The influence of the size and condition of the reamers on bone temperature during intramedullary reaming.
BACKGROUND
The objectives of this study were to determine whether intramedullary reaming increases bone temperature in vivo to a level that is high enough to produce bone necrosis and to determine the influence of the size and the condition of the reamers on the temperature increase.


METHODS
Bone temperature variations were recorded in vivo during intramedullary tibial reaming in fourteen minipigs. The left tibiae were progressively reamed from 6 to 9 mm. The right tibiae were reamed with only 8 and 9-mm reamers. The variables studied were the initial and final temperature and the increase in the temperature. Two weeks after reaming, the tibiae were removed and studied histologically.


RESULTS
Intramedullary reaming produced an average increase (and standard deviation) in bone temperature of 6.9 degrees C +/- 4.1 degrees C. The peak temperatures ranged from 34.9 degrees C to 49.4 degrees C. The average maximum bone temperature was 38.1 degrees C +/- 2.8 degrees C when the reaming was done progressively from 6 to 9 mm and 41.1 degrees C +/- 4.4 degrees C when the reaming was done only with the 8 and 9-mm reamers. The mean increase in the temperature in the second group of animals (8.2 degrees C +/- 4.3 degrees C) was greater than that in the first group (5.4 degrees C +/- 3.5 degrees C). Reaming with sharper reamers in the first seven animals resulted in a smaller mean increase in temperature than did reaming with less sharp reamers in the last seven animals (4.6 degrees C compared with 9.2 degrees C; p = 0.001). Histological examination of the tibiae showed periosteal proliferation and an altered disposition of the osteons at the inner cortex with occasional necrotic bone fragments in the medullary canal.


CONCLUSIONS
Intramedullary reaming in the minipig increased bone temperature. When the reamer initially used was larger than the diameter of the medullary canal and when the reamers were blunted by repeated use, the maximum temperature reached by the bone was higher. This increase in temperature with use of typical medullary reaming techniques did not exceed the limits that would produce bone necrosis.
García
Oscar G Riquelme
OG
Department of Experimental Medicine and Surgery, Hospital General Universitario Gregorio Universitario Gregorio Marañón, Madrid, Spain.
Mombiela
Fausto López
FL
De La Fuente
Consuelo Jiménez
CJ
Aránguez
Margarita Gimeno
MG
Escribano
Dolores Vigil
DV
Martín
Javier Vaquero
JV
D000818:Animals; D001831:Body Temperature; D001842:Bone and Bones / Q000601:surgery*; D005594:Fracture Fixation, Intramedullary / Q000009:adverse effects*; D006358:Hot Temperature; D023421:Models, Animal; D009983:Orthopedic Equipment / Q000009:adverse effects / Q000592:standards*; D010020:Osteonecrosis / Q000209:etiology / Q000473:pathology*; D013525:Surgical Instruments / Q000009:adverse effects / Q000592:standards; D013552:Swine