title: Diagnostic accuracy of the gravity stress test and clinical signs in cases of isolated supination-external rotation-type lateral malleolar fractures.
abstract: We prospectively assessed the diagnostic accuracy of the gravity stress test and clinical findings to evaluate the stability of the ankle mortise in patients with supination-external rotation-type fractures of the lateral malleolus without widening of the medial clear space. The cohort included 79 patients with a mean age of 44 years (16 to 82). Two surgeons assessed medial tenderness, swelling and ecchymosis and performed the external rotation (ER) stress test (a reference standard). A diagnostic radiographer performed the gravity stress test. For the gravity stress test, the positive likelihood ratio (LR) was 5.80 with a 95% confidence interval (CI) of 2.75 to 12.27, and the negative LR was 0.15 (95% CI 0.07 to 0.35), suggesting a moderate change from the pre-test probability. Medial tenderness, both alone and in combination with swelling and/or ecchymosis, indicated a small change (positive LR, 2.74 to 3.25; negative LR, 0.38 to 0.47), whereas swelling and ecchymosis indicated only minimal changes (positive LR, 1.41 to 1.65; negative LR, 0.38 to 0.47). In conclusion, when gravity stress test results are in agreement with clinical findings, the result is likely to predict stability of the ankle mortise with an accuracy equivalent to ER stress test results. When clinical examination suggests a medial-side injury, however, the gravity stress test may give a false negative result.
authors.affiliation: Oulu University Hospital, PL 21, FI 90029 OYS, Oulu, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Nortunen
authors.affiliation: Oulu University Hospital, PL 21, FI 90029 OYS, Oulu, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Flinkkilä
authors.affiliation: Oulu University Hospital, PL 21, FI 90029 OYS, Oulu, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Lantto
authors.affiliation: Oulu University Hospital, PL 21, FI 90029 OYS, Oulu, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Kortekangas
authors.affiliation: Oulu University Hospital, PL 21, FI 90029 OYS, Oulu, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Niinimäki
authors.affiliation: Oulu University Hospital, PL 21, FI 90029 OYS, Oulu, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Ohtonen
authors.affiliation: Oulu University Hospital, PL 21, FI 90029 OYS, Oulu, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Pakarinen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D064386:Ankle Fractures / Q000145:classification / Q000175:diagnosis*; D005260:Female; D006112:Gravitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010808:Physical Examination / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013484:Supination
keywords: Ankle fracture; external rotation stress test; gravity stress test; supination external rotation