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. Cite this article:
Interobserver reliability of the AO system of classification of fractures of the distal radius was assessed using plain radiographs and CT. Five observers classified 30 Colles’-type fractures using only plain radiographs; two months later they were reclassified using CT in addition. Interobserver reliability was poor in both series when detailed classification was used. By reducing the categories to five, interobserver reliability was slightly improved, but was still poor. When only two AO types were used, the reliability was moderate using plain radiographs and good to excellent with the addition of CT. The use of CT as well as plain radiographs brings interobserver reliability to a good level in assessment of the presence or absence of articular involvement, but is otherwise of minor value in improving the interobserver reliability of the AO system of classification of fractures of the distal radius.
