Evaluación clínica de tres tests para la inestabilidad traumática del hombro.(I)

Adam J. Farber, MD1, Renan Castillo, MS1, Mark Clough, MD1, Michael Bahk, MD1 and Edward G. McFarland, MD1

1 c/o Elaine P. Henze, Medical Editor, Department of Orthopaedic Surgery, Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, #A672, Baltimore, MD 21224. E-mail address for E.P. Henze: ehenze1@jhmi.edu

Background: Although traumatic anterior shoulder instability is common, the usefulness of various physical examination tests as tools for the diagnosis of this condition has been studied infrequently. We hypothesized that (1) such tests would be specific but not sensitive for this condition, (2) the usefulness of the anterior drawer test would be limited because of pain during the test, and (3) an anterior drawer test would be a useful adjunct for making the diagnosis if it reproduced the instability symptoms.

Methods: Between 2000 and 2004, 363 patients underwent a physical examination followed by shoulder arthroscopy. Forty-six patients with traumatic anterior shoulder instability that had been noted arthroscopically or documented radiographically after the trauma were included in our study group, and the remaining patients served as controls. The clinical usefulness of three tests (anterior apprehension, relocation, and anterior drawer tests) performed during the physical examination to make a diagnosis of traumatic anterior instability then was evaluated with statistical methods to assess their sensitivity, specificity, and likelihood ratios.

Results: If demonstration (or relief) of apprehension was used as the diagnostic criterion for a positive test, the sensitivity, specificity, and likelihood ratio were 72%, 96%, and 20.2, respectively, for the apprehension test and 81%, 92%, and 10.4, respectively, for the relocation test. If pain (or relief of pain) was used as the diagnostic criterion for a positive test, the values for the sensitivity, specificity, and likelihood ratio of both tests were lower. The anterior drawer test could be performed successfully in the physician's office for 87% of the patients. If reproduction of instability symptoms was used as the criterion for a positive anterior drawer test, the sensitivity, specificity, and likelihood ratio values of that test were 53%, 85%, and 3.6, respectively.

Conclusions: The three physical examination tests for traumatic anterior shoulder instability are specific but not sensitive. Apprehension is a better criterion than pain for a positive apprehension or relocation test. The anterior drawer test (when pain does not prevent it from being performed) is helpful for diagnosing traumatic anterior instability.