Anatomic Rotator Cuff Repair With Dual-Layer Fixation: A Knotless Technique

Video Transcript

In this video, we present a technique for anatomic rotator cuff repair with dual-layer fixation using a knotless technique.

Background

The anatomy of the rotator cuff has been better elucidated over the past 15 years. ³ Our understanding of the native footprint directly informs our ability to anatomically restore and repair the rotator cuff.^1,2 The infraspinatus wraps around the lateral aspect of the greater tuberosity, while the supraspinatus inserts in a small triangular area at the anterior footprint, behind the biceps. ⁹ The junction between the 2 tendons is obliquely oriented. The supraspinatus insertion is smaller than originally thought, and the infraspinatus wraps more anteriorly than previously believed.

The superior capsule footprint insertion has also been better defined. The capsule inserts on the medial footprint, shaded orange in this schematic diagram. Initially described as 1 to 2 mm of interwoven fibrils on the articular surface of the rotator cuff, it is now recognized to be 3 to 9 mm thick and occupy 31% to 60% of the rotator cuff footprint. ⁷ These medial footprint fibers have less excursion compared with the lateral fibers.

The rotator cable was first described by Dr Burkhart in 1993, and Park et al ⁸ recently summarized our understanding of this anatomy. The anterior cord is the thickened anterior portion of the anterior supraspinatus, and the cable is a semicircular thickening of the superior capsule. These 2 structures become confluent behind the biceps. This “cable cord confluence” sees a disproportionate amount of force and perhaps deserves special consideration in cuff repair. This is supported by the work of Namdari et al, ⁶ who noted that disruption of the anterior supraspinatus tendon was associated with greater tear size and more advanced supraspinatus muscle degeneration. This attachment area comprises a significant portion of the relatively small supraspinatus insertion and may compromise the force-couple balance of the rotator cuff.

We now understand that the rotator cuff tears frequently have delamination,^4,10 and this must be carefully evaluated and repaired at the time of surgery. Delamination is defined as a horizontal, partial-thickness split of the tendon substance between layers of a torn rotator cuff. The deep layers comprise both the medial cuff and the superior capsule. ¹⁰ Cha et al ² found that delamination occurred in approximately 80% of all cuff repairs in a small series, noting that delaminated tears retracted in a posteromedial direction.

Understanding the anatomic footprint and common retraction patterns can inform the techniques utilized to repair the rotator cuff. Dual-layer fixation has been described by various authors to independently fix the medial footprint—including the superior capsule. This allows for anatomic restoration and appropriate tension on the layers of the rotator cuff. While various techniques have been described, these techniques have used conventional arthroscopic knot tying and focused on tears with significant delamination. We present our technique for dual-layer fixation using a knotless technique to anatomically reduce the native rotator cuff footprint even with minimal delamination of the layers.^5,11

Indications

This technique is indicated for larger tears with delamination or for anatomic repair needed due to the differential excursion of the deep and superficial fibers of the rotator cuff footprint. This patient is a 65-year-old male retired laborer who fell down a hill while clearing brush on his property. Radiographs were negative. Magnetic resonance imaging demonstrated a large rotator cuff tear with mild atrophy and some edema in the infraspinatus, suggesting some chronicity despite the recent injury.

Technique Description

After undergoing general anesthesia, the patient is placed in the lateral decubitus position with 10 pounds of axial traction. However, this technique may also be performed in the beach-chair position. Anatomic landmarks are mapped out. Standard anterior and posterior portals are created, with additional lateral working portals created as necessary. A posterolateral portal utilizing a 70° scope is created for viewing, and an anterolateral portal with placement of a soft cannula is created for passing sutures. The anterior portal, or a small accessory percutaneous portal just off the lateral edge of the acromion, is utilized to place the medial row of all suture anchors, which are best placed more perpendicular to the surface of the bone.

First, debride the subacromial space and the greater tuberosity, and perform releases as necessary. The biceps is intact and preserved, but may be tenodesed at the surgeon's preference. The cuff is mobilized to the tuberosity to plan anatomic restoration and repair. Differential mobilization of the medial cuff and superior capsule is noted.

Medial anchors with an integrated knotless mechanism are placed percutaneously from anterior to posterior. The repair suture of the knotless mechanism is shuttled to the anterolateral working portal and passed through the medial fibers, securing this layer to the medial footprint. This process of passing and deploying the knotless mechanism through the medial, more articular fibers is repeated with the central and posterior anchors. This secures the medial fibers to the medial footprint.

The more superficial infraspinatus fibers, which have retracted medially and posteriorly, are secured with a luggage tag suture. The remaining posterior tapes are then passed in a suture bridge construct through the infraspinatus. A V-shaped gap was noted at the posterior supraspinatus, corresponding with the oblique juncture between the supraspinatus and infraspinatus footprint insertion laterally. The anterior tapes were split to pass 1 through the infraspinatus and 1 through the supraspinatus tissue.

The anterolateral anchor was deployed to complete the suture bridge construct, followed by the posterolateral anchor. The luggage tag suture was incorporated into the lateral anchors as well. Inspection revealed anatomic reconstruction of the rotator cuff to the greater tuberosity. After passing a simple stitch, it was noted that a small gap remained between the supraspinatus and infraspinatus. An additional knotless anchor was deployed and passed in inverted mattress fashion to secure the cuff tissue down to the footprint. Again, the anchor was placed percutaneously, and the repair suture was passed via the anterolateral working portal to simplify suture management. This anchor closed the space between the supraspinatus and infraspinatus and secured the tissue to the tuberosity.

Results

Inspection of the final repair from the bursal side reveals full coverage of the tuberosity and appropriate tension on the soft tissues. Inspection of the articular side of the repair confirmed a secure anatomic reduction of the medial fibers to the footprint as demonstrated by gently sweeping the cuff away from the tuberosity.

Discussion/Conclusion

Utilization of the knotless mechanism avoids knot stacks within the substance of the cuff repair while providing demonstrated benefits of dual-layer fixation—including improved patient-reported outcomes and range of motion as noted by Nakamizo and Horie. ⁵

Postoperative rehabilitation is not accelerated or advanced for dual-layer fixation, and a standard protocol is utilized.

Supplemental Material