[Ultrasonography as a diagnostic measure in the rupture of fibular ligaments. Comparative study: sonography versus radiological investigations].

Purpose: The present prospective clinical study was designed to verify the value of ultrasound examination concerning injuries of the fibular ligaments of the ankle using functional examinations under ultrasound supervision.

Method: 34 patients who had sustained a lesion of the fibular ligaments of the ankle were compared with 42 healthy persons. The lateral malleolus and the collum tali were used as reproducible bony landmarks in ultrasound. The distance between those two points is first of all was measured in neutral position and later on under the influence of supinating force of 15 kp using a Telos fixation device.

Results: The average lateral opening of the upper ankle joint measured with the dynamic ultrasound examination was 4.4 mm (1-12 mm) in the group of patients who had been suffering from rupture of the fibular ligaments. In comparison the average lateral opening of the healthy contralateral ankle was 3.9 mm (1-9 mm). The control group showed an average lateral opening of 0.9 mm (0-5 mm).

Conclusion: Direct ultrasonic visualisation of the fibular ligament is not yet reliable. The described method allows an estimation of the stability of the fibular ligaments even in cases of chronic instability. The ultrasound investigation method discussed is difficult to handle and for that reason it cannot replace the standardised x-ray examination.