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Diagram showing the rake angle and clearance angles of a cutting edge. 

Diagram showing the rake angle and clearance angles of a cutting edge. 

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Article
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An innovative Kirschner (K-) wire point was developed and compared in fresh pig femora in terms of drilling efficiency and temperature elevation with the trochar and diamond points currently used in clinical practice. The tips of thermal couples were machined to the defined geometry and the temperature measured during drilling. Using the same drill...

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... different wire points were tested (Fig. 1). The trochar point had three facets ground to a point with a rake angle of -28° and clearance angle of +6°. Figure 2 shows the rake and clearance angles. The diamond point had two opposing flat facets ground to a pair of cutting edges with rake angles of 12° and clearance angles of +60°. The new point design (Medin K-wire; Medin AC, Nove Mesto na Morave, Czech Republic) had two steep flutes for removal of bone frag- ments during drilling and was ground with a rake angle of +20° and a clearance angle of +30°. All the wires tested were manufactured by the same manufacturer (Medin AC) using implant steel (ISO ...

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Citations

... One reason may lie in heating due to wire rotation within the bone. Some authors found that drilling holes with smooth wires induced higher temperatures than drilling with threaded wires of the same diameter [18,19]; this is attributed to geometry, with efficient evacuation of bone debris and lower friction and heating. We also showed that, with threaded K-wires, pullout strength was better at higher speeds. ...
Article
Introduction: The aim of the present study was to assess the impact, combined and in interaction, of diameter, threading length and drilling speed on K-wire pullout strength in a synthetic model of a hand bone. Material & methods: The material comprised Sawbones® (20 x20 x50 mm), K-wires (diameter 1.2 mm, 1.5 mm, 1.8 mm; threading 0 mm, 5 mm, 10 mm, 15 mm), a universal chuck with T handle and a drill (speed 0, 320, 500, 830, 1,290 rpm), and tensile testing machine and a digital decision aid. The Sawbones® were drilled, varying diameter, threading and speed. The Statistical Design Of Experiments (SDOE) methodology enabled the number of trials to be reduced from 300 to 70. Tensile tests at 1 mm/sec was imposed on the K-wire up to pullout (pullout strength). Results: There was no interaction between threading length and diameter effects or between drilling speed and diameter effects, but a strong interaction between drilling speed and threading length effects. Conclusion: Before using K-wires for internal fixation in wrist or hand fracture, the surgeon has to select their characteristics, optimal holding power being theoretically ensured by large diameter wires with long threading inserted by a high-speed drill. Level of evidence: I, experimental study
... However, when K-wires are used into bones to fix fractures, some complications could occur. There are many factors that affect K-wires stability into bone: their design (smooth/threaded), their insertion technique, the dynamic load of K-wires (Abouzgia and Symington 1996;Piska et al. 2002) and the bone quality. Currently, both the manual and the motorized drilling motor techniques are used during surgical procedures. ...
... In bone drilling, a higher clearance angle lowers the bone temperature, thrust force, and torque. 41,148,167 Farnworth and Burton 68 theorized that the clearance angle of 15°is sufficient for drilling of the porcine femur. Likewise, Saha et al. 153 integrated clearance angle ranging from 12-15°in the new drill and observed an improvement in drilling performance. ...
Article
As drilling generates substantial bone thermomechanical damage due to inappropriate cutting tool selection, researchers have proposed various approaches to mitigate this problem. Among these, improving the drill bit design is one of the most feasible and economical solutions. The theory and applications in drill design have been progressing, and research has been published in various fields. However, pieces of information on drill design are dispersed, and no comprehensive review paper focusing on this topic. Systemizing this information is crucial and, therefore, the impetus of this review. Here, we review not only the state-of-the-art in drill bit designs—advances in surgical drill bit design—but also the influences of each drill bit geometries on bone damage. Also, this work provides future directions for this topic and guidelines for designing an improved surgical drill bit. The information in this paper would be useful as a one-stop document for clinicians, engineers, and researchers who require information related to the tool design in bone drilling surgery.
... First, temperature measurement was limited to the bone surface and the drill point during drilling. Most studies of thermal damage during bone drilling use direct temperature measurement with a thermocouple sensor [35,36,37] or thermography to measure the temperature of a region of interest [38,39]. In this experiment, it was necessary to avoid attaching a thermocouple to the tip of the drill because we are evaluating the effect of a drill point modification on thermal effects. ...
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Background: There are no medical drill specifications capable of achieving bone drilling in a short time under low-thrust and low-speed drilling. Gekkou-drill® is an industrial drill that enables drilling with low cutting resistance by its characteristic point design. Our aims were to develop Gekkou-modified drills by processing to the points of currently available medical drills and to verify whether these modified drills enable less invasive drilling procedure for bone tissue in thermal exposure compared with unmodified medical drills. Materials and methods: Two commercially available 3.2-mm drills were compared before and after Gekkou modification. Drilling of pig tibias was performed at speeds of 300, 800, and 1,500 rpm and a uniform thrust force of 10 N. Temperature at the entry point for bone drilling was measured using a digital thermometer system. The feed rates were calculated using cortical thickness and monitoring data of the digital force gauge. Results: Two unmodified drills could not penetrate the cortical bone on the near side at 300 rpm, even after 5 min of drilling. The maximum temperatures with modified drills were 54.6 °C and 46.2 °C at 300 rpm. At medium to high speeds, those were statistically significantly lower than with unmodified drills (58.5 °C vs. 90.5 °C at 800 rpm, 62.6 °C vs. 80.8 °C and 73.9 °C vs. 104.6 °C at 1,500 rpm). The feed rates for modified drills were 4.9-6.9 times as high as unmodified drills at 800 rpm, and 3.4 to 4.5 times at 1,500 rpm. On the other hand, the feed rates of modified drills at 300 rpm were equal to or higher than those of unmodified drills at 1500 rpm. Conclusion: Gekkou-modified drills clearly suppressed the temperature rise and increased the feed rate compared with conventional drills. Furthermore, it was notable that these modified drills had higher performance even at conditions of low thrust and low speed.
... 7,9 Studies have been conducted to modify the trocar tip K-wire with slots ( Fig. 1C) and notches (Fig. 1D) to improve the debris evacuation and lower bone temperature rise was observed using these modified K-wires. 11,12 Learning from surgical twist drills, Piska et al. 13 developed a new point configuration called the Medin K-wire, as shown in Figure 1E. Two short segments of steep flutes were created at the drill tip to change the rake geometry and evacuate the bone debris during drilling. ...
Article
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Kirschner wire (K‐wire) is a common tool in clinical orthopaedic surgery for bone fracture fixation. Significant amount of heat is generated in bone drilling using K‐wires, causing bone thermal necrosis and osteonecrosis. To minimize the temperature rise, a hollow notched K‐wire in a modified surgical hand drill with through‐tool cooling was developed to study the bone temperature, debris evacuation, and material removal rate. The hollow notched K‐wire was fabricated by grinding and micro‐milling on a stainless steel tube. Bone drilling tests were conducted to evaluate its performance against the solid K‐wires. Results showed that compared to solid K‐wires, hollow notched K‐wire drilling without cooling reduced the peak bone temperature rise, thrust force, and torque by 42%, 59%, and 62% correspondingly. The through‐tool compressed air reduced the peak bone temperature rise by 48% with the forced air convection and better debris evacuation. The through‐tool water cooling decreased the bone temperature by only 26% due to accumulation and blockage of bone debris in the groove and channel. This study demonstrated the benefit of using the hollow notched K‐wire with through‐tool compressed air to prevent the bone thermal necrosis. This article is protected by copyright. All rights reserved.
... For bone drilling with K-wires, tip geometry and drilling mode also affect the bone temperature. A K-wire design by Piska et al. 12 with two steep flutes for bone chip removal resulted in significantly lower bone temperature compared with commonly used trocar and diamond tips. Also, they found that trocar tip K-wires generated higher temperature than diamond tip ones. ...
Article
Heat generation during insertion of Kirschner wires (K‐wires) may lead to thermal osteonecrosis and can affect the construct fixation. Unidirectional and oscillatory drilling modes are options for K‐wire insertion, but understanding of the difference in heat generation between the two modes is lacking. The goal of this study was to compare the temperature rise during K‐wire insertion under these two modes and provide technical guidelines for K‐wire placement to minimize thermal injury. Ten orthopedic surgeons were instructed to drill holes on hydrated ex‐vivo bovine bones under two modes. The drilling trials were evaluated in terms of temperature, thrust force, torque, drilling time, and tool wear. The analysis of variance showed that the oscillatory mode generated significantly lowered peak bone temperature rise (13% lower mean value, p = 0.036) over significantly longer drilling time (46% higher mean time, p < 0.001) than the unidirectional mode. Drilling time had significant effect on peak bone temperature rise under both modes (p < 0.001) and impact of peak thrust force was significant under oscillatory mode (p < 0.001). These findings suggest that the drilling mode choice is a compromise between peak temperature and bone exposure time. Shortening the drilling time was the key under both modes to minimize temperature rise and thermal necrosis risk. To achieve faster drilling, technique analysis found that “shaky” and intermittent drilling with moderate thrust force are preferred techniques by small vibration of the drill about the K‐wire axis and slight lift‐up of the K‐wire once or twice during drilling. This article is protected by copyright. All rights reserved.
... It is often observed in the percutaneous insertion of K-wires, 8 where local temperature can exceed 47°C. 7,11 K-wire temperatures with a single pass have been reported as high as 115°C 14 and can heat up surround tissues in the human finger up to 190°C. 17 Several studies have identified significant factors that can decrease temperature and in turn can decrease the rate of thermal injury. ...
... 17 Several studies have identified significant factors that can decrease temperature and in turn can decrease the rate of thermal injury. 2,9,10,14 These changes include alternative drill tip designs, external cooling irrigation, and pneumatic hammering of K-wires into bone. These technologies are not typically available at most surgery centers. ...
Article
Background: Kirschner wires (K-wires) are commonly used in orthopedic surgery. However, the loosening of the pins can lead to delayed or improper healing or infection. Wire loosening can occur by thermal necrosis that occurs due to heat produced during wire insertion. Although the parameters that affect temperature rise in cortical bone during wire insertion and drilling have been studied, the effect of drilling mode (oscillation versus forward) is unknown. The purpose of this study was to compare the temperature changes occurring in cortical bone during wire insertions by oscillating and forward drills. Our hypothesis is that oscillation drilling would produce less heat compared with forward drilling in K-wire insertion with 2 commonly used wire diameters. Methods: We drilled K-wires in a pig metacarpal model and measured the temperature rise between forward and oscillation drilling modes using diamond-tipped 0.062- and 0.045-inch-diameter K-wires. There were 20 holes drilled for each group (n = 20). Results: The average temperature rise using the 0.062-inch K-wire under forward and oscillation insertion was 14.0 ± 5.5°C and 8.8 ± 2.6°C, respectively. For the 0.045-inch K-wire, under forward and oscillation insertion, the average temperature rise was 11.4 ± 2.6°C and 7.1 ± 1.9°C, respectively. The effects of the drilling mode and wire diameter on temperature rise were significant ( P < .05). Conclusions: In conclusion, the oscillation of K-wires during insertion causes a lower temperature rise when compared with forward drilling.
... This absence of blood has been shown to result in bone death, collapse, and non-healing. Experimentally, temperatures above 70 °C have been seen to result in immediate bone death, whereas irreversible cell death of osteocytes occurs after 30 s at a temperature of 55 °C and after 60 s at 47 °C [10][11][12][13] [20] , (b) two short flutes [21] , (c) a slot [8] , (d) two parallel channels [9] , (e) single knurling channel [9] , and (f) double knurling channels [9] . ...
... Several modified K-wires, as shown in Fig. 2 , have been studied to evaluate the potential to reduce bone temperature in drilling. Piska [20] compared regular K-wire with a Medin K-wire (shown in Fig. 2 (a)) which has two steep flutes with 20 °rake angle and 30 °clearance angle. Results of drilling porcine bone showed the thrust force and torque were reduced by 63% and 60%, respectively, and the average bone temperature after drilling 30 holes decreased from 129 °C (regular K-wire) to 66 °C (Medin K-wire). ...
... For the regular K-wire bone drilling, the mean peak temperature at 1 mm away from the hole edge is about 100 °C, which is comparable with the 129 °C measured at the hole edge by using the K-wire as a thermocouple in pig femora bone drilling [20] and 112 °C measured at 0.5 mm away from the hole edge in the human metatarsals bone drilling [4] . Compared with notched K-wire temperature, thrust force and torque results in Fig. 2 (a) and (b), the K-wire with 1 mm notched showed the similar ability to reduce the temperature (43.7% vs. 53.4%) in Fig. 2 (a) [20] , thrust force (32.5% vs. 33%) and torque (27.1% vs. 33.3%) in Fig. 2 (b) [8] . ...
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The Kirschner wire (K-wire) is a common bone drilling tool in orthopedic surgery to affix fractured bone. Significant heat is produced due to both the cutting and the friction between the K-wire and the bone debris during drilling. Such heat can result in high temperatures, leading to osteonecrosis and other secondary injuries. To reduce thermal injury and other high-temperature associated complications, a new K-wire design with three notches along the three-plane trocar tip fabricated using a thin micro-saw tool is studied. These notches evacuate bone debris and reduce the clogging and heat generation during bone drilling. A set of four K-wires, one without notches and three notched, with depths of 0.5, 0.75, and 1 mm, are evaluated. Bone drilling experiments conducted on bovine cortical bone show that notched K-wires could effectively decrease the temperature, thrust force, and torque during bone drilling. K-wires with notches 1 mm deep reduced the thrust force and torque by approximately 30%, reduced peak temperatures by 43%, and eliminated blackened burn marks in bone. This study demonstrates that a simple modification of the tip of K-wires can effectively reduce bone temperatures during drilling.
... The result of excessive heat produced by K wires is consistent with the literature. 13,18,19 K wires exerted higher forces and heat than standard drills due to lack of cutting flutes to remove bone debris. It should also be noted that the differently sized standard drills show grossly similar bony destruction (Figs. ...
Article
Significant research exists regarding heat production during single-hole bone drilling. No published data exist regarding repetitive sequential drilling. This study elucidates the phenomenon of heat accumulation for sequential drilling with both Kirschner wires (K wires) and standard two-flute twist drills. It was hypothesized that cumulative heat would result in a higher temperature with each subsequent drill pass. Nine holes in a 3 × 3 array were drilled sequentially on moistened cadaveric tibia bone kept at body temperature (about 37°C). Four thermocouples were placed at the center of four adjacent holes and 2 mm below the surface. A battery-driven hand drill guided by a servo-controlled motion system was used. Six samples were drilled with each tool (2.0-mm K wire and 2.0- and 2.5-mm standard drills). K wire drilling increased temperature from 5°C at the first hole to 20°C at holes 6 through 9. A similar trend was found in standard drills with less significant increments. The maximum temperatures of both tools increased from <5°C to nearly 13°C. The difference between drill sizes was found to be insignificant (p > 0.05). In conclusion, heat accumulated during sequential drilling, with size difference being insignificant. K wire produced more heat than its twist-drill counterparts. This study has demonstrated the heat accumulation phenomenon and its significant effect on temperature. Maximizing the drilling field and reducing the number of drill passes may decrease bone injury. This article is protected by copyright. All rights reserved.
... Depending on the operating location or simply preference, a surgeon can choose either a twist drill or a Kirschner wire (Kwire) for sequential drilling. As K-wires are known to produce more heat than twist drills due to lack of flutes [9,10], the risk of thermal damage under near-dry, sequential drilling using them is potentially dangerously high. ...
Article
Sequentially drilling multiple holes in bone is used clinically for surface preparation to aid in fusion of a joint, typically under non-irrigated conditions. Drilling induces a significant amount of heat and accumulates after multiple passes, which can result in thermal osteonecrosis and various complications. To understand the heat propagation over time, a 3D finite element model was developed to simulate sequential bone drilling. By incorporating proper material properties and a modified bone necrosis criteria, this model can visualize the propagation of damaged areas. For this study, comparisons between a 2.0 mm Kirschner wire and 2.0 mm twist drill were conducted with their heat sources determined using an inverse method and experimentally measured bone temperatures. Three clinically viable solutions to reduce thermally-induced bone damage were evaluated using finite element analysis, including tool selection, time interval between passes, and different drilling sequences. Results show that the ideal solution would be using twist drills rather than Kirschner wires if the situation allows. A shorter time interval between passes was also found to be beneficial as it reduces the total heat exposure time. Lastly, optimizing the drilling sequence reduced the thermal damage of bone, but the effect may be limited. This study demonstrates the feasibility of using the proposed model to study clinical issues and find potential solutions prior to clinical trials. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.