MRI Gaps and Instability in Posterior Shoulder Labral Tears

A posterior labral tear can occur with or without glenohumeral instability. Researchers examined whether that difference affects patient characteristics, imaging results, or surgical recovery. Their review focused on patients whose symptoms did not improve with conservative care and who later received arthroscopic posterior labral repair.

The retrospective study included 85 patients. Of them, 40 had glenohumeral instability, while 45 did not. Researchers compared demographic details, imaging results, physical examination findings, and intraoperative data. Follow-up lasted at least two years and averaged 31.8 ± 12.2 months. Doctors assessed pain with a visual analog scale. They also used American Shoulder and Elbow Surgeons and Rowe scores to measure shoulder function.

The two groups had noticeably different backgrounds. Patients without instability were older, with an average age of 31.4 years. Their symptoms had also lasted longer, averaging 30.1 months. Trauma histories were less common in this group, occurring in 16 patients. Among those with instability, 9 patients took part in competitive sports. Weightlifting was more frequent in the group without instability, where 24 patients did it. These contrasts show why the presence of instability matters when comparing patient groups.

MRI did not capture every posterior labral tear. It underestimated incomplete tears more often in patients without instability. Among tears that MRI failed to reveal but arthroscopy detected, 10 belonged to the no-instability group and 2 belonged to the instability group. That gap raises an important question for diagnosis. Both groups still showed statistically significant improvements in shoulder function after surgery. Repair produced satisfactory clinical outcomes whether instability was present or absent. The study was rated Level III evidence.