Dermal Tuberoplasty for Irreparable Supraspinatus Tears Using Self-Punching, Knotless Fixation

After the patient has undergone an interscalene block and induction of anesthesia, an examination of the involved shoulder is performed with the patient in the supine position. Passive range of motion and stability testing in all planes are assessed. The patient is then positioned in the lateral decubitus position with the operative arm slightly abducted and flexed with 10 lb of arthroscopic suspension. After the standard preparation, draping, and time-out protocols, a posterior viewing portal is established 2 cm distal and 1 cm medial to the posterolateral acromial edge and a diagnostic arthroscopy is completed. If concomitant glenohumeral pathology (e.g., long head of the biceps pathology, loose bodies, capsular constriction, or labral tearing) is encountered, it is addressed before proceeding. In an effort to maintain the shoulder’s force couples, tears of the subscapularis and/or infraspinatus tendons are repaired whenever possible.

The arthroscope is then redirected into the subacromial space, and a second inflow small-bore cannula is inserted via an anterior portal. We prefer to use dual gravity inflow for shoulder arthroscopy; however, the use of a mechanical pump to maintain intra-articular pressure eliminates the need for a second inflow. A low-lateral portal is established as a working portal, subacromial bursal tissue is debrided with a 5.5-mm shaver, and a partial acromioplasty is performed if necessary. The reparability of the supraspinatus is assessed at this point. Once it is determined that the superior rotator cuff is not anatomically reparable, bone preparation can begin. The shaver is used to debride the native supraspinatus footprint to promote graft adherence. Because the interposed graft is intended to maintain space between the acromion and the greater tuberosity throughout range of motion, medializing the graft to the articular margin is an important step so that the medial graft edge is not lateral to the acromial edge in full adduction. Anteriorly, the bone is debrided to the bicipital groove; posteriorly, to the superior edge of the infraspinatus. A 10-mm-diameter flexible button cannula (PassPort; Arthrex, Naples, FL) is placed through the lateral portal.

A 3-mm-thick dermal graft is prepared on the back table and cut to cover the exposed supraspinatus footprint. Because of the elastic properties of the dermal graft, we have found that a 20 × 25–mm dimension is adequate. A sharp, round instrument (we prefer a 3.5-mm bone punch) is used to dilate 2 holes in the medial edge of the graft approximately 4 mm from the edge. A 3.0-mm biopsy punch can also be used to create these holes in the graft. These pre-punched holes will allow for easier passage of the self-punching medial implants. A marking pen is used to mark the holes so that they can be easily identified once the graft is positioned in the subacromial space. A No. 0 FiberWire suture (Arthrex) is passed through the medial corners of the graft in a simple configuration, and these corner sutures are then passed through the suture channels at the distal end of a retractable graft spreader (Arthrex) (Fig 1). The suture ends are subsequently cleated onto the opposite side of the spreader arm through which it was passed. This creates a crisscross pattern that eases passage through the 10-mm flexible cannula and retains tension on the graft (Fig 2). The articulating arm of the graft spreader can be collapsed to introduce the graft spreader through the cannula and into the subacromial space, where the graft is then spread over the exposed supraspinatus footprint. With the graft in place, a spinal needle is used to help determine the ideal location and trajectory for a small, percutaneous port of Wilmington through which the medial anchors will be inserted. It is important to stay on the lateral edge of the acromion so that the angle of approach is as perpendicular to the bone surface as possible and medial access is not impeded. Adduction and rotation of the arm can help prevent skiving medially. A knotless, transtendinous soft anchor (SP 2.6 FiberTak RC Soft Anchor; Arthrex) is then introduced through the percutaneous access (Fig 3). This anchor allows for direct insertion into bone because it is self-punching and may be used with or without a guide. We have found that using a guide may widen the aperture of the bone, particularly if the guide is inadvertently countersunk as the anchor is malleted. This can affect anchor pullout; therefore, we do not routinely use a guide when inserting the medial anchors through the graft. With the graft stabilized by the graft spreader, the anchor is placed through the pre-punched hole at the posteromedial corner of the graft and then punched into the humerus to the appropriate depth indicated by the thick laser line on the inserter (Fig 4). The inserter is withdrawn, and the anchor is set beneath the bone surface by gentle pulling back on all the sutures. An anteromedial anchor is inserted following the same steps through a separate percutaneous portal.

Once the medial anchors have been placed, the graft spreader can be removed (Fig 5). This is accomplished by holding the graft spreader in place, uncleating the No. 0 FiberWire, and cutting 1 limb at the aperture of the lateral cannula. Pulling on the uncut limb will disengage the graft from the spreader. With both No. 0 sutures removed, the graft spreader arm is folded, and the device can be removed.

The joined tails on the anchor’s 1.7-mm FiberTape suture (Arthrex) are cut, and 1 FiberTape tail from each medial anchor is retrieved through the lateral portal and loaded through the eyelet of the lateral anchor (SwiveLock, 4.75 mm; Arthrex). At this point, the position of the lateral graft should be assessed to ensure that it remains flat against the bone and unfolded. We have found that lateral control of the graft is simple once the medial edge is secured. If the lateral graft edge needs adjustment, a probe or grasper can be used to lay it flat against the bone.

Creation of the lateral row can now be performed. By use of a punch through the lateral cannula, a bone socket is prepared just lateral to the free graft edge along the lateral and proximal humeral cortex. Slight arm abduction can help access this portion of the bone. With the socket now punched, the eyelet of the preloaded lateral implant is engaged in the edge of the bone socket. Final adjustment and tensioning of the FiberTape are completed to remove any slack and ensure compression of the underlying graft against the bone. Once this step is completed, the lateral anchor driver is advanced completely into the bone socket until the anchor body contacts bone. The thumb pad is used to provide axial compression, and the driver handle is rotated clockwise to insert the anchor body until is it flush with the bone. The FiberTape tails are cut, and the steps are repeated for the second lateral anchor (Fig 6).

With the graft secured, the knotless core mechanism of the medial anchors can provide some adjuvant repair variability. We have used the medial repair sutures in several ways depending on the associated shoulder pathology and pattern of the remaining rotator cuff tissue. If some supraspinatus tendon exists, we have often used the knotless repair suture to lateralize the torn supraspinatus tendon edge and accomplish a partial repair. If the superior edge of the subscapularis or infraspinatus is detached, the repair suture may be used to restore the force-couple effect of the tendon by advancing the torn edge over the patch anteriorly or posteriorly. If a biceps tenodesis is indicated, we have used the anteromedial repair suture to perform tenodesis of the long head of the biceps tendon at the top of the bicipital groove. Finally, interconnecting the medial sutures can create a medial bridge to further compress the graft against the humerus.

Clinical data surrounding the outcomes of arthroscopic SCR have shown that this procedure is a viable non-arthroplasty option for the patient with an irreparable rotator cuff tear and little glenohumeral arthritis.^{,  ,  ,}  However, the technical challenges associated with graft delivery, graft fixation, and suture management make this procedure challenging to perform well. Mirzayan et al. reviewed the results of patients who had glenoid-sided radiographic failure of their SCR grafts and found that they showed equal results in terms of visual analog scale scores and American Shoulder and Elbow Surgeons shoulder scores to patients in whom the graft was intact. These authors concluded that an interpositional cushion between the acromion and the humeral head decreased contact pressure and pain derived from friction of the proximally migrated humerus against the undersurface of the acromion. The findings of this study spurred several authors to explore whether glenoid fixation could be obviated completely. Griffin et al. described the use of a 5-mm dermal allograft for interpositional arthroplasty. Their technique required independent insertion of medial anchors followed by external passage of 2 or 3 repair sutures through the graft prior to its insertion. The steps required to create this construct make suture management challenging, and the authors recommended the use of a divider for the lateral cannula to prevent cross-passage of each medial suture. Mirzayan and Bouz described their technique using a folded 3-mm dermal allograft, which also necessitated external passage of medial sutures through the graft. The folded graft and suture construct required the use of a 10-mL syringe with its end cut off to accommodate insertion into the subacromial space.

Our technique has several advantages over previously described dermal allograft tuberoplasty procedures as well as SCR (Table 1). First, graft delivery is simplified by virtue of a graft inserter. This allows for the graft to be inserted into the subacromial space and held in place without the need for passing fixation through its medial edge external to the shoulder. Second, the self-punching medial implants eliminate the need for external suture passage and provide the added benefit of a knotless core, which can serve various purposes including reinforcement of the graft as a medial bridge, tenodesis of the long head of the biceps tendon, or securing of any remaining rotator cuff cable tissue to restore the shoulder’s force couple. Third, this technique obviates glenoid fixation, which is necessary when performing SCR. This results in the use of fewer implants and a potential cost savings. Although we want to emphasize the fact that there is no clinical evidence at this time to suggest that the results after dermal tuberoplasty are comparable to those after SCR, we believe that further studies should be performed to show whether this technique has a role to play in the management of patients with irreparable supraspinatus deficiency.