Biomechanical Comparison of Two Kinds of Internal Fixation in a Type C Zone II Pelvic Fracture Model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Unstable pelvic fractures are complex and serious injuries. Selection of a fixation method for these fractures remains a challenging problem for orthopedic surgeons. This study aimed to compare the stability of Tile C pelvic fractures fixed with two iliosacral (IS) screws and minimally invasive adjustable plate (MIAP) combined with one IS screw.</p><p><b>METHODS</b>This study was a biomechanical experiment. Six embalmed specimens of the adult pelvis were used. The soft tissue was removed from the specimens, and the spines from the fourth lumbar vertebra to the proximal one-third of both femurs were retained. The pubic symphysis, bilateral sacroiliac joints and ligaments, bilateral hip joints, bilateral sacrotuberous ligaments, and bilateral sacrospinous ligaments were intact. Tile C pelvic fractures were made on the specimens. The symphysis pubis was fixed with a plate, and the fracture on the posterior pelvic ring was fixed with two kinds of internal fixation in turn. The specimens were placed in a biomechanical machine at a standing neutral posture. A cyclic vertical load of up to 500 N was applied, and displacement was recorded. Shifts in the fracture gap were measured by a grating displacement sensor.</p><p><b>STATISTICAL ANALYSIS USED</b>Paired-samples t-test.</p><p><b>RESULTS</b>Under the vertical load of 100, 200, 300, 400, and 500 N, the average displacement of the specimens fixed with MIAP combined with one IS screw was 0.46, 0.735, 1.377, 1.823, and 2.215 mm, respectively, which was significantly lower than that of specimens fixed with two IS screws under corresponding load (P < 0.05). Under the vertical load of 500 N, the shift in the fracture gap of specimens fixed with MIAP combined with one IS screw was 0.261 ± 0.095 mm, and that of specimens fixed with two IS screws was 0.809 ± 0.170 mm. The difference was significant (P < 0.05).</p><p><b>CONCLUSION</b>The stability of Tile C pelvic fractures fixed with MIAP combined with one IS screw was better than that fixed with two IS screws.</p>

Femoral Condyles Tangential Views: An Effective Method to Detect the Screw Penetration of Femoral Condyles After Retrograde Nailing / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Postoperative knee soft tissue irritation is a common complication after retrograde nail fixation of femoral fractures. Distal locking screw prominence is one of the causes for soft tissue irritation. This study aimed to determine whether the use of the femoral condyles tangential views improve the diagnostic accuracy compared with anteroposterior (A-P) view in detecting distal locking screw penetrations during retrograde femoral nailing.</p><p><b>METHODS</b>The angle between the sagittal plane and lateral aspect of the condyle and the angle between the sagittal plane and medial aspect of condyle were measured on computed tomography (CT) images. After the angles were measured and recorded, cadaveric femurs were used in a simulated surgical procedure. The retrograde femoral nail was inserted into the femur and placed distal locking screws, which were left 2, 4, and 6 mm proud of the medial and lateral condyles for each femur. A-P view, lateral condyle tangential view and medial condyle tangential view were obtained. All fluoroscopic images were recorded and sent to three observers blinded to the experimental procedure to determine whether screws penetrated the condyle cortex or not.</p><p><b>RESULTS</b>According to the results of CT scan, the lateral condyle view was 20.88 ± 0.98° and the medial condyle view was 40.46 ± 3.14°. In the A-P view, we detected 0% at 2 mm penetration, 16.7% (lateral condyle screw) and 25.0% (medial condyle screw) at 4 mm, and 41.7% (lateral condyle screw) and 58.3% (medial condyle screw) at 6 mm. In the lateral tangential view, we detected 91.7% at 2 mm penetration of the lateral condyle and 100% at 4 mm and 6 mm. In the medial tangential view, we detected 66.7% at 2 mm penetration of the medial condyle and 100% at 4 mm and 6 mm. The femoral condyle tangential views provided significant improvement in detecting screw penetrations at all lengths (2, 4, and 6 mm) compared with the A-P view (P < 0.05).</p><p><b>CONCLUSIONS</b>The femoral condyles tangential views increased the accuracy of detecting screw penetrations on the medial and lateral condyles. Routine clinical use of the femoral condyles tangential views has the potential to increase accuracy in detecting distal locking screw penetration during retrograde femoral nailing.</p>

Four pins assisted reduction of complex segmental femoral fractures: a technique for closed reduction / 华中科技大学学报（医学）（英德文版）

Complex segmental femoral fractures are usually not amenable to closed reduction. The purpose of this study was to evaluate a series of patients who had undergone four pins assisted reduction and intramedullary nail fixation to determine the therapeutic effect of this closed reduction technique. Between December 2010 and January 2013, 15 consecutive patients with segmental femoral fractures were treated with four pins assisted reduction at our hospital. The patient was placed in a supine position on a radiolucent fracture table and a gentle traction was attempted on the limb. Usually, the proximal fracture segment exhibited the typical deformity of flexion, external rotation, and abduction, the middle segment exhibited adduction and distal fracture segment exhibited flexion. Four Schanz pins were placed percutaneously to fix one cortex and did not penetrate into the medullary cavity, and the "T" sharp handles were fixed on the Schanz pins. The fragments were then reduced by reversing the deforming forces for segmental fractures by two assistants. And then, the reduction could be easily achieved and intramedullary nail fixation was performed. Radiographs were evaluated for the quality of the reduction and fracture union. Closed reduction was achieved in all patients using the four pins technology. All 15 fractures united uneventfully. No patient had a rotational malunion or limb length discrepancy at the time of the last follow-up. Thirteen of the fifteen (86.7%) patients had anatomic reduction and two of them (13.3%) had minor varus alignment of 3° and 5°. Knee stiffness was observed in 2 patients and no implant failure was observed. Surgical treatment of complex segmental femoral fractures with four pins assisted reduction and intramedullary nail fixation techniques can result in excellent reductions and a high union rate.

Four pins assisted reduction of complex segmental femoral fractures: a technique for closed reduction / 华中科技大学学报（医学）（英德文版）

Complex segmental femoral fractures are usually not amenable to closed reduction. The purpose of this study was to evaluate a series of patients who had undergone four pins assisted reduction and intramedullary nail fixation to determine the therapeutic effect of this closed reduction technique. Between December 2010 and January 2013, 15 consecutive patients with segmental femoral fractures were treated with four pins assisted reduction at our hospital. The patient was placed in a supine position on a radiolucent fracture table and a gentle traction was attempted on the limb. Usually, the proximal fracture segment exhibited the typical deformity of flexion, external rotation, and abduction, the middle segment exhibited adduction and distal fracture segment exhibited flexion. Four Schanz pins were placed percutaneously to fix one cortex and did not penetrate into the medullary cavity, and the "T" sharp handles were fixed on the Schanz pins. The fragments were then reduced by reversing the deforming forces for segmental fractures by two assistants. And then, the reduction could be easily achieved and intramedullary nail fixation was performed. Radiographs were evaluated for the quality of the reduction and fracture union. Closed reduction was achieved in all patients using the four pins technology. All 15 fractures united uneventfully. No patient had a rotational malunion or limb length discrepancy at the time of the last follow-up. Thirteen of the fifteen (86.7%) patients had anatomic reduction and two of them (13.3%) had minor varus alignment of 3° and 5°. Knee stiffness was observed in 2 patients and no implant failure was observed. Surgical treatment of complex segmental femoral fractures with four pins assisted reduction and intramedullary nail fixation techniques can result in excellent reductions and a high union rate.

The effects of the autologous venous external stents on intimal hyperplasia of the vein grafts in rabbits / 中华外科杂志

<p><b>OBJECTIVE</b>To assess the effect of the autologous venous external stents on intimal hyperplasia of the vein grafts in rabbits.</p><p><b>METHODS</b>Thirty-six male New Zealand white rabbits, aged 5 months and weighing 2.8 to 3.0 kg, were randomly divided into 3 groups: group A, group B and group C, with 12 rabbits in each group. First, a section about 6 cm long of vein was cut from the right external jugular vein of each rabbit and severed to have 3 equal-length segments. Next, each distal segment prepared for anastomosis. The proximal segment invaginating middle segment in group A and only middle segment in group B were used for the external stent. Later, the left common carotid artery was separated from surrounding tissue, from it a section about 0.5 cm long was cut away. Finally, the vein graft was inverted and end-to-end anastomosed to the two ends of the artery with a 9-0 suture. After bloodstream re-established, the diameter of each vein graft was measured. At 2 and 4 weeks postoperative, the graft veins were cut off and histologically examined by the means of HE staining and Masson staining. The smooth muscle cells (SMC) proliferation was studied by the immunohistochemical detection of proliferating cell nuclear antigen.</p><p><b>RESULTS</b>After bloodstream re-established, the diameters of vein graft of group A and group B and group C were (1.6 +/- 0.3) mm, (2.2 +/- 0.4) mm and (2.6 +/- 0.6) mm respectively (P < 0.05). At 4 weeks postoperative, the data of the ratio of intima to media thickness and the index of the proliferating cells of the intima were as follow: group A (1.01 +/- 0.07 and 6.84 +/- 1.98), group B (1.32 +/- 0.08 and 11.01 +/- 2.61), group C (1.55 +/- 0.03 and 14.96 +/- 4.14). Both the data of group A were obviously less than that in group B, and that of group B was less than group C (P < 0.05).</p><p><b>CONCLUSION</b>The autologous venous two-layer external stents inhibit intimal hyperplasia of the vein grafts.</p>

Clinical observation on the different treatments targeted at different types of radial head fracture and radial neck fracture / 中华外科杂志

<p><b>OBJECTIVE</b>To assess the effect of the different treatments targeted at different types of radial head fracture and radial neck fracture.</p><p><b>METHODS</b>A retrospective study was performed in 87 patients from February 2006 to March 2007. Fifty-four patients with radial head fractures included 36 males and 18 females, aged from 18 to 65 years (the average age was 33); Forty of them resulted from crashing, 8 from traffic injury and 6 from falling injury. According to Mason classification system, there were 15 type I, 23 type II and 16 type III. Thirty-three patients with radial neck fractures included 21 males and 12 females, aged from 9 to 17 years (the average age was 13), 29 of them resulted from crashing, 1 from traffic injury and 3 from falling injury. According to O'Brien classification system, there were 8 type I, 14 type II and 11 type III. Type I of radial head fractures and radial neck fractures were immobilization with cast, the patients with type II of radial head fractures were treated with open reduction and micro-screw or T-trapezoid and bridge-shaped plate fixation and type III had operations to fix with bridge-shaped locked plate and repair the broken annular ligament, or replace heads with prosthesis. All patients with type II and type III of radial neck fractures were treated with closed reduction by leverage and percutaneous intra-medullary nailing.</p><p><b>RESULTS</b>The patients were followed up for 4-12 months (mean 7.2 months). The functional recovery degrees were evaluated with Wheeler's evaluation system. In group of radial head fractures, the results were excellent in 26 patients, good in 20, fair in 6 and poor in 2, the excellent and good rate was 85.2%. In group of radial neck fractures, the results were excellent in 20 patients, good in 9, fair in 4 and poor in no patient, and the excellent and good rate was 87.9%.</p><p><b>CONCLUSIONS</b>Different types of fractures should choose different surgical methods according to their characters. The excellent functional recovery depend on anatomical reduction, retaining the head of radius, early repairing and protecting the broken annular ligament of radius, and early functional training.</p>