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Evidence summaries

Stress Radiography in the Diagnosis of Acute and Chronic Ankle Instability

Stress radiography (talar tilt and anterior displacement tests) are probably not useful in chronic instability, and of only limited value in diagnosing instability in acute injuries. Level of evidence: "C"

A systematic review 1 including 8 studies with a total of 950 subjects was abstracted in DARE. 7 case series assessed acute ligamentous damage and one (n=17) assessed chronic ankle instability. For the talar tilt test the authors used 7, 10, and 11 degrees and 3 mm as upper limits of normal. For the anterior displacement test the authors defined 4, 6, and 7 mm as the upper limits of normal and one group defined a positive test as > 1 mm compared with the uninjured ankle. The results from 6 studies gave a sensitivity ranging from 31% to 74%, and a specificity ranging from 0% to 100%. The positive predictive values ranged from 78% to 100% and the negative predictive value from 0% to 100% (the prevalence ranged from 46% to 100%). The likelihood ratio for positive test ranged from 0.74 to 16.5, and the likelihood ratio for a negative test ranged from 0.3 to 0.8. In the series assessing chronic instability, stress radiography was negative in 6 patients who had confirmed tears at surgery and in 3 patients who had normal ligaments at surgery.

Comment: Because the treatment evolution of all acute ankle sprains is towards functional non-operative treatment and because treatment does not depend on the degree of ankle instability on stress views, the talar tilt and anterior displacement, stress X-rays have no clinical relevance in the acute situation. In chronic instability, the results of stress tests are so varied that the tests are not suitable for clinical use.

References

  • Frost SC, Amendola A. Is stress radiography necessary in the diagnosis of acute or chronic ankle instability? Clin J Sport Med 1999 Jan;9(1):40-5. [PubMed] [DARE]

Primary/Secondary Keywords