Clinical and radiological comparisons of posterior labral tears with and without posterior glenohumeral instability

Background: We compare clinical and radiological characteristics and evaluate surgical outcomes of posterior labral tears based on the presence of glenohumeral instability. Methods: Patients who were unresponsive to conservative treatment and underwent arthroscopic posterior labral repair were reviewed retrospectively. Patients were divided into two groups: those with glenohumeral instability (group 1) and those without (group 2). Demographic, radiological, physical examination, and intraoperative data were collected. Clinical outcomes were assessed at a minimum 2-year follow-up using the visual analog scale for pain, American Shoulder and Elbow Surgeons, and Rowe scores. Results: The study included a total of 85 patients (40 in group 1 and 45 in group 2) with a mean follow-up duration of 31.8±12.2 months. Patients in group 2 were older (31.4±1.0 years old, P<0.001), had longer symptom durations (30.1±5.6 months, P=0.002), and included fewer histories of trauma (16 patients, P=0.009). Competitive sports were more common in group 1 (9 patients, P=0.005), whereas weightlifting exercises were more common in group 2 (24 patients, P=0.047). Magnetic resonance imaging (MRI) underestimated incomplete posterior labral tears more frequently in group 2 than in group 1 (P=0.033). The incidence of arthroscopically detected tears among MRI-occult tears was higher in group 2 (10 patients) than in group 1 (2 patients, P=0.029). Statistically significant improvements in shoulder function were observed postoperatively in both groups. Conclusions: Clinical and magnetic resonance findings of posterior labral tears without glenohumeral instability differ from those with instability. Surgical treatment achieved satisfactory clinical outcomes regardless of the presence of instability. Level of evidence: III.