Abstract
Introduction: In clinical practice The Cascade sign is widely used to assess the rotational deformity of the fingers associated with metacarpal and phalangeal fractures. We carried out a scientific study on thirty volunteers to evaluate the validity or otherwise of this standard sign.
Material and Methods: Metal pointers were attached to the dorsum of the fingers, flexed at MCP and PIP joints. These pointers represented the mid longitudinal axis of the phalanges. Standardised AP radiographs of the closed fist were taken in all cases with the wrist placed in neutral position, in a custom made jig. The radiographs were assessed by two different observers using Picture Archiving and Communication System, software version VA42B, to determine the convergence of the metal pointers towards the scaphoid tubercle, as described in the cascade sign and Lister method..
Statistics: Power of the study was determined with an assumption of a type-2 error of 0.05 and a two sided test. Descriptive statistics and confidence limits were calculated using SPSS 11 software.
Results: We observed that the metal pointers did not equivocally converge towards the scaphoid tubercle. The persistent pattern of convergence was within a 2–3cm radius of the scaphoid tubercle. The statistical analysis, two tailed paired t-test of this pattern showed strong association with this latter finding. (p< 0.003).
Conclusion: Our study suggests that the cascade sign is sensitive but not specific to access the rotational deformity of the fingers. Radiological there is significant scatter about the scaphoid tubercle.
Correspondence should be addressed to Ms Larissa Welti, Scientific Secretary, EFORT Central Office, Technoparkstrasse 1, CH-8005 Zürich, Switzerland
