Full-thickness rotator cuff tears. A biomechanical comparison of suture versus bone anchor techniques.

We performed a biomechanical comparison of two rotator cuff repair techniques using fresh-frozen human cadavers. Nine pairs of cadaveric shoulders had standardized full-thickness tears made at the supraspinatus tendon insertion. One of each pair of the cadaveric shoulders was repaired by pulling the tendon into a bone trough in the humeral head using standard sutures. The remaining half of the pairs was repaired using anchor sutures. The repairs were tested using a servohydraulically operated material testing system. The anchor suture repair was significantly stronger than the standard suture technique irrespective of bone quality. Failure occurred predominantly through bone in the suture repairs and as a result of suture breakage in the anchor repairs. The anchors should be placed into the edge of the subchondral bone adjacent to the articular surface. The surgeon should direct the anchor so that the direction of the pull is approximately 90 degrees to the anchor, with the humerus at 30 degrees of abduction.