Abstracts & Commentary
Synopsis: Two separate studies, one a case-control and the other a nonrandomized prospective study, question the accuracy of commonly used physical exam maneuvers to diagnose SLAP tears.Sources:Stetson WB, Templin K. The crank test, the O’Brien test, and routine magnetic resonance imaging scans in the diagnosis of labral tears.Am J Sports Med. 2002;30:806-809; McFarland EG, et al. Clinical assessment of three common tests for superior labral anterior-posterior lesions.Am J Sports Med. 2002;30:810-815.
A highly sensitive and specific diagnostic physical exam test for SLAP tears has been an enigma since Snyder and colleagues1 first classified these lesions in 1990. Snyder suggested that patients with SLAP tears had pain with overhead activities and often painful catching, popping, or locking within the joint. They described a compression rotation test to evaluate for the lesion. Since that time, many authors have recommended various physical exam maneuvers to try to more accurately diagnose the lesion.
Their initial reports often indicate high sensitivity and specificity, but many have questioned the reliability of these exams. In these 2 studies, the researchers have attempted to independently evaluate 4 of these recommended tests.
The first study by Stetson and Templin is a nonrandomized, prospective study of 65 patients with shoulder pain. They evaluated the O’Brien2 and crank tests described by Liu and associates3, and also MRI used in 49 patients. These patients all underwent nonoperative treatment for at least 3 months prior to arthroscopic evaluation. Twenty-three patients received subacromial injections of cortisone when indicated for bursitis or a partial rotator cuff tear. Twelve patients were found to have biceps lesions, 10 patients had Type II SLAP lesions, and 2 patients had Type IV lesions. Fifty-eight of the 65 patients had significant inflammation in the subacromial space, and only 7 had no evidence of bursitis. In this group of patients, the crank test had a specificity of 56%, a sensitivity of 46%, a positive predictive value of 41%, and a negative predictive value of 61%. The O’Brien test had 31% specificity, 54% sensitivity, a positive predictive value of 34%, and a negative predictive value of 50%. The addition of MRI improved specificity but not sensitivity.
The second study by McFarland and associates is a case-control study of 604 surgical patients over a 7-year period. These patients were retrospectively reviewed as a consecutive case series. Of these patients, 178 were excluded for various reasons, leaving a study group of 426 patients. These patients were evaluated with Snyder’s original compression rotation test, the active compression test (O’Brien), and the anterior slide test described by Kibler.4 Thirty-nine patients had pathological SLAP lesions classified as Type II-IV by Snyder. Of these patients, all had associated diagnoses and 30 of 39 had intraarticular lesions to include partial or full thickness rotator cuff tears, Bankart lesions, Hill-Sachs lesions, or glenohumeral arthritis. Even with this amount of pathology, no patient had a positive result on all 3 tests, and only 14% had a positive result on 2 of 3 tests. The compression rotation test had 24% specificity, 76% sensitivity, a positive predictive value of 9%, and a negative predictive value of 90%. The anterior slide test had 8% specificity, 84% sensitivity, a positive predictive value of 5%, and a negative predictive value of 90%. The active compression test (O’Brien) had 47% specificity, 55% sensitivity, a positive predictive value of 10%, and a negative predictive value of 91%.
Comment by COL Patrick St. Pierre, MD
These papers independently try to quantify the accuracy of currently used diagnostic examinations for SLAP lesions. Although the studies had different study designs, a different number of patients studied, and different tests were considered, their conclusions were the same. The O’Brien active compression test, anterior slide test, crank test, and compression rotation test all were not reliable enough to be used as screening or diagnostic tests for SLAP lesions. Their results were significantly poorer than those found by O’Brien, Liu, and Kibler in their original articles.
One important finding is that most of these patients had associated pathology, often confusing the clinical picture, and leading to false-positive findings. This has been a consistent discovery in other studies, leading many authors to state that SLAP lesions usually do not occur in isolation, rather in combination with other lesions. However, most of us have operated on patients with isolated SLAP lesions, but again their symptoms have mimicked other conditions in the shoulder.
Both studies had an average age of 45 years. While older than some of the previous studies, it is not an elderly population. This age group of patients may be experiencing subtle instability, subacromial bursitis, or partial thickness articular rotator cuff tears, all of which could mimic SLAP lesions.
So the question remains, is there a current examination that can reproducibly challenge the superior labrum without also eliciting a response from a torn anterior labrum, partial or full thickness rotator cuff tear, AC or glenohumeral arthritis? Can it be reliable when there is an isolated SLAP lesion, and can it help us distinguish a SLAP lesion from other common shoulder pathology? The authors of these studies say no. Stetson and Templin also added MRI and found it was more specific (better at detecting a true negative finding), but it was not sensitive and had only a 63% positive predictive value. They suggested that the addition of gadolinium may be helpful to the use of MRI but did not evaluate that in their study. The final conclusion of these studies is that arthroscopic evaluation remains the best procedure for the diagnosis of SLAP tears. Reliance on these physical exam tests alone cannot be made at this time.
These studies are well done, and I believe their conclusions to be valid. However, a prospectively blinded study comparing physical exam with evaluation by intraarticular gadolinium MRI would be an obvious next step. The treatment of these patients has not changed. Patients are usually recommended for surgery after failure of nonoperative treatment for 3-6 months and a suspicion of intraarticular pathology. Although every effort is made to ensure an accurate preoperative diagnosis, the surgeon should be prepared to treat the entire gamut of shoulder pathology at every surgical setting. The decision to go to surgery should not be made on a positive physical exam test alone.
COL St. Pierre is Assistant Professor, Uniformed Services University, Orthopedic Co-Director, Primary Care Sports Medicine Fellowship, DeWitt Army Community Hospital, Ft. Belvoir, VA.
1. Snyder SJ, et al. SLAP lesions of the shoulder. Arthroscopy. 1990;6:274-279.
2. O’Brien SJ, et al. The active compression test: A new and effective test for diagnosing labral tears and acromioclavicular joint abnormality. Am J Sports Med. 1998;26:610-613.
3. Liu SH, et al. Diagnosis of glenoid labral tears. A comparison between magnetic resonance imaging and clinical examinations. Am J Sports Med. 1996;24: 149-154.
4. Kibler WB. Specificity and sensitivity of the anterior slide test in throwing athletes with superior glenoid labral tears. Arthroscopy. 1995;11:296-300.