Optimizing Rotator Cuff Repair

The trend toward all-arthroscopic rotator cuff repair is growing. Over the past decade all-arthroscopic rotator cuff repair has evolved, encompassing a range of options based on different forms of technology and techniques. The variation in these techniques and the results they produce has provided impetus for experts to examine the best practices in all-arthroscopic rotator cuff repair. Burkart & Low suggested that a biomechanically stable construct is critical for achieving biological healing¹ and that the evaluation of the “ideal repair construct” should incorporate:

• Suture-to-bone fixation
• Abrasion resistance of the suture
• Suture-to-tendon fixation
• Suture strength
• Know security
• Look security
• Restoration of the anatomic rotator cuff footprint

Observations from studies on how well the AutoCuff System addresses the elements of the ideal repair construct are summarized below.

Suture-to-Bone Fixation and Abrasion Resistance of the Suture

Research has shown wide variations in the pullout strength of various anchor-suture systems.² A biomechanics study performed by A.Weimann, MD and his research group evaluated the OPUS^™ AutoCuff^® System against nine other anchor-suture systems used in arthroscopic rotator cuff repair. Initial pullout strength of anchors, knot rupture, and cyclic loading of each system was assessed. All of the systems demonstrated comparable initial fixation strength, however, at higher levels in the cyclic loading, significant differences in performance were detected between systems. The smaller anchors tended to fail by suture knot rupture. The AutoCuff System “showed an advantage in the implant-and-suture locking mechanism and made the arthroscopic application very simple.³”

Suture-to-Tendon Fixation

Restoring the rotator cuff foot print can establish conditions for optimal rotator cuff healing.¹ Suture-to-tendon fixation is facilitated by providing a good degree of contact between the cuff tissue and tuberoses. A study was conducted to assess the cuff-to-bone interface and pressure consistency after rotator cuff repair using either an open transosseous tunnel technique or arthroscopic AutoCuff System. The AutoCuff System, with the SmartStitch^® Incline^® Mattress stitch combined with the Magnum^® implant, with its unique tensioning capability, provided superior interface pressure compared to the modified Mason-Allen stitch, the simple stitch, or the horizontal stitch.⁴

The researcher concluded that because the Incline Mattress stitch, coupled with the Magnum implant’s cinching mechanism, achieved excellent contact between the cuff tissue and tuberosity, reattachment of tendon-to-bone was likely to be as good as or better than that achieved using conventional repair methods.

Suture Strength, Knot Security, and Loop Security

The Incline Mattress stitch delivered by the AutoCuff SmartStitch Suturing Device provides a more secure stitch than the modified Mason-Allen stitch. In a controlled laboratory study, the SmartStitch Incline Mattress stitch was shown to be superior to the modified Mason-Allen stitch using transosseous tunnels.⁴ Superiority of the SmartStitch Incline Mattress stitch was demonstrated by significantly greater biomechanical strength, as measured using cycles of loading resulting in repair failure and load-to-failure.

Cycle Testing of Rotator Cuff Repairs in Cadaver Shoulder Pairs

Due to the ease of use of the SmartStitch Suturing Device, knotless stitches can be placed arthroscopically in 5 minutes or less, resulting in a more efficient procedure.

Restoration of the Anatomic Rotator Cuff Footprint

Absence of healing after rotator cuff repair is associated with inferior strength and poorer results.⁵ Consequently, the ideal repair must be associated with an excellent rotator cuff footprint restoration.

A prospective study to determine rotator cuff integrity using high-resolution ultrasonography in a cohort of 47 patients with consecutive AutoCuff rotator cuff repairs was recently conducted by J. Uribe, MD and his group in Miami, Florida. All rotator cuff tears were in the small to medium size range. At a mean postoperative follow-up time of 15.8 months (range 2-30 months), 96% of the shoulders demonstrated complete reattachment of the tendon-to-bone. In comparison, literature has suggested anatomical healing rates between 24% and 71% following conventional arthroscopic rotator cuff repair^5,6. Patients in the Uribe cohort reported significantly diminished VAS pain score and improved SF-36 function scores after the procedure and were generally satisfied. These results demonstrate that use of the OPUS AutoCuff System facilitates a technically demanding procedure without any apparent deterioration in clinical results.

Summary

The OPUS AutoCuff System addresses the key considerations of the ideal repair construct, which includes suture-to-bone fixation, abrasion resistance of the suture, suture-to-tendon fixation strength, knot security, loop security, and restoration of the anatomic rotator cuff footprint.

Knotless Implants

Currently, ArthroCare offers three knotless bone anchoring implants for use with the OPUS^® AutoCuff^® System:

Magnum2^®

The Magnum2 advances the field of arthroscopic rotator cuff repair with 41% greater pull out strength* versus the Magnum^®, previously the strongest implant available. The butterfly wing design provides superior bone lock purchase and increased bone lock surface area (30%) in a more compact design.

Magnum^® PI

The Magnum PI is a radiolucent implant made of PEEK-OPTIMA^® Polymer with the fixation strength of steel that is easily revised. The knotless design locks securely under the cortex, reducing the possibility of gap formation by eliminating knot tying. TensionLock™ allows for lateralization of the cuff to restore the anatomic footprint with fine 0.5mm adjustments.

TwinLock™ System

The TwinLock System completes the selection of implants needed for any type of arthroscopic rotator cuff repair. Its 1.8mm sharp-tipped, dual implant design allows for efficient placement of the implants. TwinLock’s incremental tensioning and strong locking wings like the Magnum2 allow for an ideal repair.

1. Burhart SS, Lo IK. Arthroscopic rotator cuff repair. J Am Acad Orthopo Surg 2006;14(6):333-346.

2. Barber FA, Herbert MA, Coons DA, Boothby MH. Sutures and suture anchors—update 2006. Arthroscopy 2006; 22(10):1063-1069.

3. Weimann A, KEbeck C, Zantop T, Raschke M, Petersen W. Biomechanical Evalluation of Different Anchor-Suture Systems in Rotator Cuff Repair. Presented at the annual meeting of the Arthroscopy Association of North America, April 26-29, 2007, San Francisco, CA.

4. Schlegel TF, Hawkins RJ, Lewis CW, Turner AS. An in vivo comparison of the modified Mason-Allen suture technique versus an inclined horizontal mattress suture technique with regard to tendon-to-bone healing; a biomechanical and histological study in sheep. J Shoulder Elbow Surg 2007; 16(1):115-121.

5. Boileau P, Brassart N, Watkinson DJ, Carles M, Hatzidakis AM, Krishnan SG. Arthroscopic repair of full-thickness tears of the supraspinatus: the tendon really heal? J Bone Joint Surg Am 2005; 87(6):1226-1240.

6. Bishop J, Klepps S, Lo IK, Bird J, Gladstone JN, Flatow EL. Cuff integrity after arthroscopic versus open rotator cuff repair: a prospective study. J Shoulder Elbow Surg 2006; 15(3):290-299.