# Laser Welding on Cerclage Wire Joining in Femur Surgery
## 1 Introduction  
Cerclage wire is a common procedure of orthopaedic surgeons for internal fixation. It also helps as a tool for arranging femoral bone fracture. Currently, this surgery method has an indication for the treatment of multiple bone fractures such as periprosthetic fracture, femoral fracture or patellar fracture, etc. [1; 2; 3; 4; 5; 6; 7]. [PERSON] et al. mentioned that the attachment of plates using cerclage wires obviated the need for screws and a double-loop cerclage performed better than a single-loop one [1]. Cerclage wiring technique helps to achieve stable reduction of femoral fractures which can then be supplemented with a nail or a plate [2; 3]. For clinical use, the treatments using cerclage wires with locking plate fixation for periprosthetic fractures of the femur promoted faster time to union, less complication, and fewer revisions [4]. The literature [5; 6] also presented that many cerclage-wiring technologies in difficult femoral fractures offered a minimally invasive reduction and fixation technique, low cost, and early holding. Cerclage and tension band wiring techniques can be inexpensively and effectively utilized in orthopedic surgical procedures, many of which are enumerated in the literatures [5; 6; 7]. A cerclage wire is usually bundled around two fractured bones then twisted at the end of wire to form a knot as shown in Figure 1a, or locked using a device called the crimp as shown in Figure 1b. Figure 2 is an example of fracture bone bundled with cerclage wires. Twisting is clinically the most frequently applied method for tightening and maintaining cerclage fixation [8]. Many techniques for wire twists were developed and experimentally tested in the literature. The results concluded that fastening twists were stronger than crimp techniques [9; 10]. However, cerclage wires still have problems in fixation failure which untwist failure or broken wire often occurs at the innermost turn of the twists [6; 7; 8]. Also, cerclage cable often fails. It was reported that the multifilament structure of the cable could be destroyed by the broken cable at the crimp [11]. Moreover, a cerclage cable can be loosened during surgery immediately after clamping the cable with a crimp [12]. These weak points of cerclage wires and cables result in a decrease in the efficiency of bone fracture treatment [11]. Furthermore, if surgeons fasten the wire with less tension force, wire loosening after surgery causes fixation failure as well [7; 9; 10]. As a result, the patients might suffer from repeating surgery operations. Therefore, the knot of the cerclage wire is the critical point to measure the achievement in treatment. In the study, laser techniques are proposed to weld the joints of cerclage wires [13]. As the laser has low power and high accuracy properties, the laser welding has the capacity to improve the quality and strength of common cerclage joint [14; 15]. Furthermore, dental laser techniques were applied for treating the patients. [PERSON] et al. reported that the use of laser-welded titanium frameworks along with implants in the edentulous mandible to treat patients provide 100% achievement by following up the patients for 10 years [16]. [PERSON] et al. studied the use of Nd: YAG laser to weld titanium for intra-oral implant abutments and inserted it in pig jaws. It was reported that it can provide biomechanical strength and can endure the immediate load including the thermal load and it does not  
Figure 1: Type of cerclage (**a**) cerclage wire, (**b**) cerclage cable. Figure 2: An example of fracture bone bundled with cerclage wires. harm the bone and surrounding tissues [17; 18; 19]. Previous research indicated that laser welding can be used in medicate and treat the patients without the risk of thermal effect to occur on the bone and surrounding tissues. Therefore, the laser technology is offered to prevent the cerclage wire from loosening and to reduce the broken crimp of the cerclage cable through the fused weld joint.