COMPRESSIVE CAPACITY OF HELICAL PILE FOUNDATION ON PEAT WITH VARIATION OF HELICAL PLATE DIAMETER

<p>The use of helical foundations to support structures on peat soil is still a new method. Research is needed to develop this foundation. There are 6 types of helical foundation tested on peat soil. To study the effect of helical plate diameter, plate diameters were varied with sizes 25 cm (M), 35 cm (L), and 45 cm (G). Plate positions (1, 2, 3 plates) are designed at 300 mm spacing. The axial compression bearing capacity test is carried out based on the constant rate of penetration procedure. At the beginning of loading, the load increases significantly. At a certain descent, the load begins to decrease slowly. The load-settlement curve shows that the larger the plate diameter, the greater the load it can withstand. The largest bearing capacity is produced by the GGG 30 foundation (3 plates dia.45 cm), which is 10.83 kN. LLL 30 helical foundation (3 plates dia.30 cm) provides a bearing capacity of 7.14 kN. These results clearly explain that the increase in plate diameter is directly proportional to the increase in the axial compression bearing capacity.</p>

Helical plating – a novel technique to increase stiffness in defect fractures

Single-plate fixation bridging bone defects provokes nonunion and risks plate-fatigue failure due to under- dimensioned implants. Adding a helical plate to bridge the fracture increases stiffness and balances load sharing. This study compares the stiffness and plate surface strain of different constructs in a transverse contact and gap femoral shaft fracture model. Eight groups of six synthetic femora each were formed: intact femora; intact femora with lateral locking plate; contact and gap transverse shaft osteotomies each with lateral locking plate, lateral locking plate and helical locking plate, and long proximal femoral nail. Constructs underwent non-destructive quasi-static axial and torsional loading. Plate surface strain evaluation was performed under 200 N axial loading. Constructs with both lateral and helical plates demonstrated similar axial and torsional stiffness– independent of the contact or gap situations – being significantly higher compared to lateral plating (p < 0.01). Torsional stiffness of the constructs, with both lateral and helical plates in the gap situation, was significantly higher compared to this situation stabilised by a nail (p < 0.01). Plate surface strain dropped from 0.3 % in the gap situation with a lateral plate to < 0.1 % in this situation with both a lateral and a helical plate. Additional helical plating increases axial and torsional construct stiffness in synthetic bone and seems to provide well-balanced load sharing. Its use should be considered in very demanding situations for gap or defect fractures, where single-plate osteosynthesis provides inadequate stiffness for fracture healing and induces nonunion.

One-Year Follow-Up After Treatment of Proximal and/or Middle One-Third Humeral Shaft Fractures with a Helical Plate: Healing Rates, Complications and Functional Outcome Measures

Background: Conventional plate osteosynthesis is a valuable treatment option in displaced proximal and/or middle one-third humeral shaft fractures. Nonetheless, this procedure can be complicated by a radial nerve palsy. To date, many surgical techniques have been developed in an attempt to minimize this high-impact complication. However, a helical plate has the potential to avoid an iatrogenic radial nerve palsy due to its design. This article aims to evaluate safety and functional outcomes of patients treated with a helical plate compared to conventional plate osteosynthesis. In particular healing rates, complications and functional outcome measures.Methods: We retrospectively included all patients with displaced proximal and/or middle one-third humeral shaft fractures who were treated with a helical plate from October 2016 until August 2018 at a single level-1 trauma center (AZ Groeninge, Kortrijk, Belgium). A self-molded long PHILOS plate (DePuy Synthes®) or a pre-contoured A.L.P.S proximal humeral plating system (Zimmer Biomet®) were used. Patient baseline characteristics and standard radiographs were obtained pre- and postoperatively. We retrospectively searched for complications. Patients were reassessed using the Disabilities of the Arm, Shoulder and Hand (DASH), Constant Murley (CMS) and EQ-5D-5L scores with a minimal follow-up of one year.Results: The humeral shaft fractures of all sixteen patients consolidated within three months and no iatrogenic radial nerve palsies were observed. One plate had to be removed after one year due to a late infection. With a minimum follow up of one year, the mean DASH score was 22 \ 19 and the mean normalized CMS was 80 B 19.Conclusion: Operative treatment of proximal and/or middle one-third humeral shaft fractures with a helical plate is a safe procedure with good to excellent shoulder function at one-year follow-up. Contrary to conventional plate osteosynthesis, a helical plate has the potential to completely avoid a radial nerve palsy, while maintaining similar healing rates and functional outcomes.Trial registration: B396201939564. Registered on 6 MAY 2019 – retrospectively registred. Ethics Committee: Medical Ethics Committee, AZ Groeninge, Kortrijk, Belgium.

Evaluation of the efficiencies of helical anchor plates in sand by centrifuge model tests

The uplift capacity of helical anchors normally increases with the number of helical plates. The rate of capacity gain is variable, considering that the disturbance caused by the anchor installation is generally more pronounced in the soil mass above the upper plates than above the lower plates, because the upper soil layers are penetrated more times. The present investigation examines the effect of the number of helices on the performance of helical anchors in sand, based on the results of centrifuge model tests. Uplift loading tests were performed on 12 different types of piles installed in two containers of dry sand prepared with different densities. The measured fractions of the uplift capacity related to each individual helical plate of multi-helix anchors were compared with the fractions predicted by the individual bearing method. The results of this investigation indicate that in double- and triple-helix anchors, the contributions of the second and third plate to the total anchor uplift capacity decreased with the increase of sand relative density and plate diameter. In addition, these experiments demonstrated that the variation of the anchor load–displacement behavior with the number of helices also depends on these parameters.

Minimally Invasive Helical Plating for Shaft of Humerus Fractures: Technique and Outcome

Introduction: The humerus is subjected to substantial amount of torsional stress. Conventional plating may not address this sufficiently and may lead to fixation failure or non-union. A helical plate may offer the solution. We present the surgical technique and functional outcome of 5 cases of humeral shaft fractures treated with this technique in a minimally invasive way. Materials and Methods: The operations were performed between 2004 and 2010, by three surgeons. All the patients had closed humeral shaft fractures, either simple transverse or with mild comminution. Two small incisions were made. The proximal incision was placed along the deltopectoral groove over the shaft, and the distal incision was placed as in an antero-lateral approach. The radial nerve was identified and protected. A pre-selected plate was contoured and introduced in the submuscular plane. The plate was placed in a proximal-lateral and distal-anterior position. Screws were inserted through stab incisions. The patients were followed for an average of 6 months. Functional recovery of the shoulder and elbow was assessed using the Constant and Mayo elbow performance score systems. Results: All incisions healed by first intention without complications and all the fractures went on to unite. All patients achieved good to excellent shoulder and elbow function. Conclusion: The helical plate technique is a safe and effective method of treating humeral shaft fractures and has good functional outcome.