FRACTURE STIFFNESS MEASUREMENT IN TIBIAL SHAFT FRACTURES - A NONINVASIVE METHOD

This paper presents a non-invasive method of assessing healing by meas urement of fracture stiffness. The method works on the principle that if the load (F) applied at a certain known distance (Y) from the fract ure is measured, then the moment (M = FY) at the fracture site can be calculated. By measuring the angle/deflection (theta) occurring at the fracture site using a suitable instrument (electrogoniometer), the ne cessary data to calculate fracture stiffness (FY/theta) would be avail able. The method was employed to assess the stiffness in a series of t ibial shaft fractures treated conservatively, all of which healed unev entfully. This paper concentrates on a group of tibial shaft fractures in which the radiological criteria for fracture union were not satisf ied even after a mean duration of 20 weeks treatment. The non-invasive method of measuring fracture stiffness supported the clinical impress ion of union in most cases at the first test, but was repeated on two more occasions to confirm the trend of progressive healing. The object ive evaluation of fracture healing led to avoidance of surgical interv ention in these patients, who went on to sound union. Relevance--This study has shown that fracture healing in conservatively treated fractu res could be assessed more objectively, but did not assess the suitabi lity of this method for fractures being treated with external fixators . These patients could be assessed either using this non-invasive meth od, or the electrogoniometer could be attached to the bone pins. The m ethod is thus equally applicable to fractures being treated by externa l fixators, and provides a means of comparing different methods of tre atment for tibial shaft fractures.