A device for the measurement of malleoli diastasis

Assessment of the degree of laxity of the distal tibio-fibular joint ligaments is of great importance in the treatment of some ankle pathologies resulting from traumas and when evaluating the effectiveness of re-constructive operations. This can be done by measuring the variation in the intermalleolar distance while loading and flexing the joint in a known way. So far, only X-ray techniques have been applied for this purpose, but they are invasive and do not allow for analysis under dynamic conditions. We have developed a wearable strain gauge device to be positioned directly over the malleoli for measurement of the intermalleolar distance variation. It has been tested on healthy and injured subjects, in both static and dynamic conditions. Data obtained in the static tests are in agreement with those found in literature. Dynamic analysis allowed for correlation of malleoli diastasis (MD) with the different phases of gait and different injured states.