An Extension of the Collin Subclassification to Better Characterize Subscapularis Involvement in Massive Rotator Cuff Tears: A Retrospective Cohort Study from the La Tour Group

DOI: 10.70885/hmsj.2026.06.03

Abstract

Background: Massive rotator cuff tears (MRCTs) display considerable anatomical variability, and existing classification systems do not fully account for patterns involving the superior and inferior subscapularis. Although the Collin subclassification provides a functional anatomical framework, certain anterior and anterosuperior configurations remain unclassified.Purpose: The purpose of this study was to propose an extension of the Collin subclassification to integrate these subscapularis-related patterns.Methods: A retrospective review was performed on 1338 patients who underwent arthroscopic repair of MRCTs by a single expert surgeon between January 2016 to April 2026. Tears were first classified as massive, and then according to the original Collin subclassification. Subscapularis involvement was documented with specific attention to superior and inferior portions. When lesions did not match existing types, three new subtypes extending the original type B pattern (complete subscapularis and supraspinatus) were defined: BA (isolated complete subscapularis without posterosuperior involvement), BD (complete subscapularis, supraspinatus, and infraspinatus), and BE (five-tendon tear including complete subscapularis, supraspinatus, infraspinatus, and teres minor).Results: Three previously unclassifiable patterns were found: BA in 33/432 patients (7.6%), BD in 9/432 patients (2.1%), and BE in 2/432 patients (0.5%), representing 10.2% of MRCTs with subscapularis involvement.Conclusion: This study extends the Collin subclassification of MRCTs by introducing three new subtypes — BA, BD, and BE — that capture patterns of complete subscapularis involvement not accounted for in the original system. These configurations represented 10.2% of subscapularis-involved MRCTs in our cohort and 41.1% of type B lesions, highlighting meaningful anatomical heterogeneity within this category. While the proposed extension improves descriptive completeness, its prognostic value and impact on surgical decision-making remain to be determined through future outcome-based studies.What this study adds: This study extends the Collin subclassification of massive rotator cuff tears by introducing three new subtypes (BA, BD, and BE) that capture patterns of complete subscapularis involvement previously left unclassified. It shows that these configurations represent a clinically relevant proportion of MRCTs, thereby improving anatomical characterization and potentially refining surgical decision-making.Potential impacts on research, practice, or policy: This extended subclassification may improve future research by enabling more precise phenotyping of massive rotator cuff tears and by supporting outcome studies focused on reparability, prognosis, and indication for tendon transfer or RSA.Study Design: Retrospective cohort studyLevel of Evidence: Level IIIKeywords : Shoulder; Classification; Database; Description; Treatment options.https://doi.org/10.70885/hmsj.2026.06.03

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