The Superior Glenoid Humeral Ligament's Role in Superior Labrum Anterior-Posterior Lesions and Subtype Classification Based on Arthroscopic Views: A Multicenter, Retrospective Study.

Background: Superior labrum anterior-posterior (SLAP) lesions are common shoulder injuries. The 10-type classification system has been widely used to diagnose SLAP lesions since it was proposed. However, growing evidence from arthroscopic studies indicates the existence of many SLAP lesions, especially those associated with superior glenoid humeral ligament (SGHL) injuries, that were not included in the initial classification. Purpose: To introduce a SLAP classification associated with SGHL injury based on arthroscopic views and discuss the injury mechanism and corresponding treatment options. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients with SLAP lesions who underwent shoulder arthroscopic surgical treatment between June 2011 and January 2017 in 6 level 1 centers were evaluated in this study. Preoperative radiographs and magnetic resonance imaging scans were used to diagnose SLAP lesions, and arthroscopic views from the standard posterior portal were recorded. The traditional 10-type classification system for SLAP was used to classify these cases. A classification method for SLAP lesions associated with SGHL injury was introduced. This classification system was investigated by 4 observers to evaluate inter- and intraobserver reliability (kappa coefficient [κ]). Results: A total of 828 patients were included in this analysis; 61 patients (7.4%) could not be classified by the 10-type traditional classification, and 44 patients (5.3%) had SGHL lesions. A novel classification for 3 subtypes of SLAP with SGHL lesions was introduced. The mean κ value of the interobserver reliability for the classification approach was 0.796 (range, 0.678-0.854), indicating substantial agreement. The mean κ value for the intraobserver reliability was 0.883 (range, 0.779-0.964), indicating excellent agreement. Conclusion: This study demonstrated a novel classification system for SLAP lesions associated with SGHL injury by introducing a series of cases with characteristics that showed high inter- and intraobserver reliability. Such cases have not been reported before, and the classification correlates with surgical treatment. This classification may be used as a supplement to the traditional 10-type classification.