• Vol. 44 No. 5
  • 15 May 2015

Is the Apprehension Test Sufficient for the Diagnosis of Anterior Shoulder Instability in Young Patients without Magnetic Resonance Imaging (MRI)?

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ABSTRACT

Introduction: The purpose of this study is to compare the sensitivities and positive predictive values (PPV) of the anterior apprehension test and magnetic resonance imaging (MRI) in the diagnosis of anterior labral tears in young patients with shoulder instability and to determine if surgery could be carried without this investigation in selected patients.

Materials and Methods: We undertook a retrospective study of 168 patients aged between 15 and 30 years with a history of shoulder dislocation and compared the sensitivities and the PPV of the apprehension test with both MRI and magnetic resonance arthrograms (MRA) in the diagnosis of a Bankart lesion. The radiological investigations were interpreted by general practice radiologists and specialised musculoskeletal radiologists. All patients had their diagnosis confirmed by shoulder arthroscopy.

Results: Our results showed that the apprehension test was highly reliable when it was positive with a PPV of 96%. It was more sensitive than MRI in the diagnosis of a Bankart lesion. The clinical test was significantly better when a musculoskeletal radiologist interpreted the MRI. The MRA interpreted by a musculoskeletal radiologist had the highest rates of sensitivity in detecting Bankart lesions. The figure was similar to that for the apprehension test. There was no difference in the PPVs among the clinical test, the MRI and the MRA read by the 2 categories of radiologists.

Conclusion: We conclude that a routine MRI may be unnecessary in evaluating a young patient with clinically evident anterior shoulder instability if the apprehension test is positive. A MRA that can be interpreted by a musculoskeletal radiologist will be the next best investigation if the clinical test is negative or equivocal


A good history and a detailed physical examination is often sufficient to make a diagnosis of a recurrent anterior dislocation of the shoulder, even in the absence of a radiologically documented dislocation of the joint. The anterior apprehension test has recently been supplemented with the relocation, crank, and load and shift tests to increase its accuracy. The advent of computer tomography (CT) arthrogram, magnetic resonance imaging (MRI) and magnetic resonance arthrogram (MRA) have enabled surgeons to predict preoperatively the intra-articular pathology with greater accuracy so as to counsel patients and to obtain informed consent. A small study in 19961 has shown that a physical examination using several tests had a higher sensitivity but a similar specificity in predicting a glenoid labral tear than MRI, although this study has been refuted in a 1997 study by Seeger et al. A more recent study has suggested that the need for routine MRAs may not be as crucial as currently accepted in the management of a clinically unstable shoulder especially in the young patient. However, the MRA showed a sensitivity of 95% and a specificity of 100% for detecting anterior labral tears in a study by Parmar et al. This study suggests that the MRA rather than MRI should be the investigative modality of choice. There is therefore confusion regarding the role of MRI or MRA in shoulder instability. These investigations however, have come with additional costs to the patient, both in terms of expense and time delay in obtaining them. In addition, their accuracy has also been challenged. The routine use of these modalities now, needs critical re-evaluation in the face of rising healthcare expenditure. Do these investigations provide information that may not be obtained in a routine arthroscopic evaluation of the joint and do any additional findings affect the management plan of the surgeon at the time of arthroscopy?

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