Comparison of Long-term Supraspinatus Tear Progression After Arthroscopic Isolated Subscapularis Repair With and Without Comma Tissue Preservation: A Minimum 10-Year MRI Follow-up Study

Background: Long-term outcomes after arthroscopic isolated subscapularis repair are limited, and magnetic resonance imaging (MRI)–based assessments extending to 10 years are particularly scarce. Therefore, it remains unclear whether preserving the comma tissue (in-continuity technique) provides long-term advantages over disrupting the upper subscapularis margin (margin disruption technique). Hypothesis: The in-continuity and margin disruption techniques would demonstrate comparable 10-year radiological and clinical outcomes in patients undergoing arthroscopic isolated subscapularis repair. Study Design: Cohort study; Level of evidence, 3. Methods: Among patients who underwent arthroscopic isolated subscapularis repair between 2008 and 2015, those with an intact repair on 6-month postoperative MRI and at least 2 years of clinical follow-up were identified. From this cohort, 24 patients treated with the in-continuity technique and 24 treated with the margin disruption technique were included. Ten-year MRI findings (subscapularis Goutallier grade, tendon integrity, and supraspinatus tear progression) and clinical outcomes (active range of motion [ROM], visual analog scale [VAS] pain score, Subjective Shoulder Value [SSV], American Shoulder and Elbow Surgeons [ASES] score, and University of California, Los Angeles [UCLA] score) were compared. A subgroup analysis was performed to evaluate long-term structural outcomes according to early tendon healing quality assessed on 6-month MRI. Results: A total of 48 patients were followed for a mean of 11.9 ± 1.2 years. Radiologically, among patients confirmed to have an intact repair at 6 months, none progressed to a retear during long-term follow-up. However, during the 10-year follow-up period, supraspinatus tears developed in a higher proportion of patients in the margin disruption group (11/24 vs 2/24; P = .003). Clinically, at 2 years, the in-continuity group demonstrated higher UCLA scores (median [IQR], 34.0 [29.5-36.0] vs 28.5 [26.8-31.0]; P = .047). By 10 years, the in-continuity technique showed consistently superior functional outcomes, including VAS pain (median [IQR], 2.0 [1.0-3.0] vs 3.0 [2.0-3.2]), ASES (median [IQR], 78.5 [71.0-88.5] vs 63.0 [60.0-70.0]), and UCLA (median [IQR], 28.5 [21.5-30.5] vs 21.0 [18.0-24.0]) scores (all P < .05). In the subgroup analysis, worse early tendon healing quality on 6-month MRI was associated with greater preoperative tear severity, including higher Lafosse grade ( P = .018) and greater tendon retraction ( P < .001); however, early healing status did not predict long-term structural failure at follow-up. Conclusion: Disruption of the comma tissue was associated with a higher risk of long-term supraspinatus tear progression and worse clinical outcome scores compared with the in-continuity comma tissue technique. Although 6 months is an appropriate time point to assess subscapularis tendon integrity, continued clinical deterioration should prompt evaluation for secondary supraspinatus tear progression.