Clinical and Radiological Comparison of Posterior Labral Tears based on the Combined Posterior Glenohumeral Instability

Introduction: This study aimed to compare the clinical and radiological characteristics, and surgical outcomes of posterior labral tears based on the presence of glenohumeral instability. Materials and Methods Patients who were unresponsive to conservative treatment and underwent arthroscopic posterior labral repair were reviewed retrospectively. Patients were classified into two groups on instability history and physical examinations: patients with glenohumeral instability (group I) and without instability (group II). Demographic, radiological, physical examination data, intraoperative findings were collected. Clinical outcomes were assessed at a minimum two-year follow-up using the VAS for pain, ASES, and Rowe scores. Results A total of 85 patients were included (40 in group I and 45 in group II) with mean follow-up duration of 31.8 ± 12.2 months. Patients in group II were older (31.4 ± 1.0 years old, p < 0.001), had longer symptom durations (30.1 ± 5.6 months, p = 0.002), and reported fewer trauma history (16 patients, p = 0.009). Competitive sports were more common in group I (nine patients, p = 0.047), whereas weight lifting exercises were more common in group II (24 patients, p = 0.047). MRI underestimated incomplete posterior labral tear more frequently in group II than in group I (p = 0.033). Incidence of occult posterior labral tear detected during arthroscopy was higher in group II (10 patients) than in group I (2 patients; p = 0.029). A statistically significant improvement in shoulder function was observed postoperatively in both groups. Incomplete labral healing was suspected in group I (7 patients) and group II (5 patients), with no statistically significant difference (p = 0.409). Conclusions Clinical and MR findings of posterior labral tears without glenohumeral instability are different compared with those with instability. Surgical treatment showed good clinical outcomes in patients with symptomatic posterior labral tear who failed conservative management regardless of combined instability. Level of Evidence: Retrospective Comparative Study; Level of evidence, III