A lag screw, also known as a hex lag bolt, is one of the toughest types of fasteners. They are used to fasten materials that are going to be subjected to huge forces, such as lumber. They have a high-carbon steel core and a galvanized zinc exterior. This means that they don’t rust or corrode, even when exposed to moisture or oxygen. The best part is that they’re easy to use, and they can be drilled by hand or using a power drill. To make sure that you’re using the right lag screws for your project, it’s important to have the proper tools. You’ll need a tape measure, clamps to hold the two materials together while you’re drilling, and lag screws that are the correct size for your project. To make the process as smooth as possible, it’s also a good idea to use a hex wrench to apply the necessary pressure to the screw when tightening it.
Lag screws have a unique fabrication design that allows them to achieve compression without the need for a washer. This is accomplished by having no threads in the section of the shaft closest to the head, which is equal in diameter to the portion of the screw that has threads. This design allows the head of the screw to compress bone while being secured by the threaded portion of the screw.
Compared to traditional methods of fixation, lag screws are minimally invasive and provide superior biomechanical stability for the treatment of intertrochanteric fractures. Furthermore, lag screw fixation is less likely to cause postoperative complications such as metacarpophalangeal joint stiffness and extensor tendon adhesion. However, these advantages are offset by the possibility of lag screw migration or cut-out.
This complication may be due to improper screw placement, such as the tip apex distance, which may lead to poor compression. Another cause could be the use of a washer, which increases the load but reduces the contact surface between the screw and the bone plate. Additionally, the countersinking required for most systems may weaken the cortical plate. To address these problems, a new screw system was designed that both increased the support surface and did not require countersinking.
The results of the study showed that lag screws are effective in the treatment of oblique sagittal split fractures and were found to be more stable than traditional plates. Furthermore, lag screws can be inserted through the symphysis of the mandible and compress both the near and far cortices to provide added stability. However, the lag screws must be inserted perpendicular to the fracture line or they will displace the fracture fragments. This can be a problem in oblique fractures, which often have an anteriorly directed inferior border. In addition, if the screw is placed too close to the articular surface, the screws can penetrate the cortex and cause a stress fracture in the near bone. The authors conclude that a better understanding of the mechanics of lag screws can improve their clinical effectiveness in the treatment of maxillofacial trauma.