Original article
The Belly-Off Sign: A New Clinical Diagnostic Sign for Subscapularis Lesions

https://doi.org/10.1016/j.arthro.2005.06.021Get rights and content

Purpose: We describe a new clinical sign for subscapularis lesions that we call the belly-off sign and compare its diagnostic value with standard subscapularis tests (the lift-off test, internal rotation lag sign, and belly-press test/Napoleon sign) in cases of different types of subscapularis lesions. The belly-off sign represents the inability of the patient to maintain the palm of the hand attached to the abdomen with the arm passively brought into flexion and internal rotation. Type of Study: Case series. Methods: This descriptive and explorative study included 60 patients (mean age, 55.3 years) with clinical, surgical, and/or magnetic resonance imaging–confirmed evidence of isolated or combined lesions of the subscapularis musculotendinous unit. In all patients, a complete physical shoulder examination was performed and the results were compared with the intraoperative and magnetic resonance imaging findings. Results: The belly-off sign appeared to be more reliable than any other diagnostic test or sign in detecting isolated partial tears of the subscapularis tendon (group I), combined partial subscapularis and complete supraspinatus tendon tears (group II), and postoperative subscapularis insufficiency with mild atrophy of the upper aspect of the subscapularis muscle (group VII). In cases of complete/near complete subscapularis tears with or without supraspinatus and infraspinatus tendon tears (groups IV, V, and VI), the belly-off sign appeared to be as reliable as the belly-press test, internal rotation lag sign, and lift-off test. For assessing partial subscapularis tendon tears and insufficient external rotators (group III), the belly-off sign was less reliable than any other diagnostic test or sign. Conclusions: The belly-off sign represents a promising new clinical diagnostic sign for subscapularis lesions. In particular, subtle lesions of the upper subscapularis tendon and postoperative subscapularis insufficiencies can be detected by the belly-off sign in cases of intact external rotators. In cases of an advanced lack of external rotators, the belly-off sign becomes negative and loses its diagnostic value. We therefore conclude that the belly-off sign is attributable to an unbalanced transverse force couple with overwhelming of the external rotators of the shoulder. Level of Evidence: Level IV, case series with no, or historical, control group.

Section snippets

Methods

Sixty patients (44 male and 16 female) with a mean age of 55.3 years (range, 26 to 83 years) and clinical, surgical, and/or magnetic resonance imaging (MRI)–confirmed evidence of a lesion of the subscapularis musculotendinous unit were included in this descriptive and explorative study.

In all patients, a complete physical examination of both shoulders, standard radiographic examination, and MRI were performed. On physical examination, special attention was paid to the integrity of the rotator

Group I: Isolated Partial Subscapularis Tendon Tears

Nine patients had an arthroscopically confirmed isolated partial tear of the upper subscapularis tendon. In all patients, the lift-off test, the IRLS, the Napoleon sign, and the belly-off sign could be evaluated. The lift-off test was found to be positive in 2 patients (22%). The IRLS was graded as intermediate in 3 patients (33%) and in the remaining patients it was negative. The Napoleon sign was graded as intermediate in 5 (56%) patients and negative in 4. All patients in this group had a

Discussion

Different clinical tests and diagnostic signs have been described in the literature to evaluate the function and integrity of the subscapularis musculotendinous unit. The lift-off test has been reported to be very reliable in patients with complete subscapularis tears who were able to perform the test.1, 3 Our study confirmed previous observations that the lift-off test is of limited value in patients who cannot bring the affected arm into the starting position required because of pain and/or

Conclusions

This report represents a descriptive and explorative study of a new diagnostic sign, the belly-off sign, and describes its relative diagnostic value in comparison with the lift-off test, IRLS, and belly-press/Napoleon sign in cases of different types of subscapularis lesions. A valid statistical estimation of specificity, sensitivity, and positive or negative predictive values was not possible in this study because the different diagnostic tests and signs were only evaluated in patients with

Acknowledgment

The authors thank Rüdiger Himmelhan for the illustrations.

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