Intratendinous Injection of Mesenchymal Stem Cells for the Treatment of Rotator Cuff Disease: A 2-Year Follow-Up Study

Effect of Porcine-Derived Absorbable Patch-Type Atelocollagen for Arthroscopic Rotator Cuff Repair: A Prospective Randomized Controlled Trial

BACKGROUND

Even though arthroscopic rotator cuff repair is recognized as a standard treatment option, the risk of postoperative retear is a major concern.

PURPOSE

To evaluate the effect of porcine-derived absorbable patch-type atelocollagen during arthroscopic rotator cuff repair.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 64 patients with rotator cuff tears diagnosed on magnetic resonance imaging (MRI) were enrolled prospectively from November 2020 to December 2021. Both groups had repairs using the suture bridge technique. For the atelocollagen group, before securing the lateral anchors, we inserted porcine-derived absorbable patch-type atelocollagen between the footprint and the tendon. On postoperative day 2, the patients underwent MRI to confirm containment of the patch-type atelocollagen. At 6 months and 1 year postoperatively, the signal intensity of the repaired tendon was assessed using MRI. Patients were evaluated using the Constant score as the primary outcome, along with the visual analog scale for pain; range of motion; American Shoulder and Elbow Surgeons score; University of California, Los Angeles, score; and Korean Shoulder Score preoperatively and at 2, 3, 6, and 12 months postoperatively.

RESULTS

No significant changes in the Constant score as primary outcome, pain or other functional scores, and range of motion were observed between the groups at 1 year postoperatively. The patch-type atelocollagen was confirmed to be contained by the time-zero MRI scan taken 2 days postoperatively. Among the 55 patients included in final analysis, 12 retear cases were recorded (21.8% retear rate). A significantly lower retear rate was found in the atelocollagen group, as 3 cases were observed in this group (10.3%) and 9 cases were observed in the conventional repair group (34.6%) (P = .048).

CONCLUSION

The Constant score was not different between the groups. The retear rate after rotator cuff repair was significantly lower in the group that received porcine-derived absorbable patch-type atelocollagen compared with in the conventional group.

REGISTRATION

KCT0005184 (Clinical Research Information Service [CRIS]; https://cris.nih.go.kr).

Management of partial-thickness rotator cuff tears with autologous adipose-derived regenerative cells is safe and more effective than injection of corticosteroid

Symptomatic, partial-thickness rotator cuff tears (sPTRCT) are problematic. This study tested the hypothesis that management of sPTRCT with injection of fresh, uncultured, unmodified, autologous, adipose-derived regenerative cells (UA-ADRCs) is safe and more effective than injection of corticosteroid even in the long run. To this end, subjects who had completed a former randomized controlled trial were enrolled in the present study. At baseline these subjects had not responded to physical therapy treatments for at least 6 weeks, and were randomly assigned to receive respectively a single injection of UA-ADRCs (n = 11) or a single injection of methylprednisolone (n = 5). Efficacy was assessed using the ASES Total score, pain visual analogue scale (VAS), RAND Short Form-36 Health Survey and range of motion at 33.2 ± 1.0 (mean ± SD) and 40.6 ± 1.9 months post-treatment. Proton density, fat-saturated, T2-weighted MRI of the index shoulder was performed at both study visits. There were no greater risks connected with injection of UA-ADRCs than those connected with injection of corticosteroid. The subjects in the UA-ADRCs group showed statistically significantly higher mean ASES Total scores than the subjects in the corticosteroid group. The MRI scans at 6 months post-treatment allowed to "watch the UA-ADRCs at work".

Similar outcomes between transtendon repair and tear completion repair techniques for partial articular-sided supraspinatus tendon avulsion lesions: a systematic review and meta-analysis

PURPOSE

This study aimed to review studies comparing transtendon repair (TTR) with tear completion repair (TCR) techniques for partial articular-sided supraspinatus tendon avulsion (PASTA) lesions according to postoperative patient-reported outcomes and complications.

METHODS

Databases, including PubMed, Embase, Scopus, and Cochrane, were searched for studies published between 2008 and 2022 that directly compared the postoperative patient-reported outcomes and complications of the TTR and TCR techniques for PASTA lesions. Odds ratios (ORs) were calculated for dichotomous outcomes, while mean differences (MDs) were calculated for continuous outcomes.

RESULTS

A total of seven studies (497 shoulders) were analysed. No statistically significant differences in the postoperative clinical outcomes at the final follow-up were observed between the TTR and TCR techniques for PASTA lesions. The overall retear rates of the TTR and TCR techniques were 7.7% and 11.6%, respectively (corresponding healing rates were 92.3% and 88.4%), whereas the overall occurrence rates of adhesive capsulitis were 4.7% and 3.3%, respectively. Furthermore, no significant difference was observed in postoperative range of motion (forward flexion, MD = - 1.22, 95% confidence interval (95%CI) - 5.28 to 3.34, n.s.; external rotation, MD = - 1.39, 95% CI - 3.19 to 0.42, n.s.), overall retear rate (OR 0.72, 95% CI 0.29-1.08, n.s.), and occurrence rate of adhesive capsulitis (OR 1.11, 95% CI 0.35-3.52, n.s.) between the two techniques.

CONCLUSION

Both techniques improve clinical outcomes while having a low complication rate and a high rate of healing. No significant difference in clinical outcomes was observed between the two techniques.

LEVEL OF EVIDENCE

III.

Stem cell-based therapeutic strategies for rotator cuff tendinopathy

Rotator cuff tendinopathy is a common musculoskeletal disorder that imposes significant health and economic burden. Stem cell therapy has brought hope for tendon healing in patients with final stage rotator cuff tendinopathy. Some clinical trials have confirmed the effectiveness of stem cell therapy for rotator cuff tendinopathy, but its application has not been promoted and approved. There are still many issues that should be solved prior to using stem cell therapy in clinical applications. The optimal source and dose of stem cells for rotator cuff tendinopathy should be determined. We also proposed novel prospective approaches that can overcome cell population heterogeneity and standardize patient types for stem cell applications.

The translational potential of this article

This review explores the optimal sources of stem cells for rotator cuff tendinopathy and the principles for selecting stem cell dosages. Key strategies are provided for stem cell population standardization and recipient selection.

Outcome of intraoperative injection of collagen in arthroscopic repair of full-thickness rotator cuff tear: a retrospective cohort study

BACKGROUND

Rotator cuff (RC) pathologies are considered the most common cause of shoulder disability and pain. Arthroscopic repair of RC tears has proven to be an effective operation. Nonhealing and retear remain significant clinical problems and a challenge to surgeons. In addition, the essential biological augment to enhance RC tendon-bone healing is still under research. The purpose of the study was to assess the safety and efficacy of injection of atelocollagen and acellular dermal matrix (ADM) allograft in arthroscopic repair of full-thickness RC tears.

METHODS

From January 2018 to March 2020, a total of 129 patients with full-thickness RC tear were treated by arthroscopic repair only (group 1, n = 36, with a mean age = 63.2 years), arthroscopic repair together with atelocollagen 1-mL injection (group 2, n = 44, with a mean age = 63 years), or RC tears together with ADM allograft 1-mL injection (group 3, n = 49, with a mean age = 64.6 years). They were prospectively studied. This study included patients with a repairable full-thickness tear of the supraspinatus tendon size <5 cm. We excluded patients with isolated tears of the subscapularis tendon, those with a previous shoulder surgery, and those who had any type of injection for less than 6 weeks. American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score, Constant Shoulder score, visual analog scale pain score, and range of motion were evaluated preoperatively, at 3, 6, and 12 months of the postoperative period and the final follow-up. In addition, magnetic resonance imaging was performed at 2 months and 12 months postoperatively.

RESULTS

The mean follow-up period was 20 months. All groups showed improvement in functional and pain score at the final follow-up; however, there is no superior outcome among the 3 groups (P > .05). After 2 months, the nonhealing rate was 11% (4 of 36) for group 1, 4% (2 of 44) for group 2, and 2% (1 of 49) for group 3 (P > .05). The retear rates after 12 months was 19.4% (7 of 36) for group 1, 13.6% (6 of 44) for group 2, and 20.4% (10 of 49) for group 3 (P > .05). Adverse events were not detected in any groups.

CONCLUSION

Our study did not show superior clinical or radiologic outcomes of atelocollagen and ADM allograft injections in arthroscopic RC repair over 12 months of follow-up in comparison to the control group. However, adverse events related to atelocollagen and ADM allograft injection were not observed.

Rotator cuff degeneration and healing after rotator cuff repair

Rotator cuff tear is a common shoulder injury that compromises both function and quality of life. Despite the prevalence of the injury and advancements in repair techniques, a significant percentage of these repairs fail. This review aims to explore the multifactorial reasons behind this failure, including the degenerative nature of the rotator cuff tendon, inherent and extrinsic factors, and the role of hypoxia in tissue degeneration. Additionally, it elucidates potential strategies for improving healing outcomes.

Decellularized Bovine Pericardial Patch Loaded With Mesenchymal Stromal Cells Enhance the Mechanical Strength and Biological Healing of Large-to-Massive Rotator Cuff Tear in a Rat Model

PURPOSE

The purpose of this study was to determine whether the addition of decellularized bovine pericardial patch loaded with mesenchymal stromal cells enhanced bone-to-tendon healing and improved the biomechanical strength of large-to-massive rotator cuff tears in a small animal model.

METHODS

Adipose-derived mesenchymal stromal cells (MSCs) from rat inguinal fat were isolated, cultured, and loaded onto decellularized bovine pericardium patches. To simulate large-to-massive tears, rats were managed with free cage activity for 6 weeks after tear creation. A total of 18 rats were randomly allocated to repair-only (control), repair with pericardial patch augmentation (patch), or repair with MSC loaded pericardial patch augmentation (patch-MSC). Each group had 6 rats (one shoulder of each rat was used for histological evaluation and another for biomechanical evaluation). MSCs seeded on the pericardial patches were traced on four shoulders from 2 other rats at 4 weeks after surgery. Histological evaluation for bone-to-tendon healing and biomechanical testing was carried out at 8 weeks after repair.

RESULTS

MSCs tagged with a green fluorescent protein were observed in the repair site 4 weeks after the repair. One shoulder each in the control and patch groups showed complete discontinuity between the bone and tendon. One shoulder in the control group showed attenuation with only a tenuous connection. Fibrocartilage and tidemark formation at the bone-to-tendon interface (P = .002) and collagen fiber density (P = .040) and orientation (P = .003) were better in the patch-MSC group than in the control or patch group. Load-to-failure in the patch-MSC and patch groups was higher than that in the control group (P = .001 and .009, respectively).

CONCLUSION

Decellularized bovine pericardial patches loaded with adipose-derived and cultured mesenchymal stromal cells enhanced healing in terms of both histology and mechanical strength at 8 weeks following rotator cuff repair in a rat model.

CLINICAL RELEVANCE

Large-to-massive rotator tears need a strategy to prevent retear and enhance healing. The addition of decellularized bovine pericardial patch loaded with MSCs can enhance bone-to-tendon healing and improve biomechanical healing of large-to-massive rotator cuff tears following repair.

Current Trends in Orthobiologics: An 11-Year Review of the Orthopaedic Literature

BACKGROUND

The use of "orthobiologics" or regenerative therapies in orthopaedic surgery has grown in recent years. Particular interest has been raised with regard to platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cells. Although studies have analyzed outcomes after orthobiologic treatment, no study has analyzed how the literature as a whole has evolved.

PURPOSE

To evaluate trends in platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cell publications and to assess how these might inform efforts to establish minimum reporting standards and forecast future use.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A database was compiled systematically using PubMed to identify articles published between 2009 and 2019 within 9 prominent orthopaedic journals and pertaining to the use of platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cells in the treatment of musculoskeletal conditions. Included articles were classified as clinical, nonclinical (translational or basic science), or review, and a variety of study parameters were recorded for each. Additional queries were performed to identify articles that utilized minimum reporting standards.

RESULTS

A total of 474 articles (132 clinical, 271 nonclinical, 71 review) were included, consisting of 244 (51.5%) platelet-rich plasma, 146 (30.8%) bone marrow aspirate, 72 (15.2%) adipose-derived cells, and 12 (2.5%) amniotic cells. The greatest annual increase in publications for each orthobiologic topic was from 2018 to 2019. The American Journal of Sports Medicine demonstrated the highest number of overall (34.2%) and clinical (50.0%) publications, and accounted for 44.3% of all platelet-rich plasma publications. The Journal of Orthopaedic Research accounted for the second highest overall number of publications (24.9%) and highest nonclinical publications (41.0%). Platelet-rich plasma accounted for 91.5% of all level 1 clinical studies, while much greater than half of bone marrow aspirate, adipose-derived cells, and amniotic cell publications were level 3 or lower. Out of the 207 articles that used some form of reporting protocol, 59 (28.5%) used an established algorithm and 125 (60.4%) used their own.

CONCLUSION

Interest in orthobiologics continues to grow, as evidenced by an increasing trend in publications over an 11-year period. However, current reporting on orthobiologic formulations is largely heterogeneous, emphasizing the need for minimum reporting standards and higher-quality studies.

Cell therapy efficacy and safety in treating tendon disorders: a systemic review of clinical studies

Purpose

Despite substantial animal evidence, cell therapy in humans remains in its infancy. The purpose of this study was to examine the potential therapeutic effects and safety of cell therapy in the treatment of tendon disorders.

Methods

According to the PRISMA guideline, a systematic review was performed on clinical studies concerning cell therapy in tendon disorders. A comprehensive search including the 5 databases of MEDLINE, Embase, Scopus, Web of Science, and Cochrane Library until December 2021 was carried out and associated with hand searching. The quality of the eligible studies was assessed using the tools suggested by Cochrane recommendations. Qualitative synthesis was performed in 2 tables and discussed separately for rotator cuff, elbow, patella, Achilles, and gluteal tendons.

Results

Through 6017 records, 22 studies were included in the qualitative synthesis, including 658 patients. All the studies administered autologous cells, except one that used allogenic adipose-derived mesenchymal stem cells (Allogenic AD-MSC). Almost all studies demonstrated the safety of cell injection in their follow-up period with no serious side effects or immunologic reactions, with only a few related minor adverse events in some cases.

The included studies showed the effectiveness of cell injection in tendinopathies of different sites, rotator cuff, elbow, patella, Achilles, and gluteal tendons. Among the rotator cuff studies, 4 comparative studies claimed that cell therapy is a more efficient treatment with a lower retear rate and pain level compared to the control group. However, one study found no differences between the groups. No controlled study has been performed on elbow tendinopathies, but 5 case series demonstrated the effectiveness of cell injection in elbow tendon disorders. For Achilles tendinopathies, only one randomized controlled trial (RCT) found that both cell therapy and control groups showed significant pain reduction and functional improvement with no statistical differences at the 6 months follow-up, but the cell therapy group had improved faster at earlier follow-ups. Patellar tendinopathy was studied in 2 RCTs, one did not show a significant difference and the other showed superior improvement compared to controls.

Conclusion

Cell therapy showed promising results and the available evidence suggests that it is safe at several sites of tendon disease. Based on available evidence, cell therapy should be suggested in specific conditions at each site. To approve cell therapy for tendon diseases, randomized clinical trials are required with a large sample size and long-term follow-ups.

Level of evidence

IV

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00520-9.

Advances in Stem Cell Therapies for Rotator Cuff Injuries

Rotator cuff injury is a common upper extremity musculoskeletal disease that may lead to persistent pain and functional impairment. Despite the clinical outcomes of the surgical procedures being satisfactory, the repair of the rotator cuff remains problematic, such as through failure of healing, adhesion formation, and fatty infiltration. Stem cells have high proliferation, strong paracrine action, and multiple differentiation potential, which promote tendon remodeling and fibrocartilage formation and increase biomechanical strength. Additionally, stem cell-derived extracellular vesicles (EVs) can increase collagen synthesis and inhibit inflammation and adhesion formation by carrying regulatory proteins and microRNAs. Therefore, stem cell-based therapy is a promising therapeutic strategy that has great potential for rotator cuff healing. In this review, we summarize the advances of stem cells and stem cell-derived EVs in rotator cuff repair and highlight the underlying mechanism of stem cells and stem cell-derived EVs and biomaterial delivery systems. Future studies need to explore stem cell therapy in combination with cellular factors, gene therapy, and novel biomaterial delivery systems.

All-Inside Arthroscopic Partial Articular-Sided Supraspinatus Tendon Avulsion (PASTA) Repair Without Bunching of the Bursal Side of the Tendon

PASTA (partial articular-sided supraspinatus tendon avulsion) lesions are supraspinatus tendon tears involved the articular surface. PASTA lesions are commonly repaired using trans-tendon repair or tendon takedown and repair. Systematic reviews have shown that both techniques can improve shoulder function similarly. The advantages of trans-tendon repair are the preservation of the intact tendon and superior biomechanical strength. However, there is a risk that the tendon will become overtensioned and that the technique will create tendon bunching on the bursal side, resulting in imbalanced tendon tension. This Technical Note describes an all-inside arthroscopic trans-tendon repair technique of PASTA lesion without bunching the tendon's bursal side.

Injection of adipose stem cells in the treatment of rotator cuff disease - a narrative review of current evidence

The purpose of this study is to summarize evidence for the use of adipose stem cell (ASC) injections in the treatment of rotator cuff tears (RCT) and identify future areas of study. A thorough literature search was performed to identify studies investigating the use of ASC injections in the treatment of RCTs. Among animal trials, it is unclear whether ASCs are of benefit for rotator cuff repair. In clinical trials, ASC injection may reduce retear rate with otherwise equivocal clinical outcomes. Although ASC injection may be safe, the literature does not provide a clear consensus as to the efficacy of ASC injections, nor does it delineate which patients would benefit most from this treatment.

Isolation and Characterization of Synovial Mesenchymal Stem Cells Derived From Patients With Chronic Lateral Ankle Instability: A Comparative Analysis of Synovial Fluid, Adipose Synovium, and Fibrous Synovium of the Ankle Joint

Background:

Synovial mesenchymal stem cells (MSCs) have high proliferative potential and are considered an excellent source for stem cell therapy.

Purposes:

To isolate MSCs from the synovium of ankle joints in patients with chronic lateral ankle instability (CLAI) and to compare the characteristics of MSCs derived from the synovium anterior to the talus with those from the surrounding anterior talofibular ligament (ATFL) synovium.

Study Design:

Controlled laboratory study.

Methods:

The synovium was harvested from 2 locations in the ankle, the synovium anterior to the talus and the surrounding ATFL synovium, of 14 patients who underwent arthroscopic ATFL repair for CLAI without osteochondral lesions of the talus (OLTs). Synovial fluid was also harvested. MSCs were isolated from both types of synovial tissue, as well as synovial fluid. The number of MSCs in the synovium and their viability, proliferation, colony-forming units, and potential to differentiate into adipose, bone, and cartilage tissues were determined and compared between groups. Additionally, real-time polymerase chain reaction was used to assess the differentiation capacity of adipose, bone, and cartilage tissues from both samples. The Wilcoxon signed rank test was used to compare the sample weight, number of colonies, number of nucleated cells per colony, yield obtained, and phenotypic characteristics of MSCs derived from different locations of the synovium.

Results:

No significant differences were observed in the sample weight ( P = .051), number of nucleated cells per milligram ( P = .272), number of colonies ( P = .722), and yield obtained ( P = .099) between the 2 groups. MSCs could not be isolated from synovial fluid. The frequency of oil red O–positive adipogenic colonies ( P = .028) and the expression of the adipsin gene ( P < .05) were significantly increased in the cells from the synovium anterior to the talus compared to those in the cells from the surrounding ATFL synovium. However, chondrogenic and osteogenic potentials were not significantly different between the 2 groups.

Conclusion:

Synovial MSCs obtained from the ankle joint had self-renewal and multilineage differentiation potential, although the adipogenesis potential of MSCs from the synovium anterior to the talus was superior to that from the surrounding ATFL synovium.

Clinical Relevance:

Both the adipose synovium and fibrous synovium in the ankle joints of patients with CLAI may be a good source of MSCs for stem cell therapy applications, whereas synovial fluid appeared unsuitable.

[Research progress of interfacial tissue engineering in rotator cuff repair]

Objective

To summarize the research progress of interfacial tissue engineering in rotator cuff repair.

Methods

The recent literature at home and abroad concerning interfacial tissue engineering in rotator cuff repair was analysed and summarized.

Results

Interfacial tissue engineering is to reconstruct complex and hierarchical interfacial tissues through a variety of methods to repair or regenerate damaged joints of different tissues. Interfacial tissue engineering in rotator cuff repair mainly includes seed cells, growth factors, biomaterials, oxygen concentration, and mechanical stimulation.

Conclusion

The best strategy for rotator cuff healing and regeneration requires not only the use of biomaterials with gradient changes, but also the combination of seed cells, growth factors, and specific culture conditions (such as oxygen concentration and mechanical stimulation). However, the clinical transformation of the relevant treatment is still a very slow process.

Cell-based therapies for the treatment of sports injuries of the upper limb

Introduction: The use of cell-based therapies in the management of sports injuries of the upper limb is increasingly popular despite the limited scientific evidence available for their use. We aim to evaluate the evidence for the use of cell-based therapies in these injuries and recommend areas for further research.Areas covered: In accordance with a published protocol (PROSPERO; Registration No. CRD42020193258), a comprehensive search of the literature was performed using the MEDLINE and EMBASE databases from inception to June 2020. All human studies reporting on the clinical, histological, or radiological outcomes following the use of cell-based therapies in the management of epicondylitis or rotator cuff pathology were included in this study. This resulted in 22 studies being included in this review, all of which underwent risk of bias assessments.Expert opinion: The evidence for the use of cell-based therapies in upper limb sports injuries is limited and generally of low quality. Given the heterogeneity in the cell types used, their harvesting methods and cell amounts, future research should be targeted at developing standardization of the reporting of these studies and more direct comparative studies looking at the efficacy of the different cell types.

Promising improvement of chronic lateral elbow tendinopathy by using adipose derived mesenchymal stromal cells: a pilot study

Purpose

Study the effect of Adipose derived stromal cells (ASCs) injection as therapeutic procedure on the common extensor tendinopathy.

Methods

Eighteen Tennis players with chronic, recalcitrant LET (who have previously been unsuccessfully treated with nonoperative treatments) underwent clinical evaluation and magnetic resonance imaging (MRI) before intervention. Stromal vascular fraction cells (SVF) were expanded by in vitro culture and ASCs were obtained and characterized by flow cytometry. ASCs were injected into the site of tendinopathy (identified by ultrasound imaging at the origin of the common extensor tendon) on a single occasion followed by physiotherapy. Players underwent serial clinical evaluations during a 12-month period and repeated MRI at 6-month post-injection.

Results

At 6-month clinical evaluation revealed significant improvements compared to baseline in mean Visual Analog Scale (VAS) scores for: (1) maximum pain score (from 6.28 ± 1.65, to 1.0 ± 0.43; p < .001); (2) Mean quick Disabilities of the Arm, Shoulder and Hand (QuickDASH-Compulsory score: 51.38 ± 12.02 to 12.33 ± 4.66; p < .001); (3) QuickDASH-Sport score: 56.94 ± 15.44 to 8.68 ± 8.86; p < .001). Validated MRI scoring system grade of tendinopathy also improved significantly: 4.22 ± 0.26 to 2.22 ± 0.10 (p < .001). At 12-month from injection, VAS maximun pain score further decreased to 0.74 ± 0.44 (p < .001) and QuickDASH-Compulsory score to 5.56 ± 3.58 (p < .001). Average time to return to play tennis was 3,31 ± 0,61 month post-intervention.

Conclusion

Tennis players with recalcitrant LET showed significant clinical improvement and structural repair at the origin of the common tendon origin after injection of autologous ASCs. Results of this study are promising and open a new biological therapeutic modality to treat LET. Even if the results of this pilot study are positive, future well-designed studies, i.e. prospective randomized trials are needed to define the role of cell therapy in treating LET.

Research Trends on the Rotator Cuff Tendon: A Bibliometric Analysis of the Past 2 Decades

Background:

Clinical research on the rotator cuff tendon is increasing, and new approaches are being applied to rotator cuff disease. Considering the integration of research resources and research trends, it is necessary to conduct an analysis of recent research on the topic.

Purpose:

To identity the research trends, influential journals, key researchers, and core countries of rotator cuff tendon research between 2000 and 2019.

Study Design:

Cross-sectional study.

Methods:

All the literature related to rotator cuff tendon research was retrieved from the Web of Science Core Collection on January 7, 2020. Qualitative and quantitative analyses were processed based on Web of Science and CiteSpace.

Results:

A total of 4131 studies, which included 3830 articles and 301 reviews, were obtained. There was an upward trend of studies on the topic, with small fluctuations in the past 2 decades. The United States had the most studies, and the number of studies from other countries increased over the study period. Most of the funding sources came from the United States. Articles in the Journal of Shoulder and Elbow Surgery had the most citations for rotator cuff research. Frontier topics, such as arthroscopic repair, mesenchymal stem cell, and “platelet-rich plasma, were identified. The number of citations in 2018 (r = 0.280; P = .005) and 2019 (r = 0.307; P = .002) had a weak positive correlation with publication date, indicating that the more recently published articles had a higher number of citations.

Conclusion:

Valuable information on rotator cuff research based on bibliometric analysis was identified. Arthroscopic repair, mesenchymal stem cell, and platelet-rich plasma might be the research frontiers in this field, and researchers should focus on these topics in future studies.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles - Silver Linings for Cartilage Regeneration?

As the world's population is aging, the incidence of the degenerative disease Osteoarthritis (OA) is increasing. Current treatment options of OA focus on the alleviation of the symptoms including pain and inflammation rather than on restoration of the articular cartilage. Cell-based therapies including the application of mesenchymal stromal cells (MSCs) have been a promising tool for cartilage regeneration approaches. Due to their immunomodulatory properties, their differentiation potential into cells of the mesodermal lineage as well as the plurality of sources from which they can be isolated, MSCs have been applied in a vast number of studies focusing on the establishment of new treatment options for Osteoarthritis. Despite promising outcomes in vitro and in vivo, applications of MSCs are connected with teratoma formation, limited lifespan of differentiated cells as well as rejection of the cells after transplantation, highlighting the need for new cell free approaches harboring the beneficial properties of MSCs. It has been demonstrated that the regenerative potential of MSCs is mediated by the release of paracrine factors rather than by differentiation into cells of the desired tissue. Besides soluble factors, extracellular vesicles are the major component of a cell's secretome. They represent novel mechanisms by which (pathogenic) signals can be communicated between cell types as they deliver bioactive molecules (nucleic acids, proteins, lipids) from the cell of origin to the target cell leading to specific biological processes upon uptake. This review will give an overview about extracellular vesicles including general characteristics, isolation methods and characterization approaches. Furthermore, the role of MSC-derived extracellular vesicles in in vitro and in vivo studies for cartilage regeneration will be summarized with special focus on transported miRNA which either favored the progression of OA or protected the cartilage from degradation. In addition, studies will be reviewed investigating the impact of MSC-derived extracellular vesicles on inflammatory arthritis. As extracellular vesicles are present in all body fluids, their application as potential biomarkers for OA will also be discussed in this review. Finally, studies exploring the combination of MSC-derived extracellular vesicles with biomaterials for tissue engineering approaches are summarized.

Stem Cells for the Regeneration of Tendon and Ligament: A Perspective

Tendons are structures that connect muscles to the bones in our body and transmit the force generated by contraction of the muscles to the bones. Ligaments are structures that connect bones to bones, with histological properties similar to tendons. In tendon and ligament tissue, there are very small amounts of cells similar to mesenchymal stem cells (MSCs) called tendon stem/progenitor cells (TSPCs), or tenogenic stem cells. While the role of specific growth factors and transcription factors is well established in the osteogenic and chondrogenic differentiation of stem cells, a consensus has not been established for tenogenic differentiation. Injuries to tendons and ligaments are very common, but natural healing is very slow and inefficient due to limited vascularization. Currently, there is no adequate method for restoring extensive tendon or ligament defects. Procedures addressing the unmet need for regeneration of these tissues are needed. In this review, the current knowledge, as well as the authors’ ideas and perspective on stem cell and regenerative medicine for tendon and ligament defects are presented.

The role of adipose derived stem cells in the treatment of rotator cuff tears: from basic science to clinical application

Over the last decade, regenerative medicine has become increasingly popular throughout the scientific community. The poor healing capacity at the tendon-bone interface makes the rotator cuff an appealing target for biologic agents. Adipose derived stem cells are mesenchymal cells with the capacity for self-renewal and multipotential differentiation. They have been recently proposed, both in isolation and as adjuvants to existing surgical therapies, for the treatment of rotator cuff tears. Several studies have been carried out in this research field, starting from the biological characteristics of adipose derived stem cells, their preparation and culture, up to the application in the experimental field on animal models and on humans. The purpose of this study was to provide a state of the art about the current basic science and clinical literature for the effectiveness of adipose derived stem cells in the treatment of rotator cuff tears.

Editorial Commentary: Stem Cells in Rotator Cuff Surgery: In Search of the Holy Grail

The use of stem cells in orthopaedics remains a controversial topic, stem cells remain experimental, and significant concerns exist. Studies evaluating diagnoses that may spontaneously resolve could be of low value absent a control group. Only same-day harvest of minimally manipulated stem cells is approved for use in the United States, and these minimally manipulated products may contain insufficient cells to affect outcomes. Extensively cultured cells do not qualify for use in the United States outside of an approved Investigational New Drug Application. Moreover, in other arenas, significant, serious adverse events have been reported after the use of manipulated stem cells. Both the US Food and Drug Administration and American Academy of Orthopaedic Surgeons have recognized the potential for abuse regarding this evolving technology. Published results using stems cells to treat rotator cuff disease are inconsistent, and the optimum source and preparation of the stem cells remains unknown.

Extracellular Vesicles from Mesenchymal Stem Cells as Novel Treatments for Musculoskeletal Diseases

Mesenchymal stem/stromal cells (MSCs) represent a promising therapy for musculoskeletal diseases. There is compelling evidence indicating that MSC effects are mainly mediated by paracrine mechanisms and in particular by the secretion of extracellular vesicles (EVs). Many studies have thus suggested that EVs may be an alternative to cell therapy with MSCs in tissue repair. In this review, we summarize the current understanding of MSC EVs actions in preclinical studies of (1) immune regulation and rheumatoid arthritis, (2) bone repair and bone diseases, (3) cartilage repair and osteoarthritis, (4) intervertebral disk degeneration and (5) skeletal muscle and tendon repair. We also discuss the mechanisms underlying these actions and the perspectives of MSC EVs-based strategies for future treatments of musculoskeletal disorders.