrum. The clash energy between 20 J and 25 J more easily caused type Ⅰ fractures. While fracture of the ilium and the acetabulum would happen most in static destruction. (3) The cross section of the sacrum was cracked and the bone board of Haversian system is brittle, as led to separation of bone board and malposition of a few cross bone boards. Conclusions Under dynamic state, the sacrum fractures mostly belong to type Ⅰ and type Ⅱ (Denis classification of sacral fractures), usually involving the nerve roots. The sacrum fracture is relevant to the microstructure, the distribution of the bone trabecula, the osseous lacuna and the Haversian system of the sacrum. The fractures of the ilium and the acetabulum more frquently appear in static state, with slight wound of peripheral tissues.

[Objective]Ulnar fractures fixed by interlocking intramedullary nails or dynamic compression plates were tested to compare their biomechanical function,in order to provide the theoretical basis for clinical practice.[Method]In the experiment,12 pieces of fresh ulnars were used to produce middle-part transverse fracture models;which were fixed by interlocking intramedullary nails or six-hole 3.5 mm dynamic compression plates seperately.The diameter of intramedullary nail was 4mm,and the length was 200-230mm.The specimen was set on the MTS test machine.The rigidity and strength of ulnar fractures fixed by interlocking intramedullary nails were compared with those of ulnar fractures fixed by six-hole 3.5 mm dynamic compression plates in the anti-axial test,anti-bending test,anti-torsional test.[Result]In the anti-axial test,anti-bending test and anti-torsional test,the rigidity of ulnar fractures fixed by interlocking intramedullary nails was 450.00?38.42 N/mm,45.64?5.24 N?cm/Deg,11.42?1.21N?cm/Deg in sequence;while the rigidity fixed by dynamic compression plates was 405.40?29.26 N/mm,41.00?4.78 N.cm/Deg,10.05?1.32 N?cm/Deg accordingly.Burdened 1000N axial pressure,the displacement of interlocking intramedullay nail fixing specimen was 2.20?0.11 mm,and the compression plate fixing specimen was 2.48?0.15 mm.Given a 5 N?M bending burden,the maximum radial bending degree of interlocking intramedullay nailfixing specimen was 3.25?0.15 mm,which was 3.60?0.21 mm of compression plate fixing specimen.In the anti-torsional test,the interlocking intramedullay nail and compression plate fixing specimen could burden 2.40?0.13 N?M and 1.90?0.10 N?M respectively.The experimental data were analyzed by software SPSS.10,which came to a distinguished difference by t-test(P

[Objective]To analyze the biomechanics of different positions of femoral head-and-neck nail in fixation of proximal femoral fracture.[Method]Stable and unstable fracture models were made from 24 fresh femur specimens,and fixed with r-nail and DHS.Head-and-neck nails were placed in different positions to test their mechanical properties of anti-compression,anti-bending,anti-shearing and anti-torsion,and compared with each other.[Result]Mechanical properties of the femoral strength,stiffness,stability and loading capacity were tested and compared.To the stable fracture group,head-and-neck nail should be placed in middle-lower and posterior 1/3 of femoral neck,which leads to the best loading capacity.To the unstable fracture group,it should be placed between femoral head and neck,which lead to strong obliquity mechanics and valuable for bone union.[Conclusion]Confirm of the best position of femoral head-and-neck nail could improve the effect of fixation and enhance the surgical treatment of proximal femoral fracture.

Objective:To assess the relative stability and kinematics of the lumbar intervertebral segmental stiffness among posterior lumbar interbody fusion(PLIF) using one anatomical posterolateral cage with or without transpedicular screw rod fixation. Methods: Each of the 6 bovine lumbar functional spinal units(FSV) was tested under 6 different treatments. Test order was intact and every group differed in internal fixation of transpedicular screw. Group 1 referred to the normal lumbar functional spinal units. Group 2 was treated by left unilateral facetectomy and discoidectomy. Group 3 had anatomical threaded cages inserted on the left. Group 4 had anatomical threaded cages inserted on the left and fixed by right transpedicular screws. Group 5 had left inserted anatomical threaded cages and was fixed by left transpedicular screws. Group 6 had anatomical threaded cages inserted on the left side and was fixed by bilateral transpedicular screws. Nondestructive tests were performed in pure compression, flexion, extension, and lateral bending. Results: Unilateral discectomy and facetectomy had lower stiffness than normal FSU by 69% and 44% in pure compression, flexion, extension, and lateral bending. Single anatomical posterolateral cage group had higher stiffness than discectomy and facetectomy group, up by 55% and 28%. However, its stiffness was lower than normal FSU by 41% and 23%. Single anatomical cage with unilateral transpedicular screw fixation (left or right) had higher stiffness than normal FSU by 15% 17% and 20% 50% respectively. Single anatomical cage with transpedicular screw fixation was much stiffer than normal FSU by 18% and 65%. Conclusion: Adequate postoperative stability can be achieved by posterior lumbar interbody fusion with insertion of a single anatomical cage combined with a transpedicular screw.

BACKGROUND: The biomechanical studies about calcium sulfate cement vertebroplasty are only limited to the single fracture vertebra, not performed in spinal compression fracture unit with posterior transpedicular screw fixation. Furthermore, performing experimental study in the whole function spine unit (FSU) conforms to actual clinical situation. OBJECTIVE: To assess the biomechanical properties of calcium sulfate vertebroplasty combined with posterior transpedicular screw fixation in treatment of thoracolumbar compression fractures. DESIGN, TIME AND SETTING: A controlled experiment was performed at the Biomechanical Laboratory of Shanghai University in March 2009. MATERIALS: Fifteen fresh thoracolumbar spines were harvested from male calves and made into T_(11)-L_1 FSU, then divided into 3 groups randomly: normal control group, posterior transpedicular screw fixation group and transpedicular screw fixation plus vertebroplasty group. METHODS: T_(12) flexion-compression fracture models were made in all specimens of posterior transpedicular screw fixation group and transpedicular screw fixation plus vertebroplasty group, undergoing reduction and posterior transpedicular screw fixation, and calcium sulfate vertebroplasty combined with posterior transpedicular screw fixation respectively. MAIN OUTCOME MEASURES: All specimens were placed on the WE-10A universal testing machine for mechanical test. Load-straining, load-displacing, rigidity, strength and torsion of the FSU were performed in axial compression, flexion, extension and lateral bending states. The experimental outcomes were collected and compared by statistic analysis. RESULTS: The load-strain and loed-displacement showed a linear relationship. Straining values in vertebral body and intervertebral disc of calcium sulfate vertebroplasty plus posterior transpedicular screw fixation group were 14% and 12% less than that of posterior transpedicular screw fixation group, 21% and 13% less than that of normal control group. The thoracolumbar displacement in calcium sulfate vertebroplasty Plus posterior transpedicular screw fixation group decreased 25% and 37% as compared with other 2 groups respectively. Compared with normal control and posterior transpedicular screw fixation group, the thoracolumbar stiffness in calcium sulfate vertebroplasty plus posterior transpedicular screw fixation group increased 53% and 44% respectively. The strength in vertebral body and intervertebral disc of calcium sulfate vertebroplasty plus posterior transpedicular screw fixation group were 14% and 24% higher than that of posterior transpedicular screw fixation group, 13% and 20% higher than that of normal control group. The maximal twisting strength of FSU in calcium sulfate vertebroplasty plus posterior transpedicular screw fixation group were 18% and 30% higher than that of other 2 groups, the twisting stiffness were 30% and 40% higher than that of other 2 groups. The data above were significant differences statistically (P < 0.05). CONCLUSION: Posterior transpedicular screw fixation combined with calcium sulfate vertebroplasty show superior biomechanical properties for treatment of thoracolumbar compression fractures, which exhibits not only strong strength and stiffness, but also stable FSU, thus could decrease the stress loading of the internal fixation, the incidences of screw breakage and avoid the altitude loss of vertebral body.