Initial load-to-failure and failure analysis in single- and double-row repair techniques for rotator cuff repair

This experimental study aimed to compare the load-to-failure rate and stiffness of single- versus double-row suture techniques for repairing rotator cuff lesions using two different suture materials. Additionally, the mode of failure of each repair was evaluated. In 32 sheep shoulders, a standardized tear of the infraspinatus tendon was created. Then, n = 8 specimen were randomized to four repair methods: (1) Double-row Anchor Ethibond(A (R)) coupled with polyester sutures, USP No. 2; (2) Double-Row Anchor HiFi(A (R)) with polyblend polyethylene sutures, USP No. 2; (3) Single-Row Anchor Ethibond(A (R)) coupled with braided polyester sutures, USP No. 2; and (4) Single-Row Anchor HiFi(A (R)) with braided polyblend polyethylene sutures, USP No. 2. Arthroscopic Mason-Allen stitches were placed (single-row) and combined with medial horizontal mattress stitches (double-row). All specimens were loaded to failure at a constant displacement rate on a material testing machine. Group 4 showed lowest load-to-failure result with 155.7 +/- A 31.1 N compared to group 1 (293.4 +/- A 16.1 N) and group 2 (397.7 +/- A 7.4 N) (P < 0.001). Stiffness was highest in group 2 (162 +/- A 7.3 N/mm) and lowest in group 4 (84.4 +/- A 19.9 mm) (P < 0.001). In group 4, the main cause of failure was due to the suture cutting through the tendon (n = 6), a failure case observed in only n = 1 specimen in group 2 (P < 0.001). A double-row technique combined with arthroscopic Mason-Allen/horizontal mattress stitches provides high initial failure strength and may minimize the risk of the polyethylene sutures cutting through the tendon in rotator cuff repair when a single load force is used.