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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 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 ( = 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.

Background: Stress radiographic measurements play an important role in assessing the degree of joint instability in scientific investigations and for decision making in treatment. However, their validity and reliability are still a matter of intensive debate.

Hypothesis: There is no difference regarding interobserver and intraobserver reliability with respect to anterior talar drawer, talar tilt, and calcaneocuboid stress radiographs.

Study Design: Cohort study (diagnosis); Level of evidence, 4.

Methods: Eighty-nine anterior talar drawer, 89 talar tilt, and 76 calcaneocuboid stress radiographs were selected. Analyses for anterior talar drawer (1 measurement technique), talar tilt (1 measurement technique), and lateral calcaneocuboid instability (4 measurement techniques) were performed by 4 independent raters. One rater repeated the measurements after 1 month. Intraclass and interclass correlation coefficients (ICCs) with calculated confidence intervals assessed intratester and intertester reliability of each measure.

Results: Ankle stress radiographic interobserver agreement was ICC = 0.73 to 0.97 for anterior talar drawer test and ICC = 0.78 to 0.97 for talar tilt. Interobserver reliability for calcaneocuboid angle measurement methods was lower (ICC = 0.35–0.91) than for the calcaneocuboid joint-space distance measurements (ICC = 0.81–0.95). Intraobserver ICC varied between 0.78 and 0.97 for ankle stress testing and was 0.67 to 0.94 for calcaneocuboid stress radiography, respectively.

Conclusions: Ankle stress radiographic measurements were proven to be reliable. Insufficient reproducibility was found for angular calcaneocuboid stress radiography measurements, while lateral calcaneocuboid joint-space distances offered accurate reliability.

Clinical Relevance: Measurement errors can be avoided using standardized stress radiography and measurement techniques with proven reliability.