Objective To study the development of a physiologic fixation method and investigate the effect of physiologic fixation method on porcine aortic root and aortic valve leaflets. Methods Physiological fixer of aortic root was manufactured in a factory. The fixers with different diameter were made of organic glass. Porcine aortic root with ascending aorta and anterior leaflet of mitral valve and partial ventricular septum were dissected out from the fresh heart. The roots were attached to appropriately sized inflow and outflow spigots. Physiologic fixation was utilized to maintain aortic root and leaflets natural anatomical shape, the aortic root was pressurized to the inflow and outflow portions simultaneously, and the leaflets floated freely at zero-pressure differential with in the pressurized root. Results The process of physiologic fixation retained the properties of a native valve. The leaflets were much softer and extensible than those from valves fixed under low pressure. The results of pulsatile flow testing indicated that the effective orifice areas of predilation at 80mmHg were significantly greater than those of predilation at 40 mmHg（P〈0.05）, while mean pressure differences were found to be lower comparatively（P〈0.05）. This difference translates into a mode of valve function that more closely approximates that of the native aortic valve. Conclusion Physiologic fixation process retains the valve＇s natural anatomical shape as well as the underlying structure of the leaflets, providing improved flow characteristics.
To study project of simpl icity and util ity for screw-plate system by pedicle of atlanto-axis mani pulatively hand by X-ray film and CT to prove the one success rate of putting screws. Methods Formulate personal program was used in operation by image save transmission of X-ray film and CT during January 2002 and September 2006 in 31 patients. There were 18 males and 13 femals, aged from 23 to 61 years old with an average age of 43.5 years. Putting screw points bypedicle of atlas were measured: left (19.93 ± 1.32) mm, right (19.16 ± 1.30) mm; putting screw obl iquity angle to inside by pedicle of atlas: left (23.72 ± 2.09)°, right (23.35 ± 1.91)°; putting screw obl iquity angle to side of head by pedicle of atlas: (9.00 ± 1.20)°. Screw points by pedicle of axis: left (13.14 ± 0.82) mm right (13.85 ± 0.79) mm; putting screw obl iquity angle to inside by pedicle of axis: left (24.52 ± 1.26)°, right (20.42 ± 1.42)°; putting screw obl iquity angle to side of head by pedicle of axis: (25.00 ± 3.00)°. The domestic location toward speculum was employed in operation and putting screw points and angles were formulated by X-CT program. The pedicle screws of suitable diameter and length were of exception and screws into pedicle of atlanto-axis were put by hand. Results Pain of the greater occipital nerve occurred in 2 patients after operation and was fully recovered by treatment 1 month after operation. The lateral cortical bone of pedicle was cut by 2 screws, but the spinal cord and vertebral artery were fine. The atlas and the fracture of odontoid process of axis were completely replaced in X-ray films of all patients 1 day after operation.The position relation of lag screw and vertebral artery or spinal cord was very good in CT sheets. All cases were followed up with an average of 10.5 months during 9 months to 5 years and 4 months, and obtained atlantoaxial arthrodesis. The breakage of screw and plate was not found in all cases. According to JOA score standard, 16 cases were excellent, 12 were good, 2 were fair, 1 was poor, and the excellent and good rate was 90.32% . Conclusion The personal design and cl inical appl ication of X-ray films and CT sheets are of great significance to screw-plate system by pedicle of atlanto-axis because of simpl ification of designs and methods and better personal ity.
Objective To evaluate the clinical results of bioabsorbable interference screw in knee ligament reconstruction. Methods From April 2002 to August 2004, 39 patients with knee ligament injury were treated, including 33 males and6 females with a median age of 25 years (15 to 65 years). The involved ligament included 29 anterior cruciate ligament of knee(ACL), 6 posterior cruciate ligament of knee(PCL)，4 combined ACL and PCL, 3 medial collateral or lateral collateral ligaments of knee point and 1 posterolateral complex injury of knee. All of patients underwent anatomic ligament reconstructions under arthroscopy or open surgery by autografts and fixation with bioabsorbable interference screw. Results All 34 patients were followed up 6 to 28 months (mean 13.7months). The patients were evaluated by Lysholm knee functional scales, the knee scores were 43.6±13.4 before operation and 85.4±16.3 after operation, showing significant difference (Plt;0.05). There was no limitation of rangeof motion and loosening of the screw. However, one case suffered from infection, and 3 cases suffered from effusion and synovitis after surgery and recovered after management. Conclusion Bioabsorbable interference screw fixation is a reliable method in knee ligament reconstruction and is effective to restore knee joint stability.
Objective To explore the biomechanical difference between the different fixations of cortical bone plate allograft. Methods Twenty-seven cadaveric femurs were harvested and were made into the simulated fracture models, which were equally divided into Groups A, B and C. In Group A, the models were fixed with 2 bone plate allografts (110 mm×10 mm×3 mm); in Group B, the models were fixed with 2 struts (110 mm×10 mm×3 mm) and 5 bone screws; in Group C, the models were fixed with 1 strut (110 mm×10 mm×3 mm) and 5 bone screws. The biomechanical tests for the three-piont bending, torsion, and compression were performed. The parameters studied included the values of the displacements in the three-piont bending tests and the compression tests, and the maximum loads during the bending, the compression, and the torsion. Results As for all the stiffness parameters tested, Group A showed the greatest displacements among the threegroups（P＜0.05）, except the compressive stiffness parameter, which was similar to that in Group B. The maximum loads of the three-point bending, the torsion, and the compression in Group A were 1.65±0.34 kN, 554.3±49.34 N, and 7.78±0.82 Nm, respectively; in Group B, they were 1.12±0.37 kN, 428.00±37.40 N,and 3.39±0.22 Nm, respectively; in Group C, they were 0.71±0.46 kN, 218.67±36.53N, and 1.74±0.12 Nm, respectively. Group A had a significantly greater strengththan the other 2 groups(P＜0.05). Conclusion The strength of the cortical bone plate allograft is related to its different fixations. The two cortical bone plate allografts have a greater strength and stiffness than the struts fixed with the bone screws, which can meet the clinical requirement.
Objective To study the effect of anterior plate fixation on the treatment of middle and lower thirds fractures of humerus and the possibility of operating without injuring the radial nerve. Methods Forty-nine patients with the middle and lower thirds fractures of the humerus were treated with anterior plate fixation from March 1998 to December 2002. Of the 49 patients, 27 were with new fractures, 12 with old fractures, and 10 with nonunion fractures. According to AO classification, of the 49 patients, there were 19 type A, 14 type B1, 9 type B2, 5 type B3, 2 type C1. Thirty-seven patients had closed fractures and 12 had open fractures. Of the 12 patients, 8 were type Gustilo Ⅰ, 4 were type Gustilo Ⅱ. Four out of the 49 patients were associated with radial nerve palsy. All patients were treatedwith anterior plate fixation through the anterior approach to the humerus. The radial nerves injured were explored. Results Of the 49 patients, 48 were followed up 6 to 48 months(28.7 months on average). All fractures were healed within 3 to 9 months(4.7 months on average). Fixed plates of 37 patients out of the 49 were removed. No iatrogenic radial nerve injury occurred in the82 times of the operations among the 49 patients. Conclusion The treatment of middle and lower thirds fractures of humerus by anterior platefixation through the anterior approach to the humerus does not interfere with the fracture healing and can prevent the iatrogenic radial nerve injury.
Objective To introduce the arthroscopic technique of figure-of-eight suture fixation for tibial eminence fracture, and to report its clinical results. Methods From January 1998 to June 2001, 21 cases of tibial eminence fracture were treated arthroscopically with figure-of-eight suture fixation technique. Active rehabilitation began one week after operation. The patients were followed up 6-24 months. The reduction and union of fracture, knee laxity, range ofmotion, and total knee function were evaluated. Results All fracture healed without displacement six weeks after operation. Three months postoperatively, no knee laxity or instability was detected in all patients; full range of motion of the affected knee returned in all patients when compared with the normal side. Six months postoperatively, the Lysholm knee score was 93.4±2.7. Conclusion Arthroscopic treatment of tibial eminence fracture with figure-of-eight suture fixation technique is reliable for fracture reduction , fixation and early mobilization. Arthroscopy is conducive to diagnoses and treatment of associated knee arthropathy, reduces the morbidity associated with arthrotomy, and restores knee function to the greatest extent when combined with figure-of-eight suture fixationtechniques.
ObjectiveTo design an auto-compressive and anti-circumrotate intramedullary nail( ACACIN) and to evaluate the preliminary clinical efficacy on fixing adult femur fracture. Methods From January 1998 to June 2001, 23 patientswith femur fracture were stabilized with auto-compressive and anti-circumrotateintramedullary nail. 2-4 elastic blocks were installed into the proximal and distal different distance of quincunx nail to defend circumrotate and axis compress. Results Fracture healing were obtained in all 23 patients treated with auto-compresseiveand anti-circumrotate intramedullary nail, the time of fracture healing was 6-13 weeks in 21 cases and 15-22 weeks in 2 cases of old fracture. There was no complication related to infection, nail break, abnormal union and joint ankylosis. The results were excellent in 19 cases, good in 3 cases, and moderate in 1 case according Kolmert’s criterion for function ; the effective rate was 95.7%. Conclusion Auto-compressive and anti-circumrotate intramedullary nail has a suitable radian for adult femur, can afford stable fixation, anti-circumrotate andaxis compress.
Objective To investigate the distribution of the preferred retinal locus (PRL) of eccentric fixation in eyes with high myopia.Methods A total of 40 highly myopic patients (54 eyes ) with eccentric fixation were examined by MP1 microperimeter to identify the PRL. The position of PRL relative to the fovea was estimated using the 90% confidence ellipse of normal adult foveal fixation. The differences of visual acuity between ldquo;desirablerdquo; and ldquo;undesirablerdquo; PRL were tested by analysis of variance.Results In 54 eyes with high myopia, 24 eyes (44.44%) had PRL of eccentric fixation below the scotoma after loss of central vision; 19 eyes ( 35.19% ) had a leftfield PRL; 6 eyes ( 11.11% ) had an upperfield PRL; and 5 eyes ( 9.26% ) had rightfield PRL. In 14 patients who had binocular eccentric fixation, 13 had the same fixation pattern in both eyes, including lowerfield PRL in 7 （50.00%）, leftfield PRL in 5 （35.71%）, and upperfield PRL in 1 patient （7.14%）. The difference of visual acuity between lower and leftfield PRL group and right and upperfield undesirable PRL group was not statistically significant（F=0.144, Pgt;0.05）. Conclusions The eccentric fixation in eyes with high myopia is usually situated as near as possible to the fovea. The optimal PRL is inferior visual field.
Objective To observe the relationship between position of normal central fixation and the position of the optic disc, and to find out the features of stability of fixation. Methods The position of central fixation of 120 eyes of 60 healthy adults was determined by MP-1 microperimeter. The position of central fixation relative to the position of the optic disk was measured. The relationship between the central fixation and the age or refraction was analyzed statistically. The difference between the right and left eye in each individual was analyzed with t test. Results The central fixation located at the retina with the horizontal distance of 14.48deg;plusmn;1.85deg; and vertical distance of －2.14deg;plusmn;1.26deg; from the temporal edge of the optic disk. In the 120 eyes, 90% of the central fixation located in a bivariate normal ellipse. The normal eyes usually kept in a slightly moving condition when a normal person fixing on a subject. The median of horizontal and vertical deviation was 0.4deg; and 0.3deg; respectively. Conclusion The distribution of central fixation in healthy adults is a bivariate normal ellipse. When fixing on a subject, the moving extent of the eyes in the horizontal direction is larger than that in the vertical direction.
Objective To evaluate the effectiveness of reamed versus nonreamed intramedullary nailing for femoral fractures. Methods Randomized controlled trials (RCTs) and clinical controlled trials (CCTs) were identified from MEDLINE (1966-2004.5), EMBASE (1966-2004.5), Cochrane Library (Issue 2, 2004), Cochrane Musculoskeletal Injuries Group Database (2004.5), and CBM disc (1979-2004.5). We handsearched Chinese Journal of Orthopaedy (from establishment to May 2004) and Orthopaedic Journal of China (from establishment to May 2004) . RCTs and CCTs were included. Data were extracted by two reviewers with designed extraction form. RevMan 4.2.3 software was used for data analysis. Results Five RCTs and two CCTs were included. The combined results of meta-analysis showed that reamed intramedullary nailing for femoral fractures can reduce the rate of nonunion (RR=0.38, 95%CI 0.17 to 0.83, P=0.01) and the rate of implant failure (RR=0.42, 95%CI 0.20 to 0.89, P=0.02). Conclusions Compared with nonreamed intramedullary nailing for femoral fractures, reamed intramedullary nailing can reduce the rates of nonunion and implant failure. However, the relation between reaming or pulmonary complications, the time of union, infection, malunion, operative time, and blood loss needs further study.