A dynamic ultrasound examination for the diagnosis of ankle syndesmotic injury in professional athletes: a preliminary study.

BACKGROUND

Syndesmotic ankle injuries are not easy to recognize when an associated fracture or frank diastasis is not present. There is a need for a simple, fast, inexpensive, and easily reproducible diagnostic tool to assess the integrity of the distal tibiofibular synedesmosis.

HYPOTHESIS: Dynamic ultrasound (US) examination can accurately diagnose anteroinferior tibiofibular ligament (AITFL) rupture.

STUDY

DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

We evaluated 3 groups: 9 consecutive professional athletes with recent AITFL rupture, a control group of 18 subjects without a history of ankle injury, and 20 patients with lateral ankle sprain. The dynamic US examination was performed in neutral (N), forced internal rotation (IR), and external rotation (ER) of the foot for measuring the tibiofibular clear space on the anterior aspect of the ankle, at the level of the AITFL, 1 cm proximal to the joint line.

RESULTS

The mean age of the study group was 27 years (range, 16-32). Magnetic resonance imaging (MRI) confirmed the diagnosis of AITFL rupture in all cases. Differences between the injured and control group were statistically significant for the N, IR, and ER positions (P < .001) and for the measured Delta between the AITFL in the ER and N positions (P < .01). The difference in the tibiofibular clear space between the 2 ankles of the injured athletes was significantly different compared with the control athletes for all 3 positions (P < .001). The measured difference between the ER and N positions for both sides of the study group showed a specificity and sensitivity of 100% (P < .001; cutoff point of 0.9 mm and 0.7 mm, respectively). The Delta (Delta = ER - N) of the injured side showed a specificity and sensitivity of only 89% (P < .001; cutoff point of 0.4 mm). Additionally, the third group with the history of lateral ankle sprain showed, as expected, that this type of injury does not correlate with AITFL injury on dynamic US examination.

CONCLUSION

We conclude that dynamic US examination can be used to accurately diagnose an AITFL rupture. This preliminary study has found the described method to be a simple, inexpensive, and easily reproducible examination.