Does tear origin associate with tendon delamination in degenerative full thickness rotator cuff tears?

Rotator cuff delamination is characterized by a horizontal tear between the bursal and articular surfaces. Although studies have proposed that delamination may result from the progression of partial-thickness tears to full-thickness tears through degenerative processes, there is still no consensus in the literature regarding whether delamination is associated with tears initiating from the articular or the bursal side. Therefore, this study aimed to evaluate the relationship between tear origin and delamination in degenerative full-thickness rotator cuff tears.

This retrospective case series included patients who underwent shoulder arthroscopy for rotator cuff tears between 2020 and 2024. All the patients had small- or medium-sized degenerative full-thickness rotator cuff tears. Patients were grouped based on the presence of delamination. Age, sex, dominant extremity, symptom duration, amount of retraction, tear width, and initiation side of the tear were compared between groups. The initiation side was determined by the following parameters: grade of coracoacromial ligament (CAL) degeneration, presence of capsular remnants, and presence of acromioclavicular joint osteophytes. Regression analysis was performed to identify the risk factors for delamination.

A total of 66 patients were included in the study: 28 with delamination (mean age 62.3 ± 8.3, 79% female, 79% dominant extremity) and 38 without (mean age 59.2 ± 7.6, 76% female, 74% dominant extremity). Grade 2-3 CAL degeneration (29%, n = 11 in nondelaminated tears; 79%, n = 22 in delaminated tears; P < .001), the presence of capsular remnants (32%, n = 12 in nondelaminated tears; 75%, n = 21 in delaminated tears; P = .001), and acromioclavicular joint osteophytes (19%, n = 6 in nondelaminated tears; 43%, n = 12 in delaminated tears; P = .015) were observed significantly more frequently in patients with delaminated tears. Regression analysis demonstrated that grade 2-3 CAL degeneration (odds ratio = 5.669; 95% confidence interval = 1.833-19.006; P = .002) and the presence of capsular remnants (odds ratio = 3.832; 95% confidence interval = 1.224-12.590; P = .021) were significantly associated with delamination.

Signs of tear initiation from the bursal side were potentially associated with delamination in degenerative full-thickness rotator cuff tears. Therefore, when the findings suggest a bursal-sided origin of a tear, delamination should be carefully evaluated through the lateral viewing portal, and the surgical procedure should be planned accordingly.