Summary: Rotator cuff tendons are typically reattached to the proximal humerus using transosseous sutures or suture anchors. Their primary mode of failure is at the tendon-bone interface. We investigated the addition of a novel adhesive secreted from a species of Australian frog (Notaden bennetti) to different methods of rotator cuff repair. We hypothesized that the addition of frog glue would increase the strength of the repaired rotator cuff construct. Three techniques were used to repair 42 fresh frozen sheep infraspinatus tendons with a mattress stitch configuration: transosseous sutures; 2 traditional metallic suture anchors with 1 suture per anchor, and 2 knotless metallic anchors with 1 suture per anchor. In each group, 7 shoulders were repaired with the addition of frog glue to the infraspinatus "footprint," whereas 7 were used as control with no adhesive. Failure occurred in all constructs at the tendon-bone-suture interface. Repair with suture anchors was stronger than with sutures through bone (P < .05). Frog glue significantly increased the load to failure, total energy required for failure, and maximum energy at failure in all repair techniques (P < .01). A 2-fold increase occurred in load to failure of the 2 common anchor types (143 +/- 8 and 165 +/- 20 N). The load to failure for the transosseous repair (86 +/- 8 N) increased 1.7-fold. The addition of an adhesive to the tendon-bone-suture interface significantly enhances ultimate load and total energy required to failure in 3 types of rotator cuff repair. The unique properties of this frog glue (strong, flexible and sets in water) may ultimately lead to its use as an adjunct to rotator cuff repair in humans.
Level of evidence: Basic science study.