| 1. The study of the correlation of thoracic and lumberal kyphosis with posterior pelvic tilt.Objective:prospectively investigated to the correlation of thoracic and lumberal kyphosis with posterior pelvic tilt through the patients of ankylosing spondylitis and the emulated ankylosing spondylitis model by normal volunteers,evaluated the influnce on posterior pelvic tilt for defferent digree of thoracic and lumberal kyphosisMaterials and methods :we chosed 13 subjects at random ,each case was evaluated and canculated in radiology by a standing lateral radiograph that included thoracic and lumberal spine ,pelvic ,and hip.the evaluated parameters included thoracic kyphosis(TK),lumberal lordosis(LL),pelvictilt(PT),sacral slope(SS),and pelvic incidence(PI).after that,we chosed 13 normal volunteers at random,each volunteer emulated thoracic kyphosis according to a TK of patient with ankylosing spondylitis.we canculated lumberal lordosis(LL),pelvic tilt(PT),sacral slope(SS),and pelvic incidence(PI) in lie of emulated TK.finally, canculated lumberal lordosis(LL),pelvic tilt(PT),sacral slope(SS),and pelvic incidence(PI) the obtained data were analized at last.We divided the data into three groups according to different samples .data from the patients called AS group ,from normal emulated volunteer called EV group,from normal volunteer called NV group.at first we studied the data of lumberal lordosis(LL),pelvic tilt(PT),sacral slope(SS),and pelvic incidence(PI) with linear regression and multiple linear regression.secendly we compared the data of NV group of AS group.in the end ,we analized the data of AS,NV,and EV group with student-t test.in the same time high and weight parameters was compared with t test.Result:in ankylosing spondylitis cases(AS group) ,male 10 ,female 3.the range of year 15-46,mean age 23±9 ,the range of high 150cm-178cm,mean 167 CM±3CM.TK 48°±13°LL 38°±9°,PT 20°±3°,SS 33°±6°,and PI 50°±6°. In normal volunteers(NV group) ,male 11 ,female 2.the range of year 18-45,mean age 20±11 ,the range of high 150cm-178cm,mean 164 CM±5CM. TK 25°±4°LL 55°±3°,PT 8°±3°,SS 30°±5°,and PI 33°±4°.In emulated normal volunteers, 49°±15°LL 30°±5°,PT 23°±4°,SS 30°±4°,and PI 51°±5°.The data of AS group was analized with linear regression,the values of TK and LL noted a linear negative correlation(b=-0.058765, t=1.12,P P<0.01,r=0.5329, t=1.72,P P<0.01). PT and SS scattered irregulately. TK and PT noted a linear positive correlation(b=0.073715, t=1.32,P P<0.01,r=0.3119, t=1.02,P P<0.01). TK and SS scattered irregulately. TK and PI noted a linear positive correlation(b=0.091710, t=1.52,P P<0.01,r=0.4018, t=1.12,P P<0.01). LL and PT noted a linear negative correlation(b=-0.036460, t=1.72,P P<0.01,r=0.6331, t=1.42,P P<0.01). LL and SS noted a linear positive correlation(b=0.060775, t=1.52,P P<0.01,r=0.5109, t=1.62,P P<0.01). LL and PI noted a linear negative correlation(b=-0.041430, t=1.92,P P<0.01,r=0.8331, t=2.02,P P<0.01). pt and pi noted a linear positive correlation(b=0.070715, t=2.12,P P<0.01,r=0.5339, t=1.98,P P<0.01). SS and PI scattered to note a linear positive correlation (b=0.09189, t=1.13,P P<0.01,r=0.7329, t=1.65,P P<0.01).We compared the parameters of NV group of AS group with t test.as result ,the parameter of TK had significantly different between NV group and AS group in statistic(t= 2.17,P<0.01). the parameter of LL had significantly different between NV group and AS group in statistic(t= 3.27,P<0.01). the parameter of PT had significantly different between NV group and AS group in statistic(t= 2.74,P<0.01). the parameter of SS had nˊt significantly different between NV group and AS group in statistic(t= 5.73,P>0.5). the parameter of PI had significantly different between NV group and AS group in statistic(t= 1.11,P<0.01).we could concluded that the parameter of LL had no relation with pelvic morphology. The TK was important factor that affected pelvic morphology.therefore ,we analized the parameters of TK,LL,PT ,and PI with multiple linear regression.we obtained a multiple linear regression equation aboutTK, LL,PT,and PI. y=0.1379x1-0.0917x2+0.7342x3+9.0107. y represented PI, x1 repersented PT, x2 repersented LL, x3 represented PT. b1=0.1379 ,b2=-0.0917, b3=0.7342.so we concluded that the PT was more weight than other parameters to PI.We analized and compared of the parameters of AS ,NV,and EV groups with SNK-q test. the parameter of TK had significantly different between NV group and AS group in statistic(q=1.23,P<0.01). the parameter of LLhad significantly different between NV group and AS group in statistic(q=1.33,P<0.01) the parameter of PT had significantly different between NV group and AS group in statistic(q=2.01,P<0.01). the parameter of SS hadnˊt significantly different between NV group and AS group in statistic(q=5.53,P>0.05). the parameter of PI had significantly different between NV group and AS group in statistic(q=1.01,P<0.01). Statistical analysis was performed using the SNK-q test test for comparison of the parameters between AS and EV group, the parameter of TK hadnˊt significantly different between EV group and AS group in statistic(q=4.23,P>0.05). the parameter of LL had nˊt significantly different between EV group and AS group in statistic(q=6.13,P>0.05). the parameter of PT had nˊ t significantly different between EV group and AS group(q=5.81,P>0.05) , the parameter of SS had nˊt significantly different between NV group and AS group (q=4.13,P>0.05). the parameter of PI had nˊt significantly different between NV group and AS group(q=6.01,P>0.05). SNK-q test test for comparison of the parameters between NV and EV group, the parameter of TK had nˊt significantly different between NV group and EV group (q=1.43,P<0.01). the parameter of LL had nˊt significantly different between NV group and EV group (q=1.98,P<0.01). the parameter of PT had nˊ t significantly different between NV group and EV group(q=2.31,P<0.01). the parameter of SS had nˊt significantly different between NV group and EV group(q=5.25,P>0.05). the parameter of PI had nˊt significantly different between NV group and EV group(q=1.54,P<0.01).Conclusion:thoracic and lumberal kyphosis conduced to pelvic posterior tilt , thoracic kyphosis was more weight than other parameters to pelvic posterior tilt. the parameter of SS had nˊt correlation with pelvic posterior tilt. the PT affected on pelvic morphology more significantly.we could studied the thoracic and lumberal kyphosis influence on pelvic morphology in sagttal plane through normal volunteer emulated model,so we could research deeply the balance of spine and pelvic.2. The experimental studies of pelvic tilt compacting on acetabular component anteversion in primary total hip arthroplasty.Objective: To investigate pelvic tilt influence on acetabular component anteversion and evaluate the correlation of pelvic tilt and acetabular component anteversion.Materials and methods: nine cadaver pelves were prepared by disarticulating the hip and sectioning the pelvis through the lower lumbar vertebrae and symphysis pubis. The pelvis was held in what would be the patientˊs lateral position on expremental table that could adjusted the digree of pelvic tilt in sagittal.at first ,CT scaned the cadaver for keeping the cadaver a absolutely decubits.secondly, we placed the acetabular component in pelvic posterior tilt 10°,15°,20°,25°,30°35°and anterior pelvic as same as degree.left acetabular were defined as subject.methed of placing component was preformed to two times in same degree.first placement refered the longitude of table ,the other placement refered the alignment of pelvic. Acetabular component orientation was aimed at 45°vertical tilt and 20°anteversion.finally CT scaned the acetabular socket,We measured the angle between aix of compoment and aix of acetabular.α1 was represented the ange of the first placement,we called A groupα2 was represented the ange of the first placement.we called B group t-test applied to analized both group of data.that hip center translated or not was used to analized the pair t-test.Result: in pelvic 10°anterior tilt,α1 was 10°±4°,α2 was 9°±2°. in 15°anterior tilt,α1 was 9°±3°,α2 was 10°±2°. in 20°anterior tilt,α1 was 10°±6°,α2 was 8°±3°. in 25°anterior tilt,α1 was 13°±6°,α2 was 8°±3°. in 30°anterior tilt,α1 was 16°±10°,α2 was 11°±2°. in 35°anterior tilt,α1 was 18°±9°,α2 was 10°±4°. in pelvic 10°posterior tilt,α1 was 11°±5°,α2 was 9°±2°. in 15°posterior tilt,α1 was 10°±3°,α2 was 7°±4°. in 20°posterior tilt,α1 was 13°±5°,α2 was 9°±3°. in 25°posterior tilt,α1 was 12°±4°,α2 was 8°±4°. in 30°anterior tilt,α1 was 17°±8°,α2 was 7°±5°. in 35°anterior tilt,α1 was 18°±11°,α2 was 10°±2°.We compared the A group of B group, t-test was applied to analyse.the result was signficent difference(t=1.12,p <0.05). The degree ofα1 and the pelvic inclination was analized with linear regression.in state of pelvic inclination larger than 20°, The degree ofα1 and pelvic inclination noted a linear positive correlation.but The degree ofα2 and pelvic inclination noted to scatter irregulatly.Conclusion: in state of pelvic inclination larger than 20°, acetabular component anteversion was diffcult to control component orientation in safe range, Bias of component was significant than less than 20°.3. The anatomical study on safe area of fixing scraw in Acetabular Revision SurgeryObjective: To evaluate the safe areas of fixing scraw in Acetabular Revision Surgery and test the valuability of safe quadrant system in primary THR for theoretically minimal risk to the intrapelvic neurologic and vascular structures because of fixing scraw .Materials and methods: eleven bilateral cadaver hemipelves were prepared by disarticulating the hip and sectioning the pelvis through the lower lumbar vertebrae and symphysis pubis. The outer table of the ileum was cleaned of all soft tissues, leaving only the intrapelvic musculature and the nervous and vasculature structures. The inner acetabular diameter for each specimen was measured with a trial cup from the Trilogy (Zimmer) acetabular system. The hemipelvis was held in what would be the patient's supine position with an extremity clamp , while the acetabular trial shell was positioned in 45°inclination and 15°of anteversion from the patient's midcoronal and midsagittal axes. The trial shell was secured with a single screw, while an anteroposterior radiograph at 80 mA and 250 kV was taken as a baseline to determine the center of rotation of the acetabular component.we defined exposed thread 15mm as standard. If a screw came within 5 mm of any nervous or vascular structure, it was recorded as an insult. The nervous and vascular structures that were examined for insult, or encroachment of the screw beyond the reasonable limits of safety, were the external iliac artery, external iliac vein, femoral nerve, sarcial nerve,obturator artery, and pudendal artery.Each left acetabulum was enlarged to create a void using Trilogy acetabular reamers in 2-mm increments until the 68-mm diameter reamer had been used. The superior lip of the acetabulum, anterior column of the pelvis, and medial wall were sacrificed preferentially during the reaming to simulate a large acetabular void with an intact posterior column. A 68-mm hemispherical porous-coated II (HG II) (Zimmer) acetabular shell was inserted into the acetabular void. The pelvis was oriented in the extremity clamp to a position simulating that of a patient supine on an x-ray table. A screw was placed in the trial shell and used for provisional fixation, and an anteroposterior radiograph was taken to calculate the horizontal and vertical displacements of the cup's center of rotation and to ensure that it was seated medially. Student's t-test was used to examine statistically significant changes in the position of the reconstruction's center of rotation in the vertical and medial direction, and P values were recorded.All screw holes were drilled, measured, and filled, and the medial side was inspected with insults recorded. The acetabular component was removed, and a 44-mm HG II (Zimmer) acetabular component was placed high on the wall of the ileum, at least half diameter of cadaver acebatular proximal from the cotyloid notch but still inside the acetabular void. The hemipelves and acetabular components were positioned as before in the clamp. Similar radiographs were taken for calculation of the implant's position, and any displacement was measured. Then all screws were drilled, measured, and inserted, and neurovascular insults on the medial side were recorded.In the right hemipelves, the diameter of the acetabulum was enlarged to 58 mm with the reamers, and a reconstruction ring for that size was tested. A provisional screw was placed in the implant after it was positioned centrally in the acetabular void with as close to 45°of inclination and 15°of anteversion that could be reproduced manually. The hemipelvis was held in the positioner for radiographs and screw placement, as was done on the contralateral side. Radiographs were obtained, and measurements were made to calculate any statistically significant displacement of the implant resulting from reaming. All of the screw holes were drilled, measured, and filled, and any insults on the medial side of the specimen were recorded. The acetabular void was enlarged to 68mm with the reamers, and an acetabular reconstructionring with an obturator hook (Ganz ring) for that size of defect was inserted,centralized, positioned, and secured with a single screw. Similar radiographs and measurements were obtained to check for displacement caused by the reaming. The remaining screw holes were drilled, measured, and filled, and any insults to the medial neurovascular structures were recorded. An acetabular reconstruction cage with ischial fixation (Burch-Schneider cage) was fastened to the ileum in the 68-mm acetabular defect that already had been created, while the hemipelves and implant were held and positioned identically to the previous testing parameters in the extremity clamp, and similar radiographic measurements were obtained to check for displacement. Each of the screw holes was drilled, measured, and filled, and any insults to the medial neurovascular structures were recorded.Result: jumbo component: screws in the superoanterior ,anteroinferior quadrants and apex caused insults . High Hip Center: all of quadrants caused insults except inferoposterior and posterior half of superoposterior quadrants. Muller ring: insults were found from screws placed in the intra-acetabular and extra-acetabular areas of the superoanterior quadrant. Ganz ring: In the superoanterior(intra-acetabular and extra-acetabular) quadrant and apex , insults were confirmed. Burch-Schneider ring: the superoanterior(intra-acetabular and extra-acetabular)quadrant recorded insults to the medial structures and insults were recorded from screws in available for ischial fixation.Conculsion: Patient safety requires modification of the commonly used quadrant method for screw placement in the HHC design, in which the superoanterior quadrant, the anterior half of the superoposterior quadrant and the implant's central area are unsafe for screw fixation. The jumbo uncemented acetabular component ,acetabular reconstruction rings and cages tested here follow the same quadrant recommendations as would be used in a primary uncemented THR.
|
PDF Full Text Request