Interposition Dermal Matrix Xenografts: A Successful Alternative to Traditional Treatment of Massive Rotator Cuff Tears

Background: Management of massive rotator cuff tears in shoulders without glenohumeral arthritis remains problematic for surgeons. Repairs of massive rotator cuff tears have failure rates of 20% to 94% at 1 to 2 years postoperatively as demonstrated with arthrography, ultrasound, and magnetic resonance imaging. Additionally, inconsistent outcomes have been reported with debridement alone of massive rotator cuff tears, and limitations have been seen with other current methods of operative intervention, including arthroplasty and tendon transfers. Hypothesis: The use of interposition porcine acellular dermal matrix xenograft in patients with massive rotator cuff tears will result in improved subjective outcomes, postoperative pain, function, range of motion, and strength. Study Design: Case series; Level of evidence, 4. Methods: Sixty patients (61 shoulders) were prospectively observed for a mean of 50.3 months (range, 24-63 months) after repair of massive rotator cuff tears with porcine acellular dermal matrix xenograft as an interposition graft. Subjective outcome data were obtained with visual analog scale for pain score (0-10, 0 = no pain) and Modified American Shoulder and Elbow Surgeons (MASES) score. Active range of motion in flexion, external rotation, and internal rotation were recorded. Strength in the supraspinatus and infraspinatus muscles was assessed manually on a 10-point scale and by handheld dynamometer. Ultrasound was used to assess the integrity of the repair during latest follow-up. Results: Mean visual analog scale pain score decreased from 4.0 preoperatively to 1.0 postoperatively (P < .001). Mean active forward flexion improved from 140.7 degrees to 160.4 degrees (P < .001), external rotation at 0 degrees of abduction from 55.6 degrees to 70.1 degrees (P = .001), and internal rotation at 90 degrees of abduction from 52.0 degrees to 76.2 degrees (P < .001). Supraspinatus manual strength increased from 7.7 to 8.8 (P < .001) and infraspinatus manual strength from 7.7 to 9.3 (P < .001). Mean dynamometric strength in forward flexion was 77.7 N in nonoperative shoulders (shoulder that did not undergo surgery) and 67.8 N (P < .001) in operative shoulders (shoulder that underwent rotator cuff repair with interposition porcine dermal matrix xenograft). Mean dynamometric strength in external rotation was 54.5 N in nonoperative shoulders and 50.1 N in operative shoulders (P = .04). Average postoperative MASES score was 87.8. Musculoskeletal ultrasound showed that 91.8% (56 of 61) of repairs were fully intact; 3.3% (2 of 61), partially intact; and 4.9% (3 of 61), not intact. Conclusion: Patients who underwent repair of massive rotator cuff tears with interposition porcine acellular dermal matrix graft have good subjective function as assessed by the MASES score. Patients have significant improvement in pain, range of motion, and manual muscle strength. Postoperative ultrasound demonstrated that the repair was completely intact in 91.8% of patients, a vast improvement compared with results previously reported for primary repairs of massive rotator cuff tears.