Author Reply to “Regarding ‘Glenoid Labral Articular Disruption Lesions in the Setting of First‐Time Anterior Shoulder Instability’”

We thank Qin et al.1 for their interest regarding our recent publication examining the impact of glenoid labral articular disruption (GLAD) lesions on postoperative outcomes after arthroscopic Bankart repair in the setting of first-time anterior shoulder instability.2 We also thank the editors for the opportunity to address and respond to each of their concerns, which we hope will be beneficial to all readers. The 2 primary discussion points center around (1) further stratifying GLAD patients based on lesion severity and (2) surgically managing the cartilage intraoperatively for patients with GLAD lesions. To expand, the first concern of Qin et al. is that the cohort of patients with GLAD lesions was not further stratified and grouped based on severity of the GLAD lesion (i.e. size, depth, or type of associated cartilage damage). In response, we recognize that stratifying patients based on lesion severity would be more ideal. However, this represents a limitation of retrospective studies where that may not be possible, as electronic medical records may lack consistency across operative reports and intraoperative imaging, limiting the ability to reliably stratify lesions by severity. In addition, there are some questions and considerations we pose in response to this concern: How should GLAD lesion severity be objectively defined and measured? Lesion size and surface area are difficult to quantify and qualitatively assess on magnetic resonance imaging, and intraoperative assessments remain subjective as to what is considered less or more severe.3 Is a larger area of grade 2-3 chondrosis more severe than a smaller area of grade 4 chondrosis? This also remains unclear. Nonetheless, all patients in our study had at least grade 3-4 chondral loss, consistent with a true GLAD lesion. As such, our study would represent a worst-case scenario of severe chondral damage. Furthermore, the assumption in the letter is that higher degrees of cartilage loss leads to higher rates of shoulder instability is not uniformly supported in the literature as studies have shown mixed results regarding this association (Davey et al., Pogorzelski et al.).4, 5 Lastly, the GLAD lesion cohort in our study consisted of only 14 patients (a recognized limitation and is consistent with the infrequent nature of the pathology) and additional subgrouping would have significantly compromised statistical power and interpretability, making analysis difficult. However, we appreciate the critique and acknowledge its relevance to this study. In response to their second concern regarding whether any cartilage-specific treatment was performed intraoperatively for GLAD lesions, the labrum was not incorporated into the cartilage defect but was repaired anatomically in standard fashion. Although addressing the cartilage injury may be beneficial or potentially alter outcomes as the letter stated, the role of microfracture for cartilage repair in the shoulder remains controversial given that it is a nonweight bearing joint. To our knowledge there are no large scale, longitudinal studies that support its routine clinical use. The retrospective work by Elrick et al. cited in our article included 27 GLAD patients, of which only 17 had microfracture performed.6 Still, they reported that patients achieved nearly identical outcomes regardless of whether they were treated with microfracture or labral advancement at mean follow-up of 4.5 years, which is less than the mean follow-up of 7.6 years in our GLAD cohort. As such, it remains unclear whether cartilage treatment for GLAD lesions alters long-term shoulder outcomes, particularly with respect to the development of glenohumeral arthritis. Again, this is a limitation that applies not only to our study, but also to others in the existing literature on GLAD lesions, and this is acknowledged in our study. Overall, the literature on GLAD lesions is limited; however, there are multiple retrospective studies in addition to our work that similarly reported no differences in outcomes between patients with and without GLAD lesions in the setting of anterior instability (Davey et al., Elrick et al., Vieder et al.).4, 6, 7 We look forward to future research on GLAD lesions and their impact on long-term patient outcomes related to the degree of cartilage involvement and risk of developing arthritis. The author (A.L.) declares the following financial interests/personal relationships which may be considered as potential competing interests: A.L. reports Consulting fees from Arthrex and Stryker/Tornier; participation on a Data Safety Monitoring Board or Advisory Board with Restor3d. The other authors (J.L.D., R.T.L.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.