L-shaped morphology is a key risk factor for delamination in degenerative full-thickness rotator cuff tears.

Purpose: To evaluate the relationship between delamination and tear patterns in degenerative full-thickness rotator cuff tears.

Methods: This retrospective cohort study was conducted on patients who underwent shoulder arthroscopy for rotator cuff tears between December 2020 and September 2024. The study included chronic, degenerative, full-thickness rotator cuff tears without concomitant shoulder pathology. Patients were grouped based on the presence of delamination, defined as the horizontal cleavage of the torn tendons. Age, sex, dominant extremity, symptom duration, amount of retraction, tear width and tear pattern (crescent-shaped, anterior L-shaped, posterior L-shaped and U-shaped) were compared between groups. Regression analysis was conducted to identify risk factors that may be associated with the presence of delamination.

Results: The study included 130 patients, 75 with delamination (mean age 61.1 ± 8.8 years) and 55 without (mean age 61.1 ± 8.3 years). Demographic characteristics were similar among patients with and without delamination. The rate of anterior and posterior L-shaped tears was significantly higher in delaminated tears (24% and 33%, respectively) compared to non-delaminated tears (6% and 9%, respectively) (p = 0.003 and p = 0.001, respectively). Regression analysis demonstrated that anterior L-shaped tears and posterior L-shaped tears were significantly related to delamination (p = 0.002 and p = 0.001, respectively).

Conclusion: This study demonstrates that anterior and posterior L-shaped tear patterns are significantly associated with delamination in degenerative full-thickness rotator cuff tears.

Level of evidence: Level III, retrospective cohort study.