Biomechanical advantages of triple-loaded suture anchors compared with double-row rotator cuff repairs.
OBJECTIVE
To evaluate the strength and suture-tendon interface security of various suture anchors triply and doubly loaded with ultrahigh-molecular weight polyethylene-containing sutures and to evaluate the relative effectiveness of placing these anchors in a single-row or double-row arrangement by cyclic loading and then destructive testing.


METHODS
The infraspinatus muscle was reattached to the original humeral footprint by use of 1 of 5 different repair patterns in 40 bovine shoulders. Two single-row repairs and three double-row repairs were tested. High-strength sutures were used for all repairs. Five groups were studied: group 1, 2 triple-loaded screw suture anchors in a single row with simple stitches; group 2, 2 triple-loaded screw anchors in a single row with simple stitches over a fourth suture passed perpendicularly ("rip-stop" stitch); group 3, 2 medial and 2 lateral screw anchors with a single vertical mattress stitch passed from the medial anchors and 2 simple stitches passed from the lateral anchors; group 4, 2 medial double-loaded screw anchors tied in 2 mattress stitches and 2 push-in lateral anchors capturing the medial sutures in a "crisscross" spanning stitch; and group 5, 2 medial double-loaded screw anchors tied in 2 mattress stitches and 2 push-in lateral anchors creating a "suture-bridge" stitch. The specimens were cycled between 10 and 180 N at 1.0 Hz for 3,500 cycles or until failure. Endpoints were cyclic loading displacement (5 and 10 mm), total displacement, and ultimate failure load.


RESULTS
A single row of triply loaded anchors was more resistant to stretching to a 5- and 10-mm gap than the double-row repairs with or without the addition of a rip-stop suture (P < .05). The addition of a rip-stop stitch made the repair more resistant to gap formation than a double row repair (P < .05). The crisscross double row created by 2 medial double-loaded suture anchors and 2 lateral push-in anchors stretched more than any other group (P < .05).


CONCLUSIONS
Double-row repairs with either crossing sutures or 4 separate anchor points were more likely to fail (5- or 10-mm gap) than a single-row repair loaded with 3 simple sutures.


CONCLUSIONS
The triple-loaded anchors with ultrahigh-molecular weight polyethylene-containing sutures placed in a single row were more resistant to stretching than the double-row groups.
Barber
F Alan
FA
Plano Orthopedic Sports Medicine and Spine Center, Plano, Texas 75093, USA.
Herbert
Morley A
MA
Schroeder
F Alexander
FA
Aziz-Jacobo
Jorge
J
Mays
Matthew M
MM
Rapley
Jay H
JH
D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D004868:Equipment Failure; D008422:Materials Testing; D020959:Polyethylene; D017006:Rotator Cuff / Q000601:surgery*; D013314:Stress, Mechanical; D053441:Suture Anchors; D013536:Suture Techniques
D020959:Polyethylene