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1.  Clinical and Radiological Evaluation after Arthroscopic Rotator Cuff Repair Using Suture Bridge Technique 
Clinics in Orthopedic Surgery  2013;5(4):306-313.
Background
We retrospectively assessed the clinical outcomes and investigated risk factors influencing retear after arthroscopic suture bridge repair technique for rotator cuff tear through clinical assessment and magnetic resonance arthrography (MRA).
Methods
Between January 2008 and April 2011, sixty-two cases of full-thickness rotator cuff tear were treated with arthroscopic suture bridge repair technique and follow-up MRA were performed. The mean age was 56.1 years, and mean follow-up period was 27.4 months. Clinical and functional outcomes were assessed using range of motion, Korean shoulder score, Constant score, and UCLA score. Radiological outcome was evaluated with preoperative and follow-up MRA. Potential predictive factors that influenced cuff retear, such as age, gender, geometric patterns of tear, size of cuff tear, acromioplasty, fatty degeneration, atrophy of cuff muscle, retraction of supraspinatus, involved muscles of cuff and osteolysis around the suture anchor were evaluated.
Results
Thirty cases (48.4%) revealed retear on MRA. In univariable analysis, retear was significantly more frequent in over 60 years age group (62.5%) than under 60 years age group (39.5%; p = 0.043), and also in medium to large-sized tear than small-sized tear (p = 0.003). There was significant difference in geometric pattern of tear (p = 0.015). In multivariable analysis, only age (p = 0.036) and size of tear (p = 0.030) revealed a significant difference. The mean active range of motion for forward flexion, abduction, external rotation at the side and internal rotation at the side were significantly improved at follow-up (p < 0.05). The mean Korean shoulder score, Constant score, and UCLA score increased significantly at follow-up (p < 0.01). The range of motion, Korean shoulder score, Constant score, and UCLA score did not differ significantly between the groups with retear and intact repairs (p > 0.05). The locations of retear were insertion site in 10 cases (33.3%) and musculotendinous junction in 20 cases (66.7%; p = 0.006).
Conclusions
Suture bridge repair technique for rotator cuff tear showed improved clinical results. Cuff integrity after repair did not affect clinical results. Age of over 60 years and size of cuff tear larger than 1 cm were factors influencing rotator cuff retear after arthroscopic suture bridge repair technique.
doi:10.4055/cios.2013.5.4.306
PMCID: PMC3858092  PMID: 24340151
Rotator cuff tear; Suture bridge technique; Retear; Magnetic resonance arthrography
2.  Long-term outcome and structural integrity following open repair of massive rotator cuff tears 
Background:
Surgical repair of massive rotator cuff tears is associated with less favorable clinical results and a higher retear rate than repair of smaller tears, which is attributed to irreversible degenerative changes of the musculotendinous unit.
Materials and Methods:
During the study period, 25 consecutive patients with a massive rotator cuff tear were enrolled in the study and the tears were repaired with an open suture anchor repair technique. Preoperative and postoperative clinical assessments were performed with the Constant score, the simple shoulder test (SST) and a pain visual analog scale (VAS). At the final follow-up, rotator cuff strength measurement was evaluated and assessment of tendon integrity, fatty degeneration and muscle atrophy was done using a standardized magnetic resonance imaging protocol.
Results:
The mean follow-up period was 70 months. The mean constant score improved significantly from 42.3 to 73.1 points at the final follow-up. Both the SST and the pain VAS improved significantly from 5.3 to 10.2 points and from 6.3 to 2.1, respectively. The overall retear rate was 44% after 6 years. Patients with an intact repair had better shoulder scores and rotator cuff strength than those with a failed repair, and also the retear group showed a significant clinical improvement (each P<0.05). Rotator cuff strength in all testing positions was significantly reduced for the operated compared to the contralateral shoulder. Muscle atrophy and fatty infiltration of the rotator cuff muscles did not recover in intact repairs, whereas both parameters progressed in retorn cuffs.
Conclusions:
Open repair of massive rotator tears achieved high patient satisfaction and a good clinical outcome at the long-term follow-up despite a high retear rate. Also, shoulders with retorn cuffs were significantly improved by the procedure. Muscle atrophy and fatty muscle degeneration could not be reversed after repair and rotator cuff strength still did not equal that of the contralateral shoulder after 6 years.
Level of evidence:
Level IV
doi:10.4103/0973-6042.94304
PMCID: PMC3326749  PMID: 22518073
Magnetic resonance imaging; massive rotator cuff tear; open rotator cuff repair; rotator cuff strength; subscapularis function
3.  Teres Minor Hypertrophy is a Common and Negative Predictor of Outcomes after Rotator Cuff Repair 
Orthopaedic Journal of Sports Medicine  2016;4(7 suppl4):2325967116S00102.
Objectives:
The teres minor has received increased attention in its role as a rotator cuff muscle, particularly in the setting of large infraspinatus tears. Studies have shown that it plays an important beneficial role after total (TSA) and reverse (RSA) shoulder arthroplasty, as well as in maintenance of function in the setting of infraspinatus wasting in patients with large rotator cuff tears. No study, however, has investigated how often teres minor hypertrophy occurs in a population of rotator cuff tears, whether it occurs in the absence of infraspinatus tearing, or whether it is a positive or negative prognostic indicator on outcomes after rotator cuff repair. The purpose of this study was to determine the prevalence of teres minor hypertrophy in a cohort of patients undergoing rotator cuff repair, and to determine its prognostic effect, if any, on outcomes after surgical repair.
Methods:
Over a 3 year period, all rotator cuff repairs performed in a single practice by 3 American Shoulder and Elbow Society (ASES) member surgeons were collected. One hundered forty-four patients who had preoperative and postoperative (ASES) outcomes (minimum 2 year), and preoperative Magnetic Resonance Imaging (MRI) were included in the study. All MRIs were evaluated for rotator cuff tear tendon involvement, tear size, and Goutallier changes of each muscle. In addition, occupational ratios were determined for the supraspinatus, infraspinatus, and teres minor muscles. Patients were divided into 2 groups, based upon whether they had teres minor hypertrophy or not, based on a previously established definition. A 2 way univariate ANOVA was used to determine the effect of teres minor hypertrophy(tear size by hypertrophy) and Goutallier changes(tear size by fatty infiltration) on ASES change scores(α=0.05)
Results:
Teres minor hypertrophy was a relatively common finding in this cohort of rotator cuff patients, with 51% of all shoulders demonstrating hypertrophy. Interestingly, in patients without an infraspinatus tear, teres minor hypertrophy was still present in 19/40 (48%) of patients. Teres minor hypertrophy had a significant, negative effect ASES scores after rotator cuff repair in patients with and without infraspinatus tearing, infraspinatus atrophy, and fatty infiltrative changes(P<0.05). In general, the presence of teres minor hypertrophy demonstrated a 15% lower score (Figure 1) than when no hypertrophy was present, and this was consistent across all tear sizes, independent of Goutallier changes.
Conclusion:
Teres minor hypertrophy is a common finding in the setting of rotator cuff tearing, including in the absence of infraspinatus tearing. Contrary to previous publications, the presence of teres minor hypertrophy in patients with rotator cuff repair does not appear to be protective as a compensatory mechanism. While further study is necessary to determine the mechanism or implication of teres minor hypertrophy in setting of rotator cuff repair, our results show it is not a positive predictor of outcomes following rotator cuff repair.
Summary Sentence:
The mechanism of teres minor hypertrophy was found to be a negative predictor in rotator cuff repair after pre and post-op measures were collected on patients undergoing cuff repair.
doi:10.1177/2325967116S00102
PMCID: PMC4968368
4.  Does an Arthroscopic Suture Bridge Technique Maintain Repair Integrity?: A Serial Evaluation by Ultrasonography 
Biomechanical studies suggest a suture bridge technique enhances rotator cuff tendon footprint contact area, holding strength, and mean contact pressure. Based on these studies, we asked whether (1) the suture bridge technique would provide a high rate of cuff integrity after surgery, (2) the status of the repaired cuff would change with time, (3) preoperative factors could predict postoperative cuff integrity, and (4) patients with retears had less favorable pain, functional scores, range of motion (ROM), and muscle strength compared with those with intact repairs. We prospectively followed 78 patients with arthroscopic repairs in whom we used the suture bridge technique. The integrity of the rotator cuff repair was determined using ultrasonographic evaluation at 4.5 and 12 months after surgery. Ultrasonography revealed intact cuffs in 91% at 4.5 months postoperatively, all of which were maintained at the 12-month followup. Failure rates were 17.6% (three of 17) for massive tears, 11.1% (two of 18) for large tears, 6.3% (two of 32) for medium tears, and no failures for small tears. Preoperative fatty degeneration of the supraspinatus muscle was a strong predictor of cuff integrity. We found no correlation between the integrity and clinical outcomes except for a temporary decrease of abduction strength at 6 months. Arthroscopic repair using suture bridge technique can achieve a low retear rate in shoulders treated for rotator cuff tears, but the occurrence of retear did not influence the outcome.
Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-009-0990-8
PMCID: PMC2865619  PMID: 19629607
5.  Perivascular Stem Cells Diminish Muscle Atrophy and Retain Viability in a Rotator Cuff Tear Model 
Orthopaedic Journal of Sports Medicine  2016;4(7 suppl4):2325967116S00147.
Objectives:
Rotator cuff tears (RCTs) are a common cause of shoulder pain and often necessitate surgical repair. Muscle changes including atrophy, fibrosis, and fatty degeneration can develop after RCTs, which may compromise surgical repair and clinical outcomes. Lipoaspirate-derived human perivascular stem cells (PSCs) have demonstrated myogenic and angiogenic potential in other small animal models of muscle injury. We hypothesized that the administration of PSCs following massive RCTs may help to diminish these muscle changes in a small animal model.
Methods:
A total of 90 immunodeficient mice were used (15 groups, N=6). Each was assigned to one of three surgical groups: i) sham, ii) supraspinatus and infraspinatus tendon transection (TT), or iii) TT and suprascapular nerve denervation (TT+DN). PSCs were harvested from human lipoaspirate and sorted using fluorescence-activated cell sorting into small blood vessel residing pericytes (CD146+ CD34- CD45- CD31-) and large blood perivascular adventitial cells (CD146- CD34+ CD45- CD31-). Mice received either a) no injection, b) saline injection, c) pericyte injection, or d) adventitial cell injection at the time of the index procedure or at two weeks following index surgery. The supraspinatus muscles were harvested six weeks after the index procedure. Muscle atrophy was assessed by measuring percent wet muscle weight change for each sample. Muscle fiber cross-sectional area (CSA), fibrosis, and fatty degeneration were analyzed using Image J™. Additionally, pericytes and adventitial cells were transduced with a luciferase-containing construct. Animals were given injections of luciferin and imaged using IVIS to track in vivo bioluminescence following injections to assess cell viability.
Results:
Treatment with PSC injection after TT resulted in less wet weight loss and greater muscle fiber CSA than control groups (P<0.05). The TT+DN groups treated with PSC injections two weeks post-op also had less muscle weight loss and greater muscle fiber CSA than their respective control groups. The TT+DN groups treated with PSC injections at the time of surgery demonstrated no differences in weight loss, but had greater muscle fiber CSA than their respective controls. There was no difference in fibrosis between the TT groups. However, TT+DN groups treated with pericyte injections at both time points and adventitial cell injections two weeks post-op had less fibrosis than TT+DN controls. There was less fatty degeneration in the TT groups treated with pericyte injections at both time points and adventitial cells at the time of surgery compared to matched controls. There were no differences in the amount of fatty degeneration between the TT+DN groups. Bioluminescence imaging demonstrated viability of the injected cells at three weeks following injections (Figure 1).
Conclusion:
Our findings demonstrate significantly less muscle atrophy in the groups treated with PSC injections compared to respective controls for both TT and TT+DN procedures. These results suggest that the use of PSCs may have a role in the prevention of muscle atrophy by aiding in the maintenance of muscle bulk without leading to increased fibrosis or fatty infiltration. Additionally, bioluminescence data suggests that these cells maintain viability and engraft within the native muscle to improve muscle bulk. Improved muscle quality in the setting of rotator cuff tears may increase the success rates of rotator cuff repair and lead to superior clinical outcomes.
doi:10.1177/2325967116S00147
PMCID: PMC4968302
6.  Chronic Degeneration Leads to Poor Healing of Repaired Massive Rotator Cuff Tears in Rats 
Background
Chronic rotator cuff tears present a clinical challenge, often with poor outcomes after surgical repair. Degenerative changes to the muscle, tendon, and bone are thought to hinder healing after surgical repair; additionally, the ability to overcome degenerative changes after surgical repair remains unclear.
Purpose/Hypothesis
The purpose of this study was to evaluate healing outcomes of muscle, tendon, and bone after tendon repair in a model of chronic rotator cuff disease and to compare these outcomes to those of acute rotator cuff injuries and repair. The hypothesis was that degenerative rotator cuff changes associated with chronic multitendon tears and muscle unloading would lead to poor structural and mechanical outcomes after repair compared with acute injuries and repair.
Study Design
Controlled laboratory study.
Methods
Chronic rotator cuff injuries, induced via detachment of the supraspinatus (SS) and infraspinatus (IS) tendons and injection of botulinum toxin A into the SS and IS muscle bellies, were created in the shoulders of rats. After 8 weeks of injury, tendons were surgically reattached to the humeral head, and an acute, dual-tendon injury and repair was performed on the contralateral side. After 8 weeks of healing, muscles were examined histologically, and tendon-to-bone samples were examined microscopically, histologically, and biomechanically and via micro–computed tomography.
Results
All repairs were intact at the time of dissection, with no evidence of gapping or ruptures. Tendon-to-bone healing after repair in our chronic injury model led to reduced bone quality and morphological disorganization at the repair site compared with acute injuries and repair. SS and IS muscles were atrophic at 8 weeks after repair of chronic injuries, indicating incomplete recovery after repair, whereas SS and IS muscles exhibited less atrophy and degeneration in the acute injury group at 8 weeks after repair. After chronic injuries and repair, humeral heads had decreased total mineral density and an altered trabecular structure, and the repair had decreased strength, stiffness, and toughness, compared with the acute injury and repair group.
Conclusion
Chronic degenerative changes in rotator cuff muscles, tendons, and bone led to inferior healing characteristics after repair compared with acute injuries and repair. The changes were not reversible after repair in the time course studied, consistent with clinical impressions.
Clinical Relevance
High retear rates after rotator cuff repair are associated with tear size and chronicity. Understanding the mechanisms behind this association may allow for targeted tissue therapy for tissue degeneration that occurs in the setting of chronic tears.
doi:10.1177/0363546515596408
PMCID: PMC4750378  PMID: 26297522
shoulder; rotator cuff; fatty degeneration; rotator cuff repair
7.  PDGFRα+ Progenitor Cells Contribute to Muscle Fibroadipogensis Following Massive Rotator Cuff Tears in a Mouse Model 
Orthopaedic Journal of Sports Medicine  2016;4(7 suppl4):2325967116S00149.
Objectives:
Rotator cuff tears affect an estimated 10% of patients over the age of 60, leading to significant activity related pain and decreased quality of life. After sustaining a tear, the rotator cuff musculature often undergoes muscle atrophy and fatty degeneration, which have been shown to result in poor clinical outcomes and high failure rates for surgical repairs. The cellular processes underlying these fibroadipogenic changes remain unknown although PDGFRβ+ cells have previously been implicated. Recently, it has been demonstrated in hind limb muscle that following acute, reversible injury via Cardiotoxin injection, PDGFRα-expressing cells are responsible for fibrotic and adipogenic muscle degeneration. Our study aimed to distinguish between the contribution of PDGFRα+ PDGFRβ+ cells and PDGFRα- PDGFRβ+ cells to fibroadipogenesis following massive rotator cuff tears.
Methods:
We performed supraspinatus tenotomy and denervation (TT+DN) operations on 8-10 week-old PDGFRβ-Cre x mTmG mice. These transgenic mice express GFP in cells co-expressing PDGFRβ, which allows PDGFRβ+ cell populations to be tracked via their GFP expression. At 5 days, 2-, 4- and 6-weeks postop, these mice and sham surgery controls were sacrificed and their supraspinatus muscles were harvested. We stained tissue sections with Oil Red O and Picro Sirius to compare levels of adipogenesis and fibrosis after TT+DN, respectively. In addition, sectioned muscle tissues were immuno-labeled with anti-PDGFRα and anti-PDGFRβ to assess differences in PDGFRα+ PDGFRβ+ cell localization. GFP expression was used to trace PDGFRβ cells and their progenies after TT+DN. Dissociated cells from supraspinatus tissue of TT+DN versus sham mice were either analyzed by flow cytometry for PDGFRα and GFP expression at established postop time points or sorted and cultured for in vitro differentiation experiments to assess the fibroadipogenic potential of these cell populations.
Results:
Oil Red O and Picro Sirius staining demonstrated that supraspinatus tissue reliably underwent significant fibroadipogenic changes that increased over time and were more pronounced 6 weeks following TT+DN. At 6 weeks following massive rotator cuff tears, PDGFRα+ GFP+ cells, GFP+ fibrotic tissue, and GFP+ adipocytes were detected in interstitial scar tissue (Fig. 1), indicating a contribution of PDGFRα+ PDGFRβ+ cells to fibroadipogenesis. Flow cytometry analyses revealed that the frequency of adipogenic PDGFRα+ sub-population was significantly increased 5 days postop and subsequently decreased to basal levels within 2 weeks. PDGFRα+ GFP+ cell populations were significantly more fibrogenic than other cell populations and increased fibrogenic potential was detected in PDGFRα cells from TT+DN mice in vitro (Table 1).
Conclusion:
PDGFRα+ fibroadipogenic progenitor cells directly contribute to post-injury rotator cuff fibroadipogenesis in a mouse model of massive rotator cuff tears. This cell population likely contributes to muscle atrophy and fatty degeneration of the rotator cuff in human pathology as well. With further development of clinical protocols, perioperative inhibition of this cell population or depletion of PDGFRα+ cells prior to cell transplantation in a regenerative treatment strategy may diminish fatty degeneration and improve clinical outcomes associated with rotator cuff tears.
doi:10.1177/2325967116S00149
PMCID: PMC4968245
8.  Muscle Injury Induced At the Time of Acute and Chronic Rotator Cuff Repair 
Orthopaedic Journal of Sports Medicine  2014;2(2 Suppl):2325967114S00103.
Objectives:
Rotator cuff tears are a common source of shoulder pain and disability. Even after surgical repair of these tears, many patients continue to have reduced shoulder function and a progression of intramuscular fatty degeneration. Previous work in a sheep model demonstrated that a slow, progressive lengthening of chronically torn cuff muscles followed by surgical repair of the tendon reversed fatty degeneration and improved muscle function. As patients with chronic cuff tears often experience a shortening of the muscle fibers, it is possible that repairing the torn tendon to its original anatomical footprint induces a massive stretch-induced muscle injury that could contribute to poor outcomes after repair. Evans Blue Dye (EBD) is a water soluble, membrane impermeable dye, that is used to identify muscle fibers that have suffered an injury to their plasma membrane. We hypothesized that, compared with acutely torn and repaired rotator cuff muscles, the substantial stretch that is required to repair a chronically torn and shortened rotator cuff would result in significant muscle fiber damage.
Methods:
This study was approved by our IACUC. Male Sprague-Dawley retired breeder rats (n=30) were placed into 5 groups: control, sham surgery, acute tear no repair, acute tear and repair, chronic tear no repair and chronic tear and repair, with each modality performed bilaterally (Fig 1A). An intraperitoneal injection of 1% EBD was administered 24 hours before the harvest surgery. At harvest, the supraspinatus muscles of each rat were removed and the length and mass of each muscle was measured. To determine EBD+ fibers the supraspinatus muscles were snap frozen in OCT and the muscles were cryosectioned and incubated with WGA-Lectin-AF488 to mark the extracellular matrix (ECM), DAPI to identify nuclei and EBD was used to identify the fibers with a damaged sarcolemma (Fig 1B-C). A one-way ANOVA (p<0.05) and Tukey’s post-hoc sorting was used to evaluate the differences between groups.
Results:
Compared with controls, rats that had a chronic supraspinatus tear but did not undergo repair had a 35% decrease in muscle mass compared to controls, while rats that had a chronic tear and also underwent repair had a 24% decrease in wet mass compared to controls (Fig 1D). Both groups of rats that underwent a chronic tear experienced an approximate 20% decrease in supraspinatus length when compared to the muscle length of other groups (Fig 1E). In the sham, acute and chronic tear and repair groups there were a greater number of EBD+ fibers in the mid-distal region of the muscle than in the mid-proximal region (Fig 1F). At the mid-distal end of the control and chronic tear no repair groups there were very few EBD+ fibers, in the sham 27% of the fibers were EBD+ and the remaining groups had almost 90% EBD+ fibers (Fig 1F). At the mid-proximal portion of the muscle the chronic tear and repair group had nearly 70% EBD+ fibers while none of the other groups showed a significant increase in EBD+ fibers over the control group (Fig 1G).
Conclusion:
A massive injury to muscle fibers is induced when the tendons of chronically torn rotator cuffs are repaired to their anatomical footprint. The repair of chronically torn cuff muscles results in extensive injury throughout the muscle that may contribute to poor long-term surgical outcomes even in the setting of a structurally intact repair. Therapeutic interventions that protect the muscle fiber plasma membrane may improve outcomes in patients with rotator cuff tears.
doi:10.1177/2325967114S00103
PMCID: PMC4597569
9.  Reduction in Muscle Fiber Force Production, Disruption of Muscle Cell Architecture and Accumulation of Fatty Macrophages in Patients with Chronic Rotator Cuff Tears 
Orthopaedic Journal of Sports Medicine  2013;1(4 Suppl):2325967113S00099.
Objectives:
A common pathophysiological change that occurs in torn rotator cuff muscles is atrophy of muscle fibers and an accumulation of intramuscular fat, collectively referred to as "fatty degeneration." For many patients with chronic rotator cuff tears that undergo surgical repair, fatty degeneration is not resolved. The etiology of fatty degeneration has not been characterized in humans, and gaining greater insight into the mechanisms that lead to the development of atrophy and fat accumulation will likely improve the recovery of patients who undergo surgical repair of a torn rotator cuff. The purpose of this study was to gain a greater understanding of the changes in muscle fiber contractility, myofibril architecture and fat accumulation in patients with rotator cuff tears. We hypothesized that torn rotator cuff muscles have reduced muscle fiber force production, disordered myofibrils and an accumulation of fat vacuoles and lysosomes.
Methods:
This study was approved by our institution's IRB. Prior to enrollment in the study, informed consent was obtained from patients with a full thickness supraspinatus tear as verified by MRI or ultrasound by a fellowship-trained musculoskeletal radiologist. Biopsies of the supraspinatus and anterior deltoid were obtained at the time of repair and prepared for muscle contractility testing or microscopy. The contractility of permeabilized muscle fibers was performed as previously described, and force values of torn supraspinatus and intact deltoid muscles were compared to age-matched force values of healthy fibers sampled from the vastus lateralis muscle in a previous study. Scanning electron micrographs and immunohistochemistry were also performed on select muscle biopsies.
Results:
Compared with healthy muscle fibers from the vastus lateralis, there was a 29% reduction in specific force (maximum isometric force normalized to fiber cross-sectional area) in torn supraspinatus muscles, and a 34% reduction in specific force for deltoid muscle fibers (Figure 1A, P<0.05). Numerous large intramuscular lipid vacuoles and lysosomes were observed in areas of myofibril degradation (Figure 1B) and streaming of force transmitting Z-disks was often present (Figure 1C). Fatty macrophages, also known as foam cells, were also observed in the ECM between muscle fibers in electron micrographs (Figure 1D) and using a macrophage/foam cell surface marker and BODIPY fluorescent lipid stain (Figure 1E).
Conclusion:
Combined, these results identify chronic structural and mechanical changes in torn rotator cuff muscles that may explain the poor functional capacity of the muscles after repair. While the supraspinatus muscle had reduced force production, a reduction in force was also noted in the deltoid which may parallel symptomatic rotator cuff disease. Further, the accumulation of fat in large lipid vacuoles and high lysosome densities near myofibrils suggest that a portion of the intramyocellular fat that accumulates in torn cuff muscles likely comes as a result of myofibril degradation. We have also identified for the first time that a portion of the extramyocellular fat in torn rotator cuff muscles accumulates in fatty macrophages/foam cells. Future therapies that target lysosomal-mediated myofibril degradation or macrophage accumulation may help to ameliorate the severity of fatty degeneration in patients with rotator cuff tears.
doi:10.1177/2325967113S00099
PMCID: PMC4588941
10.  Is the Supraspinatus Muscle Atrophy Truly Irreversible after Surgical Repair of Rotator Cuff Tears? 
Clinics in Orthopedic Surgery  2013;5(1):55-65.
Background
Atrophy of rotator cuff muscles has been considered an irreversible phenomenon. The purpose of this study is to evaluate whether atrophy is truly irreversible after rotator cuff repair.
Methods
We measured supraspinatus muscle atrophy of 191 patients with full-thickness rotator cuff tears on preoperative magnetic resonance imaging and postoperative multidetector computed tomography images, taken at least 1 year after operation. The occupation ratio was calculated using Photoshop CS3 software. We compared the change between pre- and postoperative occupation ratios after modifying the preoperative occupation ratio. In addition, possible relationship between various clinical factors and the change of atrophy, and between the change of atrophy and cuff integrity after surgical repair were evaluated.
Results
The mean occupation ratio was significantly increased postoperatively from 0.44 ± 0.17 to 0.52 ± 0.17 (p < 0.001). Among 191 patients, 81 (42.4%) showed improvement of atrophy (more than a 10% increase in occupation ratio) and 33 (17.3%) worsening (more than a 10% decrease). Various clinical factors such as age tear size, or initial degree of atrophy did not affect the change of atrophy. However, the change of atrophy was related to repair integrity: cuff healing failure rate of 48.5% (16 of 33) in worsened atrophy; and 22.2% (18 of 81) in improved atrophy (p = 0.007).
Conclusions
The supraspinatus muscle atrophy as measured by occupation ratio could be improved postoperatively in case of successful cuff repair.
doi:10.4055/cios.2013.5.1.55
PMCID: PMC3582872  PMID: 23467404
Atrophy; Occupation ratio; Postoperative change; Rotator cuff
11.  Time-dependent Changes After Latissimus Dorsi Transfer: Tenodesis or Tendon Transfer? 
Background
Transfer of the latissimus dorsi tendon to the posterosuperior part of the rotator cuff is an option in active patients with massive rotator cuff tears to restore shoulder elevation and external rotation. However, it is unknown whether this treatment prevents progression of cuff tear arthropathy.
Questions/purposes
The purpose of this study was to determine whether the observed improvement in shoulder function in the early postoperative period with latissimus dorsi tendon transfer for irreparable rotator cuff tears will be permanent or will deteriorate in the midterm period (at 1–5 years after surgery).
Methods
During a 6-year period, we performed 11 latissimus dorsi tendon transfers in 11 patients for patients with massive, irreparable, chronic tears of the posterosuperior part of the rotator cuff (defined as > 5 cm supraspinatus and infraspinatus tendon tears with Goutallier Grade 3 to 4 fatty infiltration on MRI), for patients who were younger than 65 years of age, and had high functional demands and intact subscapularis function. No patients were lost to followup; minimum followup was 12 months (median, 33 months; range, 12–62 months). The mean patient age was 55 years (median, 53 years; range, 47–65 years). Shoulder forward elevation, external rotation, and Constant-Murley and American Shoulder and Elbow Surgeons scores were assessed. Pain was assessed by a 0- to 10-point visual analog scale. Acromiohumeral distance and cuff tear arthropathy (staged according to the Hamada classification) were evaluated on radiographs.
Results
Shoulder forward elevation, external rotation, Constant-Murley scores, and American Shoulder and Elbow Surgeons scores improved at 6 months. However, although shoulder motion values and Constant-Murley scores remained unchanged between the 6-month and latest evaluations, American Shoulder and Elbow Surgeons scores decreased in this period (median, 71; range, 33–88 versus median, 68; range, 33–85; p = 0.009). Visual analog scale scores improved between the preoperative and 6-month evaluations but then worsened (representing worse pain) between the 6-month and latest evaluations (median, 2; range, 0–5 versus median, 2; range, 1–6; p = 0.034), but scores at latest followup were still lower than preoperative values (median, 7; range, 4–8; p = 0.003). Although acromiohumeral distance values were increased at 6 months (median, 8 mm; range, 6–10 mm; p = 0.023), the values at latest followup (median, 8 mm; range, 5–10 mm) were no different from the preoperative ones (mean, 7 mm; range, 6–9 mm; p > 0.05). According to Hamada classification, all patients were Grade 1 both pre- and postoperatively, except one who was Grade 3 at latest followup.
Conclusions
The latissimus dorsi tendon transfer may improve shoulder function in irreparable massive rotator cuff tears. However, because the tenodesis effect loses its strength with time, progression of the arthropathy should be expected over time. Nevertheless, latissimus dorsi tendon transfer may help to delay the need for reverse shoulder arthroplasty for these patients.
Level of Evidence
Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-014-3770-z
PMCID: PMC4397763  PMID: 25002218
12.  Advantages of Arthroscopic Transosseous Suture Repair of the Rotator Cuff without the Use of Anchors 
Background
Although arthroscopic anchor suturing is commonly used for rotator cuff repair and achieves good results, certain shortcomings remain, including difficulty with reoperation in cases of retear, anchor dislodgement, knot impingement, and financial cost. In 2005, we developed an anchorless technique for arthroscopic transosseous suture rotator cuff repair.
Description of Technique
After acromioplasty and adequate footprint decortication, three K-wires with perforated tips are inserted through the inferior margin of the greater tuberosity into the medial edge of the footprint using a customized aiming guide. After pulling the rotator cuff stump laterally with a grasper, three K-wires are threaded through the rotator cuff and skin. Thereafter, five Number 2 polyester sutures are passed through three bone tunnels using the perforated tips of the K-wires. The surgery is completed by inserting two pairs of mattress sutures and three bridging sutures.
Methods
We investigated the retear rate (based on MR images at least 1 year after the procedure), total score on the UCLA Shoulder Rating Scale, axillary nerve preservation, and issues concerning bone tunnels with this technique in 384 shoulders in 380 patients (174 women [175 shoulders] and 206 men [209 shoulders]). Minimum followup was 2 years (mean, 3.3 years; range, 2–7 years). Complete followup was achieved by 380 patients (384 of 475 [81%] of the procedures performed during the period in question). The remaining 91 patients (91 shoulders) do not have 1-year postsurgical MR images, 2-year UCLA evaluation or intraoperative tear measurement, or they have previous fracture, retear of the rotator cuff, preoperative cervical radiculopathy or axillary nerve palsy, or were lost to followup.
Results
Retears occurred in 24 patients (24 shoulders) (6%). The mean overall UCLA score improved from a preoperative mean of 19.1 to a score of 32.7 at last followup (maximum possible score 35, higher scores being better). Postoperative EMG and clinical examination showed no axillary nerve palsies. Bone tunnel-related issues were encountered in only one shoulder.
Conclusions
Our technique has the following advantages: (1) reoperation is easy in patients with retears; (2) surgical materials used are inexpensive polyester sutures; and (3) no knots are tied onto the rotator cuff. This low-cost method achieves a low retear rate and few bone tunnel problems, the mean postoperative UCLA score being comparable to that obtained by using an arthroscopic anchor suture technique.
Level of Evidence
Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
Electronic supplementary material
The online version of this article (doi:10.1007/s11999-013-3148-7) contains supplementary material, which is available to authorized users.
doi:10.1007/s11999-013-3148-7
PMCID: PMC3792255  PMID: 23836242
13.  A Radiographic Classification of Massive Rotator Cuff Tear Arthritis 
Background
In 1990, Hamada et al. radiographically classified massive rotator cuff tears into five grades. Walch et al. subsequently subdivided Grade 4 to reflect the presence/absence of subacromial arthritis and emphasize glenohumeral arthritis as a characteristic of Grade 4.
Questions/purposes
We therefore determined (1) whether patient characteristics and MRI findings differed between the grades at initial examination and final followup; (2) which factors affected progression to a higher grade; (3) whether the retear rate of repaired tendons differed among the grades; and (4) whether the radiographic grades at final followup differed from those at initial examination among patients treated operatively.
Patients and Methods
We retrospectively reviewed 75 patients with massive rotator cuff tears. Thirty-four patients were treated nonoperatively and 41 operatively.
Results
Patients with Grade 3, 4, or 5 tears had a higher incidence of fatty muscle degeneration of the subscapularis muscle than patients with Grade 1 or 2 tears. In 26 patients with Grade 1 or 2 tears at initial examination, duration of followup was longer in patients who remained at Grade 1 or 2 than in those who progressed to Grade 3, 4, or 5 at final followup. The retear rate of repaired supraspinatus tendon was more frequent in Grade 2 than Grade 1 tears. In operated cases, radiographic grades at final followup did not develop to Grades 3 to 5.
Conclusions
We believe cuff repair should be performed before acromiohumeral interval narrowing. Our observations are consistent with the temporal concepts of massive cuff tear pathomechanics proposed by Burkhart and Hansen et al.
Level of Evidence
Level III, Therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-011-1896-9
PMCID: PMC3148384  PMID: 21503787
14.  Rotator Cuff Integrity Correlates With Clinical and Functional Results at a Minimum 16 Years After Open Repair 
Background
Recurrent or persistent defects in the rotator cuff after its repair are common. Short- and medium-term surveys have revealed, after open repair, patients with an intact rotator cuff have increased function and ROM. However, no long-term studies have verified cuff integrity on MR arthrography or correlated it with clinical and functional outcomes.
Questions/purposes
We evaluated long-term cuff integrity and fatty infiltration after open repair using MR arthrography and determined whether these findings correlated with clinical and functional results.
Methods
Using MR arthrography, we retrospectively evaluated 67 patients (48 men, 19 women) who underwent open rotator cuff repair between 1980 and 1989. Their mean age at surgery was 52 years. Minimum followup was 16 years (mean, 20 years; range, 16–25 years).
Results
The retear rate was 94%, and mean size of rerupture was 3.5 × 3.6 cm (ranges, 0.5–5.0 cm × 0.5–5.2 cm; median, 4 × 4 cm). The remaining four patients had a partial supraspinatus tendon tear. Fatty infiltration was marked in the supraspinatus and infraspinatus tendons. Cuff integrity correlated with clinical results: active external rotation and forward flexion, and flexion, abduction, and external rotation strengths, were better in patients with an intact rotator cuff or a small retear of 4 cm2 or less than in patients with larger tears. Cuff integrity also correlated with functional results.
Conclusions
Rotator cuff integrity was lost in 94% of patients after a minimum followup of 16 years. Cuff integrity correlates well with clinical and functional results even several years postoperatively. A large retear seems to be the most important factor in deteriorating long-term clinical and functional results after open rotator cuff repair.
Level of Evidence
Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
Electronic supplementary material
The online version of this article (doi:10.1007/s11999-012-2494-1) contains supplementary material, which is available to authorized users.
doi:10.1007/s11999-012-2494-1
PMCID: PMC3549157  PMID: 22895686
15.  Does Open Repair of Anterosuperior Rotator Cuff Tear Prevent Muscular Atrophy and Fatty Infiltration? 
Background
Repair of cuff tears involving rotator interval reportedly improves function. However, it is unclear whether successful repair prevents shoulder degenerative changes.
Questions/purposes
Therefore, we (1) documented the minimal 4-year function of patients who underwent open surgical repair for rotator interval tears; (2) evaluated repaired tendon healing with postoperative MRI; and (3) sought to determine the influence of tendon healing on muscular and glenohumeral joint changes.
Methods
We retrospectively analyzed 22 patients (23 shoulders) treated by open transosseous reinsertion of supraspinatus and subscapularis tendons. The mean age of the patients was 53 years (range, 37–64 years). The tear was traumatic in four cases. Repair healing and muscular changes were assessed using MRI. The minimum followup was 46 months (mean, 75 months; range, 46–103 months).
Results
We observed an improvement in the absolute Constant-Murley score from 63 points preoperatively to 76 points postoperatively. With the last followup MRI, the supraspinatus tendon repair had failed in two of the 23 shoulders, whereas the subscapularis tendon repair had healed in all cases. Once healing of the repaired tendon occurred, supraspinatus muscle atrophy never worsened. However, on MRI fatty infiltration of the rotator cuff muscles increased despite successful tendon repair. Glenohumeral arthritis remained stable. Postoperative abduction and internal rotation strengths were better when the standardized supraspinatus muscle area was greater than 0.5 at the final evaluation.
Conclusion
Durable functional improvement and limited degenerative articular and muscular changes can be expected in most patients 4 to 10 years after open repair of anterosuperior cuff tears provided that healing of the cuff is obtained.
Level of Evidence
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-012-2443-z
PMCID: PMC3441980  PMID: 22733186
16.  The Factors Affecting the Clinical Outcome and Integrity of Arthroscopically Repaired Rotator Cuff Tears of the Shoulder 
Clinics in Orthopedic Surgery  2009;1(2):96-104.
Background
The purpose of this study was to evaluate the functional and anatomic results of arthroscopic rotator cuff repair, and to analyze the factors affecting the integrity of arthroscopically repaired rotator cuff tears of the shoulder.
Methods
One hundred sixty-nine consecutive shoulders that underwent arthroscopic rotator cuff repair, had a postoperative MRI evaluation and were followed for at least two years were enrolled in this study. The mean age was 57.6 years (range, 38 to 74 years) and the mean follow-up period was 39 months (range, 24 to 83 months).
Results
The rotator cuff was completely healed in 131 (77.5%) out of 169 shoulders and recurrent tears occurred in 38 shoulders (22.5%). At the last follow-up visit, the mean score for pain during motion was 1.53 (range, 0 to 4) in the completely healed group and 1.59 (range, 0 to 4) in the group with recurrent tears (p = 0.092). The average elevation strength was 7.87 kg (range, 4.96 to 11.62 kg) and 5.25 kg (range, 4.15 to 8.13 kg) and the mean University of California at Los Angeles score was 30.96 (range, 26 to 35) and 30.64 (range, 23 to 34), respectively (p < 0.001, p = 0.798). The complete healing rate was 87.8% in the group less than 50 years of age (49 shoulders), 79.4% in the group over 51 years but less than 60 years of age (68 shoulders), and 65.4% in the group over 61 years of age (52 shoulders, p = 0.049); it was 96.7% in the group with small-sized tears (30 shoulders), 87.3% in the group with medium-sized tears (71 shoulders), and 58.8% in the group with large-sized or massive tears (68 shoulders, p = 0.009). All of the rotator cuffs with a global fatty degeneration index of greater than two preoperatively had recurrent tears.
Conclusions
Arthroscopic repair of full-thickness rotator cuff tears led to a relatively high rate of recurrent defects. However, the minimum two-year follow up demonstrated excellent pain relief and improvement in the ability to perform the activities of daily living, despite the structural failures. The factors affecting tendon healing were the patient's age, the size and extent of the tear, and the presence of fatty degeneration in the rotator cuff muscle.
doi:10.4055/cios.2009.1.2.96
PMCID: PMC2766755  PMID: 19885061
Shoulder; Rotator cuff tear; Arthroscopic repair; Repair integrity; Retear
17.  Interposition Porcine Acellular Dermal Matrix Xenograft Successful Alternative in Treatment for Massive Rotator Cuff 
Orthopaedic Journal of Sports Medicine  2016;4(3 suppl3):2325967116S00077.
Objectives:
Despite advances in the surgical techniques of rotator cuff repair (RCR), the management of massive rotator cuff tears in shoulders without glenohumeral arthritis poses a difficult problem for surgeons. Failure of massive rotator cuff repairs range from 20-90% at one to two years postoperatively using arthrography, ultrasound, or magnetic resonance imaging. Additionally, there are inconsistent outcomes reported with debridement alone of massive rotator cuff tears as well as limitations seen with other current methods of operative intervention including arthroplasty and tendon transfers. The purpose of this prospective, comparative study was to determine if the repair of massive rotator cuff tears using an interposition porcine acellular dermal matrix xenograft improves subjective function, pain, range of motion, and strength at greater than two years follow-up. To our knowledge, this is the largest prospective series reporting outcomes of using porcine acellular dermal matrix xenograft as an interposition graft.
Methods:
Thirty-seven patients (37 shoulders) with an average age of 66 years (range 51-80 years) were prospectively followed for 33 months (range 23-48) following massive RCR using porcine acellular dermal matrix interposition xenograft. Subjective outcomes were measured using the Visual Analog Scale (VAS) pain score (0-10, 0 = no pain), Modified American Shoulder and Elbow Score (M-ASES), and Short-Form12 (SF-12) scores. Preoperative and postoperative objective outcome measures included active range of motion and supraspinatus and infraspinatus manual muscle strength. Postoperative outcome measures included quantitative muscle strength using a dynamometer and static and dynamic ultrasonography to assess the integrity of the repair.
Results:
Average VAS pain score decreased from 4.5 to 1.1 (P<0.001). Average postoperative M-ASES was 89.23. Average postoperative SF-12 was 52.6. Mean forward flexion, external and internal rotation significantly improved from 133.2° to 157.9° (P=0.003), 51.56° to 64.25° (P=0.001), and 49.8° to 74.0° (P<0.001), respectively. Manual strength (10 point scale) in supraspinatus and infraspinatus increased from 7.3 to 8.9 (P<0.001) and 7.4 to 9.4 (P<0.001), respectively. Using a dynamometer, supraspinatus quantitative strength was a mean of 68.6N and infraspinatus quantitative strength was a mean of 50.6N. Ultrasound evaluation of repairs showed 33 (89.1%) to be fully intact, three (8.1%) had partial tears, and one repair (2.7%) was not intact. The one patient whose repair was not intact by ultrasound was a revision repair. No infections, evidence of inflammatory reaction, tissue rejection, or major adverse outcomes were identified. Three patients underwent ipsilateral shoulder surgery for lysis of adhesions due to post-operative decreased ROM during the follow-up period.
Conclusion:
Following repair of massive rotator cuff tears with interposition porcine acellular dermal matrix xenografts, patients had significant improvement in pain, range of motion, strength and reported good subjective function based on M-ASES and SF-12 scores. The repair was completely intact in 89% of patients, a vast improvement compared with results reported for primary repairs of massive rotator cuff tears. Tissue grafts such as the porcine acellular graft used in our study hold great promise in the treatment of massive, retracted rotator cuff tears.
doi:10.1177/2325967116S00077
PMCID: PMC4901922
18.  Arthroscopic Superior Capsule Reconstruction for Irreparable Rotator Cuff Tears 
Orthopaedic Journal of Sports Medicine  2016;4(3 suppl3):2325967116S00076.
Objectives:
An arthroscopic superior capsule reconstruction, in which the fascia lata autograft attached medially to the superior glenoid and laterally to the greater tuberosity, restores shoulder stability and muscle balance in patients with irreparable rotator cuff tears; consequently, it improves shoulder function specifically deltoid muscle function and relieves pain. We assessed the clinical outcome of arthroscopic superior capsule reconstruction (Figure 1) in 100 consecutive patients with irreparable rotator cuff tears. Specifically, we focused on the rates of return to sport and work.
Methods:
From 2007 to 2014, we performed arthroscopic superior capsule reconstruction on 107 consecutive patients (mean 66.7 years; range, 43 to 82) with irreparable rotator cuff tears that had failed conservative treatment. Seven patients were lost to follow-up because of other medical problems or reasons. In the remaining 100 patients there were 56 supraspinatus and infraspinatus tears; 39 supraspinatus, infraspinatus, and subscapularis tears; 3 supraspinatus, infraspinatus, teres minor, and subscapularis tears; and 2 supraspinatus, infraspinatus, and teres minor tears. Physical examination, radiography, and MRI were performed before surgery; at 3, 6, and 12 months after surgery; and yearly thereafter. Rates of return to sport and work were also investigated in those patients who had been employed (34 patients: 21 manual workers, 10 farmers, 1 butcher, 1 cook, and 1 athletic trainer) or played sport (26 patients: 6 golf, 4 table tennis, 4 swimming, 3 martial arts, 2 baseball, 2 yoga, 1 tennis, 1 badminton, 1 skiing, 1 mountain-climbing, and 1 ground golf) before injury.
Results:
The average preoperative American Shoulder and Elbow Surgeons (ASES) score was 31.6 points (range, 3.3 to 63.3 points) and the average Japanese Orthopaedic Association (JOA) score was 51.6 points (26.5 to 68.5 points). Average postoperative clinical outcome scores all improved significantly at final follow-up (mean, 36.6 months after surgery; range, 12 to 96 months; ASES, 93.3 points; JOA, 92.2 points) (P < .00001). Ninety-two patients (92%) had neither graft tear nor re-tear of the repaired rotator cuff tendon during the follow-up period (5 to 8 years of follow-up, 17 patients; 3 to 4 years of follow-up, 19 patients; 1 to 2 years of follow-up, 56 patients). Postoperative clinical outcome scores and active elevation at final follow-up were significantly better in healed patients (ASES, 95.5 points; JOA, 93.7 points, 154.8° ± 24.2°) than in unhealed patients suffering from graft tear or re-tear of the repaired rotator cuff tendon (ASES, 76.3 points, P < 0.0001; JOA, 79.5, P < 0.001; 115.0° ± 41.8°, P < 0.001). Thirty-two patients returned fully to their previous jobs, whereas two patients returned with reduced hours and workloads. All 26 patients who had played sport before their injuries returned fully to their previous sports, although most of the patients had been playing at recreational level before their injuries.
Conclusion:
Arthroscopic superior capsule reconstruction restored shoulder function and resulted in high rates of return to recreational sport and work. Graft tear or re-tear of the repaired rotator cuff tendon exacerbated the clinical outcome after superior capsule reconstruction. These results suggest that arthroscopic superior capsule reconstruction is a viable surgical option for irreparable rotator cuff tears, especially in patients who work and enjoy sport.
doi:10.1177/2325967116S00076
PMCID: PMC4901921
19.  Arthroscopic Suture Bridge Repair Technique for Full Thickness Rotator Cuff Tear 
Clinics in Orthopedic Surgery  2010;2(2):105-111.
Background
The purpose of our study is to evaluate the clinical results of arthroscopic suture bridge repair for patients with rotator cuff tears.
Methods
Between January 2007 and July 2007, fifty-one shoulders underwent arthroscopic suture bridge repair for full thickness rotator cuff tears. The average age at the time of surgery was 57.1 years old, and the mean follow-up period was 15.4 months.
Results
At the last follow-up, the pain at rest improved from 2.2 preoperatively to 0.23 postoperatively and the pain during motion improved from 6.3 preoperatively to 1.8 postoperatively (p < 0.001 and p < 0.001, respectively). The range of active forward flexion improved from 138.4° to 154.6°, and the muscle power improved from 4.9 kg to 6.0 kg (p = 0.04 and 0.019, respectively). The clinical results showed no significant difference according to the preoperative tear size and the extent of fatty degeneration, but imaging study showed a statistical relation between retear and fatty degeneration. The average Constant score improved from 73.2 to 83.79, and the average University of California at Los Angeles score changed from 18.2 to 29.6 with 7 excellent, 41 good and 3 poor results (p < 0.001 and p = 0.003, respectively).
Conclusions
The arthroscopic suture bridge repair technique for rotator cuff tears may be an operative method for which a patient can expect to achieve clinical improvement regardless of the preoperative tear size and the extent of fatty degeneration.
doi:10.4055/cios.2010.2.2.105
PMCID: PMC2867195  PMID: 20514268
Shoulder; Arthroscopy; Rotator cuff; Suture bridge repair technique
20.  Clinical Outcomes and Structural Healing After Arthroscopic Rotator Cuff Repair Reinforced With A Novel Absorbable Biologic Scaffold: A Prospective, Multicenter Trial 
Orthopaedic Journal of Sports Medicine  2015;3(7 suppl2):2325967115S00071.
Objectives:
Arthroscopic rotator cuff repair has been demonstrated to provide reliable clinical outcomes, but the rate of retear remains high (11% to 94%). Retears are associated with poorer outcomes and the majority of retears have been shown to occur within 6 months after surgical repair. Improving the mechanical and/or biological environment during index repair is a common strategy utilized to reduce retear rate. Biofiber© is a bi-layer, absorbable reinforced poly (4)-hydroxybutyrate scaffold that can be used to reinforce rotator cuff repair. Rotator cuff repairs augmented with Biofiber appear to have improved biomechanical properties as compared to standard repair constructs in cadaveric study. Therefore, BioFiber augmented rotator cuff repair may be a viable consideration for patients with larger tears, poorer tissue quality, or in revision repairs. The purpose of this prospective multi-center clinical trial is to evaluate the clinical outcomes and rates of successful healing by ultrasound evaluation in patients undergoing augmented arthroscopic rotator cuff repair using a BioFiber scaffold.
Methods:
A cohort of 50 patients were prospectively enrolled from three study sites in the US (2 sites) and France (1 site). Patients with an imaging demonstrated and arthroscopically confirmed full-thickness rotator cuff tear who underwent arthroscopic rotator cuff repair augmented with a BioFiber scaffold were included in the study. All patients were evaluated clinically at baseline prior to surgery, and subsequently at 6 months and 1 year post-operatively using functional outcomes evaluation (Constant Score and WORC Index), ROM, and strength testing. Ultrasound evaluation at 6 months and 1 year was also carried out to assess repair integrity.
Results:
The average patient age of the cohort was 61 ± 9 years with an average BMI of 28.4. There were 27 female (54%) and 23 male (46%) patients; 10% of those enrolled were worker's compensation patients, 12% were undergoing revision rotator cuff repair. The average AP tear length was 25.2mm ± 1.8mm with an average retraction of 17.1mm ± 1.2mm from the greater tuberosity. Arthroscopic repairs were achieved in all 50 patients using either double-row (78%) or single-row (22%) constructs. The total surgical time for the procedure averaged 77 minutes, with a mean time required for placement of the Biofiber scaffold of 17 minutes. At 6 months post-operatively, the mean adjusted Constant Score was 94.0 (baseline 61.0) and the mean WORC Index was 82.1 (baseline 37.5). Ultrasound evaluation demonstrated intact repairs in 96% of the evaluated patients at the 6 month time point, with no additional evidence of repair failure at 1 year.
Conclusion:
This interim analysis suggests that reinforcement of rotator cuff repairs with Biofiber may result in a mechanically superior repair leading to a high rate of tendon healing. Tear size and quality of repair have been the best predictors for tendon healing in rotator cuff surgery, with recent studies demonstrating improved Constant scores when tendon healing is seen on ultrasound. This cohort had 96% rate of repair integrity on ultrasound evaluation. Furthermore, functional outcome scores after Biofiber-augmented repair were equal to or better than those recently reported for similar populations. Given this data, arthroscopic rotator cuff repair using a BioFiber augmented repair may provide a promising option in the treatment of patients with full-thickness rotator cuff tears.
doi:10.1177/2325967115S00071
PMCID: PMC4901628
21.  Evaluation of cartilage degeneration in a rat model of rotator cuff tear arthropathy 
Introduction
Rotator cuff tears are the most common injury seen by shoulder surgeons. Many late stage rotator cuff tear patients develop glenohumeral osteoarthritis as a result of torn cuff tendons, termed cuff tear arthropathy. However, the mechanisms of cuff tear arthropathy have not been fully established. It has been hypothesized that a combination of synovial and mechanical factors contribute equally to the development of cuff tear arthropathy. The goal of this study was to assess the utility of this model in investigating cuff-tear arthropathy.
Methods
We utilized a rat model which accurately reflects rotator cuff muscle degradation after massive rotator cuff tears through either infraspinatus and supraspinatus tenotomy or suprascapular nerve transection. Using a Modified-Mankin Scoring System (MMS), we found significant glenohumeral cartilage damage following both rotator cuff tenotomy and suprascapular nerve transection after only 12 weeks.
Results
Cartilage degeneration was similar between groups, and was present on both the humeral head and the glenoid. Denervation of the supraspinatus and infraspinatus muscles without opening the joint capsule caused cartilage degeneration similar to that found in the tendon transection group.
Conclusions
These results suggest that altered mechanical loading after rotator cuff tears is the primary factor in cartilage degeneration after rotator cuff tears. Clinically, understanding the process of cartilage degeneration after rotator cuff injury will help guide treatment decisions in the setting of rotator cuff tears.
Level of evidence
Basic Science Study, Animal Model
doi:10.1016/j.jse.2013.03.014
PMCID: PMC3806888  PMID: 23664745
massive rotator cuff tear; arthropathy; osteoarthritis; histology; articular cartilage
22.  Aging-associated exacerbation in fatty degeneration and infiltration following rotator cuff tear 
Background
Rotator cuff tears are one of the most common musculoskeletal complaints and a substantial source of morbidity in elderly patients. Chronic cuff tears are associated with muscle atrophy and an infiltration of fat to the area, a condition known as “fatty degeneration.” To improve the treatment of cuff tears in elderly patients, a greater understanding of the changes in the contractile properties of muscle fibers and the molecular regulation of fatty degeneration is essential.
Methods
Using a full-thickness, massive supraspinatus and infraspinatus tear model in elderly rats, we measured fiber contractility and determined changes in fiber type distribution that develop 30 days after tear. We also measured the expression of mRNA and miRNA transcripts involved in muscle atrophy, lipid accumulation, and matrix synthesis. We hypothesized that a decrease in specific force of muscle fibers, an accumulation of type IIb fibers, and an upregulation in atrophic, fibrogenic, and inflammatory gene expression would occur in torn cuff muscles.
Results
Thirty days following tear, we observed a reduction in muscle fiber force and an induction of RNA molecules that regulate atrophy, fibrosis, lipid accumulation, inflammation and macrophage recruitment. A marked accumulation of advanced glycation end products, and a significant accretion of macrophages in areas of fat accumulation were observed.
Conclusions
The extent of degenerative changes in old rats was greater than that observed in adults. Additionally, we identified that the ectopic fat accumulation that occurs in chronic cuff tears does not occur by activation of canonical intramyocellular lipid storage and synthesis pathways.
doi:10.1016/j.jse.2013.04.011
PMCID: PMC3785561  PMID: 23790676
fatty degeneration; rotator cuff; sarcopenia; atrophy; lipid droplets; macrophages
23.  Retraction pattern of delaminated rotator cuff tears: dual-layer rotator cuff repair 
Background
There has been no report to date regarding retraction patterns of delaminated rotator cuff tears. The purpose of this study was to evaluate the incidence and tearing patterns of delamination and repair integrity after the dual-layer repair of delaminated cuff tears.
Methods/design
A consecutive series of 64 patients with posterosuperior rotator cuff tears underwent arthroscopic rotator cuff repair from August 2011 to September 2012. Among the patients, 53 who received either dual-layer double-row (DLDR) repair or dual-layer suture bridge (DLSB) repair and 11 who received a single-layer repair were evaluated. The mean follow-up period after surgery was 26.5 months. The retraction direction of the deep and superficial layers was analyzed, and the integrity of the repaired constructs was determined in 37 patients through magnetic resonance imaging at a mean of 12.1 months after surgery.
Results
The incidence of delamination was 82.8 %. Posteromedial retraction of the deep and superficial layers was observed in 98.1 and 88.5 % of cases, respectively. The Constant score and UCLA score increased preoperatively to postoperatively, showing no significant differences between the dual-layer repair group and single-layer repair group. Retear was found in two (7.6 %) patients in the dual-layer repair group and three (27.2 %) patients in the single-layer repair group (p = 0.016).
Conclusions
Differential rotator cuff repair strategies are needed to address rotator cuff tears, since recent studies have changed our concept of rotator cuff tears. We have focused on three areas: incidence, retraction patterns, and clinical outcomes. The incidence of delamination was extremely high. Both the superficial layer and deep layer were mainly retracted posteromedially. The retraction of the deep layer and superficial layer may be affected by the infraspinatus. Dual-layer rotator cuff repair based on the retraction pattern of delamination is recommended for improvement of repair integrity and of clinical outcomes.
doi:10.1186/s13018-016-0407-9
PMCID: PMC4936190  PMID: 27384069
Shoulder; Rotator cuff tear; Delaminated; Delamination; Tear pattern
24.  Rotator Cuff Repair in Patients over 75 Years of Age: Clinical Outcome and Repair Integrity 
Clinics in Orthopedic Surgery  2016;8(4):420-427.
Background
Some studies have shown significant functional improvement after rotator cuff (RC) repair in elderly patients. However, few studies have reported the healing potential of RC tears in elderly patients.
Methods
Twenty-five patients aged ≥ 75 years who underwent RC repair were enrolled. The mean age at the time of surgery was 78.3 years (range, 75 to 88 years) while the mean follow-up was 36.3 months (range, 18 to 114 months). We evaluated clinical and structural outcomes after RC repair in the retear and healed groups.
Results
Of 25 patients, 16 (64%) had healed RC lesions and 9 (36%) had retorn cuff lesions. The retear rate increased significantly with increasing initial tear size (small to medium, 13%; large, 60%; massive, 80%; p = 0.024) but not with increasing age (p = 0.072). The mean visual analog scale (VAS), University of California Los Angeles (UCLA), and Constant scores significantly improved from 5.2, 15.8, and 49.3 preoperatively to 1.4, 31.1, and 71.9 in the healed group and from 6.0, 14.4, and 39.5 preoperatively to 2.4, 28.3, and 63.6 in the retear group at the final follow-up (p < 0.05, respectively). There were no significant differences in clinical outcomes between the 2 groups at the final follow-up. Retear was significantly correlated with initial tear size (p = 0.001; odds ratio [OR], 2.771; 95% confidence interval [CI], 1.394 to 5.509 for large to massive tears) (p = 0.001; OR, 0.183; 95% CI, 0.048 to 0.692 for small to medium tears).
Conclusions
There were significant improvements in clinical outcomes after RC repair in patients ≥ 75 years. Structural integrity after cuff repair did not affect the final clinical outcome. Even in elderly patients aged ≥ 75 years, healing of repaired RC can be expected in cases of small to medium tears. Although the retear rate was relatively high for large to massive tears, clinical outcomes still showed significant improvement.
doi:10.4055/cios.2016.8.4.420
PMCID: PMC5114255  PMID: 27904725
Shoulder; Rotator cuff; Aged; Treatment outcome
25.  THE EFFECT OF TEAR SIZE AND NERVE INJURY ON ROTATOR CUFF MUSCLE FATTY DEGENERATION IN A RODENT ANIMAL MODEL 
Background
Irreversible muscle changes following rotator cuff tears is a well-known negative prognostic factor after shoulder surgery. Currently, little is known about the pathomechanism of fatty degeneration of the rotator cuff muscles after chronic cuff tears.
Hypothesis/Purpose
The purposes of this study were: 1) to develop a rodent animal model of chronic rotator cuff tears that can reproduce fatty degeneration of the cuff muscles seen clinically, 2) to describe the effects of tear size and concomitant nerve injury on muscle degeneration, and 3) to evaluate the changes in gene expression of relevant myogenic and adipogenic factors following rotator cuff tears using the animal model.
Methods
Rotator cuff tears were created in rodents with and without transection of the suprascapular nerve. The supraspinatus and infraspinatus muscles were examined 2, 8, and 16 weeks after injury for histological evidence of fatty degeneration and expression of myogenic and adipogenic genes.
Results
Histological analysis revealed adipocytes, intramuscular fat globules, and intramyocellular fat droplets in the tenotomized and neurotomized supraspinatus and infraspinatus muscles. Changes increased with time and were most severe in the muscles with combined tenotomy and neurotomy. Adipogenic and myogenic transcription factors and markers were upregulated in muscles treated with tenotomy or tenotomy combined with neurotomy compared to normal muscles.
Conclusions
The present study describes a rodent animal model that produces fatty degeneration of the rotator cuff muscles similar to human muscles after chronic cuff tears. The severity of changes was associated with tear size and concomitant nerve injury.
doi:10.1016/j.jse.2011.05.004
PMCID: PMC3217129  PMID: 21831663
adipogenesis; myogenesis; tenotomy; neurotomy; tendon

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