Slightly better load to failure with one vs. two suture anchors for type II SLAP repairs

A cadaveric study showed no advantage to using two single-loaded anchors for arthroscopic repairs.

FLORENCE — One double-loaded suture anchor used for arthroscopic repair of simple type II superior labral anterior posterior lesions produced results similar to those with two single-loaded anchors, but investigators said using one anchor may reduce operative time and be more cost-effective.

"One anchor with two sutures is a biomechanically sound construct in this model of testing a type II class repair," Eric C. McCarty, MD, said. "One anchor with two sutures often has the same mechanical pullout as two anchors for fixation of type II repairs."

McCarty presented results during the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine Congress.

Cadaveric analysis

The study involved 10 matched pairs of cadaveric shoulders. For each shoulder, researchers resected the surrounding shoulder structures and used a knife to create a simple type II superior labral anterior posterior (SLAP) lesion under the labral biceps attachment at the 12:00 position. They then arthroscopically reconstructed the flaps with one or two 5.0-mm suture anchors and heavy nonabsorbable #2 sutures.

"The [single] double-loaded anchors were placed in the central position" in 10 shoulders, McCarty said. "Then in 10 shoulders two single-loaded anchors, the same type anchor but with just one suture, were placed anterior or posterior with one loop in a similar area as the double-loaded anchor."

Instron testing to failure

Researchers placed the shoulders in an Instron machine and loaded each to failure by moving them in the same directions in which healthy shoulders move.

There were no significant differences between repairs with one or two anchors in this investigation, although load to failure with one anchor was slightly higher, he said.

"The most common mode of failure was a tendon failure," according to McCarty. Investigators actually observed a variety of modes of failure, including tissue tears, but anchor pullout was not one they commonly saw.

Of the research conducted into fixing SLAP lesions with different numbers of anchors or tacks, little has been of a biomechanical nature, McCarty said. "With an increased use of anchors, and potentially an increase in operative time, it is quite attractive to maybe do this with one anchor," he said.

For more information:
Eric C. McCarty, MD, can be reached at CU Sports Medicine, 311 Mapleton Ave., Boulder, CO 80304; 303-441-2219; e-mail: eric.mccarty@uchsc.edu. He indicated his study received support from Stryker.
McCarty EC, Snyder RL, Gines JL, et al. How many anchors are necessary for adequate fixation for simple type II SLAP lesions? #59. Presented at the 2007 International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine Congress. May 27-31, 2007. Florence.