Anchors and Fixation Devices for Cuff Tears: What Is the State of the Art?

The design for an effective rotator cuff tendon suture anchor should have several characteristics. It should secure the sutures into the bone, not pull out of the bone when subjected to cyclic loading, be easy to place arthroscopically, facilitate arthroscopic knot tying or securing the suture, have at least three sutures, and not cause long-term morbidity. Designs have changed over time, and rotator cuff tendon repair suture anchors currently have several common characteristics: triple-loaded with braided, high-strength sutures, fully-threaded screw-in designs, distal eyelets, and nonmetallic materials ( Fig. 10.1 ).

Suture anchor designs vary and must be chosen for the specific insertion site and application.

The glenoid is smaller and denser than the greater tuberosity. Consequently, an anchor designed for the glenoid will not be as effective if used in a rotator cuff repair. It is helpful to classify rotator cuff anchors as medial row rotator cuff anchors and lateral row rotator cuff anchors.

Anchor size: with screw-in designs, both the outside and core diameters of the anchor are important. Larger anchors (6.5 mm outer diameter; OD) are not any stronger than 5.5 mm OD anchors. Smaller anchors (4.5 mm OD) are often just as strong and may work better than the larger anchors, especially in denser bone sites such as the lesser tuberosity ( Fig. 10.2 ). This is partially because of fully threaded designs, improvements in thread pitch, and the increased surface area of the threads.

Anchor eyelet: eyelet location and shape influence anchor performance. Currently the clear trend is for a distal crossbar eyelet that allows tying sliding locking knots in all three sutures ( Fig. 10.3 ). This type of eyelet is less likely to break and allows for arthroscopically reloading of the anchor with another suture if one breaks or is mistakenly “off-loaded.” The eyelet’s rotation relative to the suture can affect suture fretting and failure load. Therefore it is important to understand the position of the suture-eyelet interface before completely inserting the anchor into bone. Sometimes it is helpful to back out or advance the anchor a half turn to align the sutures and the crossbar perpendicularly to the direction of tissue passing.

Medial row rotator cuff anchors should be robust and have higher load to failure strength than lateral row anchors. These anchors can also be used in a biceps tenodesis. Medial row anchors are typically screw-in anchors, loaded with 2–3 No. 2 UHMWPE- containing sutures, and require knot tying.

Lateral row anchors used in current suture-bridging constructs are knotless. In the double-row, suture-bridging technique sutures from the medial row anchors are passed through the rotator cuff tendon as a mattress stitch, tied in a knot, and then fixed laterally in the knotless anchor to compress the lateral tendon segment onto the greater tuberosity to restore the footprint attachment ( Fig. 10.4 ). Such a technique provides greater footprint coverage and less rotational uncovering.