Three-pack exam diagnosed biceps-labral complex lesions more accurately than MRI
Researchers found a “three-pack” physical examination, which incorporated direct palpation of the groove, a throwing test and active compression test, was better than MRI alone to diagnose biceps-labral complex lesions.
“The three-pack examination is more active than MRI for diagnosing symptomatic biceps labrum complex lesions,” study presenter Stephen J. O’Brien, MBA, MD, said during a recent presentation. “We view the biceps labrum complex as one functional unit that can have multiple sites of anatomic and clinical pathology. A fair amount of the three-pack examination is dynamic rather than static, which a magnetic resonance image would not be expected to pick up. The active compression test is a sensitive test for the biceps-labrum complex is still not as specific as we would want, and we think that an arthroscopic active compression test is an essential test for diagnosis and treatment of biceps-labrum complex pain.”
He noted the arthroscopic active compression test in an anesthetized patient involves putting the shoulder joint through the same range of motion as the active compression test, looking for whether the biceps “incarcerates,” that is, displaces posteriorly between the humeral head and the glenoid. This in no way is associated with a subscapularis tendon tear, he said. It is a normal finding in approximately 20% of patients, but can represent patients’ pathology if it is their source of pain.
One unit, three components
O’Brien added, “The best way to look at the biceps and the labrum is not in isolation, but as one functional unit that has three components for clinical concern.”
The three-pack examination involves examination of the bicipital groove with direct palpation of the groove according to O’Brien. For the second part, the surgeon conducts a throwing test to check for biceps dislocation or biceps chondromalacia and the third part is an active compression test to look for biceps incarceration and labrum tears..
“The active compression test is more sensitive than specific, but it is a good test for letting you know that something is wrong with the biceps labrum complex,” he said.
In the first part of the study, the researchers performed a retrospective chart review of 277 patients who underwent a three-pack examination and compared the findings to the radiologist’s preoperative MRI report to determine which method was more accurate in the diagnosis of biceps-labrum complex lesions seen and recorded at surgery, according to O’Brien.
The second phase was a prospective study of 145 patients who underwent examination by three blinded, independent examiners including a fellow at Hospital for Special Surgery, a physician’s assistant and O’Brien. The three-pack examination was compared to Speed’s, Yergason’s, and full and empty can tests for sensitivity, specificity, positive and negative predictive values, and interobserver reliability.
The MRI findings predicted labral tears at the time of surgery in 66% of patients, and 32% of biceps lesions found at surgery were ready as abnormal on preoperative MRI, O’Brien said. When the arthroscopic active compression test was positive preoperatively, the researchers found labral tears or biceps incarceration in 88% of patients during surgery. In patients who had biceps incarceration as their essential lesion, the average age was 34 years.
“As you get older, however, the lesions go from inside the joint to outside the joint and become more predominant in the junction and groove,” O’Brien said. This was statistically significant.
Prospective study results
For the second part of the study, the interobserver reliability showed Kappa values between 0.7 and 0.85 for each test that was “substantial to almost perfect,” O’Brien said. The Speed’s, Yergason’s, and full and empty can tests had moderate agreement between 0.41 and 0.6. The palpation of the groove test had a sensitivity of 0.98 and specificity of 0.703; the throwing test had a sensitivity of 0.694 and specificity of 0.745; and the active compression test had a sensitivity of 0.897 and sensitivity of 0.914 for labral tears, and sensitivity of 0.562 and specificity of 0.602 for biceps incarceration.
“The throwing test and the active compression test were all highly acceptable as far as their value for both sensitivity and specificity,” O’Brien said. In addition, 70% of patients had more than one site of pain and pathology, confirmed at surgery, and O’Brien warned to examine more than the labrum.
“In addition, 18% of control patients in our study, people that have never had shoulder problems in their life, had a positive active compression test,” O’Brien said. “It is a normal finding. It becomes a source of pain, however, in some patients, especially in the dominant shoulder in an overhead sport with overuse.” – by Renee Blisard Buddle
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Disclosure: O’Brien has no relevant financial disclosures.