BACKGROUND:
The purpose of this study was to evaluate the angle between the long head of the biceps tendon (LHBT) and the glenoid during arthroscopic surgery and its correlation with biceps subluxation on magnetic resonance imaging (MRI). Furthermore, we evaluated the relationship of this angle with subscapularis tears and biceps pathologies.

METHODS:
MRI and arthroscopic images of 270 consecutive patients who had undergone arthroscopic surgery were retrospectively evaluated. On MRI, 60 shoulders with biceps subluxation and 210 shoulders without subluxation were identified. On the arthroscopic view from the posterior portal, the angle between the LHBT and the glenoid (biceps-glenoid angle) was measured. The biceps-glenoid angle, tears of the LHBT, degenerative superior labrum anterior to posterior (SLAP) lesions, and presence of a subscapularis tear were compared according to the presence of biceps subluxation on MRI.

RESULTS:
In the subluxation group, 51 (85%) had a subscapularis tendon tear and all shoulders showed biceps tendon pathologies. In the non-subluxation group, 116 (55.2%) had a subscapularis tendon tear, 125 (60%) had tears in the biceps tendon, and 191 (91%) had degenerative SLAP lesions. The incidences of subscapularis tears (p < 0.001) and biceps pathologies (p < 0.001) showed significant differences. The mean biceps-glenoid angle was 87.0° (standard deviation [SD], 11.4°) in the subluxation group and 90.0° (SD, 9.6°) in the non-subluxation group, showing a statistically significant difference (p = 0.037).

CONCLUSIONS:
Shoulders with subluxation of the biceps tendon on the preoperative MRI revealed more pathologies in the subscapularis tendon and biceps tendon during arthroscopy. However, the arthroscopically measured biceps-glenoid angle did not have clinical relevance to the determination of subluxation of the LHBT from the bicipital groove.