[Composition and Distribution Characteristics of Microplastics in Danjiangkou Reservoir and Its Tributaries].

Microplastic pollution is a hot topic in environmental science. To explore the microplastics in Danjiangkou Reservoir, a national first-class water source protection area, we studied their types, abundance, and material characteristics using density flotation and micro-Raman spectroscopy. The spatial distribution characteristics of microplastics were also revealed according to the hydrologic and hydrodynamic conditions of the reservoir. The results showed that the main types of microplastics were fragments (84.2% of the total), granules, films, and fibers, of which 84.2% were fragments. The numbers of each type of microplastic were significantly different in different areas. A variety of colors were observed, with transparent and brown microplastic being most common. During the wet season, the average abundance of microplastics in the reservoir was 7248 n·m-3, which is higher than that observed in the Han Reservoir. The particle sizes of the microplastics in the research area ranged 75-4703 µm, of which 73.4% had a particle size of less than 500 µm; microplastic abundance was inversely related to particle size. Nylon was the most common form of microplastic in Danjiangkou Reservoir, accounting for 36.4% of the total, followed by polyethylene (PE) and polypropylene (PP).

Biomechanical study comparing a new combined rod-plate system with conventional dual-rod and plate systems.

Most anterior spinal instrumentation systems are designed as either a plate or dual-rod system and have corresponding limitations. Dual-rod designs may offer greater adjustability; however, this system also maintains a high profile and lacks a locking design. Plate systems are designed to be stiffer, but the fixed configuration is not adaptable to the variety of vertebral body shapes. The authors designed a new combined rod-plate system (D-rod) to overcome these limitations and compared its biomechanical performance with the conventional dual-rod and plate system. Eighteen pig spinal specimens were divided into 3 groups (6 per group). An L1 corpectomy was performed and fixed with the D-rod (group A; n=6), Z-plate (Sofamor Danek, Memphis, Tennessee) (group B; n=6), or Ventrofix (Synthes, Paoli, Pennsylvania) (group C; n=6) system. T13-L2 range of motion was measured with a 6 degrees of freedom (ie, flexion-extension, lateral bending, and axial rotation) spine simulator under pure moments of 6.0 Nm. The D-rod and Ventrofix specimens were significantly stiffer than the Z-plate specimens (P<.05) based on results obtained from lateral bending and flexion-extension tests. The D-rod and Z-plate specimens were significantly stiffer than the Ventrofix specimens (P<.05) in axial rotation. The D-rod combines the advantages of the plate and dual-rod systems, where the anterior rod exhibits the design of a low-profile locking plate, enhanced stability, and decreased interference of the surrounding vasculature. The posterior rods function in compression and distraction, and the dual-rod system offers greater adjustability and control over screw placement. The results indicate that it may provide adequate stability for anterior thoracolumbar reconstruction.

Modified technique using allograft-prosthetic composite in the distal femur after bone tumor resection.

BACKGROUND: The purpose of this retrospective study was to analyze the results of treatment of bone tumor resection of the distal femur with the modified technique of allograft-prosthetic composite. METHODS: Twelve patients with distal femoral bone tumors were treated with deep-frozen cortical allograft struts and allograft-prosthesis composites. There were five males and seven females with a median age of 29.5y. The minimum follow-up time was 12mo (median, 45.7mo; range, 12-81mo). Diagnoses included osteosarcoma in five patients, chondrosarcoma in three patients, giant cell tumors in three patients, and malignant fibrous histiocytoma in one patient. Five osteosarcoma patients were treated with adjuvant chemotherapy. RESULTS: At the latest follow-up examination, 11 patients were alive with no evidence of disease, and the limb was preserved in nine patients. One patient died of pulmonary metastases with no evidence of local recurrence. Seven healed without complications. A surgical procedure was performed in four patients because of complications, which included a fracture (one patient), deep infection (one patient), instability (one patient), and local recurrence (one patient). CONCLUSION: The modified technique of allograft-prosthetic composite is an effective treatment for bone tumor resection of the distal femur. This technique has many advantages, including augmentation of the bone stock, minimizing the risk of allograft fracture and nonunion, and decreasing the need for revision operations.

Anterior versus posterior approach in the treatment of chronic thoracolumbar fractures.

The purpose of this study was to compare the results of anterior approach vs posterior approach in the treatment of chronic thoracolumbar fractures. A total of 36 patients with chronic thoracolumbar fractures were divided into 2 groups. Group A was treated by an anterior approach and group B was treated by a posterior approach. During the minimum 24-month follow-up period (range, 24-62 months), all patients were prospectively evaluated for clinical and radiologic outcomes. Intraoperative blood loss, operative time, operative complications, pulmonary function, Frankel scale, and American Spinal Injury Association (ASIA) motor score were used for clinical evaluation, and Cobb angle was examined for radiologic outcome. All patients in this study achieved solid fusion, with significant neurologic improvement. Operative time, perioperative blood loss, ASIA score on admission and at final follow-up, and complications of respiratory tract infection and intercostal nerve pain were not significantly different between the 2 groups (P>.05), but complications of hemopneumothorax, abdominal distension, and constipation were fewer in group B (P<.05). Postoperative pulmonary function (P<.05) and correction of posttraumatic kyphosis were better in group B (P<.05).

Effects of a sliding plate on morphology of the epiphyseal plate in goat distal femur.

The aim of this study was to observe the effects of a sliding plate on the morphology of the epiphyseal plate in goat distal femur. Eighteen premature female goats were divided randomly into sliding plate, regular plate and control groups. Radiographic analysis and histological staining were performed to evaluate the development of epiphyseal plate at 4 and 8 weeks after surgery. In the sliding plate group, the plate extended accordingly as the epiphyseal plate grows, and the epiphyseal morphology was kept essential normal. However, the phenomenon of the epiphyseal growth retardation and premature closure were very common in the regular plate group. In addition, the sliding plate group exhibited more normal histologic features and Safranin O staining compared to the regular plate group. Our results suggest that the sliding plate can provide reliable internal fixation of epiphyseal fracture without inhibiting epiphyseal growth.

[Ulnar osteotomy and internal fixation for old anterior dislocation of radial head in children].

OBJECTIVE: To evaluate the clinical results of ulnar osteotomy and internal fixation in treating old anterior dislocation of radial head in children. METHODS: From Jan.2004 to Jan.2010, 18 patients with old anterior dislocation of radial head were treated with open reduction for radial head and ulnar osteotomy and internal fixation, including 12 males and 6 females with an average age of (6.9 +/- 1.3) years (3 to 15 years). Among them, 15 cases had history of external injury, from injury to operation was for 5-65 months with an average of (24.0 +/- 5.5) months. Limitation of activity occurred in all patients including flexion and extension of elbow joint and rotation of forearm, without radial nerve injury and obviously radial head deformation. RESULTS: All incisions obtained primary healing and no nonunion, re-dislocation of radial head and nerve injury were found. All patients were followed up from 9 to 38 months with an average of (17.0 +/- 4.5) months. Union time of fracture was from 2.3 to 3.9 months with an average of (2.8 +/- 0.5) months. Postoperative activity in flexion and extension of elbow joint and rotation of forearm improved significantly compared with preoperative. The clinical effects were evaluated according to Zhuyukui criteria, 14 patients got excellent results, 3 good, 1 fair. CONCLUSION: Ulnar osteotomy and internal fixation in treating old anterior dislocation of radial head in children can obtain satisfactory results and effectively improve the activities in flexion and extension of elbow joint and rotation of forearm and prevent re-dislocation of radial head.

Operative versus nonoperative management of Pipkin type-II fractures associated with posterior hip dislocation.

Little has been written on randomized, controlled studies of operative versus nonoperative management of Pipkin type-II fractures associated with posterior dislocation of the hip. It is difficult to validate the optimal management of these fractures. The goals of this study were to (1) evaluate the results of conservative and surgical treatment for Pipkin type-II fractures associated with posterior dislocation of the hip and supply the optimal management for these fractures and (2) identify whether the Smith-Petersen approach is a safe and reliable surgical approach for Pipkin type-II fractures.Twenty-four patients were randomly divided into 2 groups: the conservative group (n=12) was treated by closed reduction, and the surgical group (n=12) was treated by primary open reduction internal fixation (ORIF) by bioabsorbable screws via a Smith-Petersen approach. Minimum follow-up was 24 months. Functional outcome was measured using the Thompson and Epstein score and the d'Aubigné-Postel score. Heterotopic ossification was classified based on the Brooker classification. The outcome of the conservative group was worse than that of the surgical group (P=.037). Two patients in the conservative group needed joint replacement for avascular necrosis of the femoral head. Heterotopic ossification was found in 6 patients (1 patient in the conservative group and 5 in the surgical group).Primary ORIF by bioabsorbable screws via a Smith-Petersen approach is an effective treatment for Pipkin type-II fractures associated with posterior dislocation.

Conservative versus surgical management of Pipkin type I fractures associated with posterior dislocation of the hip: a randomised controlled trial.

The aim of this study was to evaluate the long-term results of conservative and surgical fragment excision treatment in patients with Pipkin type 1 fractures of the femoral head associated with posterior dislocation of the hip by a randomised controlled trial. Sixteen patients were randomly divided into two groups: the conservative group was treated by closed reduction, and the surgical group was treated by closed reduction followed with fragment excision. Functional outcome was determined using the Thompson and Epstein score and the Merle d'Aubigne and Postel score. Outcome of the conservative group was worse than that of the surgical group (p = 0.032). The randomised controlled trial proves surgical fragment excision after closed reduction is an effective treatment for Pipkin type 1 fractures.

[Tunnel enlargement after anterior cruciate ligament reconstruction with peroneus longus muscle combined with BMP and allogeneic bone].

OBJECTIVE: To investigate the incidence and variation of tunnel enlargement after anterior cruciate ligament (ACL) reconstruction with peroneus longus muscle combined with BMP and allogeneic bone. METHODS: ACL reconstructions with peroneus longus muscle combined with BMP and allogeneic bone were performed in 18 patients (18 knees)in the study from March 2007 to July 2009. Among the patients,14 patients were male and 4 patients were female, ranging in age from 21 to 47 years, with an average of 35.5 years. Twelve patients had the injuries in the right knee and 6 patients in the left knee. The CT scans were taken in a consistent manner at the 1st week and the 3rd, 6th, 12th months after surgery to measure tibial and femoral tunnel expansion. RESULTS: Tunnel enlargement didn't happen in 18 knees. The average enlargement of 18 cases of femoral tunnel was (1.10 +/- 0.42) mm; and the average enlargement of 18 cases of tibial tunnel was (1.00 +/- 0.51) mm. There was statistical significance of femoral tunnel between the 1st week and the 3rd month after surgery (P < 0.05); and there were no significant difference of the tunnel diameters among the 3rd, 6th, and the 24th months postoperatively (P > 0.05). There was statistical significance of tibial tunnel between the 1st week and the 3rd month after surgery (P < 0.05); there were no significant differences of the tunnel diameters among the 3rd, 6th, and 24th months postoperatively (P > 0.05). CONCLUSION: Anterior cruciate ligament reconstruction with peroneus longus muscle combined with BMP and allogeneic bone could obviously reduce the incidence of tunnel enlargement. The tunnel diameter obviously increase in 3 months after surgery,and it remains basically unchanged later.

[Treatment of infected bone defect with one stage open cancellous bone grafting].

OBJECTIVE: To explore the feasibility of the treatment of infected bone defect with one stage open cancellous bone grafting and summarize the key factors improving the curative effects. METHODS: Twelve cases of infected bone defects were reviewed, which involved 8 male and 4 female with an average age of 42 years (range, 22 to 68 years). The study consisted of 7 cases of calcaneal defects, 4 tibial defects and 1 femoral defect. The procedure included dressing change, resection of the devitalized soft tissue and bone tissue. After the debridement, the bone defect at one stage was treated with cancellous bone grafting and the wound was open. The wound was closed with skin transplantation when it was covered by granulation tissue completely. RESULTS: The wound was covered with granulation tissue in the average 24.1 days after operation and was closed in the average 30.3 days. All the patients were followed up for 8 to 30 months with an average time of 18 months. All the bone defects were healing after bone grafting and there was no infection recurrence. CONCLUSION: One stage open cancellous bone graft is an easy and feasible treatment for infected bone defect. Resecting of the devitalized tissue before operation, radical debridement, enough bone graft in operation and careful dressing change after operation are all the key factors to acquire the satisfactory outcome.

[Design and experimental study of an epiphyseal slide-traction plate].

OBJECTIVE: To develop an epiphyseal slide-traction plate in child, which can supply the fracture a sufficient internal fixation, and will not restrain the growth of epiphyses. Animal experiments were carried out with the plates to compare the slide-traction with traditional plate. METHODS: Develop a slide-traction plate for the configuration of the femur condylus of children. Thirty adolescent goats in the experiment were divided into control group (12 goats) and plate group (18 goats). In plate group, right femurs of goats were fixed with common plates and the left femurs with slide-traction plates. All the goats were given X-ray examination at different time after surgery. And the goats were sacrificed at 3 and 6 month, histological method and electron microscopy were performed to evaluate the development of epiphyseal plate. RESULTS: The both femurs of the goats in control group have no difference in evidence in length at all time we examined. And the both femurs of the goats fixed with plates have no difference in evidence in length at 1 day after surgery. However, the both femurs of the goats fixed with plates have difference in evidence in length at 1 month, 2 month, 3 month, 6 month after surgery. The increased length of the femurs at I month, 2 month, 3 month, 6 month after surgery was also compared with the length at 1 day after surgery, there was difference in evidence between the right femurs of the control group and the femurs were fixed with common plates, but no difference in evidence between the left femurs of the normal control group and the femurs were fixed with slide-traction plate (P > 0.05). More thicker epiphyseal plate were found in the left femurs than the right femurs of the group fixed with plates at 3 and 6 month after surgery (P < 0.01). In the plate group, safranine O staining showed epiphyseal plates at the left femurs had more fuscous staining than the right femurs at 3 and 6 month after surgery and electron microscopy also found that the cells of the epiphyseal plates of left femurs were more eugenic than the right femurs at 3 and 6 month after surgery. CONCLUSION: The epiphyseal slide-traction plate can slide with the growth of epiphyses, which is suitable for fixation of the fracture in this part.

[Controlled clinical study of treatment of non-operation and surgical operation for scapular fracture].

OBJECTIVE: To investigate the effect of treatment methods of non-operation and surgical operation for scapular fracture. METHODS: A retrospective analysis of 52 patients (male 37, female 15, ranging in age from 20 to 48 years, meanly 31 years)with scapular fractures was done. According to Hardegger classification: the scapular body fracture in 24 cases, the surgical neck fracture in 12 cases, the anatomical neck fracture in 3 cases, the glenoidal lip fracture in 6 cases, the scapular spine fracrure in 7 cases. Of all 52 patients,17 cases were treated conservatively, and 35 were undergone surgical internal fixation. When followed up,the clinical examination was done and the X-ray films were taken to measure glenopolar angle (GPA). Hardegger function evaluation system was adopted. The results were analysed statiscally. RESULTS: Fifty-two cases were all followed up for 9 weeks to 48 months. Among 17 patients treated by non-operation, Hardegger function evaluation system showed that the result were excellent in 7 cases, good in 6, fair in 2 and poor in 2; the X-ray film results showed that there were 14 cases of GPA > 20 degrees and 3 cases of GPA < 20 degrees. Of 35 patients treated by surgical operation, Hardegger function evaluation system showed that the result were excellent in 20 cases,good in 12 and fair in 3; the X-ray film results showed that there were 33 cases of GPA > 20 degrees and 2 cases of GPA < 20 degrees. There was no significant difference between the two groups (P = 0.27). CONCLUSION: Before treatment of scapular fracture, with CT 3D -recontruction, complete understanding of fragments displacement, and correction indication selection, and perform early exercises, both of the two procedures can provide satisfactory outcome.

[Treatment of refracture in plate-screw fixation of femoral shaft with plate and xenogenic bony plate].

OBJECTIVE: To evaluate curative effect of plate and xenogenic bony plate were applied in refracture in plate-screw fixation of femoral shaft. METHODS: Thirteen cases of refracture in plate-screw fixation of femoral shaft included 8 males and 5 females, average age was 31.2 years ranging from 14 to 57. Fracture type was comminuted fracture in 7 cases, oblique fracture in 4 cases, transverse fracture in 2 cases. Fixation type used eight holes femoral LC-DCP in 5 cases, eight holes epipodite LC-DCP in 2 cases, six holes femoral LC-DCP in 2 cases, 8 holes La-Plate in 4 cases. All the patients were treated by femoral LC-DCP and xenogenic bony plate. RESULTS: All of the patients were followed up from 16 to 40 months with average of 32 months. All cases had undergone only one operation and achieved bony union. Average time of bony union was 9 months. The lower limbs resumed walk and beared a heavy burden. According to criterion of Merchan, the results were excellent in 7 cases,good in 4,fair in 1 and poor in 1, the excellent and good rate of knee function was 84.6% (11/13) in one year after operation. CONCLUSION: Treatment of refracture in plate-screw fixation of femoral shaft with armor plate and xenogenic bony plate is a reliable treatment.

Bone splint technique and plating application in adolescent high-energy comminuted fracture of distal femur with bone defects.

Comminuted fracture of distal femur is a common lower limb injury from traffic accidents, especially from motor accidents. Routine dynamic condylar screw (DCS) or 95-degree condylar plate (CP) sometimes cannot solve the bone defect in the center of alignment and contralateral diaphysis for the reason of absent screw anchor point, especially for AO C2.2-2.3 types. Many authors recommended open reduction and fixation with less invasive stabilization system (LISS) as the treatment of choice, but there are still problems in fusion and alignment. In this study, we reported our experiences with the use of bone splint technique in the high-energy commimuted fracture of distal femur with central and medial bone defect in adolescents.

[Salvage of lower limb with long-time injury of popliteal artery].

OBJECTIVE: To evaluate the rate of salvage of lower limb with long-time injury of popliteal artery. METHODS: Twenty-one patients with injury of popliteal artery were treated. The interval between injury and repair of artery ranged from 12 hrs to 48 hrs. The essences of operation were thorough debridement of the ischemic and necrotic muscles, primary suture of wound, and repair of popliteal artery on the basis of reduction and fixation of fracture. RESULTS: The limb salvage were achieved in 19 cases. The saved limbs could fulfill the basic function of walk. CONCLUSION: Thorough debridement of ischemic and necrotic muscle and primary suture of wound were reasonable methods which could treat long-time injury of popliteal artery without amputation.