Treatment of displaced intra-articular calcaneal fractures by ligamentotaxis: current concepts’ review

Introduction: A large variety of therapeutic modalities for calcaneal fractures have been described in the literature. No single treatment modality for displaced intra-articular calcaneal fractures has proven superior over the other. This review describes and compares the different percutaneous distractional approaches for intra-articular calcaneal fractures. The history, technique, anatomical and fracture considerations, limitations and the results of different distractional approaches reported in the literature are reviewed. Method: Literature review on different percutaneous distractional approaches for displaced intra-articular calcaneal fractures. Results: Eight studies in which application of a distraction technique was used for the treatment of calcaneal fractures were identified. Because of the use of different classification, techniques, and outcome scoring systems, a meta-analysis was not possible. A literature review reveals overall fair to poor result in 10-29% of patients. Ten up to 26% of patients are unable to return to work after percutaneous treatment of their fracture. A secondary arthrodesis has to be performed in 2-15% of the cases. Infectious complications occur in 2-15%. Some loss of reduction is reported in 4-67%. Conclusion: Percutaneous distractional reduction and fixation appears to be a safe technique with overall good results and an acceptable complication rate, compared with other treatment modalities for displaced intra-articular calcaneal fractures. A meta-analysis, based on Cochrane Library criteria is not possible, because of a lack of level 1 and 2 trials on this subject

Early Weight Bearing of Calcaneal Fractures Treated by Intraoperative 3D-Fluoroscopy and Locked-Screw Plate Fixation

Operative therapy of intraarticular fractures of the calcaneus is an established surgical standard. The aim is an accurate reduction of the fracture with reconstruction of Boehler’s angle, length, axis and subtalar joint surface. Intraoperative 3D-fluoroscopy with the Siremobil Iso-C 3D® mobile C-arm system is a valuable assistant for accurate reconstruction of these anatomical structures. Remaining incongruities can be recognized and corrected intraoperatively. The achieved reduction can be fixed by the advantages of an internal fixator (locked-screw plate interface). In the period of October 2002 until April 2007 we operated 136 patients with intraarticular fractures of the calcaneus by means of anatomical reduction, and internal plate fixator under intraoperative control of 3D-fluoroscopy. All patients were supplied with an orthesis after the operation which allowed weight bearing of 10 kg for 12 weeks for the patients operated between October 2002 and October 2004 (Group A). Transient local osteoporosis was observed in all X-Rays at follow-up after an average of 8,6 months. Therefore we changed our postoperative treatment plan for the patients operated between November 2004 and April 2007 (Group B). Weight bearing started with 20 KG after 6 weeks, was increased to 40 KG after 8 weeks and full weight bearing was allowed after 10 weeks for these patients. In no case a secondary dislocation of the fracture was seen. No bone graft was used. At follow up the average American Foot and Ankle Society Score (AOFAS) were 81 for Group_A, compared to 84 for Group B, treated with earlier weight bearing. Autologous bone graft was not necessary even if weight bearing was started after a period of six weeks postoperatively. The combination of 3D-fluoroscopy with locked internal fixation showed promising results. If the rate of patients developing subtalar arthrosis will decrease by this management will have to be shown in long term follow up

Biological production of copper sulfide concentrate from flotation tailings and low grade ore

Publisher Copyright: © 2017 Trans Tech Publications, Switzerland.Flotation tailings are hazardous due to their physical and chemical instability and are considered one of the main pollution concerns of the mining industry. Most of these tailings are fine-grained residues with low copper content (0.1-0.8%) and include toxic compounds, such as heavy metals, arsenic, and flotation reagents, amongst others. The generation of acid mine drainage (AMD) due to biological oxidation of tailings represent another environmental concern. On the other hand, low-grade ore as copper source is challenging the mining industry to commercially produce this metal. The main objective of this work was to assess the use of flotation tailings and low-grade ore to biologically produce copper sulfide for further pyrometallurgical or fine chemistry processing. Low-grade ore and flotation tailings were first agglomerated at different proportions and leaching tests were performed in 1 m columns, using either industrial or synthetic raffinate solution. Then, the pregnant leach solution (PLS) obtained from the column tests was subjected to selective precipitation of copper by using biogenic hydrogen sulfide (H2 S) generated from a mixed culture of neutrophilic sulfate reducing bacteria (SRB), enriched from sediments of the Caracarani river (located at 4,600 m above sea level in northern Chile). Over 91% of the soluble copper present in the PLS was recovered as copper sulfide in 28 days, whilst ferrous iron, other metals and arsenic remained in solution. Analysis performed by X-Ray diffraction confirmed the presence of copper in the precipitate (58% as covellite). This work demonstrates the possibility of applying bioleaching and bio-precipitation technologies to treat tailings and low-grade copper ore to produce high quality copper sulfide