The failure mode of two reabsorbable fixation systems: Swivelock with Fibertape versus Bio-Corkscrew with Fiberwire in bovine rotator cuff.
BACKGROUND
Despite technical advances in rotator cuff surgery, recurrent or persistent defects in the repaired tendon continue to occur. The improved strength of sutures and suture anchors has shown that the most common site of failure is the suture-tendon interface. The purpose of this study was to compare two different types of repair under both cyclic and load-to-failure conditions. The hypothesis is that the use of a fixation system with knotless anchor and taped suture results in better biomechanical performance, under both cyclic and load-to-failure conditions.


METHODS
Thirty bovine shoulder specimens were randomly assigned to two group tests: the Swivelock 5-mm anchor with Fibertape (Group A) and the Bio-Corkscrew 5 mm with Fiberwire (Group B). We simulated the reconstruction of a rotator cuff tear with a single-row technique, performing a tenodesis with types A and B fixation. Each specimen underwent cyclic testing from 5 to 30 N for 30 cycles, followed by load-to-failure testing, in order to calculate the ultimate failure load (UFL).


RESULTS
Load-to-failure tests revealed a significantly higher UFL in Group A than in Group B. Wire fixing failed at the anchor loop whereas tape fixing failed at the sutures, suture-tendon interface, and anchors. Cyclic testing revealed no significantly greater slippage between the two groups. Stiffness values were not statistically significantly different. In all cases, tendons remained intact until the end of the cyclic testing.


CONCLUSIONS
The tape structure is biomechanically stronger than the wire structure.
Orthopaedic Unit, Sant'Andrea Hospital, Sapienza University of Rome, Via di Grottarossa 1035, 00189 Rome, Italy. angelo.decarli@gmail.com
Angelo
A
De Carli
Riccardo Maria
RM
Lanzetti
Edoardo
E
Monaco
Luca
L
Labianca
Luigi
L
Mossa
Andrea
A
Ferretti
Andrea
A
Feretti
D000818:Animals; D002417:Cattle; D008422:Materials Testing; D023421:Models, Animal; D017006:Rotator Cuff / Q000601:surgery*; D053441:Suture Anchors; D013536:Suture Techniques / Q000295:instrumentation*; D013537:Sutures; D053656:Tenodesis / Q000295:instrumentation*; D013718:Tensile Strength; D016474:Weight-Bearing