Can Dynamic Rotation during Arthro-MRI Be Useful in the Diagnosis of Long Head of Biceps Tendon (LHBT) Instability in Patients with Biceps Pulley Lesions of the Shoulder?

PURPOSE Arthro-MRI is proven to be the diagnostic gold standard in the evaluation of biceps pulley anatomy and lesions. The purpose of our study was to evaluate the added value of the internal and external rotation during arthro-MRI scans in identifying the LHBT instability and the possible development of an antero-superior impingment (ASI). METHOD AND MATERIALS We retrospectively analyzed MRI exam of 70 patients (55 males and 15 females) who underwent arthro-MRI exam with a 1.5 T U and arthroscopy within the following 7-45 days. All patients had clinical suspicion of biceps pulley lesions and all were positive to Palm-up, O’Brien and Hawkins tests. During the MRI, the shoulder was studied with a dedicated coil with the arm in neutral position, in internal and external rotation to evaluate the LHBT. ABER position was used in 12 patients. We did an intrarticular injection of 13-18 cc of contrast agent under fluoroscopic guide. RESULTS Patients were divided in 4 groups based on the Habermayer classification and then evaluated for the presence of an unstable LHBT. According to the Habermeyer classification: 10 patients had superior gleno-humeral ligament (SGHL) tear (Type I), 16 patients SGHL and supraspinatus (SSP) tendon tears (Type II), 21 patients SGHL and subscapularis (SSC) tendon tears (Type III) and 23 patients SGHL, SSP and SSC tears (Type IV) . At arthroscopy 2 patients were negative, 8 patients had Type I, 16 patients Type II, 19 patients Type III and 25 patients Type IV lesions. MRI internal and external rotation showed no subluxation in patients with type I lesion, an initial anteromedial subluxation of the LHBT in 8 patients with Type II lesion and an anteromedial subluxation of the LHBT in all patients with Type III and Type IV lesions. The dynamic tests during arthroscopy, confirmed LHBT instability and ASI features in all patients with Type III and Type IV lesions. CONCLUSION Only high grade lesions of the biceps pulley can be associated with LHBT instability. MRI external and internal rotation scans led to a better identification of structures of the biceps pulley and the detection of LHBT instability could suggest the presence of ASI. CLINICAL RELEVANCE/APPLICATION Dynamic arthro-MRI scans allow a correct evaluation of the LHBT instability , and it is a very important diagnostic tool in the planning of arthroscopic treatment.