Association of Coracoacromial Ligament Degeneration With Rotator Cuff Tear Patterns and Retear Rate

BACKGROUND: Coracoacromial ligament (CAL) degeneration is thought to be a factor in external impingement in bursal-sided rotator cuff tears, but CAL release is associated with adverse effects. PURPOSE: To investigate the association between CAL degeneration and the patterns of massive rotator cuff tears using multiple modalities and to assess the effect of CAL degeneration on supraspinatus tendon retear rates. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The authors prospectively recruited 44 patients who had undergone arthroscopic rotator cuff repair without acromioplasty or CAL release. Preoperative radiographs and magnetic resonance imaging (MRI) scans were reviewed to determine acromial morphology and CAL thickness, respectively. Rotator cuff tears were categorized as isolated supraspinatus or massive (involvement of ≥2 tendons), with massive tears categorized using the Collin classification. Acromial degeneration was analyzed using the Copeland-Levy classification. The CAL was biopsied intraoperatively and histologically analyzed using the Bonar score. At 6-month follow-up, the integrity of the repaired supraspinatus tendon was analyzed on MRI using the Sugaya classification. Finally, the associations among CAL degeneration, rotator cuff tear pattern, and arthroscopic grading were investigated. RESULTS: Patients with Collin type B rotator cuff tear had significantly higher CAL Bonar scores than those with Collin type A or isolated supraspinatus tears (10.0 vs 6.8 and 3.4; P = .03 and P < .001, respectively). Patients with a degenerative acromial undersurface of Copeland-Levy stage 2 or 3 had CALs with significantly higher Bonar scores than those with an intact acromial undersurface (8.4 and 8.2 vs 3.5; P = .034 and P = .027, respectively). The CAL Bonar scores of patients with different stages of the 6-month postoperative Sugaya classification were comparable (6.5, 7.2, 8.0, and 7.8 for stages 1, 2, 3, and 4, respectively; P = .751). CONCLUSION: CAL degeneration was more severe in anterosuperior-type massive rotator cuff tears. Interestingly, even without acromioplasty, the severity of CAL degeneration did not affect the retear rate of the supraspinatus tendon.