Glenoid Bone Loss in the Setting of an Anterior Labroligamentous Periosteal Sleeve Avulsion Tear

Abstract

Background: Glenoid bone loss is a factor that has been inversely associated with the success of shoulder instability repair. Recently, patients with an anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion have also been identified as having a higher failure rate after surgical repair. Purpose: To determine differences in the amount of glenoid bone loss and to compare demographic factors of instability in patients with and without ALPSA tears. Study Design: Case-control study; Level of evidence, 3. Methods: Over a 3-year period, all patients (N = 83) who were treated for anterior shoulder instability at a single institution were reviewed retrospectively. A total of 39 (47%) were identified as having an ALPSA lesion and 44 (53%) as having no ALPSA tear. Glenoid bone loss was determined in 2 ways: (1) radiographically by 3-dimensional computed tomography (3D CT) (humeral head digitally subtracted by 3 blinded observers) and (2) with arthroscopic techniques at the time of surgery. Demographic data such as the time from the initial instability event to advanced imaging and surgery were noted. These data were then analyzed with the Student t test to determine any significant differences between the 2 groups. Results: The patients with an ALPSA lesion had more preoperative instability events than those without (8.2 vs 3.6, respectively; P = .04). The mean glenoid bone loss measured by 3D CT was 12.7% (range, 0%-22.3%) for those with ALPSA tears versus 6.25% (range, 0%-23.1%) for those without ( P = .002). The mean duration of total instability for those with ALPSA tears was 42.9 months versus 46.3 months for those without ( P = .95). Lastly, the mean bone loss based on arthroscopic measures was 11.4% for patients with ALPSA tears and 4.3% for those without ALPSA tears ( P = .017). From the existing magnetic resonance imaging/arthrography scans reviewed, 82% of patients could be correctly identified as having an ALPSA lesion. Conclusion: Patients with anterior shoulder instability who have an ALPSA lesion have nearly twice the amount of glenoid bone loss as those with a standard Bankart tear (no ALPSA lesion). Patients with ALPSA lesions had statistically more instability events, and this may be an additional factor in either developing an ALPSA lesion or glenoid bone loss or both.