Every cowboy knows that a spirited horse cannot be restrained with only one lead rope. However, a cowboy can wrap a lead rope around a “snubbing post” and thereby gain complete control over the animal, despite the horse’s superior size and strength. The cable friction between the rope and the post creates such a large restraining force that the cowboy can easily hold the animal without the help of a knotted rope (Figure 3). In similar fashion in the Hong Kong scaffolding, fixation strength results from the significant amount of cable friction produced when the lashings wrap around one another and around the bamboo poles.
The cable friction concept was pivotal in the development of knotless fixation in arthroscopic rotator cuff repair. In lateral row fixation, the eyelet of the PushLock and SwiveLock suture anchors (Arthrex) produces significant cable friction at the eyelet–suture interface, in addition to frictional force wedging the suture between anchor and bone.
As with so many other devices in shoulder arthroscopy, the SwiveLock suture anchor developed in stages. In the first stage, a chainlike suture with consecutive intersecting links was used (FiberChain). The idea for an adjustable fixation construct came to me because I thought that a forked eyelet on a SwiveLock would provide a firm fixation point when inserted into the appropriate suture link, yet would be totally adjustable simply by choosing a tighter or looser link (Figure 4). Although the system worked very well, it was technically challenging. The process was greatly simplified after Don Grafton and I developed FiberTape and recognized that the power of cable friction was dramatically increased by the larger contact area between the eyelet and the braided FiberTape. The SpeedBridge construct (Arthrex), which enhanced cable friction fixation by means of passing FiberTape through the anchor eyelets, also provided a larger compressive interface at the repair site by using FiberTape rather than conventional suture. These incremental improvements led to what I would characterize as today’s gold standard for arthroscopic rotator cuff repair: a largely knotless linked double-row construct using FiberTape, with cinch-loop sutures at the anterior and posterior margins of the tear to reinforce the cable attachments and simultaneously reduce the dog-ears that typically occur in those locations, and a double-pulley medial mattress if tendon quality is poor (Figure 5).
The Burden of Craft
With all the recent enthusiasm for level I studies, I think we need to examine whether they will accelerate technological advancement in rotator cuff repair. The answer, in my opinion, is a resounding no. This answer is based on a major disconnect I have detected in how we evaluate these studies in rotator cuff disease and repair.
An irony related to technological advancement in surgery is that the more technically advanced the surgery becomes, the more skill is required. This fact is completely at odds with the public’s perception that technological advances make procedures easier. In arthroscopic rotator cuff repair, the surgeon must look, feel, and be aware to a greater degree than in open surgery.
Edward Tenner, in his book Why Things Bite Back, described the burden of the practitioner of any advanced technology as the burden of craft.14 The burden of craft is the inherent demand on all craftspeople, but particularly surgeons, to “up our game” if we are to be successful in our craft. For arthroscopic rotator cuff repair, the burden of craft requires patience, attention to detail, and the ability to work in a virtual space. Not everyone has these skills. But anyone who wants to practice in this discipline has an obligation to learn the skills required, and then to teach them to others and assess how well they are being applied.
The problem with relying on level I studies to assess the efficacy of a surgical procedure is that they are inherently biased by the surgeons involved. As results depend on surgeons’ skills, and surgeons’ skill levels are not equal, level I studies cannot prove what is possible, cannot demonstrate the limits of a technique, and cannot demonstrate the equivalence of techniques.
Amazingly enough, there are still rotator cuff repair “deniers” who confidently assert from the podium that a large percentage of massive cuff tears cannot be repaired and that, even if they can be repaired, they do not have the biological potential to heal. Given the disparity in surgeons’ skills and results, however, one must ask whether poor results are a consequence of a biological deficit in the patient, or of a skill deficit in the surgeon.