Figure 17.1
Plain radiographs demonstrating a centered glenohumeral joint, cystic changes in the greater tuberosity, and sclerosis of the undersurface of the acromion
MRI is the most common tool used to assess rotator cuff integrity. MRIs provide important insight into three critical factors that can predict failure of structural healing: (1) tear size, (2) retraction, and (3) muscle atrophy. Studies have shown that larger tears [6, 7], retracted tears [8], and tears with higher grades of muscle atrophy [6, 8] are predictors of poor tendon healing. While ultrasound and CT arthrogram studies are less commonly used, they can provide similar information. In this case, selected MRI images demonstrated full-thickness tears of the supraspinatus and infraspinatus tendons with retraction to the medial humeral head (Fig. 17.2). On the T1 sagittal oblique images, there was Grade 2 atrophy of the supraspinatus, superior infraspinatus, and upper subscapularis. Additionally, there was an upper border subscapularis tear and medial subluxation of the biceps tendon.
Figure 17.2
MRI views demonstrating a rotator cuff tear involving the supraspinatus, infraspinatus, and upper border of the subscapularis. There is also medial subluxation of the biceps tendon and evidence supraspinatus muscle atrophy
Management
The decision to proceed with dermal augmentation of a rotator cuff tear is multifactorial. We typically consider preoperative patient-specific factors and both radiographic and intraoperative tear-specific factors when considering dermal augmentation. With regard to patient-specific factors , we consider patients older than 65 years of age, those undergoing revision repairs, smokers, and those with degenerative tears to be at greatest risk for repair failure. In terms of tear-specific factors, we consider massive tears, retracted tears, those with fatty atrophy, and tears with poor intraoperative tendon quality to be appropriate for dermal augmentation. In our practice, the intraoperative assessment of the tendon quality and its perceived ability to hold suture without “pull-through” is the most substantial factor when deciding to augment a repair with a dermal allograft patch.
There is biomechanical data to suggest that dermal or fascial grafts reduce the cyclic gapping and increase the ultimate load to failure at the repair site [9–13]. Both biologic and synthetic grafts are commercially available (Table 17.1). Biologic grafts can vary in their tissue of origin (human, bovine, porcine, or equine dermis) as well as their postharvest processing techniques. Postharvest processing can influence the sterility and mechanical properties of the graft. Grafts can undergo acellularization (removal of cellular and genetic material from the graft), lyophilization (drying process used to improve product shelf life), lamination (layering of multiple sheets of tissue to improve material properties), and/or cross-linking (improves stiffness and material properties of the graft). A comprehensive review of all available graft options is beyond the scope of this chapter which will focus on human dermal graft augmentation. (Can you write a sentence why you prefer the dermal graft?)
Table 17.1
The most popular commercially available scaffolds
Product | Company | Source | Cross-linking |
---|---|---|---|
Artelon and sportmesh | Artimplant AB, Sweden and Biomet Sports | Polyurethane urea polymer | Not applicable |
Bio-blanket | Medicine (IN, USA) Kensey Nash | Bovine dermis | Yes |
Cuff Patch | Corporation (PA, USA) Arthrotek (IN, USA) | Porcine SIS | Yes |
Gore-Tex patch WL | Gore and associates, | Polytetrafluoroethylene (ePTFE) | Not applicable |
GraftJacket | Flagstaff (AZ, USA) Wright Medical (TN, USA) | Human cadaver dermis | No |
Dijon (France) | Terephthalic polyethylene, polyester | Not applicable | |
Permacol | Zimmer (IN, USA) | Porcine dermis | Yes |
Restore | DePuy Orthopedics (IN, USA) | Porcine SIS | No |
Arthroflex | LifeNet Health, Virginia Beach, VA | Acellular human dermal extracellular matrix | Yes |
TissueMend | Stryker Orthopedics (NJ, USA) | Fetal bovine dermis | Yes |
We prefer to perform arthroscopic rotator cuff repair in the beach-chair position . After diagnostic arthroscopy and treatment of any concomitant shoulder pathology, the rotator cuff tendon is debrided and mobilized. In our practice, tears must be reducible to at least the medial aspect of the rotator cuff footprint, with minimal tension, in order to consider a repair and dermal augmentation as there must be improvement of the normal muscle tension that has diminished with the tear, for the muscle to function after repair.
In this case, a debridement of degenerative labrum fraying, a biceps tenodesis, and an upper border subscapularis repair were performed prior to proceeding with the posterior-superior rotator cuff repair (Fig. 17.3). Two double-suture-loaded anchors were placed arthroscopically at the medial aspect of the greater tuberosity, and sutures were passed through the native tendon in a horizontal mattress configuration (Fig. 17.4). We performed acellular dermal extracellular matrix graft augmentation by the double-row technique previously described by Chalmers et al. [14]. We used a posterolateral viewing portal , an 8.25 mm cannula in the anterolateral portal, and a 5.5 mm cannula anteriorly. The anterior-to-posterior and medial-to-lateral dimensions of the residual cuff and footprint were measured with a graduated probe or arthroscopic measuring device (Fig. 17.4). The human dermal patch (Arthroflex, Arthrex, Naples Fl) was cut to fit the dimensions of the rotator cuff medially and the footprint laterally. The anterior limb of the anterior mattress suture was brought through the anterior cannula, and the posterior limb of the posterior mattress suture was brought through the posterior portal. The remaining sutures were then brought through the lateral cannula, from anterior to posterior sequentially, and passed through the medial border of the patch in the same order as they were passed through the rotator cuff. A mulberry knot was tied behind the patch for the anterior and posterior corners. These knots allowed the corner sutures to drag the patch into the subacromial space. The patch was then rolled and fed into the lateral cannula by gentle tension on the free limbs of suture through the anterior and posterior portals (Fig. 17.5). Once the patch was unraveled, and the mulberry knots were secured, the medial-row sutures were retrieved sequentially out of the lateral portal and tied. The lateral humeral cortex was then cleared of soft tissue, the patch was temporarily held in the proper orientation with spinal needles to prevent bunching, and one suture limb from each knot of the medial row was placed into independent knotless lateral-row anchors (Fig. 17.6).