Drilling k-wires, what about the osteocytes? An experimental study in rabbits

Abstract

Introduction The function of osteocytes regarding osteonecrosis has been underestimated for a long time. Recently it has been suggested that apoptosis of osteocytes results in strong osteoclastic bone resorption. Death of osteocytes due to drilling may therefore increase the risk of K-wire loosening. The purposes of our in vivo study were to assess the minimal drill time needed to notice disappearance of osteocytes and to measure the distance of the empty osteocyte lacunae surrounding the drill tract in relation with the insertion time, directly and 4 weeks after drilling Kirschner (K-) wires into the femur and tibia of rabbits. Materials and methods Trocar tipped K-wires (70 mm length and 0.6 mm thickness) were drilled into the femur and tibia of 14 New Zealand white rabbits [mean body weight 2.81 kg (2.66-3.09 kg)]. Six rabbits were terminated following surgery (t = 0) and eight rabbits were terminated 4 weeks (t = 4) after surgery. Following termination, hematoxylin and eosin stained sections were cut from femur and tibia until the drill hole was visible. The sections were evaluated under a light microscope for the presence or absence of osteocytes in osteocyte lacunae surrounding the drill holes.Results All osteocyte lacunae were empty around the Kwires in 50 and 87% of the cases, directly and 4 weeks after the surgery, respectively. The osteocytes disappeared especially beyond a drilling time of 37 s (P = 0.011) and 27 s (P = 0.008) at t = 0 and t = 4, respectively. Furthermore, a signiWcantly positive correlation was seen between the distances of the empty osteocyte lacunae surrounding the drill holes in relation with time at t = 0 (P = 0.008) and t = 4 (P = 0.000). Conclusion Although only drilling without cooling was studied, short drilling times may prevent the disappearance of osteocytes in case cooling is not used in clinical practice as is the case in percutaneous K-wire insertion.

Drilling of Bone: Practicality, Limitations and Complications Associated with Surgical Drill-Bits

“…Specifically, in vivo studies have been conducted in the ovine, laprine, porcine and canine models, and it appears that the extent of the effects which heat has on bone tissue depends on the maximal temperature attained and duration of the exposure. Of particular interest in these studies is viability of cortical bone following a thermal insult, with a histological hallmark of osteonecrosis being the presence of empty osteocyte lacunae (Eriksson, Albrektsson et al 1984b;Franssen, van Diest et al 2008) (Figure 13). Using rabbits, Eriksson et al (Eriksson, Albrektsson et al 1984b) created full-thickness defects in the femoral diaphysis using a 3mm diameter drill-bit at 20,000rpm with irrigation.…”

“…Healthy osetocytes (circled) are also evident. (Franssen, van Diest et al 2008) Franssen et al (Franssen, van Diest et al 2008) investigated the biological effects of k-wire implantation on the viability of cortical bone in rabbits. Using a carefully constructed jig, trochar-tipped k-wires were drilled into the tibiae and femur under a constant load and speed of 1.5kg and 1200rpm, respectively.…”

“…Drill-bits are also used in the preparation of bony tunnels, such as in anterior cruciate ligament reconstruction. Drilling is associated with the conversion of mechanical work energy into thermal energy causing a transient rise in temperature of adjacent bone and soft tissues to above normal physiological levels (Matthews and Hirsch 1972;Lavelle and Wedgwood 1980;Eriksson and Albrektsson 1984;Eriksson, Albrektsson et al 1984b;Abouzgia and Symington 1996;Natali, Ingle et al 1996;Toews, Bailey et al 1999;Bachus, Rondina et al 2000;Davidson and James 2003;Augustin, Davila et al 2008;Franssen, van Diest et al 2008;Bertollo, Milne et al 2010). Primary sources of this thermal energy are plastic deformation and shear failure of bone and friction at the machining face.…”

Eficácia na remoção da necrose óssea térmica: realizada por implantes osseointegráveis com câmaras coletoras

“…A reabilitação de pacientes desdentados, totais ou parciais tornou-se mais uma opção de tratamento com prognóstico altamente previsível e favorável (BRÅNEMARK; ZARB; FRANCISCHONE, 2010 (FROST, 1960;CURREY, 1964;FRANSSEN et al, 2008).…”

“…Entre os métodos indiretos encontram-se estudos microscópicos histológicos (morfologia celular) (KENZORA et al, 1978;FRANSSEN et al, 2008;TAVEIRA, 2009;BARBOSA et al, 2009) e testes histoquímicos observando-se a desnaturação da fosfatase alcalina destes tecidos (LUNDSKOG, 1972).…”