22 Superior Capsular Reconstruction with Allograft

David M. Dines, Michael C. Fu, and Joshua S. Dines

Summary

Irreparable rotator cuff tears in the setting of minimal glenohumeral arthropathy is a challenging clinical problem, especially in young active patients. Reverse shoulder arthroplasty has been considered in these patients despite the absence of glenohumeral arthritis; however, concerns persist regarding implant longevity and activity limitations. Alternatively, superior capsular reconstruction (SCR) has emerged as a method of reconstructing the superior capsule and rotator cuff arthroscopically. Originally described in 2013, utilizing a fascia lata autograft, we have adopted a similar SCR technique but with a dermal allograft, which has higher tensile strength with decreased operative time and donor site morbidity. In this article, we describe our SCR technique with an accompanying video demonstration.

Keywords: dermal allograft, irreparable, massive, rotator cuff tear, shoulder arthroscopy, superior capsular reconstruction

22.1 Patient Positioning

At our institution, the vast majority of shoulder arthroscopy cases are performed with the use of regional anesthesia, if possible, for enhanced postoperative pain control. The patient is positioned in the beach chair position for superior capsular reconstruction (SCR), with the operative extremity secured to a pneumatic articulated arm holder. The back of the bed is elevated to approximately 60�, with the medial aspect of the scapula just lateral to the lateral edge of the bed. A kidney post and head holder are also used to secure the patient. We prefer the beach chair position because of ease of positioning, ability to dynamically position the arm intraoperatively, which is especially helpful in presenting the anterior and posterior aspects of the supraspinatus footprint to the arthroscopic field of view, and ease of conversion to open procedures if necessary.

22.2 Portal Placement

A standard posterior glenohumeral viewing portal is established first, followed by an anterior portal through the rotator interval. Typically, one or two lateral portals are used. Medial fixation on the glenoid is achieved with an anterior percutaneous portal just anterior to the acromion or the distal clavicle, and a posterior percutaneous portal, either through the Neviaser Portal or just posterior to the scapular spine.

22.3 Surgical Technique

Following induction of anesthesia and patient positioning, diagnostic arthroscopy is first performed through the posterior glenohumeral viewing portal along with an anterior portal through the rotator interval (? Video 22.1). Particular attention is directed toward the integrity of the subscapularis, which must be repaired if torn. If there is irreparable insufficiency of the subscapularis and/or infraspinatus, alternative treatment options such as reverse shoulder arthroplasty should be considered. There is also a high incidence of concomitant biceps pathology in patients undergoing SCR, and biceps tenodesis is performed in most cases.

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Video 22.1 Accompanying video of our preferred superior capsular reconstruction technique with dermal allograft. Individual surgical steps are detailed in the video captions.

Attention is then directed toward the subacromial space, first by establishing a lateral working portal. A 10-mm flexible cannula (PassPort Cannula, Arthrex, Naples, FL) is placed in the lateral portal to facilitate later graft passage and suture management. A limited subacromial decompression is performed in the standard fashion. The remaining supraspinatus tendon is carefully dissected from any attachments to the internal deltoid fascia, and an intraoperative determination is made whether to attempt rotator cuff repair or to proceed with SCR based on tissue quality and excursion.

After deciding to proceed with SCR, the bone beds medial to the superior glenoid labrum and over the humeral greater tuberosity are prepared with a shaver. Two single-loaded 3.0-mm biocomposite SutureTak anchors (Arthrex) are placed in the superior glenoid neck, at about the 2o?clock and 10o?clock positions. Then, two threaded 4.75-mm biocomposite SwiveLock(Arthrex) suture anchors preloaded with FiberTape(Arthrex) sutures are placed at the medial aspect of the greater tuberosity footprint just lateral to the articular margin, for the medial row of a double-row technique.

The distances between the anchors are measured arthroscopically using a calibrated probe. The positions of the anchors are marked accordingly on a 3.0-mm acellular dermal allograft (ArthroFlex, Arthrex). We typically add 5?10 mm of tissue on each of the four sides to reduce the chance of sutures cutting out. All sutures are retrieved through the lateral cannula, and the greater tuberosity sutures are passed through their respective holes in the graft. For the sutures from the medial glenoid anchors, each limb is passed individually through the graft, approximately 2 mm anterior and 2 mm posterior to the anchor marks on the graft. Therefore, there are four passes through the medial aspect of the graft. In the middle of the graft, one suture limb from each of the medial anchors are then tied to each other over a drill guide or a switching stick. By pulling on the two remaining outside sutures from the glenoid anchors, a double-pulley technique in combination with a tissue grasper are used to deliver the graft into the joint. Once the graft is docked onto the superior glenoid, the two remaining sutures from the glenoid anchor are then tied to each other in a static knot. In many cases, we may also augment the glenoid neck fixation with a previously placed FiberWire suture (Arthrex) at the center position on the graft, which is then fixed at the 12 O?clock position of the glenoid with a PushLock anchor (Arthrex).

Attention is then turned toward lateral fixation of the graft in a double-row fashion. One limb from each of the previously passed FiberTape sutures are retrieved in a criss-crossed fashion and secured at the lateral row using two unloaded 4.75-mm SwiveLock anchors. At this point, additional glenoid anchors may be placed for added fixation if necessary. Finally, the graft is repaired posteriorly to the infraspinatus with side-to-side sutures.

22.4 Surgeon Tips and Tricks

? Thorough bursectomy should be performed to view the entire rotator cuff defect to the glenoid surface.

? The medial glenoid anchors can be placed either through the NeviaserPortal, anterior to the acromion or distal clavicle, or posterior to the scapular spine, whichever allows for the best angle of approach.

? If a biceps tenodesis with an interference screw is placed at the edge of the bicipital groove, this anchor may be preloaded with FiberTape to serve as the anteromedial anchor for lateral graft fixation.

? All sutures should be passed through the graft outside of the body, with an assistant maintaining gentle constant tension to minimize the risk of sutures getting tangled.

? Using a tissue grasper to help in delivering the graft through the cannula and into the joint reduces the risk of the glenoid anchors pulling out when performing the double-pulley technique.

? Prior to completing the lateral fixation, redundancy in the FiberTape can be eliminated by pushing a retriever down each suture to reduce the graft onto the tuberosity bed, while tensioning the suture. The arm is placed at 30� of abduction during the lateral reconstruction.

? Perform margin convergence anteriorly if there is adequate tissue; however, care must be taken to not overconstrain the shoulder.

22.5 Pitfalls/Complications

? The suprascapular nerve may be injured during bursectomy or placement of anchors into the glenoid. Stay at least 5 mm lateral to the base of the scapular spine to avoid damage to the suprascapular nerve.

? Inadequate suture management will lead to tangling of the sutures.

? Inaccurate measurement of the distances between the anchors will result in a graft that is either too large or too small. A graft that is too small may result in postoperative stiffness, increased risk of re-tear, and overtightening of the sutures. Conversely, a graft that is too large may result in joint instability and dog-ear formation.

22.6 Rehabilitation

Postoperative rehabilitation following SCR is carried out rather slowly and cautiously to protect the reconstruction. To allow for adequate graft incorporation and healing, patients are typically immobilized with a shoulder immobilizer with limited motion allowed for the first 6 weeks. Gentle motion is then allowed, with progression to more aggressive mobilization and strengthening at 12?14 weeks.

22.7 Rationale and/or Evidence for Approach

In a cadaveric biomechanical study, Mihata et al1 compared shoulders with intact rotator cuffs, shoulders with absent supraspinatus, and shoulders following SCR with a fascia lata allograft.2 The authors found that relative to the intact condition, absence of the supraspinatus tendon resulted in significantly increased superior humeral translation, subacromial contact pressure, and significantly decreased glenohumeral contact force. Following SCR, superior translation and subacromial contact forces were fully restored. They also demonstrated that SCR with medial graft fixation to the glenoid was biomechanically superior to grafts that were medially repaired to remnant supraspinatus tendon.2 Furthermore, in a separate cadaveric biomechanical study, Mihata et al1 showed that performing acromioplasty concurrently with SCR reduced the subacromial contact area, which may reduce subacromial abrasion and tearing of the graft.3 Finally, in the largest clinical series to date, Mihata et al1 reported on the clinical outcomes of 23 patients that underwent SCR with fascia lata autograft. At an average follow-up of 34.1 months (24?51 months), all patients had an improved American Shoulder and Elbow Surgeons score from an average preoperative score of 23.5 to 92.9 postoperatively. Active elevation also improved from 84� to 148�. In terms of radiographic outcomes, the acromiohumeral distance increased from 4.6 mm to 8.7 mm, and 83% of patients had intact reconstructions without progression of muscle atrophy in postoperative magnetic resonance imaging.

References

[1] Mihata T, Lee TQ, Watanabe C, et al. Clinical results of arthroscopic superior capsule reconstruction for irreparable rotator cuff tears. Arthroscopy. 2013; 29(3):459?470

[2] Mihata T, McGarry MH, Pirolo JM, Kinoshita M, Lee TQ. Superior capsule reconstruction to restore superior stability in irreparable rotator cuff tears: a biomechanical cadaveric study. Am J Sports Med. 2012; 40(10): 2248?2255

[3] Mihata T, McGarry MH, Kahn T, Goldberg I, Neo M, Lee TQ. Biomechanical effects of acromioplasty on superi- or capsule reconstruction for irreparable supraspinatus tendon tears. Am J Sports Med. 2016; 44(1):191?197