Research Review by Dr. Shawn ThistleĀ©

Date:

July 2006

Study Title:

Clinical assessment of three common tests for traumatic anterior shoulder instability

Authors:

Farber AJ et al.

Publication Information:

The Journal of Bone & Joint Surgery 2006; 87-A(7): 1467-1474.

Summary:

The shoulder is the most commonly dislocated joint in the body. The majority of shoulder dislocations are traumatic in nature, and occur in an anterior direction. As such, traumatic anterior shoulder instability is the most common form of shoulder instability evaluated by clinicians. The diagnosis of anterior shoulder instability is based on the history (primarily mechanism of injury) and physical examination.

Numerous physical tests for diagnosing anterior shoulder have been proposed, despite a dearth of evidence which clarifies their accuracy, sensitivity, and specificity. These include the apprehension, relocation, anterior drawer test, and the load and shift test.

The first three tests mentioned above were the focus of this study, in which 363 patients underwent arthroscopic shoulder surgery. Of the 363, 46 were diagnosed with traumatic unidirectional anterior instability, and subsequently formed the study group. The remaining patients became the comparison group. Each patient completed a pre-operative questionnaire, and underwent a physical examination including the three tests being studied.

All tests were performed by the senior author. For each test, the clinician noted whether pain was elicited, or if the patient became apprehensive of another episode of instability (a feeling that the shoulder would "come out" again), or both.

Pertinent Results:

  • generally, the sensitivity of all tests was low (81%)
  • specificity of the tests varied depending on whether pain or apprehension was used as the diagnostic criterion
  • when apprehension was used as the criterion for a positive test, the likelihood ratio of a patient with a positive anterior apprehension test having anterior instability was 20.2, while for the relocation test it was 10.4
  • in contrast, when pain was used as the criterion for a positive test, the likelihood ratios were only 1.1 and 3.0 respectively - this essentially means that when pain (or relief of pain) is used as the criterion for a positive test, the likelihood that the patient has anterior instability is not much higher than the likelihood that the patient does not have anterior instability

Conclusions & Practical Application:

I reviewed this study because I think it helps to clarify the proper clinical application of commonly used tests for anterior shoulder instability. Although the authors used slight variations of the orthopedic tests (for example, performing the apprehension test seated instead of supine), the take home message remains that these tests are much more useful when patient apprehension is used as the criterion for a positive test. A positive test based on apprehension or reproduction of a sense of instability increases the chances that a patient has anterior shoulder instability.

The authors remind us however that these tests demonstrated poor sensitivity. Therefore, if no radiographic evidence of dislocation is noted (Hill-Sachs deformity, Bankart lesion, humeral avulsion), diagnostic arthroscopy is still the gold standard for diagnosing this condition.

As always, it is prudent to include all clinical and imaging information when arriving at a diagnosis and determining appropriate treatment or referral options.