Comparison of the shetty test and ottawa ankle rules for foot and ankle fractures in the emergency department: a prospective validation study.

PURPOSE: The Shetty test has been proposed as a simpler alternative to the Ottawa Ankle Rules (OAR) for excluding fracture in foot and ankle trauma and was reported to have perfect sensitivity in its derivation study. We compared its diagnostic accuracy with that of the OAR against imaging in an emergency department population.

METHODS

One hundred consecutive patients with acute foot and/or ankle trauma were enrolled after at least one of two attending physicians judged radiography indicated. Both index tests were performed independently by two blinded emergency physicians; where they differed, the patient was classified positive if either was positive. The reference standard was fracture on radiography, or on CT obtained on clinical suspicion. McNemar and DeLong tests were used, and inter-test agreement Cohen kappa.

RESULTS

Fractures occurred in 26 patients (26%); 8 (30.8%) were occult, detected only on CT. The Shetty test had lower sensitivity than the OAR (76.9% vs. 92.3%) but higher specificity (67.6% vs. 18.9%). It missed 6 of 26 fractures, including two talar and one base-of-fifth-metatarsal fracture, all of which were managed with plaster-splint immobilisation. Used alone it would have avoided 56 radiographs while missing 6 fractures, versus 16 avoided and 2 missed for the OAR. Agreement was poor (kappa 0.19).

CONCLUSION

The Shetty test did not reproduce the sensitivity reported in its derivation study and missed nearly a quarter of fractures, all requiring immobilisation. It cannot be recommended as a stand-alone tool to exclude foot and ankle fracture; its higher specificity may justify evaluation as an adjunct applied after, not instead of, the OAR.