Biomechanical validation of load-sharing rip-stop fixation for the repair of tissue-deficient rotator cuff tears.

BACKGROUND

Poor-quality tendon is one of the most difficult problems the surgeon must overcome in achieving secure fixation during rotator cuff repair. A load-sharing rip-stop construct (LSRS) has recently been proposed as a method for improving fixation strength, but the biomechanical properties of this construct have not yet been examined.

PURPOSE

To compare the strength of the LSRS construct to that of single-row fixation for rotator cuff repair.

STUDY DESIGN

Controlled laboratory study.

METHODS

Rotator cuff tears were created in 6 cadaveric matched-pair specimens and repaired with a single row or an LSRS. In the LSRS repair, a 2-mm suture tape was placed as an inverted mattress stitch in the rotator cuff, and sutures from 2 anchors were placed as simple stitches that passed medial to the suture tape. The suture tape limbs were secured with knotless anchors laterally before sutures were tied from the medial anchors. Displacement was observed with video tracking after cyclic loading, and specimens were loaded to failure.

RESULTS

The mean load to failure was 371 ± 102 N in single-row repairs compared with 616 ± 185 N in LSRS repairs (P = .031). There was no difference in displacement with cyclic loading between the groups (3.3 ± 0.8 mm vs. 3.5 ± 1.1 mm; P = .561). In the single-row group, 4 of 6 failures occurred at the suture-tendon interface. In the LSRS group, only 1 failure occurred at the suture-tendon interface.

CONCLUSION

The ultimate failure load of the LSRS construct for rotator cuff repair was 1.7 times that of a single-row construct in a cadaveric model.

CLINICAL RELEVANCE

The LSRS rotator cuff repair construct may be useful in the repair of difficult tears such as massive tears, medial tears, and tears with tendon loss.