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 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.
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.
ObjectiveTo investigate the effectiveness of a modified surgical treatment of old Monteggia fracture. MethodsBetween March 2006 and December 2013, 40 cases of old Monteggia fracture were treated with modified operation. Modified operation procedure included expanding excision of pedicled forearm fascia flap for reconstruction of the annular ligament and repair of elbow radial lateral collateral ligament complex and extending osteotomy of the ulna, callus replantation, and internal fixation with steel plate. There were 26 boys and 14 girls, aged 2-10 years with an average age of 4 years. Injury was caused by falling in 24 cases, by traffic accident in 8 cases, and by falling from height in 8 cases. The disease duration was 2-11 months (mean, 4 months). Four patients had combined radial nerve palsy. ResultsIncision healed by first intention after operation, without early complication of radial nerve palsy, fascial compartment syndrome, or decreased hand extensor muscle strength. All the children were followed up 1-5 years (mean, 2.5 years). X-ray films showed fracture healing, and the healing time was 10-20 weeks (mean, 15 weeks). During follow-up, 3 cases had re-dislocation. Neither hand dysfunction caused by hand muscle adhesion nor radial head bottleneck shape change was found. On the basis of the functional evaluation criteria by Mackay, the results were excellent in 32 cases, good in 5 cases, and poor in 3 cases; the excellent and good rate was 92.5% at last follow-up. ConclusionThe modified surgical treatment of old Monteggia fracture is an effective method, with good matching of humeroradial joint and without internal fixation of the humeroradial joint.
ObjectiveTo explore a better segment of fixation and fusion for high-grade spondylolisthesis. MethodsA total of 21 patients with high-grade spondylolisthesis who had undergone reduction and posterior instrumented fusion between July 2007 and March 2012, were retrospectively reviewed. All cases underwent posterior spinal canal decompression, Schanz screws fixation and reduction, and intervertebral and posterolateral fusion. The concept of "unstable zone" and the feature of spinal deformity helped us to identify the most appropriate segment to fuse. The pre/post-operative differences on slip percentage, pelvic incidence (PI) and lumbosacral angle were compared and analyzed. The nerve function was evaluated by physical examination and neurological Frankel grade. The Visual Analogue Scale (VAS) and Oswestry Disability Index were used to assess clinical and functional outcomes of lower limbs. Bone fusion was assessed using CT reconstruction. ResultsAll patients were followed up between 12 and 48 months. The clinical and radiological outcomes such as VAS scores and PI angle were all improved compared with that of preoperative, and the differences were all statistically significant (P<0.05). ConclusionFor children with severe spondylolisthesis, if not combined with structural scoliosis, the fixation and fusion level should be up to the upper vertebra which PI angle>60°, and try to protect the posterior longitudinal ligament complex in case adjacent segments become instability or even slip. For adults with severe spondylolisthesis, if not combined with other spinal disorders such as severe osteoporosis, only mono-segmental fusion is recommended after reduction. If the slipped vertebrae could not be reduced to Meyerding gradeⅠ, two or more segments would need to be fixed and fused.
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.
Prosthesis loosening is the leading cause of postoperative revision in unicompartmental knee arthroplasty (UKA). The deviation of medial and lateral translational installation of the prosthesis during surgery is a common clinical phenomenon and an important factor in increasing the risk of prosthesis loosening. This study established a UKA finite element model and a bone-prosthesis fixation interface micromotion prediction model. The predicted medial contact force and joint motion of the knee joint from a patient-specific lower extremity musculoskeletal multibody dynamics model of UKA were used as boundary conditions. The effects of 9 femoral component medial and lateral translational installation deviations on the Von Mises stress of the proximal tibia, the contact stress, and the micro-motion of the bone prosthesis fixation interface were quantitatively studied. It was found that compared with the neutral position (a/A of 0.492), the lateral translational deviation of the femoral component significantly increased the tibial Von Mises stress and the bone-prosthesis fixation interface contact stress. The maximum Von Mises stress and the maximum contact stress of the fixation interface increased by 14.08% and 143.15%, respectively, when a/A was 0.361. The medial translational deviation of the femoral component significantly increased the bone-prosthesis fixation interface micro-motion. The maximum value of micromotion under the conditions of femoral neutral and medial translation deviation was in the range of 20–50 μm, which is suitable for osseointegration. Therefore, based on considerations such as the micromotion range suitable for osseointegration reported in the literature, the risk of reducing prosthesis loosening, and factors that may induce pain, it is recommended that clinicians control the mounting position of the femoral component during surgery within the safe range of 0–4 mm medial translation deviation.
ObjectiveTo observe the changes of visual acuity and fixation properties of eyes with idiopathic macular hole (IMH) before and after surgery. MethodsA prospective clinical study. From September 2019 to December 2020, 25 patients with 25 eyes of IMH diagnosed in Department of Ophthalmology of The Fourth People's Hospital of Shenyang were included in the study. All patients underwent pars plana vitrectomy (PPV) combined with internal limiting membrane stripping. All eyes underwent best corrected visual acuity (BCVA), optical coherence tomography (OCT), and microperimetry before and after surgery. The BCVA examination was carried out using the Snellen visual acuity chart, which was converted into logarithmic minimum resolution angle (logMAR) visual acuity during statistics. The 12° macular sensitivity (MS) and bivariate contour ellipse area (BCEA) were measured by MP-3 microperimetry. The minimum diameter (MIN) and base diameter (BASE) of the macular hole were measured by OCT; the distance between the preferred retinal location (PRL) and the center of the fovea was measured by Image-proplus 6.0 image processing software. At 1 and 3 months follow-up after surgery, the same equipment and methods as before surgery were used to conduct related examinations. The changes of BCVA, PRL distance from the fovea, MS, BCEA, and macular hole shape before and after surgery were compared and observed. One-way analysis of variance was used to compare the indicators before and after surgery. Pearson correlation analysis was used for the correlation between BCVA and preoperative BCVA, PRL and foveal center distance at 3 months after surgery. The correlation between MIN, BCVA, PRL and foveal center before surgery distance, MS, BCEA and BCVA at 3 months after surgery were analyzed by multiple linear regression. ResultsAmong 25 eyes of 25 cases, 1 male had 1 eye, and 24 females had 24 eyes. The macular hole in stage Ⅲ and Ⅳ were 11 eyes and 14 eyes, respectively. MIN and BASE were 537.68±200.09 and 905.48±278.79 μm, respectively. One month after surgery, the hiatus was closed. Before surgery and 1 and 3 months after surgery, the logMAR BCVA of the affected eyes were 0.80±0.17, 0.70±0.21, 0.60±0.25, and the MS were 22.20±3.86, 23.60±3.14, 24.38±2.68 dB, the distances between PRL and the center of the fovea were 537.72±426.05, 402.00±395.06, 236.80±219.54 μm, and BCEA were 7.90±3.43, 6.40±2.67, 4.80±2.32 deg2. Compared with before operation, BCVA (F=7.047, 20.104) and MS (F=1.980, 5.390) were significantly improved at different time after operation, the distance between PRL and fovea center (F=1.265, 9.530), BCEA (F=2.762, 13.617) were decreased, the difference were statistically significant (P＜0.05). The results of correlation analysis showed that BCVA at 3 months after surgery was significantly associated with preoperative MIN (r=0.810), BASE (r=0.664), BCVA before surgery and 1 month after surgery (r=0.854, 0.940), preoperative and surgical MS at 1 month after surgery (r=－0.548, －0.578), distance between PRL and foveal center before surgery and at 1 month after surgery (r=0.833, 0.915), BCEA before surgery and at 1 month after surgery (r=0.636, 0.732) were significantly correlated (P＜0.05). The results of multiple linear regression analysis showed that the distance between PRL and foveal center before surgery and BCVA were risk factors for poor prognosis of BCVA at 3 months after surgery. ConclusionsThe BCVA and MS of eyes with IMH are significantly improved after surgery, and the distance between PRL and foveal center and BCEA decreased. BCVA, PRL and foveal center distance before surgery are risk factors for poor visual acuity after surgery.
ObjectiveTo explore the effectiveness of a new method to repair severe soft tissue defects of the leg, foot, and ankle with contralateral saphenous neurocutaneous vascular flaps combined with assembly external frisket for fixation in parallel-leg position. MethodsBetween August 2009 and August 2013, 29 cases with leg, foot, or ankle wound were treated. There were 18 males and 11 females, with an average age of 37.6 years (range, 11-65 years). The interval of injury and operation was 14-36 days (mean, 22.3 days). The locations were the planta pedis and heel in 5 cases, the dorsal foot in 2 cases, the ankle in 4 cases, middle and lower leg in 14 cases, and upper leg in 4 cases. The area of trauma ranged from 5 cm×3 cm to 19 cm×9 cm. The assembly external frisket was used for fixation in parallel-leg position; a bridge flap was transplanted to repair defects, and the area of flap ranged from 6 cm×4 cm to 22 cm×11 cm. The donor sites were directly sutured or repaired with skin graft. The pedicle of the bridge flap was cut off and the assembly external frisket was removed after 3-4 weeks. ResultsThe flaps in all patients survived completely; primary healing of wound and incision at donor site was obtained. The patients were followed up 6-18 months (mean, 13.2 months). The appearance of flaps was satisfactory, and the sensation of the heel recovered. Moreover, the patients had a comfortable feeling, and the ankle and knee joints can move freely, and had good function. ConclusionThe assembly external frisket in parallel-leg position instead of cross-leg can make patients comfortable position, and achieve reliable fixation. The saphenous neurocutaneous vascular flap has the advantages of no need for anastomosis vein and for sacrifice of the main vein. Contralateral saphenous neurocutaneous vascular flap combined with assembly external frisket for fixation in parallel-leg position is a favorite method to repair severe soft tissue defects of the leg, foot, and ankle.
ObjectiveTo investigate the classification and treatment strategies of symptomatic severe osteoporotic vertebral fracture and collapse. MethodsBetween August 2010 and January 2014, 42 patients with symptomatic severe osteoporotic vertebral fracture and collapse were treated, and the clinical data were retrospectively analyzed. According to clinical symptom and imaging materials, 23 cases were classified as type I (local pain, limitation of motion, no neurological symptom, and no obvious deformity), 12 cases as type II (slight neurological symptom and kyphotic Cobb angle ≤ 30°), and 7 cases as type III (severe neurological symptom and kyphotic Cobb angle <30°). In 23 type I patients, 17 underwent percutaneous vertebral augmentation, 6 underwent posterior pedicle screw fixation strengthened with bone cement combined with percutaneous vertebral augmentation. In 12 type II patients, they were treated with local spinal decompression and internal fixation strengthened with bone cement. In 7 type III patients, 5 underwent posterior osteotomy, and 2 underwent one stage posterior approach of vertebral resection and reconstruction. The visual analogue scale (VAS), Oswestry disability index (ODI), and local kyphotic Cobb angle were used to evaluate the neurological function. The complications were recorded. ResultsThe operation was successfully completed in all patients. Wound infection and ketoacidosis secondary to stress blood glucose rise occurred in 1 case of type III patients respectively, and were cured after corresponding treatment; primary healing of wound was obtained in the other patients. The patients were followed up from 6 to 36 months (mean, 11.6 months). The nerve function was improved in 17 cases, and micturition disability was observed in 2 cases. Asymptomatic cement leakage occurred in 13 cases (30.95%) (7 cases in type I, 4 cases in type II, and 2 cases in type III). No bone cement dislocation and internal fixation failure were found during follow-up. The VAS score, ODI, and the local kyphotic Cobb angle at 1 week and last follow-up were significantly improved when compared with preoperative ones (P<0.05), but no significant difference was found between at 1 week and last follow-up (P>0.05). ConclusionIn order to improve the effectiveness and reduce the risk and complications of operation, individualized strategies should be performed according to different types of severe osteoporotic vertebral fracture and collapse.