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Objective:To explore the curative effects of Nice knot fixation on tuberosity healing in hemiarthroplasty for complex proximal humeral fractures.Methods:A retrospective analysis was conducted of the eligible 32 complex proximal humeral fractures which had been treated at Department of Trauma and Orthopedics, Peking University People's Hospital between May 1, 2016 and May 1, 2019. Nice knot fixation was used to repair greater and lesser tuberosities in hemiarthroplasty for all the patients. There were 6 males and 26 females, aged from 60 to 90 years (mean, 74.9 years). By the Neer classification, there were 4 three-part fractures combined with dislocation, 20 four-part fractures, and 8 four-part fractures combined with dislocation. Shoulder joint X-rays were taken at postoperative 1, 2, 3, 6, and 12 months at the outpatient clinic to evaluate the patients' shoulder joint mobility, visual analog scale (VAS) pain score and Constant-Murley shoulder score. Tuberosity healing was assessed based on the X-rays and related complications were recorded.Results:The 32 patients received complete follow-up for 12 to 25 months (average, 17.82 months). At the 12-month follow-up, their shoulder flexion averaged 131.3° (from 80° to 155°), abduction 126.9° (from 80° to 155°), external rotation 48.4° (from 30° to 60°), internal rotation the L2 level, VAS pain score 0.9 (from 0 to 5), and Constant-Murley score 83.4 (from 58 to 96). The rate of patient satisfaction was 87.5%(28/32). Tuberosity-related complications were observed in 6 cases with an incidence of 18.8%. Complications like infection and prosthetic loosening were found in none of the patients.Conclusion:In hemiarthroplasty for complex proximal humeral fractures, application of Nice knot to fixate greater and lesser tuberosities can lead to rigid fixation, definite curative effects and a low incidence of tuberosity-related complications.
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Objective:To study the reason for failed fixation with dynamic hip screws (DHS) and the indications for DHS fixation in the treatment of intertrochanteric fracture based on the lever-balance-reconstruction theory.Methods:A retrospective analysis was performed of the data of 32 patients with intertrochanteric fracture who had been treated by DHS fixation at Department of Orthopaedic Trauma, Peking University People's Hospital from January 1999 to December 2019. There were 22 males and 10 females, aged from 34 to 91 years (average, 67.7 years). By the AO classification, 15 fractures were type 31-A1, 13 ones type 31-A2, and 4 ones type 31-A3. According to the lever-balance-reconstruction theory, after the position of postoperative fulcrum was determined depending on the relationship between fracture line and internal fixation, the medial and lateral force arms were measured after internal fixation. The 32 patients were divided into 2 groups according to the position of fulcrum after internal fixation. In group A of 13 patients, the fulcrum was located in or within the center of the medullary cavity; in group B of 19 patients, the fulcrum was located outside the center of the medullary cavity. The incidence of internal fixation failure was compared between the 2 groups.Results:Internal fixation failure occurred in 15 of the 32 patients: cutting out of the head and neck screws without penetration in 2 cases, screw withdrawal in 8 cases, hip varus deformity in 10 cases, and femoral neck shortening in 15 cases. The 2 groups were comparable because there were no statistically significant differences in their preoperative general data or types of internal fixation between them except AO classification ( P>0.05). The length of medial force arm (power arm) averaged 51.12 mm (from 39.4 to 57.9 mm) and the length of lateral force arm (resistance arm) 23.37 mm (from 15.1 to 31.0 mm) in group A where 3 patients experienced internal fixation failure after operation; the length of medial force arm (power arm) averaged 63.71 mm (from 52.3 to 74.5 mm) and the length of lateral force arm (resistance arm) 9.94 mm (from 3.1 to 18.3 mm) in group B where 12 patients experienced internal fixation failure after operation. There was a significant difference between the 2 groups in internal fixation failure ( P=0.036). Conclusions:In the DHS fixation of intertrochanteric fracture, the postoperative fixation failure is associated with the fulcrum position after reconstruction. DHS is only indicated for intertrochanteric fractures whose fracture line (post-reconstruction fulcrum) is near and inside the center of the medullary cavity, but not for those whose fracture line (post-reconstruction fulcrum) is outside the medullary cavity.
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Objective:To compare the biomechanical properties of traditional surface hip prosthesis and bionic surface hip prosthesis.Methods:The Sawbone digital model (#3908, Left, Medium) was selected as the research object. Mimics 21.0 software was used to reconstruct the physical model of femur. Solidworks 16.0 software was used to build the model of prostheses, including the traditional and bionic (type 1-4) protheses and their assembly. The distances from the screw cross position to the top of pressure screw of type 1 to type 4 protheses were 20.22 mm, 30.12 mm, 32.17 mm and 37.76 mm, respectively. The mechanical distribution characteristics of the whole model were measured and the stress distribution cloud map was obtained.Results:The peak stresses at bone-stem junction of traditional prosthesis and type 1-4 hip prostheses were 32.18 MPa, 13.80 MPa, 15.01 MPa, 23.46 MPa and 34.51 MPa, respectively. With the fulcrums away from the top of the femur, the peak stresses at the fulcrums of type 1-4 hip protheses were 37.98 MPa, 48.60 MPa, 54.80 MPa, and 53.87 MPa, respectively. The maximum stress above femoral neck of traditional prosthesis and type 1-4 hip prostheses were 8.00 MPa, 7.80 MPa, 7.04 MPa, 7.03 MPa and 7.51 MPa, respectively. The maximum stresses under femoral neck was 15.38 MPa, 14.20 MPa, 11.11 MPa, 13.10 MPa and 12.18 MPa, respectively. The maximum stresses in the greater trochanter region of femur were 13.08 MPa, 11.61 MPa, 13.09 MPa, 11.02 MPa and 39.51 MPa, respectively.Conclusion:Compared with the traditional surface hip prosthesis, the type I bionic surface hip prosthesis is designed based on the lever balance reconstruction theory. With the bionic reconstruction of the tension trabeculae and compression trabeculae through reasonable screw placement angles and the inward movement of the fulcrum closer to the center of the femoral head, the new type prothesis make up for the design defects of the traditional surface hip prosthesis, optimize the stress distribution in the proximal femur, and improve the stability of the prosthesis after replacement, which help reduce the risk of femoral neck fracture and prosthesis loosening, and extend the service life of the prosthesis.
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<p><b>OBJECTIVE</b>To use combined comparative genome hybridization (array-CGH) and conventional karyotype analysis to study the relationship between ultrasonographic abnormalities of fetuses and chromosomal aberrations.</p><p><b>METHODS</b>One hundred twenty two fetuses with ultrasonographic abnormalities in middle and late trimesters suspected with chromosomal abnormalities were collected between March 2012 and February 2013.</p><p><b>RESULTS</b>The pregnant women had an average age of 31 yr (22-38), among whom 35 were above the age of 35. The average gestational age was 27(+5) weeks (18-37 weeks), and the most common abnormal findings have involved heart, central nervous system and bones. Multiple malformations were found in 49 cases. The success rate of the combined methods was 100%. In 24 (19.7%) of the cases, a chromosomal abnormality was detected. Among all cases, 16 (13.1%) were detected by the combined method (12.3%). Seventeen cases (13.9%) of chromosomal abnormalities and 4 cases (3.3%) of polymorphic variation were detected by karyotype analysis, and 23 cases (8.9%) of abnormalities were detected by array-CGH. Meanwhile, 7 cases (5.7%) of abnormalities were detected by array-CGH, but the results of karyotype analysis were normal. One case (0.8%) with low level of chromosome chimerism detected by the karyotype analysis was missed by array-CGH.</p><p><b>CONCLUSION</b>The results suggested that multiple congenital deformity of the fetus has a strong correlation with chromosomal abnormalities. For fetuses with ultrasonographic abnormalities, array-CGH can improve the detection sensitivity of the chromosomal disease.</p>