Anterior and Posterior Instability of the Long Head of the Biceps Tendon in Rotator Cuff Tears: A New Classification Based on Arthroscopic Observations

Abstract

The purpose of this study was to evaluate arthroscopically the frequency and type of instability of the long head of the biceps (LHB) tendon in patients undergoing rotator cuff repair. In 200 consecutive patients undergoing arthroscopic rotator cuff repair, LHB instability was assessed statically and dynamically in the anteroposterior direction. In addition, macroscopic lesions of the LHB, as well as lesions of the adjacent rotator cuff tendons, were documented. LHB instability (subluxation or dislocation) was found in 45% of patients, with isolated anterior instability in 16%, isolated posterior instability in 19%, and combined anteroposterior instability in 10%. Whereas LHB subluxations were observed in both directions, dislocations were only seen in anterior LHB instability. Anterior instability was more associated with a subscapularis lesion, whereas posterior instability was more associated with a supraspinatus tear. Lesions of the LHB tendon were strongly associated with LHB instability and the size of the rotator cuff tear. In 200 patients with rotator cuff tears LHB instability could be observed arthroscopically in 45%, with 16% being anterior, 19% being posterior, and 10% being anteroposterior. LHB instability was associated with LHB lesions, with 15% of the LHB tendons showing a normal appearance when unstable versus 70% when stable. Preoperative O'Brien and Speed tests did not correlate with intraoperative observed LHB pathology. The size of the rotator cuff tear could be correlated with the grade of LHB lesion, becoming more significant with augmenting tear size. On the basis of these observations, we created a new arthroscopic classification of LHB instability with respect to the direction and extent of LHB instability, lesions of the LHB, and status of the adjacent rotator cuff tendons. Level IV, diagnostic study with poor reference standard.