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Editorial Commentary: Superior Capsule Reconstruction With Dermal Allograft: Effective Marketing or the Real Deal?

      Abstract

      The young patient with a massive, irreparable rotator cuff tear is a challenging problem. Not only is this patient population demanding, but of the few surgical options that exist to manage this problem, each have their own unique limitations; as such, the orthopaedic community continues to search for a treatment that maximizes outcome and durability, while minimizing risk and preserving the native shoulder. Over the past few years, there has been considerable interest in a new surgical technique: the superior capsule reconstruction (SCR). Japanese surgeon, Dr. Teruhisa Mihata, originally described this technique using fascia lata autograft; however, dermal allograft has become the primary graft option in North America, and despite a lack of evidence to support its clinical use, the annual volume of SCR with dermal allograft has risen exponentially. Although this increasing popularity speaks to limitations of the current treatment options for this complex clinical problem, it also calls into question the potential for commercial bias and begs the question: is SCR with dermal allograft truly an effective treatment for the young patient with a massive, irreparable rotator cuff tear?
      Drs. Denard, Brady, Adams, Tokish, and Burkhart are to be congratulated on their collaborative effort to publish the first study pertaining to the clinical outcomes of superior capsule reconstruction (SCR) using dermal allograft, entitled “Preliminary Results of Arthroscopic Superior Capsule Reconstruction With Dermal Allograft.”
      • Denard P.
      • Brady P.
      • Adams C.
      • Tokish J.
      • Burkhart S.
      Preliminary results of arthroscopic superior capsule reconstruction with dermal allograft.
      Before this study, our understanding of SCR has been based on several biomechanical studies
      • Ishihara Y.
      • Mihata T.
      • Tamboli M.
      • et al.
      Role of the superior shoulder capsule in passive stability of the glenohumeral joint.
      • Mihata T.
      • McGarry M.H.
      • Kahn T.
      • Goldberg I.
      • Neo M.
      • Lee T.Q.
      Biomechanical role of capsular continuity in superior capsule reconstruction for irreparable tears of the supraspinatus tendon.
      • Mihata T.
      • McGarry M.H.
      • Kahn T.
      • Goldberg I.
      • Neo M.
      • Lee T.Q.
      Biomechanical effect of thickness and tension of fascia lata graft on glenohumeral stability for superior capsule reconstruction in irreparable supraspinatus tears.
      • Mihata T.
      • McGarry M.H.
      • Kahn T.
      • Goldberg I.
      • Neo M.
      • Lee T.Q.
      Biomechanical effects of acromioplasty on superior capsule reconstruction for irreparable supraspinatus tendon tears.
      • Mihata T.
      • McGarry M.H.
      • Pirolo J.M.
      • Kinoshita M.
      • Lee T.Q.
      Superior capsule reconstruction to restore superior stability in irreparable rotator cuff tears: A biomechanical cadaveric study.
      and one clinical study using fascia lata autograft in only 23 patients (24 shoulders).
      • Mihata T.
      • Lee T.Q.
      • Watanabe C.
      • et al.
      Clinical results of arthroscopic superior capsule reconstruction for irreparable rotator cuff tears.
      Despite the exponential surge in interest and use of SCR with dermal allograft across North America, there had not been one single peer-reviewed clinical study reporting short- or long-term outcomes of this variation on Dr. Mihata's original technique (dermal allograft in substitution for fascia lata autograft). As such, there was a certain need to generate evidence in support of the clinical use of SCR with dermal allograft, and the authors of the present study attempt to fill this notable void in the literature. However, this study generates more questions than it answers, and should serve to temper expectations among surgeons moving forward.
      In the present study, the authors report a success rate of approximately 70%, whereby the authors defined success as achieving the minimal clinically important difference between the pre- and postoperative American Shoulder and Elbow Surgeons functional outcome score. On the surface, this seems promising, but we need to look at this number critically. First, nearly 1 in 5 patients required a reoperation within 1 year, including early conversion to reverse total shoulder arthroplasty (RTSA) in approximately 12% of the entire cohort. Conversely, the reported 5-year conversion rate to RTSA after partial repair of a massive, irreparable rotator cuff tear was only 11%.
      • Cuff D.J.
      • Pupello D.R.
      • Santoni B.G.
      Partial rotator cuff repair and biceps tenotomy for the treatment of patients with massive cuff tears and retained overhead elevation: Midterm outcomes with a minimum 5 years of follow-up.
      This comparison should not only raise concerns regarding appropriate health care expenditure and utilization, but also how prior surgery with numerous suture anchors and a large dermal allograft influences outcomes and complications after RTSA—an area that has yet to be explored. Second, and perhaps the most important finding of this study, was the low rate of allograft healing (45% healing rate among the 20 patients who underwent magnetic resonance imaging [MRI] at 1-year follow-up). This is striking, especially when compared with Dr. Mihata's landmark paper that reported an autograft healing rate of 83.3%,
      • Mihata T.
      • Lee T.Q.
      • Watanabe C.
      • et al.
      Clinical results of arthroscopic superior capsule reconstruction for irreparable rotator cuff tears.
      and raises the question: why? Perhaps the most likely reason is a difference in graft selection, and this would not be the first time that allografts were inferior graft choices for patients undergoing orthopaedic procedures.
      • Wasserstein D.
      • Sheth U.
      • Cabrera A.
      • Spindler K.P.
      A systematic review of failed anterior cruciate ligament reconstruction with autograft compared with allograft in young patients.
      MARS GroupMARS Group
      Effect of graft choice on the outcome of revision anterior cruciate ligament reconstruction in the Multicenter ACL Revision Study (MARS) Cohort.
      It is worthwhile to note that the reported rate of allograft healing in the present study may be influenced by an inherent selection bias (patients were given the option to undergo an MRI, and patients may be more likely to undergo an MRI if not doing well), but irrespective of this methodological limitation, this finding should give the orthopaedic community pause for thought. Third, despite theories that SCR improves the biomechanical function of the shoulder by depressing and re-centering the humeral head, the present study did not find an improvement in the acromiohumeral interval (AHI) at 1-year follow-up. Again, this is contrary to the findings of Dr. Mihata's original study, where at a mean follow-up of almost 3 years (34 months) the authors reported a significant improvement in the AHI of ∼4 mm.
      • Mihata T.
      • Lee T.Q.
      • Watanabe C.
      • et al.
      Clinical results of arthroscopic superior capsule reconstruction for irreparable rotator cuff tears.
      This discrepancy may be explained by differences in graft thickness and type (a 6- to 8-mm fascia lata autograft in the original procedure popularized in Japan
      • Mihata T.
      • Lee T.Q.
      • Watanabe C.
      • et al.
      Clinical results of arthroscopic superior capsule reconstruction for irreparable rotator cuff tears.
      vs a 3-mm dermal allograft in the variation of the procedure common in North America), a theory that is supported by a recent publication demonstrating that SCR with a thicker (∼8 mm) fascia lata allograft has superior biomechanical properties to SCR with a thinner (∼3 mm) dermal allograft,
      • Mihata T.
      • Bui C.N.H.
      • Akeda M.
      • et al.
      A biomechanical cadaveric study comparing superior capsule reconstruction using fascia lata allograft with human dermal allograft for irreparable rotator cuff tear.
      but further study is certainly warranted to better understand how various graft properties impact clinical outcomes. Given all of the above-mentioned findings, I believe that the definition of clinical success in the present study is inadequate for such a complex problem, and I question the notion that this procedure can be considered a success in approximately 70% of patients. In addition, I am concerned that the low rate of graft healing and lack of improvement in the AHI will negatively impact the long-term durability and outcome of this procedure—a concern that will only be addressed in the years to come, and after thousands of these procedures have been performed across North America.
      Given how new SCR with dermal allograft is, there are many questions that remain unanswered, including the influence of allograft thickness and graft healing on outcome. The authors do attempt to answer these 2 questions, but it cannot be overlooked that their observations are potentially biased by the exceedingly small patient sample. For instance, the authors discuss the idea that a thinner graft size negatively influences clinical outcome. Looking deeper at the data, this is based on their observation that 2 of only 5 patients with a 1-cm dermal allograft achieved a clinical success. Similarly, the authors discuss the idea that graft healing influences outcome, but again this is based on comparing outcomes between 9 patients whose grafts healed on MRI and 11 patients whose grafts did not heal on MRI. In addition to the small sample size, there are other methodological limitations in this study that make drawing any meaningful conclusions challenging, such as observer bias (surgeon performed the postoperative assessments), the above-mentioned selection bias in postoperative imaging, and the infrequent collection of postoperative outcomes (outcome scores only collected at one time point after surgery, limiting the capacity to understand how patients are truly faring, including the trajectory in their recovery—are they improving, worsening, or plateauing at 1 year after surgery?). Going forward, there is a need for larger prospective trials—free of a potential for commercial bias—to improve our understanding of the outcomes of this surgery, and answer important, yet fundamental questions like does SCR even work (in the short and long term)? Who is the appropriate patient to undergo this procedure? What graft type and thickness should be used? What rehabilitation protocol should we be using? Ultimately, we currently know very little of this procedure, including its safety, durability, and outcome, and patients should be counseled appropriately before electing to undergo SCR with dermal allograft.
      The surgical management of the young patient with a massive, irreparable rotator cuff tear is a challenging problem. Historically, partial repair with biceps tenotomy or tenodesis, latissimus dorsi transfer (LDT), and shoulder arthroplasty have been the mainstay of treatment. In the present study, the authors do attempt to contextualize their results by drawing comparisons to 2 procedures: LDT
      • Gerber C.
      • Maquieira G.
      • Espinosa N.
      Latissimus dorsi transfer for the treatment of irreparable rotator cuff tears.
      and RTSA.
      • Mulieri P.
      • Dunning P.
      • Klein S.
      • Pupello D.
      • Frankle M.
      Reverse shoulder arthroplasty for the treatment of irreparable rotator cuff tear without glenohumeral arthritis.
      In their discussion, they state that their results are not inferior to these options (more or less the same), but what goes largely unsaid is the considerable difference in follow-up, whereby the referenced studies pertaining to LDT and RTSA have a mean follow-up of 53 and 54 months, respectively. In other words, greater than 4 times the duration of follow-up in the present study, and as such, a direct comparison is not truly possible. Above all, these discrepancies in follow-up highlight that SCR is still in its infancy and the orthopaedic community must resist the temptation to put the cart before the horse—a practice that has burned us in the past.
      Finally, this commentary would not be complete without a discussion pertaining to cost and a potential for performance bias. First, it is not debatable that the SCR with dermal allograft is a very expensive procedure. As such, it is likely that in the current health care system where the finances of a surgical practice are increasingly scrutinized, we will (if not already) be asked to demonstrate the value of this procedure to justify its cost and continued use. This study is hopefully the first of many that will attempt to prove its merit, and ultimately its cost-effectiveness. Second, we must realize that the SCR with dermal allograft is a complex procedure, and that the findings of this study reflect the experiences of some of the most technically gifted shoulder arthroscopists in the world. For surgeons who practice shoulder arthroscopy in lower volume, a watch-and-wait approach would be reasonable to ensure that both the short- and long-term evidence support the clinical use of SCR with dermal allograft before embarking on a potentially steep and expensive learning curve.

      Supplementary Data

      References

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