HAND (2009) 4:108–112 DOI 10.1007/s11552-008-9153-8 ORIGINAL PAPER Hammering K-wires is Superior to Drilling with Irrigation Bas B. G. M. Franssen & Arnold H. Schuurman & Pascal C. R. Brouha & Moshe Kon Received: 28 September 2008 / Accepted: 14 November 2008 / Published online: 10 December 2008 # The Author(s) 2008. This article is published with open access at Springerlink.com Abstract Cooling during drilling Kirschner wires is not always effective in preventing thermal related damage. In this study, we used a human in vitro model and compared temperature elevation, insertion time, and extraction force between three Kirschner wire insertion methods—drilling with and without irrigation and pneumatic hammering. Forty five Kirschner wires were inserted into 15 fresh human cadaver metacarpals. All three insertion methods were applied in each metacarpal. Drilling without irrigation resulted in a temperature elevation of 67.25 ± 5.4 ºC with significantly lower values for drilling with irrigation (4.15 ± 0.6 ºC) and pneumatic hammering (31.52 ± 3.4 ºC). The insertion time for pneumatic hammering (47.63 ± 8.8 s) was significantly lower compared to drilling without irrigation (263.16 ± 36.5 s) and drilling with irrigation (196.10 ± 28.5 s). Extraction forces after drilling without irrigation, drilling with irrigation, and pneumatic hammer- ing were 39.85 ± 4.1 N, 57.81 ± 6.5 N, and 62.23 ± 6.7 N, respectively. Pneumatic hammering is superior to drilling without irrigation, especially when irrigation is not possible. Keywords Drilling . Metacarpal . Pneumatic hammer . Irrigation . K-wire B. B. G. M. Franssen (*) : A. H. Schuurman : P. C. R. Brouha : M. Kon Department of Plastic Reconstructive and Hand Surgery, University Medical Center Utrecht, Room number G.04.122, P.O. Box 85500, 3508 GA Utrecht, The Netherlands e-mail: bbgmfranssen@gmail.com Introduction Kirschner wires (K-wires) are often used in hand surgery because it is a quick and simple method for stabilization of fractures [19]. Multiple passes, type of K-wire configuration, quality of soft tissues, and accuracy of placement are important issues in K-wire fixation. The drilling technique itself may play an important role in the occurrence of frictional-heat-related complications like necrotic bone around the wires [8, 12]. This predisposes to pin–track infections and loosening of K-wires which can result in early removal or even osteomyelitis [3, 16]. Thermal necrosis is a product of time [4, 6] temperature [2, 7], drill speed [4, 21], insertion force [1, 20], K-wire characteristics [13, 18], and the factor irrigation [14, 24]. The influence of heat generation on bone has long been recognized. Hippocrates (500 BC) even recommended that the trepanning tool must be cooled during bone removal to avoid injury to the surrounding bone [17]. Temperature elevation during drilling into bone is nowadays kept to a minimum by external or more effectively by internal irrigating [15, 24]. Internal irrigation however is not useful when drilling K-wires, because it is not possible to let the cooling agent passing down the center of the K-wire [14]. Therefore, the external irrigation technique must be used. This technique is effective when a constant flow is provided at the point of insertion. In areas of limited access, however, this can not be realized and therefore will result in less or no cooling effect at all [15, 22, 24]. Also, constant external irrigation at the opposite cortex or during percutaneous drilling is usually impossible, resulting in a very low or absent cooling effect [9]. The ultimate K-wire insertion method would be a technique without the necessity of irrigation but with the advantages of drilling and without thermal related compli-