Hello, this is Dr. Lewis McIntyre, I'm very pleased to be part of the online part of the faculty. I'd like to thank Nick and Joe and Kevin and Ian for inviting me to speak today on the topic of partial thickness rotator cuff tears, both articular and bursal sided, and the techniques we might employ in 2020 to treat these. Here are some of my disclosures. I am a consultant for the company that makes the bio-inductive implant. So what exactly is rotator cuff disease? More and more it's recognized as an age-related phenomenon that manifests itself as changes in the bone-tendon interface, which is the enthesis. So this is an enthesopathy, leads to tendonitis, fibrosis, and delamination of the tendon layers, and on to partial thickness tearing and then full thickness tearing. This of course can be affected by occupation, activity, or trauma, but in essence it's a degenerate phenomenon and orthopedic surgeons have addressed this traditionally as a mechanical problem, but it really is both biologic and mechanical and we need to be addressing both of those phenomenon in our treatment modalities. Nick Mafului has written extensively on this and I find his writing enlightening regarding especially the biologic portion of this, and as you can see there are extrinsic and intrinsic causes of rotator cuff degeneration and tearing. Some of the ones in the extrinsic are certainly related to impingement phenomenon and mechanical overuse, the traditional etiologies that we've thought about with rotator cuff tearing, but really what's going on is something intrinsic inside the tendon with cell death or apoptosis, increase in various cytokines and metallomucoproteinases that cause degeneration of the collagen matrix in the tendon. Glucose and lipid content can also affect the cuff and we've known things like this for a long time. There's a drawing from Codman in the lower right from his book from the late 1920s where he recognized that these changes were inherent in the tendon itself and the video that's looping up on top is certainly consistent with a degenerative problem, was certainly maybe some attritional tendinopathy from a true impingement phenomenon. So the natural history of cuff tears is when they increase with age because it is a biologic phenomenon so that the younger you are, the more likely you are not to have a rotator cuff tear. About half of rotator cuff tears will become symptomatic at some point in time and symptomatic tears tend to be those that are increasing in size, larger tears and tend to have more of a tendency to become symptomatic. In regards to partial thickness tears, 40% of those will go on to be full thickness if they are painful and these can't really be treated with a chromioplasty and we've known this for decades now. What the problem is is that the tendon tissue that is left is abnormal. This is a biopsy study from the treatment of partial thickness rotator cuff tears and it shows that 93% of the residual tendon had moderate degenerative changes with these vacuoles and disorganized collagen fibrils. So the tendon that's left in a partial thickness rotator cuff tear is not necessarily normal. And then we have the location phenomenon, obviously articular sided tears are more common than bursal sided tears, but bursal sided tears in my experience and also in Steve Webber's and Frank Cardasco's tend to be poor actors and more difficult to treat, especially since it seems that they are more attritional with tendon loss. So it is a biologic and a mechanical problem and so we have tissue quality and strain. So if we, in a finite element analysis, create partial thickness tears, either on the articular side, bursal side or even intratendinously, we see that there's a significant increase in the strain in the remaining tendon. So those fibers which are already abnormal or under increased strain and more likely to fail. Gus Mazzocca created partial thickness cuff tears and found that strain was increased for at all angles for those tears that were 50 or 75% thickness. So this is where our 50% rule comes from. So that 50% rotator cuff partial thickness tears probably should be fixed because the strain is increased in the other parts of the tendon. Traditionally we've treated these with acromioplasty or debridement in acromioplasty or a trans tendinous pasta type repair or conversion to a full thickness repair. We know that the debridement and acromioplasty alone doesn't work. We've known this for a long time. The results of either trans tendinous or takedown and repair are fairly similar and this is a good systematic review out of Rush that demonstrated that across several studies. The inherent problem here is that although the long-term results at two years are similar, the morbidity of these two procedures in regards to pain and stiffness is considerable in the short term in the first three to six months. So what happens if we could somehow induce new tissue in these partial thickness tears? What would happen? We could reduce the peak strains considerably on both the articular and the bursal side if we can induce new tissue formation with in mind an implant was devised to try to do that. This is a highly purified bovine type 1 collagen from the Achilles tendon of cows. It's highly oriented and porous and it's minimally cross-linked. It has no inherent strength. This is not meant to share a load. This is rather only meant to induce new tissue formation. If we look at the preclinical studies in sheep over a six-month time frame, what happens is that the graft becomes incorporated with fibroblast-like tissues and we get a tendon-like tissue between three and six months. And this has actually been recreated in the human population in biopsy studies done by Steve Arnosky in the same time frames. Regards to the evidence, there's several studies now that show that we can induce some healing in these tissue formation with the use of this graft. This is a study looking at pre and post MRIs in 13 patients and shows consistent filling of the lesions with the use of the graft. This is from Australia and Bokar's work where the tendon thickness increased an average of two millimeters when the graft is placed on the bursal side of the cuff. Interestingly enough, healing can be induced throughout the cuff even though the graft is applied to the bursal side. The mechanism of this is still being elucidated, but an interesting phenomena in that it may be related to load sharing and increased vascularization. There are several studies now that demonstrate the clinical results of this and show safety and efficacy at a two-year follow-up. Here's the procedure. This is a left shoulder viewed from behind, humeral head to your left, biceps, tendon. Tendon markers come out through the skin and mark the anterior aspect of the supraspinatus. A guide wire is in place five millimeters off the footprint and the graft is delivered over the guide wire. The graft is then deployed with this proprietary device and then through auxiliary lateral portals, these PLA bioabsorbable staples are placed to fix the graft to the bursal side of the rotator cuff. Once that's accomplished, the deployment device is removed as well as the guide wire and then some peak bone staples are placed out laterally to fix the graft over the footprint and to the greater tuberosity. The rotator cuff repair for partial thickness tears recovery protocol is pretty much similar to what you would do for a acromioplasty. The sling is for comfort only for 24 to 48 hours. They begin pendulum and supine external rotation exercises right away. They progress to full range of motion between one and six weeks with a cane and then at four to six weeks, they begin strengthening and return to a sport can be between six and 12 weeks. This is a study that I did with some colleagues, a database that we created called Rebuild that collected patients from all over the country, 16 centers. We had 90 partial thickness tears and 83 full thickness tears. As you can see, the patient reported outcomes all improved significantly over the one year time frame of the study. The interesting thing on the partial thickness tear is that the recovery was rather steep and in the first six to 12 weeks, we noticed a significant improvement and rapid recovery from the procedure. Regards to complications and regards to the partial thickness group, we have one adhesive capsulitis, one patient with recurrent infusions treated with steroid injection and one failure to heal that was then taken down and repaired in the full thickness group. We have one infection, a DVT with acute capsulitis and three retears. When we looked in the literature, we can only find two of the studies that documented the results of patients before two years, and that's the Shin study in arthroscopy and the Peters in the JBJS. If you compare our results to either transtendent or takedown and repair in the first three months, we're significantly better than both Peters and Shin for partial thickness tears and still better than the Peters study at six months. The morbidity of the procedure in regards to pain and stiffness in the partial thickness group can be treated a little bit more effectively with the graft instead of takedown, repair or transtendent repair. Another interesting finding was that the patients returned to driving and work in considerably less time than the literature would indicate, much less time in a sling and also less narcotic use. Here's the implant being used with a bursal-sided partial tear. These are difficult to treat with tissue loss and attenuation. You can get muscle tendon mismatch easily if you try to bind this up. So this is a nice way to treat this without instrumenting the rotator cuff at all and creating those mismatches. So a nice indication for the device here. In addition, calcifying tendonitis, once the calcium is extruded from the cuff itself, many times you're left with some significant tissue deficits, especially if the calcium is of the chalky variety and treating that is exceedingly difficult too because of tendon loss. So the graft is a nice way to treat this pathology also. And this video demonstrates that in this right shoulder with graft application over the cuff after the extrusion of the calcium. Another indication would be massive tears. This is a two-tendon U-shaped tear. We're going to do an interval slide and then do our margin convergence to repair the cuff back to the greater tuberosity. Then we're going to augment this with a patch. The patch comes in laterally. You can put these in through an anterior portal also. I usually come all laterally. And then this goes on over top of the repair and is fixed with the PLA staple and then the peak staples. Steve Thon, part of Buddy Savoie's group, came out with this article two years ago. And if you notice, these results are stellar, a small series of patients, only 23 patients. But it significantly increased healing rates here, 100% for the primary massive repairs and then 80% and 89% for revision situation. These numbers are really impressive as literature indicates that there can be up to 78% non-healing of these type of tears. So in summary, tendonitis, partial and full thickness tears are aid-related and biologic in etiology. They tend to progress from tendonitis to partial to full, especially with symptoms. There's associated degeneration of the remaining tendon tissue. And the literature indicates that tears, partial to thickness tears greater than 50% should be fixed. But perhaps with newer techniques, we can bring that number down as we can hopefully get some new tissue formation for our patients who are symptomatic with less percentage tears. So, I think you might want to consider patch augmentation in partial thickness tears, both articular and bursal-sided that are symptomatic and resistant to conservative treatment in massive tears to help increase the rate of healing. In the revision situation where there's decreased vascularity and increased fibrosis, in any situation where you think the healing milieu and environment might be poor. Thank you very much and enjoy the online and lab portions of the course.

rotator cuff tears

bio-inductive implant

partial thickness tears

tendon degeneration

patch augmentation