Background: The difference between subluxations and dislocations of the long head of the biceps tendon (LHB) combined with the complete rotator cuff (RC) tear was examined.
Methods: There were 7 shoulders with dislocation and 5 with subluxation, which had open cuff surgery. The clinical observations, image findings, and condition of LHB and RC were evaluated.
Results: Major trauma at onset was found in 3 shoulders with dislocation and 2 with subluxation. Biceps muscle deformity was not found, and the active shoulder elevation angles were an average of 74 degrees. There were no significant differences in these factors between dislocations and subluxations. XP revealed ascent of the humeral head in 5 shoulders with dislocation. MRI revealed medial displacement of LHB from the biceps groove in all cases. All 7 dislocations had supraspinatus, infraspinatus and subscapularis tendon tears, and 5 subluxations had supraspinatus tendon tears in all, infraspinatus tendon tears in 2 and upper half of subscapularis tendon tears in all. The tear size in dislocations was significantly larger than that in subluxations. The flattening of LHB was present in 9 shoulders. The remaining 3 shoulders, without the flattening, had major trauma at onset. All RC tears were repaired by using tenodesis of LHB at the superior facet.
Conclusion: The progress of displacement of LHB was thought to be related to the expansion of RC tear. When there is no biceps muscle deformity and no LHB in the biceps groove at surgery, it is necessary to suspect subluxation and dislocation of LHB.
