Preoperative MRI demonstrating massive rotator cuff tear with retraction to the glenoid
This patient has a symptomatic severe, full-thickness tear involving two tendons of the rotator cuff with disproportionate loss of external rotation strength. She had already failed nonoperative treatments and was referred for consideration of operative treatment. The decision was made to attempt repair of the rotator cuff because the humeral head was centered on the glenoid; there were normal rotator cuff muscle with no glenohumeral arthritis, and despite the severe tendon retraction, the history indicated that she was likely to have had an acute-on-chronic tear. We thought that anatomic repair of the tendons would likely yield better function and specifically better external rotation strength than a functional muscle transfer, reverse shoulder arthroplasty, or reverse arthroplasty with latissimus dorsi tendon transfer. She understood that if a rotator cuff repair was not possible, a partial repair, patch augmentation, or debridement would be done, as well as treatment of the biceps tendon for pain relief.
Anesthesia was induced and the patient was placed in the beach chair position with an interscalene regional block. Diagnostic arthroscopy was performed which demonstrated tears of the supraspinatus and infraspinatus tendons, with severe retraction of the infraspinatus (Fig. 8.2). Double-traction sutures were placed in the supraspinatus and infraspinatus tendons. A rotator interval slide in continuity was performed by releasing circumferentially around the corocoid intra- and extra-articularly, but retaining the lateral rotator interval tissue in continuity with the subscapularis tendon. Intra- and extra-articular releases were also performed about the supraspinatus and infraspinatus tendons which allowed the rotator cuff to be brought out to length onto the greater tuberosity. A reverse “L”-shaped tear pattern was present, with softer bone present in the greater tuberosity at the infraspinatus tendon insertion.
Posterior arthroscopic view of severely retracted supra and infraspinatus tear
Two suture anchors were placed posteriorly with a tunnel between them to repair the infraspinatus tendon (Fig. 8.3). A transosseous equivalent-type repair with two lateral row anchors was then completed posteriorly, while the supraspinatus tendon was repaired with arthroscopic transosseous tunnels anteriorly. High-strength sutures in transosseous tunnels were utilized, which created simultaneous medial and lateral row fixation, obviating the need for lateral row anchors and sparing bone in this location. The medial tunnel was 2.9 mm in diameter, while the lateral tunnel was 1.9 mm in diameter (Fig. 8.4).
Posterior view of infraspinatus repair using a transosseous equivalent technique with two anchors medially and two laterally
Arthroscopic transosseous tunnels are utilized to repair the supraspinatus and rotator interval anteriorly
The patient was placed in a sling for 6 weeks postoperatively. She had an uneventful recovery until she fell on her outstretched arm 4 months postoperatively and presented with worsening pain and function. A repeat MRI showed failure at the anchor-based infraspinatus repair, with the transosseous repair of the supraspinatus predominantly intact (Fig. 8.5). The decision was made to proceed with revision rotator cuff repair.
Coronal T2 MRI image showing intact supraspinatus repaired transosseously. Sagittal and coronal views show type 2 re-tear of the infraspinatus
At surgery , arthroscopy confirmed a tendon remnant medially, but the majority of the lateral tendon remained on the tuberosity (Fig. 8.6). A 12–14 mm anchor void was created by removal of the loose anchor, creating concern of placing an anchor or stacked anchors in this void and obtaining fixation (Fig. 8.7). The anterior transosseous tunnels had healed to the rotator cuff. The previous tunnels had healed with bone and offered good bone which was available for revision anchor placement (Figs. 8.8 and 8.9). The previous tunnels were replaced with anchors, and transosseously placed sutures were placed in the previous anchor holes, inverting the prior construct. Figure 8.10 shows the guide arm of the suture tunneler in the anchor void. The tendon remnant was repaired with the inverted hybrid construct with anchor placed in the previous tunnels and tunnels placed in the previous anchor hole positions. This allowed the rotator cuff to heal to the remaining bone with ample access to marrow elements. A “side-to-side” repair effect was also done at the tunneled sites, essentially mimicking a biological patch (Fig. 8.11).
Arthroscopic views confirming a reparable tendon remnant with a type 2 failure of the previous repair. The anatomic footprint of the infraspinatus remains on the tuberosity
Large 12–14 mm anchor void is shown in the footprint of the rotator cuff
A small posteriorly based transosseous tunnel with a suture healed in the bone is seen adjacent to the large void created by the loose anchor. The anterior tunnel shows healing of the rotator cuff into the defect
The previously placed tunnels are revised to anchors with excellent purchase of the bone
Sutures are placed in the bone void, while anchors are used to revise the previous transosseous tunnels. The tunneling guide is shown in position
Lateral and posterior views of final revision repair
At 6-month follow-up, the patient was pleased with the pain relief, range of motion, and strength of the shoulder, and she had an ASES score of 75.
Open transosseous repair of tendons offers a cost-effective [1–9], biologically desirable [10, 11], biomechanically sound [12–16], and clinically effective [17–27] fixation method for healing of human tendons to bone. As a result, it has been considered the gold standard of rotator cuff repair for decades [27–31]. Anchor-based single- or double-row repairs became popular in the 1990s and early 2000s because of technical advances of arthroscopic treatments. Although healing of early single-row anchor constructs was relatively poor [30, 32], more recent double-row and transosseous repairs have had satisfactory outcomes . There is no substantial difference in outcomes or re-tear rates between anchor-based and transosseous techniques . Regardless of the technique, re-tear rates of the rotator cuff are about 25% overall and are even higher after repair of severe rotator cuff tears. Surprisingly, functional outcomes may fail to correlate with repair integrity [34, 35].
Arthroscopic methods of transosseous cuff repair have been described which have similar clinical results and decreased cost to anchor-based repairs [17–19, 23, 36]. Anchor-based and transosseous techniques have various benefits, but are not mutually exclusive, and thus can be used synergistically to treat severe rotator cuff tears . This is advantageous when there is tendon or bone loss, revision scenarios, need for multiple fixation points, and poor local biology, and when the surgeon wants to use allograft or synthetic tissue augments and other biologically active substances.
Basic science has supported several principles for rotator cuff repair: high initial fixation strength, adequate resistance to cyclic loading, and anatomic footprint reconstruction with crossing sutures meant to provide compression and decrease shear forces at the tendon-bone interface . Anchor-based constructs can satisfy many of these requirements including stiff and strong initial fixation, as well as ease of insertion and inherent bone augmentation in areas of soft bone at risk for anchor pullout. Transosseous equivalent (TOE) methods can mimic the cerclage effect about the footprint created by transosseous repair . Because one anchor per fixation point is necessary, multiple anchors must be used, increasing cost and hardware in the greater tuberosity, as well as creating abrupt stress and strain transitions across delicate and poorly vascularized tissue which remains the weakest link in the repair. Some mechanical and biological concerns regarding anchor fixation are tissue strangulation , stress concentration , and modulus mismatch at the anchor-suture-tendon interface. Since the healing capability of the rotator cuff is poor and consists predominantly of controlled reparative, scar-based healing rather than regenerative healing with a new tendon insertion , these factors can produce “failure in continuity” seen as failure at the medial anchor. Previous authors have described this failure mode to be associated with, if not unique to, anchor constructs [42, 43]. When there is cuff failure it can be a type 1 failure defined as a torn cuff with no tendon left on the tuberosity, or type 2 failure where the tendon is torn at the medial anchors, leaving the tendon attached to the greater tuberosity. With a type 2 failure the shortened remaining tendon makes revision more difficult and increases tension in the repair. Techniques such as patch augmentation, bridging of tendon gaps, superior capsular reconstruction, bone loss management around anchor voids, and tension reduction strategies increase cost and technical difficulty. The exact interplay of biological factors such as vascularity and mechanical factors such as tension, stiffness, and ultimate failure strength necessary for healing remains unknown but matching local tissue mechanics rather than trying to exceed them may be more beneficial to biological healing. In summary, we consider both biological and mechanical factors for each patient in their rotator cuff repair.