23 Superior Capsular Reconstruction with Porcine Xenograft

Ruth A. Delaney and Daniel B.L. Garcia

Summary

Outcomes are variable with current nonarthroplasty techniques for treating massive, irreparable rotator cuff tears. Reverse shoulder arthroplasty may be a more reliable option but high complication rates in younger patients and in revision reverse arthroplasty are cause for concern. Superior capsular reconstruction (SCR) recreates superior stability, thereby restoring the glenohumeral fulcrum. In some countries, human allograft tissue is not readily available, therefore we use porcine xenograft. In this chapter, we describe our surgical technique for SCR using the DX Matrix xenograft. Technical pearls for portal placement, graft passage, and suture management are discussed. We also report clinical outcome data on our first 20 cases: 14 males, 6 females, mean age 60.8 years, mean follow-up 12.2 months, range 6?25 months. Seven patients were pseudoparalytic preoperatively; in five, the pseudoparalysis was reversed postoperatively. In one patient, the graft failed at the glenoid on magnetic resonance imaging at 15 months. Overall, mean visual analog scale improved from 5 preoperatively to 1.4 postoperatively, p = 0.0013; American Shoulder and Elbow Surgeons (ASES) score from 46.85 to 76.34, p = 0.004; and subjective shoulder value from 46% to 72%, p = 0.018. There was a significant difference in postoperative ASES scores (p = 0.034) and active forward elevation (p = 0.002) in patients who were pseudoparalytic preoperatively compared to those who were not.

Keywords: massive rotator cuff tear, porcine xenograft, pseudoparalysis, superior capsular reconstruction

23.1 Patient Positioning

We prefer to perform the superior capsular reconstruction (SCR) in the beach chair position, but it can also be performed in the lateral decubitus position. An iodine-impregnated adhesive drape is used to cover the skin, so that the allograft does not come into contact with skin flora prior to insertion.

23.2 Portal Placement

A standard posterior viewing portal and anterosuperior instrumentation portal are created to start. Thereafter, two lateral portals are created to allow for graft and suture passage as well as viewing from lateral. This does not differ from the typical approach to rotator cuff repair. Additional portals are created for insertion of the glenoid anchors, using an outside-in technique with a spinal needle. A separate portal is required for each glenoid anchor, anterior and posterior (? Video 23.1).

23.3 Surgical Technique

As with any arthroscopic procedure, visualization and preparation are critical. A mean arterial blood pressure of less than 80 mmHg is typically required, with a pump pressure of 40 mmHg. A higher pump pressure can be used, but we prefer to do as much of the case as possible before increasing the pressure, as the resultant swelling can make the lateral row anchors difficult to visualize well for insertion on the humerus. The SCR becomes essentially a double-row cuff repair with a side-to-side posterior repair, once you have placed the glenoid anchors and passed the graft.

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Video 23.1 Preparatory steps and anchor placement.

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Video 23.2 Graft placement, lateral row fixation and posterior side to side repair.

23.3.1 Key Steps (Steps 1?5, ? Video 23.1; Steps 6?15, ? Video 23.2)

? Prepare superior glenoid and rotator cuff footprint. The long head of biceps, if present, is usually tenotomized or tenodesed, depending on patient age, activity level, and body habitus; therefore, the superior labrum can be completely debrided to give access to a good bony surface for healing of the graft to the superior glenoid.

? Insert an anterior and a posterior anchor into the superior glenoid. We use 2.9-mm SutureTak anchors. These do not need to be double-loaded. If they are, then pull out one suture from each. It is a good idea to have a color-coding system, so have the blue suture in the posterior anchor and the white suture in the anterior anchor.

? Insert a cannula into the anterior of the two lateral portals. A 10-mm PassPort cannula facilitates graft passage without taking up too much space. A 12 mm cannula is also available if needed.

? Place medial row anchors in the humerus at the margin of the articular cartilage. Again, color code these so that the SwiveLock with blue FiberTape is posterior and white anterior. We do not typically use the safety suture in the reconstruction, but pull it out and use it later as a free suture for the side-to-side repair. It is also possible to use it for a medial double pulley on the graft at this stage, but we have not found that to add to the reconstruction, and it tends to complicate suture management.

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Fig. 23.1 Suture management is critical. All sutures and tapes are retrieved out the lateral PassPort portal and clipped to the drapes in a configuration that corresponds to their respective anchors.

? Bring all sutures and tapes out through the PassPort cannula laterally (? Fig. 23.1).

? Measure the distance between the anchors on all four sides, while an assistant draws out the shape and writes down the measurements on the back table. Take care to measure as accurately as possible. There is a disposable measuring device (as seen in ? Fig. 23.1) or a reusable instrument available.

? Measure out the graft, add 5 mm on each side, mark suture placement, and double the graft over (? Fig. 23.2, ? Fig. 23.3). The porcine xenograft, DX Matrix, is licensed for use as a reinforcement of large rotator cuff repairs. When using it for SCR, it is recommended to double the graft over.

? Pass a traction suture through the middle of the glenoid end of the graft (? Fig. 23.4). We have found that the Scorpion device is the easiest instrument for passing all sutures and tapes through the graft, and leaves a smaller hole in the graft. Bring the graft over to the operative field. Pass the traction stitch in through one of the lateral portals (usually the more anterior one) and retrieve it out through the Neviaser portal created for the posterior glenoid anchor. Clip the traction stitch to the drapes while the remainder of the sutures are being passed.

? Pass two limbs of one suture from each glenoid anchor through the graft, therefore, four passes along the medial end of the graft. (See below for a modification to the glenoid suture configuration to reduce the risk of graft failure at the medial side.)

? Pass the tapes from each medial row humeral anchor through the graft. This can be done at this stage, or the graft can be passed first and then the humeral side tapes passed.

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Fig. 23.2 The graft is measured, cut, and marked for orientation.

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Fig. 23.3 Skin glue is used to double the graft over and fix the two layers.