Triple-loaded single-anchor stitch configurations: An analysis of cyclically loaded suture-tendon interface security

Purpose: This study evaluated the strength and suture-tendon interface Security of different suture configurations from triple-suture-loaded anchors. Methods: A juvenile bovine infraspinatus tendon was detached and repaired by use of 4 different suture combinations from 2 suture anchors: 3 simple 2 peripheral simple stitches and I sutures in each anchor (ThreeVo anchor; Linvatec Largo, FL), central horizontal mattress suture passed deeper into the tendon, creating a larger footprint (bigfootprint anchor); 2 peripheral simple stitches with I central horizontal mattress stitch passed through the same holes as the simple sutures (stitch-of-Burns); and 2 simple stitches (TwoVo anchor, Linvatec). The constructs were cyclically loaded between 10 N and 180 N for 3,500 cycles and then destructively tested. The number of cycles required to create a 5-mm gap and a 10-mm gap and the ultimate load to failure and failure mode were recorded. Results: The ThreeVo anchor was strongest and most resistant to cyclic loading (P <.01). The TwoVo anchor was least resistant to cyclic loading. The stitch-of-Burns anchor was more resistant to cyclic loading than both the bigfoot-print anchor and the TwoVo anchor (P <.03). The ThreeVo, stitch-of-Burns, and TwoVo anchors were stronger than the bigfoot-print anchor (P <.05). Conclusions: Three simple sutures in an anchor hold better than two simple sutures. Three simple sutures provide superior suture-tendon Security than combinations of one mattress and two simple stitches subjected to cyclic loading, A central mattress stitch placed more medially than two peripheral simple stitches (bigfoot-print anchor) configured to enlarge the tendon-suture footprint was not as resistant to cyclic loading or destructive testing as three simple stitches (ThreeVo anchor). Clinical Relevance: Placing a central mattress stitch more medially than 2 peripheral simple stitches to enlarge the tendon-suture footprint was not as resistant to cyclic loading or destructive testing as 3 simple stitches.