Multiple channeling improves the structural integrity of rotator cuff repair

Similar Healing Rates of Arthroscopic Rotator Cuff Repair With and Without Bone Marrow Stimulation: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Bone marrow stimulation (BMS) techniques such as microfracture, nanofracture, and the crimson duvet procedure expose the bone marrow of the proximal humerus to the rotator cuff tendon footprint. The effect of performing BMS on tendon healing is a subject of interest.

PURPOSE

To compare studies on arthroscopic rotator cuff repair with BMS versus without BMS for rotator cuff tears according to healing rates and clinical and radiological outcomes.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 2.

METHODS

The 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed in conducting a search. Studies that compared arthroscopic rotator cuff repair with and without BMS were included if they provided postoperative patient-reported outcomes and healing rates. Dichotomous outcomes were expressed as mean differences (MDs), while continuous outcomes were expressed as odds ratio.

RESULTS

Included were 5 studies (N = 499 shoulders); 4 studies had level 1 evidence, and 1 study had level 2 evidence. The healing rate of rotator cuff repair was similar between the 2 groups (ie, with and without BMS) (odds ratio, 1.58 [95% CI, 0.63 to 4.00]; P = .33). Furthermore, there were no significant differences in the postoperative Constant score (MD, 1.41 [95% CI, -0.58 to 3.39]; P = .16), American Shoulder and Elbow Surgeons score (MD, 0.77 [95% CI, -1.43 to 2.96]; P = .49), or range of motion for forward flexion (MD, 2.45 [95% CI, -0.66 to 5.57]; P = .12) and external rotation (MD, 0.81 [95% CI, -2.35 to 3.97]; P = .62) at the final follow-up between the 2 groups.

CONCLUSION

The healing rate of rotator cuff repair was similar, regardless of whether BMS was performed or not. Additionally, there was no significant difference in postoperative patient-reported outcome scores, range of motion, and complications.

REGISTRATION

CRD42023388427 (PROSPERO).

Interventions used to mitigate muscle fatty degeneration following the repair of massive rotator cuff tears. A systematic review of animal studies

BACKGROUND

Muscle fatty degeneration following rotator cuff tears has been unequivocally associated with poorer functional outcomes and increased risk for retear following rotator cuff repair. Promising results have emerged from animal studies, with the implementation of various interventions for biologic inhibition of this fatty muscle degeneration. The lack of high quality randomized human evidence on this topic, increases the impact of pooled results from animal literature. The aim of the present study was to systematically review the available published literature for animal studies evaluating the ability of several interventions used to mitigate muscle fatty degeneration following the repair of massive rotator cuff tears.

PATIENTS AND METHODS

A comprehensive search was conducted on Pubmed, Scopus and Google Scholar, covering the period from conception until 16th April 2022. Datasets were stratified based on the type of intervention performed. SYRCLE risk of bias instrument was implemented for quality assessment of the included studies.

RESULTS

Rotator cuff repair augmentation with Adipose derived stem cells (ADSC's), Mesenchymal stem cells (MSC's) and Nandrolone was effective against fatty infiltration, but less effective against muscle atrophy. More beneficial effect was shown by the utilization of Beige adipose tissue - Fibroadipogenic progenitors (BAT-FAP) stimulation, using either Amibregon or BAT-FAPs transplantation. Both provided good results in mitigating muscle atrophy, fatty infiltration and fibrosis.

DISCUSSION

ADSC's, MSC's, Nandrolone and BAT-FAP stimulation may have a role in mitigating muscle fatty degeneration following rotator cuff tears. Large scale human studies are required to further elucidate their role in the clinical setting.

LEVEL OF EVIDENCE

V; systematic review of pre-clinical studies.

Effect of Bone Marrow Stimulation on Arthroscopic Rotator Cuff Repair: A Systematic Review and Meta-analysis

Background

Arthroscopic rotator cuff repair (RCR) is a common orthopaedic procedure, but it has a high rate of retears that can negatively affect the functional outcomes. Bone marrow stimulation (BMS) has been suggested as an additional treatment to improve the outcomes of RCR.

Purpose

To compare the effectiveness of the BMS procedure during RCR with conventional RCR.

Study Design

Systematic review; Level of evidence, 2.

Methods

A systematic literature search was conducted in MEDLINE/PubMed, Embase, Cochrane Library, and Scopus, on March 1, 2023, for studies comparing postoperative retear rates and functional outcomes between patients who underwent primary arthroscopic RCR with and without the BMS procedure. Only level 1 and 2 randomized controlled trials with a minimum 12-month follow-up were included. The primary outcomes were retear rates and functional outcomes as measured by the Constant; American Shoulder and Elbow Surgeons (ASES); and University of California, Los Angeles (UCLA) scores and by postoperative range of motion. Subgroup analyses were performed based on repair technique (single-row repair vs double-row or suture-bridge repair). The standardized mean difference (SMD) and odds ratio (OR) were utilized to synthesize continuous and dichotomous outcomes, respectively. Homogeneity was evaluated using the chi-square test and I2 statistic.

Results

The literature search yielded 661 articles, of which 6 studies (522 patients; 261 with BMS, 261 without BMS) met the eligibility criteria. The combined analysis showed no significant decrease in retear rates with the utilization of the BMS procedure during RCR (OR, 0.60; 95% CI, 0.35 to 1.03; P = .07; I2 = 24%). There was no significant intergroup difference in functional outcomes (Constant score: SMD, 0.13; 95% CI, -0.04 to 0.31; P = .13; I2 = 0%; ASES score: SMD, 0.04; 95% CI, -0.20 to 0.28; P = .73; I2 = 0%; UCLA score: SMD, -0.13; 95% CI, -0.50 to 0.23; P = .47; I2 = 0%). Subgroup analyses revealed no significant differences in postoperative retear risk or total Constant score according to the repair technique.

Conclusion

Based on the available evidence, this systematic review did not find a significant benefit of the BMS procedure at the footprint during arthroscopic RCR compared with conventional RCR in terms of retear rates and functional outcomes at short-term follow-up.

Editorial Commentary: Bone Marrow Stimulation and Losartan Augmentation of Shoulder Rotator Cuff Repair

Rotator cuff retear rates after repair have been variously reported as ranging from 5% to 40% for small to mediums tears and as high as 40% to 94% for large to massive tears. Thus strategies to enhance structural healing are relevant. In rabbits, combining oral losartan (which has antifibrotic effects by downregulating transforming growth factor-β1) and bone marrow stimulation (BMS) of the greater tuberosity, showed improved rotator cuff repair pull-out strength and highly organized tendon matrix in a chronic injury model, whereas BMS alone did not improve the mechanical properties. However, clinical studies show that BMS techniques have a positive impact on healing and retear rates. BMS stimulates migration of mesenchymal stem cells from bone marrow to the lesion, and this approach has been widely used to fill cartilage defects by fibrocartilage metaplasia. BMS is a straightforward and cost-effective technique; the use of multiple deeper bone tunnels is recommended.

Microfracture Lateral to the Greater Tuberosity of the Humerus Enhances Tendon-to-Bone Healing in a Rat Rotator Cuff Model

BACKGROUND

Microfracture at the rotator cuff insertion is an established surgical marrow-stimulation technique for enhancing rotator cuff healing. However, the effect of lateralized or medialized microfracture on the insertion is unknown.

PURPOSE

To compare the biomechanical and histologic effects of microfracture at 3 different regions for rotator cuff repair in a rat model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 72 Sprague-Dawley rats with bilateral supraspinatus tendon insertion detachment were allocated into 4 groups with 4 different interventions: no microfracture at the humeral head as a control group (Con), traditional microfracture at the footprint area (MFA), and medialized microfracture to the footprint area (MMFA) on the articular surface of the humerus or lateralized microfracture to the footprint area at the greater tuberosity (LMFA). All underwent immediate repair. Tendon-to-bone healing was assessed by biomechanical and histologic tests 4 and 8 weeks postoperation.

RESULTS

At 4 weeks, the LMFA group showed a significantly superior failure load compared with the other groups (all P < .05). The LMFA and MFA groups showed significantly superior stiffness compared with the Con and MMFA groups (all P < .01). At 8 weeks, superior failure load and stiffness were observed in the LMFA group compared with the control group (all P < .05). Histologic examination revealed that the LMFA group had superior collagen composition and tendon-to-bone maturation at the interface at 4 and 8 weeks compared with the Con group (all P < .05).

CONCLUSION

Lateralized microfracture at the greater tuberosity improved the histologic quality of repair tissue and biomechanical strength at the tendon-to-bone insertion after rotator cuff repair in a rat model.

CLINICAL RELEVANCE

Microfracture lateral to the footprint area might be a better way to enhance rotator cuff healing clinically.

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.

A network meta-analysis of arthroscopic rotator cuff repair

OBJECTIVE

Rotator cuff tear is a common shoulder injury that often leads to serious limitations in daily life. Herein, a network Meta-analysis using frequency theory was performed to evaluate the clinical outcomes of five rotator cuff repair techniques, including single-row repair, double-row repair, suture bridge repair, platelet-rich plasma therapy, and bone marrow stimulation, thus guiding clinical decision-making on rotator cuff repair.

METHODS

PubMed, EMbase, The Cochrane Library, and Web of Science were searched for randomized controlled trials and cohort studies comparing rotator cuff repair techniques published from inception to May 2022. Combined analysis and quality assessment were performed using software STATA15.1 and Review Manager5.3.

RESULTS

A total of 51 articles were finally included, including 27 randomized controlled trials and 24 cohort studies. Results from the network Meta-analysis showed that: (1) In terms of the American Shoulder and Elbow Surgeons score, platelet-rich plasma therapy, double-row repair, bone marrow stimulation, and single-row repair were significantly better than suture bridge repair. (2) In terms of Constant score, bone marrow stimulation was significantly better than double-row repair, single-row repair, and suture bridge repair. (3) In terms of visual analog scale score, platelet-rich plasma therapy was significantly better than double-row repair and suture bridge repair. (4) In terms of the Shoulder Rating Scale of the University of California at Los Angeles score, platelet-rich plasma therapy and double-row repair were relatively better but not significantly different from the other treatments. (5) In terms of the risk of re-tear, the re-tear rate of platelet-rich plasma therapy and double-row repair was significantly lower than that of single-row repair and suture bridge repair.

CONCLUSION

Based on the results of network Meta-analysis and surface under the cumulative ranking, platelet-rich plasma therapy, bone marrow stimulation, and double-row repair have good overall rehabilitation effects. It is recommended to choose appropriate repair techniques as per the actual clinical situation.

The role of bone marrow stimulation in rotator cuff repair: a systematic review and meta-analysis

PURPOSE

The objective of this study was to investigate whether RCR (rotator cuff repair) with BMS (bone marrow stimulation) can provide a lower retear rate and better shoulder function than arthroscopic RCR alone in rotator cuff tear (RCT) patients.

METHOD

The PubMed, Cochrane Library, EMBASE and Web of Science databases were searched until Feb 2022. Risk of bias for randomized controlled trials was evaluated by two independent reviewers with Cochrane collaboration risk bias of tool, and that for cohort studies was evaluated with the Newcastle-Ottawa Scale (NOS). The primary outcome was the retear rate. Secondary outcomes included the American Shoulder and Elbow Surgeons (ASES) score, University of California, Los Angeles Shoulder Scale (UCLA) score, Constant-Murley score (CMS) and visual analogue scale (VAS) score. Subgroup analysis was performed to explore the effect of suture method and tear size on BMS procedure.

RESULT

Five randomized controlled trials and four cohort studies with a total of 827 patients were included. The pooled retear rate between the RCR with BMS group and the RCR alone group was significantly different (17.5% vs. 28.9%; P < 0.0001). There were no differences in the ASES score, UCLA score and VAS score. The CMS was significantly higher in RCR with BMS group than the RCR alone groups (P = 0.02), while the difference was well below the MCID. RCR with BMS resulted in a significantly lower retear rate than RCR alone for large and massive RCTs (19.7% vs. 32.5%; P = 0.01).

CONCLUSION

Compared with RCR alone, RCR with BMS can significantly reduce the retear rate in arthroscopic RCT patients while not clinically relevant differences were found. BMS may further reduce the retear rate of large and massive RCTs.

LEVEL OF EVIDENCE

Level III; Systematic Review and Meta-analysis.

Exosomes from CD133+ human urine-derived stem cells combined adhesive hydrogel facilitate rotator cuff healing by mediating bone marrow mesenchymal stem cells

Background

The inadequate regeneration of natural tissue (mainly fibrocartilage) between tendon and bone during rotator cuff (RC) repair results in an unsatisfactory quality of RC healing. Cell-free therapy based on stem cell exosomes is a safer and more promising approach for tissue regeneration. Here, we investigated the effect of exosomes from human urine-derived stem cells (USCs) and their subpopulations (CD133⁺USCs) on RC healing.

Methods

USCs were isolated from urine and sorted by flow cytometry to obtain CD133⁺ urine-derived stem cells (CD133⁺ USCs). Urine-derived stem cell exosomes (USC-Exos) and CD133⁺ urine-derived stem cell exosomes (CD133⁺ USC-Exos) were subsequently isolated from the cell supernatant and identified by transmission electron microscopy (TEM), particle size analysis, and Western blot. We performed in vitro functional assays to evaluate the effects of USC-Exos and CD133⁺ USC-Exos on human bone marrow mesenchymal stem cells (BMSCs) proliferation, migration, osteogenic differentiation, and chondrogenic differentiation. In vivo experiments were performed by local injection of exosome-hydrogel complexes for the treatment of RC injury. The effects of CD133⁺ USC-Exos and USC-Exos on RC healing were assessed from imaging, histological, and biomechanical tests.

Results

CD133⁺ USCs were positive for CD29, CD44, CD73, CD90, CD133, but negative for CD34 and CD45. Differentiation ability test results showed that both USCs and CD133⁺ USCs had the potential for osteogenic, chondrogenic, and adipogenic differentiation, but CD133⁺ USCs had stronger chondrogenic differentiation ability. CD133⁺ USC-Exos and USC-Exos could be efficiently taken up by BMSCs and promote their migration, osteogenic and chondrogenic differentiation. However, CD133⁺ USC-Exos could promote the chondrogenic differentiation of BMSCs more than USC-Exos. Compared with USC-Exos, CD133⁺ USC-Exos could promote the healing of bone-tendon interface (BTI) more effectively, which might be related to its ability to promote the differentiation of BMSCs into chondroblasts. Although the two exosomes exhibited the same effect in promoting subchondral bone repair in BTI, the CD133⁺ USC-Exos group had higher histological scores and stronger biomechanical properties.

Conclusion

CD133⁺ USC-Exos hydrogel complex may become a promising therapeutic approach for RC healing based on stem cell exosomes.

The translational potential of this article

This is the first study to assess the specific role of CD133⁺ USC-Exos in RC healing which may be related to the activation of BMSCs by CD133⁺ USC-Exos towards chondrogenic differentiation. Further, our study provides a reference for possible future treatment of BTI by applying CD133⁺ USC-Exos hydrogel complex.

Local Intraoperative Marrow-Derived Augmentation for Primary Rotator Cuff Repair: An Updated Systematic Review and Meta-analysis of Studies From 2010 to 2022

Background

Recurrent tears of the rotator cuff pose a substantial problem despite advances in repair technique. Biologic augmentation via marrow stimulation or vented anchors may strengthen the suture-tendon junction and improve healing rates of native tissue, thereby enhancing outcomes of primary surgical repair.

Purpose

To provide a focused systematic review and meta-analysis of local, intraoperative marrow-derived augmentation techniques in clinical primary rotator cuff repair.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review of PubMed, Embase, and Cochrane was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A total of 2131 studies from 2010 to 2022, focused on either marrow stimulation or vented anchors, were isolated and classified as either preclinical or clinical. Meta-analysis was performed for comparative marrow stimulation and vented anchor studies. Heterogeneity was tested through calculation of I ².

Results

A total of 13 clinical studies were included in the review. All 9 comparative studies included in the meta-analysis demonstrated high methodologic quality or a low risk of bias. The pooled retear rate across all 9 clinical studies for patients undergoing marrow stimulation was 11%. For the 5 studies in the meta-analysis, the pooled retear rates were 15% for marrow stimulation and 30% for controls. Meta-analysis demonstrated a significant difference in the overall retear rate that favored marrow stimulation (odds ratio [OR], 0.41; 95% CI, 0.25-0.66; P = .0003; I ² = 0%). Similarly, meta-analysis of the Constant score at final follow-up demonstrated a statistically significant difference between the 2 groups that favored a higher Constant score in the marrow stimulation group (mean difference, 2.84; 95% CI, 1.02-4.66; P = .002; I ² = 29%). Vented anchors demonstrated improved ossification and bone density at the anchor site, but no difference in outcomes or retear. Pooled retear rates were 22.5% for vented anchors and 27.8% for controls.

Conclusion

Current evidence demonstrates that marrow-stimulation techniques may have a positive impact on healing and retear rate, while vented anchors have a muted impact relative to nonvented anchors. Although available evidence is limited and more research is needed, findings to date suggest that marrow stimulation techniques may be an inexpensive, straightforward technique to consider in qualifying patients to prevent rotator cuff retears.

Outcomes After Combined Remnant Preservation and Bone Marrow Stimulation for Acute Rotator Cuff Tears

Background

Both remnant preservation (RP) and bone marrow stimulation (BMS) enhance the healing potential of the repaired rotator cuff by improving the biological milieu of the tendon-bone interface.

Purpose

To evaluate the clinical and imaging outcomes of arthroscopic rotator cuff repair using a combined RP-BMS technique in patients with acute rotator cuff tears.

Study Design

Cohort study; Level of evidence, 3.

Methods

Between January 2016 and June 2019, a total of 56 patients were diagnosed with acute rotator cuff tears; 29 patients underwent conventional repair (group 1), and 27 patients underwent RP-BMS (group 2). At a minimum follow-up period of 2 years, the authors compared clinical outcomes with the University of California-Los Angeles; Constant; American Shoulder and Elbow Surgeons; and pain visual analog scale scores as well as shoulder range of motion. Tendon integrity and retear were assessed on magnetic resonance imaging according to the Sugaya classification (intact, grades 1-3; retear, grades 4-5). Between-group comparisons were conducted using the Student t test or Mann-Whitney U test for continuous variables and the Pearson chi-square test or Fisher exact test for categorical variables.

Results

In both groups, patients had significant preoperative to postoperative improvement on all clinical outcome measures (P = .001 for all). Shoulder abduction in group 2 was significantly greater compared with group 1 at the postoperative 3-month (107.37° ± 8.32° vs 95.44° ± 8.78°; P = .001), 6-month (155.25° ± 10.02° vs 144.72° ± 9.28°; P = .001), and final (165.15° ± 9.17° vs 158.31° ± 8.01°; P = .021) follow-ups. At the final follow-up, significantly more patients in group 2 had intact tendons (Sugaya grades 1-3) compared with group 1 (P = .015), and the tendon retear rate was lower in group 2 (1/27; 3.70%) than in group 1 (7/29; 24.14%) (P = .033).

Conclusion

Both surgical techniques led to satisfactory clinical outcomes, but shoulder abduction was greater after the RP-BMS technique compared with conventional repair. RP-BMS may be an alternative surgical technique to improve tendon integrity and retear rates after the repair of acute rotator cuff tears.

Bone marrow stimulation in arthroscopic rotator cuff repair is a cost-effective and straightforward technique to reduce retear rates: A systematic review and meta-analysis

Background

Bone marrow stimulation (BMS) has been considered a well-established method for treating knee and ankle osteochondral lesions. Some studies have also shown that BMS can promote healing of the repaired tendon and enhance biomechanical properties during rotator cuff repair. Our purpose was to compare the clinical outcomes of arthroscopic repair rotator cuff (ARCR) with and without BMS.

Methods

A systematic review with meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). PubMed, Embase, Web of Science, Google scholar, ScienceDirect, and the Cochrane Library were searched from inception to March 20, 2022. Data on retear rates, shoulder functional outcomes, visual analog score and range of motion were pooled and analyzed. Dichotomous variables were presented as odds ratios (OR), and continuous variables were presented as mean differences (MD). Meta-analyses were conducted with Review Manager 5.3.

Results

Eight studies involving 674 patients were included, with mean follow-up period ranging from 12 to 36.8 months. Compared to ARCR alone, the intraoperative combination of the BMS resulted in lower retear rates (P < 0.0001), but showed similar results in Constant score (P = 0.10), University of California at Los Angeles (UCLA) score (P = 0.57), American Shoulder and Elbow Surgeons (ASES) score (P = 0.23), Disabilities of the Arm, Shoulder and Hand (DASH) score (P = 0.31), VAS (visual analog score) score (P = 0.34), and range of motion (ROM) (forward flexion, P = 0.42; external rotation, P = 0.21). After sensitivity analyses and subgroup analyses, no significant changes in statistical results were observed.

Conclusion

Compared to ARCR alone, the combination of intraoperative BMS can significantly reduce the retear rates, but showed similar short-term results in functional outcomes, ROM and pain. Better clinical outcomes are anticipated in the BMS group by improving structural integrity during long-term follow-up. Currently, BMS may be a viable option in ARCR based on its straightforward and cost-effective advantages.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022323379.

Clinical perspectives for repairing rotator cuff injuries with multi-tissue regenerative approaches

Background

In the musculoskeletal system, bone, tendon, and muscle form highly integrated multi-tissue units such as the rotator cuff complex, which facilitates functional and dynamic movement of the shoulder joint. Understanding the intricate interplay among these tissues within clinical, biological, and engineering contexts is vital for addressing challenging issues in treatment of musculoskeletal disorders and injuries.

Methods

A wide-ranging literature search was performed, and findings related to the socioeconomic impact of rotator cuff tears, the structure-function relationship of rotator cuff bone-tendon-muscle units, pathophysiology of injury, current clinical treatments, recent state-of-the-art advances (stem cells, growth factors, and exosomes) as well as their regulatory approval, and future strategies aimed at engineering bone-tendon-muscle musculoskeletal units are outlined.

Results

Rotator cuff injuries are a significant socioeconomic burden on numerous healthcare systems that may be addressed by treating the rotator cuff as a single complex, given its highly integrated structure-function relationship as well as degenerative pathophysiology and limited healing in bone-tendon-muscle musculoskeletal tissues. Current clinical practices for treating rotator cuff injuries, including the use of commercially available devices and evolving trends in surgical management have benefited patients while advances in application of stem/progenitor cells, growth factors, and exosomes hold clinical potential. However, such efforts do not emphasize targeted regeneration of bone-tendon-muscle units. Strategies aimed at regenerating bone-tendon-muscle units are thus expected to address challenging issues in rotator cuff repair.

Conclusions

The rotator cuff is a highly integrated complex of bone-tendon-muscle units that when injured, has severe consequences for patients and healthcare systems. State-of-the-art clinical treatment as well as recent advances have resulted in improved patient outcome and may be further enhanced by engineering bone-tendon-muscle multi-tissue grafts as a potential strategy for rotator cuff injuries.

Translational Potential of this Article

This review aims to bridge clinical, tissue engineering, and biological aspects of rotator cuff repair and propose a novel therapeutic strategy by targeted regeneration of multi-tissue units. The presentation of these wide-ranging and multi-disciplinary concepts are broadly applicable to regenerative medicine applications for musculoskeletal and non-musculoskeletal tissues.

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.

The "Greenhouse" Technique Using Knotless Single-Row Suture Bridge Combined With Bone Marrow Stimulation for the Arthroscopic Treatment of Rotator Cuff Tears

To simplify the arthroscopic rotator cuff repair technique and improve tendon healing, we have developed a method named the "Greenhouse" technique to repair rotator cuff. With bone marrow stimulation combined with knotless single-row suture bridge fixation, we provide a technique for reliable cuff fixation with enhanced biological features.

Anatomic based microfracture technique of insertion for rotator cuff repair in Vietnamese people: Case series study

Abstract

Postoperative tendon healing is still a matter of concern after rotator cuff repair. Several techniques have been introduced to help improve this healing process. Among them, the bone marrow is commonly used source and a research subject for methods using stem cells to promote wound healing process. A number of studies have shown that bone marrow stem cells can travel up through the holes on the rotator cuff insertion sites, contributing into the rotator cuff repair process, increasing the efficiency of tendon healing and improving clinical results.

Patients and methods

Cross-sectional descriptive study was performed on 41 rotator cuff tear patients. The microfractures for these patients were calculated beforehand, which have great depth but small diameter, based on the anatomical characteristic of the rotator cuff tear insertions of Vietnamese people. Patients' rotator cuff tendon healing processes were evaluated using ultrasound after surgery. Final tendon healing and clinical results ultimately rely on MRI assessments, classified according to Sugaya's classification, UCLA and ASES scale.

Results

No cases of rupture and fracture of the greater tubercle was recorded. There was a clear progression of tendon healing on ultrasound according to postoperative follow-up time-stamps (1 month, 3 months). MRI images evaluation also reveals at the latest follow-up time, according to Sugaya classification, the ratio of tendon healing was 87.8%, while the percentage of re-rupture was 12.2%. ASES and average UCLA scale were collected at the end of the study, respectively as 95.41 ± 5.45 and 32.36 ± 2.53.

Conclusion

The technique's microfractures characteristics based on the rotator cuff tear insertion anatomy ensures a secure, straightforward approach along with promising results in terms of tendon healing rate and postoperative functional outcomes.

Stem cell therapies in tendon-bone healing

Tendon-bone insertion injuries such as rotator cuff and anterior cruciate ligament injuries are currently highly common and severe. The key method of treating this kind of injury is the reconstruction operation. The success of this reconstructive process depends on the ability of the graft to incorporate into the bone. Recently, there has been substantial discussion about how to enhance the integration of tendon and bone through biological methods. Stem cells like bone marrow mesenchymal stem cells (MSCs), tendon stem/progenitor cells, synovium-derived MSCs, adipose-derived stem cells, or periosteum-derived periosteal stem cells can self-regenerate and potentially differentiate into different cell types, which have been widely used in tissue repair and regeneration. Thus, we concentrate in this review on the current circumstances of tendon-bone healing using stem cell therapy.

Footprint preparation with nanofractures in a supraspinatus repair cuts in half the retear rate at 1-year follow-up. A randomized controlled trial

PURPOSE

To evaluate if adding nanofractures to the footprint of a supraspinatus tear repair would have any effect in the outcomes at one-year follow-up.

METHODS

Multicentric, triple-blinded, randomized trial with 12-months follow-up. Subjects with isolated symptomatic reparable supraspinatus tears smaller than 3 cm and without grade 4 fatty infiltration were included. These were randomized to two groups: In the Control group an arthroscopic supraspinatus repair was performed; in the Nanofracture group the footprint was additionally prepared with nanofractures (1 mm wide, 9 mm deep microfractures). Clinical evaluation was done with Constant score, EQ-5D-3L, and Brief Pain Inventory. The primary outcome was the retear rate in MRI at 12-months follow-up. Secondary outcomes were: characteristics of the retear (at the footprint or at the musculotendinous junction) and clinical outcomes.

RESULTS

Seventy-one subjects were randomized. Two were lost to follow-up, leaving 69 participants available for assessment at 12-months follow-up (33 in the Control group and 36 in the Nanofracture Group). The Nanofracture group had lower retear rates than the Control group (7/36 [19.4%] vs 14/33 [42.4%], differences significant, p = 0.038). Retear rates at the musculotendinous junction were similar but the Nanofracture group had better tendon healing rates to the bone (34/36 [94.4%] vs. 24/33 [66.71%], p = 0.014). Clinically both groups had significant improvements, but no differences were found between groups.

CONCLUSION

Adding nanofractures at the footprint during an isolated supraspinatus repair lowers in half the retear rate at 12-months follow-up. This is due to improved healing at the footprint.

LEVEL OF EVIDENCE

Level I.

Preoperative bone marrow stimulation does not improve functional outcomes in arthroscopic cuff repair: a prospective randomized controlled trial

AIMS

Despite recent advances in arthroscopic rotator cuff repair, re-tear rates remain high. New methods to improve healing rates following rotator cuff repair must be sought. Our primary objective was to determine if adjunctive bone marrow stimulation with channelling five to seven days prior to arthroscopic cuff repair would lead to higher Western Ontario Rotator Cuff (WORC) scores at 24 months postoperatively compared with no channelling.

METHODS

A prospective, randomized controlled trial was conducted in patients undergoing arthroscopic rotator cuff repair. Patients were randomized to receive either a percutaneous bone channelling of the rotator cuff footprint or a sham procedure under ultrasound guidance five to seven days prior to index surgery. Outcome measures included the WORC, American Shoulder and Elbow Surgeons (ASES), and Constant scores, strength, ultrasound-determined healing rates, and adverse events.

RESULTS

Overall, 94 patients were randomized to either bone channelling or a sham procedure. Statistically significant improvements in all clinical outcome scores occurred in both groups from preoperative to all timepoints (p < 0.001). Intention-to-treat analysis revealed no statistical differences in WORC scores between the two interventions at 24 months postoperatively (p = 0.690). No differences were observed in secondary outcomes at any timepoint and healing rates did not differ between groups (p = 0.186).

CONCLUSION

Preoperative bone channelling one week prior to arthroscopic rotator cuff repair was not associated with significant improvements in WORC, ASES, Constant scores, strength, or ultrasound-determined healing rates. Cite this article: Bone Joint J 2021;103-B(1):123-130.

Arthroscopic Repair of Medium to Large Rotator Cuff Tears With a Triple-Loaded Medially Based Single-Row Technique Augmented With Marrow Vents

PURPOSE

The primary purpose of this study was to evaluate the repair integrity on magnetic resonance imaging (MRI), and secondarily, clinical outcomes, of medium to large (2-4 cm) rotator cuff tears treated using an arthroscopic triple-loaded medially based single-row repair technique augmented laterally with bone marrow vents.

METHODS

This is a retrospective outcomes study of patients with full-thickness medium to large (2-4 cm) rotator cuff tears repaired by 4 surgeons at a single institution over a 2-year period with a minimum of 24 months' follow-up. A single-row repair with tension-minimizing medially based triple-loaded anchors and laterally placed bone marrow vents was used. Patients completed a satisfaction and pain survey, the Western Ontario Rotator Cuff index questionnaire, and a Short Form-36 version 2 survey to evaluate clinical outcomes. MRI was obtained at a minimum of 24 months follow-up to assess repair integrity.

RESULTS

A total of 64 males and 27 females with a mean age of 59.7 (range, 34-82) were included. The mean tear size was 2.6 cm in anteroposterior dimension, treated with a mean of 2.2 anchors. Eighty-three of 91 shoulders (91%) reported being completely satisfied with their result. The median Western Ontario Rotator Cuff score was 95.2% of normal, with a significant difference found between those with an intact repair and those with a full-thickness recurrent defect (median, 95.9% vs. 73.8%; P = .003). Postoperative MRI obtained at a median of 32 months (range, 24-48) demonstrated an intact repair in 84 of 91 shoulders (92%), with failure defined as a full-thickness defect of the tendon.

CONCLUSIONS

Arthroscopic repair of medium to large rotator cuff tears using triple-loaded medially based single-row repair augmented with marrow vents resulted in a 92% healing rate by MRI and excellent patient-reported outcomes LEVEL OF EVIDENCE: Level IV, retrospective case series.

Bone Marrow Stimulation in Arthroscopic Repair for Large to Massive Rotator Cuff Tears With Incomplete Footprint Coverage

BACKGROUND

There is no research on incomplete footprint coverage with single-row repair related to bone marrow stimulation (BMS) in large to massive rotator cuff tears (RCTs).

PURPOSE/HYPOTHESIS

The purpose was to compare the clinical results and structural integrity between BMS and non-BMS groups that underwent arthroscopic repair of large to massive rotator cuff tears with <50% footprint coverage. It was hypothesized that both groups would exhibit improved clinical outcomes at 2 years after surgery but the BMS group would have significantly better clinical outcomes and structural integrity.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study included 98 patients who underwent arthroscopic repair with <50% footprint coverage for large to massive RCTs with (BMS group; n = 56) or without (non-BMS group; n = 42) BMS. Functional outcomes at the 2-year follow-up were assessed using the visual analog scale for pain score, subjective shoulder value; American Shoulder and Elbow Surgeons score; University of California, Los Angeles, shoulder score; and active range of motion. Structural integrity was evaluated using magnetic resonance arthrography or computed tomography arthrography results at 6 months postoperatively.

RESULTS

At the 2-year follow-up, all functional outcomes significantly improved in both groups compared with preoperative values (P < .001). However, there were no significant postoperative differences between groups. On follow-up magnetic resonance arthrography or computed tomography arthrography, the overall retear rate was not significantly different between the BMS group (30.3%; 17/56) and the non-BMS group (35.7%; 15/42).

CONCLUSION

While both groups exhibited functional improvement after single-row repair with <50% footprint coverage for large to massive RCTs, BMS did not produce better clinical outcomes or structural integrity.

Safety and efficacy of treating symptomatic, partial-thickness rotator cuff tears with fresh, uncultured, unmodified, autologous adipose-derived regenerative cells (UA-ADRCs) isolated at the point of care: a prospective, randomized, controlled first-in-human pilot study

Background

This study tested the hypothesis that treatment of symptomatic, partial-thickness rotator cuff tears (sPTRCT) with fresh, uncultured, unmodified, autologous adipose-derived regenerative cells (UA-ADRCs) isolated from lipoaspirate at the point of care is safe and more effective than corticosteroid injection.

Methods

Subjects aged between 30 and 75 years with sPTRCT who did not respond to physical therapy treatments for at least 6 weeks were randomly assigned to receive a single injection of an average 11.4 × 10⁶ UA-ADRCs (in 5 mL liquid; mean cell viability: 88%) (n = 11; modified intention-to-treat (mITT) population) or a single injection of 80 mg of methylprednisolone (40 mg/mL; 2 mL) plus 3 mL of 0.25% bupivacaine (n = 5; mITT population), respectively. Safety and efficacy were assessed using the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), RAND Short Form-36 Health Survey, and pain visual analogue scale (VAS) at baseline (BL) as well as 3 weeks (W3), W6, W9, W12, W24, W32, W40, and W52 post treatment. Fat-saturated T2-weighted magnetic resonance imaging of the shoulder was performed at BL as well as at W24 and W52 post treatment.

Results

No severe adverse events related to the injection of UA-ADRCs were observed in the 12 months post treatment. The risks connected with treatment of sPTRCT with UA-ADRCs were not greater than those connected with treatment of sPTRCT with corticosteroid injection. However, one subject in the corticosteroid group developed a full rotator cuff tear during the course of this pilot study. Despite the small number of subjects in this pilot study, those in the UA-ADRCs group showed statistically significantly higher mean ASES total scores at W24 and W52 post treatment than those in the corticosteroid group (p < 0.05).

Discussion

This pilot study suggests that the use of UA-ADRCs in subjects with sPTRCT is safe and leads to improved shoulder function without adverse effects. To verify the results of this initial safety and feasibility pilot study in a larger patient population, a randomized controlled trial on 246 patients suffering from sPTRCT is currently ongoing.

Trial registration

Clinicaltrials.gov ID NCT02918136. Registered September 28, 2016, https://clinicaltrials.gov/ct2/show/NCT02918136.

Level of evidence

Level I; prospective, randomized, controlled trial.

Editorial Commentary: Rotator Cuff Tendon Healing May Be Enhanced With a Blanket

After rotator cuff repair, the regeneration of the anatomic enthesis may be beneficial. Although many cell and growth factor studies have been performed, none have shown a consistent regeneration of this structure. The use of bone marrow vents in the greater tuberosity has been associated with improved healing. The resultant clot has been dubbed a "crimson duvet" or blanket. The use of this readily available-and inexpensive-modality should be maximized in patients undergoing rotator cuff repair. In the end, a goal could be to enhance tendon-to-bone healing via a scaffold, cells, and growth factors. Pending inevitable reliable advances in biological augmentation, mesenchymal stem cells and growth factors from the greater tuberosity are just a marrow-stimulating pick away.

Small Subchondral Drill Holes Improve Marrow Stimulation of Rotator Cuff Repair in a Rabbit Model of Chronic Rotator Cuff Tear

BACKGROUND

Microfracture of the greater tuberosity has been proved effective for enhancing tendon-to-bone healing after rotator cuff repair. However, no standard diameter for the microfracture has been established.

PURPOSE/HYPOTHESIS

This study aimed to assess treatment with large- and small-diameter microfractures to enhance healing during rotator cuff repair surgery in a rabbit model of chronic rotator cuff tear. It was hypothesized that a small-diameter microfracture had advantages in terms of tendon-to-bone integration, bone-tendon interface maturity, microfracture healing, and biomechanical properties compared with a large-diameter microfracture.

STUDY DESIGN

Controlled laboratory study.

METHODS

Bilateral supraspinatus tenotomy from the greater tuberosity was performed on 21 New Zealand White rabbits. Bilateral supraspinatus repair was performed 6 weeks later. Small-diameter (0.5 mm) microfracture and large-diameter microfracture (1 mm) were performed on the left side and right side, respectively, in 14 rabbits as a study group, and simple repair without microfracture was performed in 7 rabbits as a control group. At 12 weeks later, 7 of 14 rabbits in the study group were sacrificed for micro-computed tomography evaluation and biomechanical testing. Another 6 rabbits were sacrificed for histological evaluation. In the control group, 3 of the 7 rabbits were sacrificed for histological evaluation and the remaining rabbits were sacrificed for biomechanical testing.

RESULTS

Significantly better bone-to-tendon integration was observed in the small-diameter microfracture group. Better histological formation and maturity of the bone-tendon interface corresponding to better biomechanical results (maximum load to failure and stiffness) were obtained on the small-diameter microfracture side compared with the large-diameter side and the control group. The large-diameter microfracture showed worse radiographic and histological properties for healing of the microfracture holes on the greater tuberosity. Additionally, the large-diameter microfracture showed inferior biomechanical properties but similar histological results compared with the control group.

CONCLUSION

Small-diameter microfracture showed advantages with enhanced rotator cuff healing for biomechanical, histological, and radiographic outcomes compared with large-diameter microfracture, and large-diameter microfracture may worsen the rotator cuff healing.

CLINICAL RELEVANCE

This animal study suggested that a smaller diameter microfracture may be a better choice to enhance healing in clinical rotator cuff repair surgery in humans.

The clinical and radiologic outcome of microfracture on arthroscopic repair for full-thickness rotator cuff tear

BACKGROUND

The persistent incidence of retear despite improvements in techniques led orthopedic surgeons to the application of principles of tissue bioengineering to achieve enhanced repair and functional outcomes. The purpose of this study was to compare clinical and radiologic outcomes of arthroscopic single-row repair augmented with microfracture (SRM) at the greater tuberosity with single-row (SR) and double-row (DR) repair in the treatment of full-thickness rotator cuff tears.

MATERIALS AND METHODS

This is a retrospective comparative study. A total of 123 patients were enrolled for arthroscopic repair of full-thickness rotator cuff tears, with 40 patients treated by SR, 44 by SRM, and 39 by DR. The minimum follow-up was 2 years. The primary outcome was retear rate, which was detected by magnetic resonance imaging, and the secondary outcome was functional outcome.

RESULTS

The mean age of the patients was 59.2 years, 58.1 years, and 60.6 years in the SR, SRM, and DR groups, respectively. The retear rate was 33%, 14%, and 36% in the SR, SRM, and DR groups, respectively (P = .045). The SRM group had significantly improved functional outcomes compared with the SR and DR groups in terms of the postoperative Constant score and visual analog scale score (P = .001 and .002, respectively). Delta Constant scores were nonsignificant for retear and intact tendons (P = .137).

CONCLUSION

SRM has a significantly lower retear rate and better functional outcome than SR and DR repair.

A Prospective Randomized Trial Comparing Suture Bridge and Medially Based Single-Row Rotator Cuff Repair in Medium-Sized Supraspinatus Tears

PURPOSE

To compare the clinical and imaging outcomes between the suture bridge technique (SB) and the medially based single-row technique (medSR) in patients with 1- to 3-cm tear sizes.

METHODS

All patients were evaluated preoperatively and postoperatively (at 12 and 24 months) using the modified University of California, Los Angeles scoring system; active range of motion (flexion and external rotation); and a visual analog scale for pain. Healing status was examined by postoperative magnetic resonance imaging.

RESULTS

Clinical and imaging evaluations were completed by 92 patients at 1-year follow-up and by 74 patients at 2 years. No significant differences were found between the 2 groups across all measures at final follow-up: The University of California, Los Angeles scores were 33.4 points in SB patients and 33.0 points in medSR patients (P = .58); the visual analog scale scores were 6 mm and 7 mm, respectively (P = .38); the active flexion angles were 161° and 159°, respectively (P = .34); and the external rotation angles were 49° and 52°, respectively (P = .37). Retears were observed in 6.5% of SB patients and 2.1% of medSR patients (P = .31). Medial cuff failure was observed only in SB patients (4.3%, 2 cases), whereas incomplete healing (deep-layer retraction pattern) was observed only in medSR patients (8.7%, 4 cases). Neo-tendon regeneration in the medSR group was observed in 93% of patients.

CONCLUSIONS

This study did not show any significant differences in the clinical outcomes and cuff integrity between the 2 treatment groups at final follow-up; however, medial cuff failure was observed only in the SB group, and incomplete healing was more frequent in the medSR group. One should consider the risk of medial cuff failure and incomplete healing of the repaired cuff before choosing the repair technique for medium-sized supraspinatus tears.

LEVEL OF EVIDENCE

Level I, therapeutic, prospective, randomized trial.

Tendon contains more stem cells than bone at the rotator cuff repair site

BACKGROUND

The rotator cuff (RC) repair failure rate is high. Tendon and bone represent sources of mesenchymal stem cells (MSCs), but the number of MSCs from each has not been compared. Bone channeling may increase bone-derived MSC numbers participating in enthesis re-formation at the "footprint" repair site. The effect of preoperative channeling on increasing bone MSC numbers has never been reported. We asked (1) whether bone contains more MSCs than tendon at the time of arthroscopic repair and (2) whether bone preoperative channeling at the RC repair site increases the number of bone-derived MSCs at the time of surgery.

METHODS

In 23 participants undergoing arthroscopic RC repair, bone was sampled from the footprint and tendon was sampled from the distal supraspinatus. We randomized participants to the channeling or no-channeling group 5 to 7 days before surgery. We enumerated MSCs from both tissues using the colony-forming unit-fibroblast (CFU-F) assay (10 per group). We identified MSC identity using flow cytometry and MSC tri-differentiation capacity (n = 3).

RESULTS

Tendon CFU-F per gram exceeded bone CFU-F per gram for both groups (479 ± 173 CFU-F/g vs. 162 ± 54 CFU-F/g for channeling [P = .036] and 1334 ± 393 CFU-F/g vs. 284 ± 88 CFU-F/g for no channeling [P = .009]). Ninety-nine percent of cultured cells satisfied the MSC definition criteria.

CONCLUSIONS

The distal supraspinatus tendon contained more MSCs per gram than the humeral footprint. Tendon may represent an important and overlooked MSC source for postoperative enthesis re-formation. Further studies are needed to evaluate the repair role of tendon MSCs and to recommend bone channeling in RC repair.

The gelling effect of platelet-rich fibrin matrix when exposed to human tenocytes from the rotator cuff in small-diameter culture wells and the design of a co-culture device to overcome this phenomenon

Objectives

Platelet-rich fibrin matrix (PRFM) has been proved to enhance tenocyte proliferation but has mixed results when used during rotator cuff repair. The optimal PRFM preparation protocol should be determined before clinical application. To screen the best PRFM to each individual's tenocytes effectively, small-diameter culture wells should be used to increase variables. The gelling effect of PRFM will occur when small-diameter culture wells are used. A co-culture device should be designed to avoid this effect.

Methods

Tenocytes harvested during rotator cuff repair and blood from a healthy volunteer were used. Tenocytes were seeded in 96-, 24-, 12-, and six-well plates and co-culture devices. Appropriate volumes of PRFM, according to the surface area of each culture well, were treated with tenocytes for seven days. The co-culture device was designed to avoid the gelling effect that occurred in the small-diameter culture well. Cell proliferation was analyzed by water soluble tetrazolium-1 (WST-1) bioassay.

Results

The relative quantification (condition/control) of WST-1 assay on day seven revealed a significant decrease in tenocyte proliferation in small-diameter culture wells (96 and 24 wells) due to the gelling effect. PRFM in large-diameter culture wells (12 and six wells) and co-culture systems induced a significant increase in tenocyte proliferation compared with the control group. The gelling effect of PRFM was avoided by the co-culture device.

Conclusion

When PRFM and tenocytes are cultured in small-diameter culture wells, the gelling effect will occur and make screening of personalized best-fit PRFM difficult. This effect can be avoided with the co-culture device.Cite this article: C-H. Chiu, P. Chen, W-L. Yeh, A. C-Y. Chen, Y-S. Chan, K-Y. Hsu, K-F. Lei. The gelling effect of platelet-rich fibrin matrix when exposed to human tenocytes from the rotator cuff in small-diameter culture wells and the design of a co-culture device to overcome this phenomenon. Bone Joint Res 2019;8:216-223. DOI: 10.1302/2046-3758.85.BJR-2018-0258.R1.

Bone marrow stimulation decreases retear rates after primary arthroscopic rotator cuff repair: a systematic review and meta-analysis

BACKGROUND

Despite the optimization of biomechanical and patient factors in the setting of rotator cuff repair (RCR), postoperative retear rates remain high in many series reported in the literature. Preclinical studies have suggested bone marrow stimulation (BMS) at the rotator cuff footprint may reduce the rate of retear after RCR. The objective of this meta-analysis was to analyze the clinical evidence investigating the effect of arthroscopic RCR, with and without BMS, on rotator cuff healing and functional outcomes.

METHODS

PubMed, MEDLINE, Embase, and the Cochrane Library were searched through December 2017. Two reviewers selected studies based on the inclusion criteria and assessed methodologic quality. Pooled analyses were performed for continuous and binomial variables where appropriate.

RESULTS

Four studies (365 patients), including 2 Level I randomized controlled trials and 2 Level III retrospective comparative cohort studies were included. There was no statistical difference in the Disabilities of the Arm, Shoulder and Hand score, University of California Los Angeles Shoulder Rating Scale score, or the Constant score between the BMS and conventional repair groups. The pooled retear rates were 18.4% (28 of 152) and 31.8% (56 of 176) for patients treated with and without BMS, respectively. The pooled analysis of rotator cuff retear rates from the 4 studies (328 patients) showed a statistically significant difference favoring BMS over conventional repair (odds ratio, 0.42; 95% confidence interval, 0.25-0.73; P = .002; I² = 0%).

CONCLUSION

BMS reduces the retear rate after RCR but shows no difference in functional outcomes compared with conventional repair. This study provides evidence for the use of BMS as a potential cost-effective biological approach toward improving rotator cuff healing.

Efficacy of bone marrow stimulation in arthroscopic repair of full thickness rotator cuff tears: a meta-analysis

Background

To conduct a meta-analysis to compare the curative effect of treating the full thickness tear of the rotator cuff using the arthroscopic bone marrow stimulation (BMS) technology and provide the evidence for its extensive clinical application.

Methods

A systematic literature search was conducted to evaluate the studies on comparison of the curative effect of routine surgery with or without BMS on rotator cuff tear in the major medical databases. The literature was screened according to the inclusion and exclusion standards, and the quality assessment was conducted, then Review Manager 5.3 software was used for meta-analysis.

Results

Eight articles were eligible for inclusion. There were no statistically significant differences between BMS and control groups for overall outcome scores (P > 0.05). Except the Constant score of BMS group was significantly higher than that of the control group at the third follow-up month (P = 0.007). However, the postoperative re-tear rate of the BMS group was significantly lower than that of the control group (P < 0.001). Furthermore, we made a subgroup analysis and found that the postoperative Constant and UCLA score had no significant differences among all groups (P > 0.05), and the re-tear rates of the BMS groups were lower than those of the control groups (P = 0.001, P = 0.0002).

Conclusions

BMS technology has no significant influence on the postoperative clinical result of patients. However, it can obviously promote the tendon-to-bone healing of the rotator cuff and decrease the re-tear rate, which provides evidence for the clinical treatment.

Use of stem cells and growth factors in rotator cuff tendon repair

The management of rotator cuff tears continues to prove challenging for orthopaedic surgeons. Such tears affect most age groups and can lead to significant morbidity in patients. The aetiology of these tears is likely to be multifactorial; however, an understanding of the mechanisms involved is still under review. Despite advancements in surgical operative techniques and the materials used, post-operative recurrence rates after surgical repair remain high. A growing area of research surrounds biological adjuncts used to improve the healing potential of the repaired tissues. This review of recent publications focuses on the strengths and limitations of using stem cells and growth factors in rotator cuff repair.

Technologies to Augment Rotator Cuff Repair

Healing rates after rotator cuff repair vary widely. New technologies seek to improve tendon to bone healing with the addition of platelet-rich plasma, stem cells, and biological and synthetic grafts. Platelet-rich plasma and mesenchymal stem cells are used to help create a favorable environment for tendon to bone healing, and grafts and scaffolds provide structural support for repair. The efficacy of platelet-rich plasma and stem cell products seems to be variable, with different products offering different levels of cytokine and growth factors. Scaffold material is also variable with a wide range of synthetic and biological grafts.

The Surgical Applications of Biologics in Sports Medicine

Over the past 25 years an increased appreciation of the positive impact of biologic interventions has driven significant advances in the surgical treatment of shoulder and knee conditions. These biologic adjuncts to treatment promote improved outcomes and have set the stage and increased research and development in this arena.

Rotator cuff tear healing process with graft augmentation of fascia lata in a rabbit model

Background

Fascia lata augmentation of massive rotator cuff tears has shown good clinical results. However, its biological effect during the early healing process is not clearly understood. The purpose of the study was to evaluate the biological efficacy of fascia lata augmentation during the early healing process of rotator cuff tears using a rabbit rotator cuff defect model.

Methods

The infraspinatus tendon was resected from the greater tuberosity of a rabbit to create a rotator cuff tear. The tendon edge was directly sutured to the humeral head. The rotator cuff repaired site was augmented with a fascia lata autograft (augmentation group, group A). The rotator cuff defect in the contralateral shoulder was repaired without augmentation (reattachment group, group R). A group with intact rotator cuff was set as the control group. Histological examinations and mechanical analysis were conducted 4 and 8 weeks postoperatively.

Results

In the HE staining, the tendon maturing score of group A was higher than that of group R at 4 weeks postoperatively. In the safranin O staining, proteoglycan staining at the repaired enthesis in group A at 4 weeks postoperatively was stronger than that in group R. Picrosirius red staining showed that type III and type I collagen in group A was more strongly expressed than that in group R at 4 weeks postoperatively. The ultimate failure load of the infraspinatus tendon–humeral head complex in group A was statistically higher than that in group R at 4 weeks postoperatively. The ultimate failure load of group A was similar to that of the control group.

Conclusion

The biological and mechanical contribution of fascia lata augmentation for massive rotator cuff tears was analyzed in this study. Type III collagen was reported to be expressed during the tendon healing process. Although the biological action similar to natural ligament healing occurred around the fascia lata grafts, type III collagen was gradually replaced by type I collagen as the tissue matured. Our results suggest that fascia lata augmentation could stimulate biological healing and provide initial fixation strength of the repaired rotator cuff.

The greater tuberosity angle: a new predictor for rotator cuff tear

BACKGROUND

The implication of scapular morphology in rotator cuff tears has been extensively studied. However, the role of the greater tuberosity (GT) should be of equal importance. The aim of this study was to propose a new radiographic marker, the GT angle (GTA), which measures the position of the GT in relation to the center of rotation of the humeral head. The hypothesis was that a higher angle value would be associated with a higher likelihood in detecting a rotator cuff tear.

METHODS

During 1 year, patients were prospectively recruited from a single institution specialized shoulder clinic in 2 different groups. The patient group consisted of individuals with a degenerative rotator cuff tear involving at least the supraspinatus. The control group consisted of individuals with no rotator cuff pathology. Individuals in both groups with congenital, post-traumatic, or degenerative alterations of the proximal humerus were excluded. The GTA was measured on an anteroposterior shoulder x-ray image with the arm in neutral rotation by 3 observers at 2 different times.

RESULTS

The study recruited 71 patients (33 patients, 38 controls). Mean GTA value was 72.5° (range, 67.6°-79.2°) in patients and 65.2° (range, 55.8°-70.5°) for controls (P <.001). A value above 70° resulted in 93-fold higher odds of detecting a rotator cuff tear (P <.001). Interobserver and intraobserver reliability were high.

CONCLUSIONS

GT morphology is implicated in rotator cuff tears. The GTA is a reliable radiographic marker, with more than 70° being highly predictive in detecting such lesions.

Supraspinatus tendon repair using anchors: a biomechanical evaluation in the rabbit

Background

Arthroscopic rotator cuff repairs are mostly secured with suture anchors and often supplemented by footprint decortication. The objectives of this study were to characterize the strength of bone–tendon healing following anchor repair and assess the effect of channeling the supraspinatus (SSP) humeral footprint 1 week ahead of reattachment surgery.

Methods

One hundred twelve rabbits underwent unilateral detachment of one SSP tendon and were randomly assigned to two groups: channeling the footprint at time of detachment and no channeling. One week later, reattachment was performed using an anchor. The repaired and contralateral shoulders were harvested at 0, 1, 2, or 4 weeks after repair and mechanically tested to failure. Outcome measures included load at failure, stiffness, and site of failure.

Results

Anchor fixation had a mean load at failure of 81 ± 32 N and a stiffness of 27 ± 9 N/mm immediately after repair compared to 166 ± 47 N and 66 ± 13 N/mm in the contralateral (both p < 0.05). Mechanical recovery of the reattached SSP tendon was achieved after 4 weeks (221 ± 73 N, 206 ± 59 N, and 198 ± 49 N in the channeling, no channeling, and contralateral groups, respectively, p > 0.05). The dominant site of failure shifted from the footprint at 0/1 week to bone avulsion/mid-substance tear at 4 weeks (p < 0.05). There were no differences in outcomes between the channeling and no channeling groups.

Conclusions

This study is the first of its kind to provide quantitative data on the mechanical properties of the enthesis following anchor repair in a rabbit model. Anchor repair led to rapid and complete restoration of SSP mechanical properties. Further evidence is needed before recommending channeling ahead of repair surgery.

Regenerative Engineering of the Rotator Cuff of the Shoulder

Rotator cuff tears often heal poorly, leading to re-tears after repair. This is in part attributed to the low proliferative ability of the resident cells (tendon fibroblasts and tendon-stem cells) upon injury to the rotator cuff tissue and the low vascularity of the tendon insertion. In addition, surgical outcomes of current techniques used in clinical settings are often suboptimal, leading to the formation of neo-tissue with poor biomechanics and structural characteristics, which results in re-tears. This has prompted interest in a new approach, which we term as "Regenerative Engineering", for regenerating rotator cuff tendons. In the Regenerative Engineering paradigm, roles played by stem cells, scaffolds, growth factors/small molecules, the use of local physical forces, and morphogenesis interplayed with clinical surgery techniques may synchronously act, leading to synergistic effects and resulting in successful tissue regeneration. In this regard, various cell sources such as tendon fibroblasts and adult tissue-derived stem cells have been isolated, characterized, and investigated for regenerating rotator cuff tendons. Likewise, numerous scaffolds with varying architecture, geometry, and mechanical characteristics of biologic and synthetic origin have been developed. Furthermore, these scaffolds have been also fabricated with biochemical cues (growth factors and small molecules), facilitating tissue regeneration. In this Review, various strategies to regenerate rotator cuff tendons using stem cells, advanced materials, and factors in the setting of physical forces under the Regenerative Engineering paradigm are described.

Excellent healing rates and patient satisfaction after arthroscopic repair of medium to large rotator cuff tears with a single-row technique augmented with bone marrow vents

PURPOSE

This study evaluated the repair integrity and patient clinical outcomes following arthroscopic rotator cuff repair of medium to large rotator cuff tears using a single-row technique consisting of medially based, triple-loaded anchors augmented with bone marrow vents in the rotator cuff footprint lateral to the repair.

METHODS

This is a retrospective study of 52 patients (53 shoulders) comprising 36 males and 16 females with a median age of 62 (range 44-82) with more than 24-month follow-up, tears between 2 and 4 cm in the anterior-posterior dimension and utilizing triple-loaded anchors. Mann-Whitney test compared Western Ontario Rotator Cuff (WORC) outcome scores between patients with healed and re-torn cuff repairs. Multivariate logistic regression analysed association of variables with healing status and WORC score. Cuff integrity was assessed on MRI, read by a musculoskeletal fellowship-trained radiologist.

RESULTS

Magnetic resonance imaging (MRI) demonstrated an intact repair in 48 of 53 shoulders (91%). The overall median WORC score was 95.7 (range 27.6-100.0). A significant difference in WORC scores were seen between patients with healed repairs 96.7 (range 56.7-100.0) compared with a re-tear 64.6 (27.6-73.8), p < 0.00056.

CONCLUSIONS

Arthroscopic repair of medium to large rotator cuff tears using a triple-loaded single-row repair augmented with bone marrow vents resulted in a 91% healing rate by MRI and excellent patient reported clinical outcomes comparable to similar reported results in the literature.

LEVEL OF EVIDENCE

IV.

An Arthroscopic Knotless Technique for Anatomical Restoration of the Rotator Cuff and Superior Capsule: The Double-Layer Cinch Bridge

Rotator cuff repairs are the most common procedures in shoulder surgery, but still show long-term retear rates of up to 70%. Nonanatomic reconstruction is one possible cause of repair failure. The rotator cuff histologically consists of 5 separate layers of which 2 are macroscopically identifiable: the superior or tendinous layer and the inferior or capsule-ligamentous layer. In case of rotator cuff tears, these layers are often retracted to different degrees. The intraoperative detectable prevalence of rotator cuff delamination reaches up to 85%. Anatomical rotator cuff repair, which also includes restoration of the layered structure, could re-establish native tendon morphology and thus potentially decreases retear rates. The use of a knotless construct to avoid cuff strangulation and maintaining tendon perfusion could further decrease the risk of repair failure. Double-layer reconstructions are challenging and time consuming because each layer needs to be penetrated separately. Only few studies reported about double-layer reconstruction of the posterosuperior rotator cuff. This Technical Note is the first to present an arthroscopic knotless transosseous-equivalent double-layer repair technique.

Management of Failed Rotator Cuff Repair in Young Patients

Management of failed rotator cuff repair may be difficult, especially in young patients. Various nonmodifiable and modifiable patient factors, including age, tendon quality, rotator cuff tear characteristics, acute or chronic rotator cuff tear, bone quality, tobacco use, and medications, affect rotator cuff repair healing. Surgical variables, such as the technique, timing, tension on the repair, the biomechanical construct, and fixation, as well as the postoperative rehabilitation strategy also affect rotator cuff repair healing. Variable outcomes have been reported in patients who undergo revision rotator cuff repair; however, a systematic surgical approach may increase the likelihood of a successful outcome. Numerous cellular and mechanical biologic augments, including platelet-rich plasma, platelet-rich fibrin matrix, mesenchymal stem cells, and acellular dermal matrix grafts, have been used in rotator cuff repair; however, conflicting or inconclusive outcomes have been reported in patients who undergo revision rotator cuff repair with the use of these augments. A variety of tendon transfer options, including latissimus dorsi, teres major, lower trapezius, pectoralis minor, pectoralis major, combined pectoralis major and latissimus dorsi, and combined latissimus dorsi and teres major, are available for the management of massive irreparable rotator cuff tears. Ultimately, the optimization of surgical techniques and the use of appropriate biologic/tendon transfer techniques, if indicated, is the best method for the management of failed rotator cuff repair.

Cell-based approaches for augmentation of tendon repair

Cell-based approaches are among the principal interventions in orthobiologics to improve tendon and ligament healing and to combat degenerative processes. The number of options available for investigation are expanding rapidly and investigators have an increasing number of cell types to choose from for research purposes. However, in part due to the current regulatory environment, the list of available cells at clinicians' disposal for therapeutic purposes is still rather limited. In this review, we present an overview of the main cellular categories in current use. Notable recent developments in cell-based approaches include the introduction of diverse sources of mesenchymal stem cells, pluripotent cells of extra-embryonic origin, and the emerging popularity of fully differentiated cells such as tenocytes and endothelial cells. Delivery strategies are discussed and a succinct discussion of the current regulatory environment in the United States is presented.

Effect of Footprint Preparation on Tendon-to-Bone Healing: A Histologic and Biomechanical Study in a Rat Rotator Cuff Repair Model

PURPOSE

To compare the histologic and biomechanical effects of 3 different footprint preparations for repair of tendon-to-bone insertions and to assess the behavior of bone marrow-derived cells in each method of insertion repair.

METHODS

We randomized 81 male Sprague-Dawley rats and green fluorescent protein-bone marrow chimeric rats into 3 groups. In group A, we performed rotator cuff repair after separating the supraspinatus tendon from the greater tuberosity and removing the residual tendon tissue. In group B, we also drilled 3 holes into the footprint. The native fibrocartilage was preserved in groups A and B. In group C, we excavated the footprint until the cancellous bone was exposed. Histologic repair of the tendon-to-bone insertion, behavior of the bone marrow-derived cells, and ultimate force to failure were examined postoperatively.

RESULTS

The areas of metachromasia in groups A, B, and C were 0.033 ± 0.019, 0.089 ± 0.022, and 0.002 ± 0.001 mm²/mm², respectively, at 4 weeks and 0.029 ± 0.022, 0.090 ± 0.039, and 0.003 ± 0.001 mm²/mm², respectively, at 8 weeks. At 4 and 8 weeks postoperatively, significantly higher cartilage matrix production was observed in group B than in group C (4 weeks, P = .002; 8 weeks, P < .001). In green fluorescent protein-bone marrow chimeric rats in group B, bone marrow-derived chondrogenic cells infiltrated the fibrocartilage layer. Ultimate force to failure was significantly higher in group B (19.7 ± 3.4 N) than in group C (16.7 ± 2.0 N) at 8 weeks (P = .031).

CONCLUSIONS

Drilling into the footprint and preserving the fibrocartilage improved the quality of repair tissue and biomechanical strength at the tendon-to-bone insertion after rotator cuff repair in an animal model.

CLINICAL RELEVANCE

Drilling into the footprint and preserving the fibrocartilage can enhance repair of tendon-to-bone insertions. This method may be clinically useful in rotator cuff repair.

Efficacy of bone marrow-stimulating technique in rotator cuff repair

BACKGROUND

This study used a chronic rotator cuff (RC) tear model to investigate the effect of microfracture as a bone marrow-stimulating (BMS) technique for RC healing.

METHODS

A chronic retracted RC tendon tear model was created bilaterally in the subscapularis tendons of 20 New Zealand rabbits. The tendons were repaired after 8 weeks using a single-row configuration. Tendons in the right shoulder were repaired in standard fashion (control group). Microfractures were performed in the left shoulders before repair (microfracture group). The animals were euthanized 8 and 16 weeks after repair. The repaired tendons were tested biomechanically for their ultimate failure load, linear stiffness, and elongation at failure. Gross and histologic evaluations of the tendon-to-bone healing were evaluated.

RESULTS

Macroscopically, subscapularis tendons were attached on the lesser tuberosity. In the microfracture group, collagen fibers were organized in relatively thicker bundles. The mean ultimate failure load of the microfracture group was significantly greater at 8 weeks (148.4 ± 31 N vs. 101.4 ± 26 N, respectively; P = .011) and 16 weeks (155 ± 30 N vs. 114.9 ± 25 N, respectively; P = .017) after repair. There were no significant differences between the groups for linear stiffness at 8 weeks (15.9 ± 2.7 N/mm vs. 15.8 ± 1.3 N/mm, respectively; P = .798) and 16 weeks (16.9 ± 4.3 N/mm vs. 17.1 ± 3.6 N/mm, respectively, P = .848) and elongation at failure at 8 weeks (4.7 ± 1.1 mm vs. 4.7 ± 1.3 mm, respectively; P = .848) and 16 weels (4.8 ± 1.5 mm vs. 4.9 ± 0.9 mm, respectively; P = .749).

CONCLUSION

The microfracture on the tuberosity of the repaired chronic rotator cuff tear promoted dynamic tendon healing with significantly increased ultimate force to failure and with thicker collagen bundles and more fibrocartilage histologically at 8 weeks.

Editorial Commentary: Remnant-Preserving Philosophy Extended to Rotator Cuff Repair: Can We Improve Tendon Healing by Preserving the Native Insertional Fibrocartilage?

Tendon-to-bone healing in rotator cuff repair is affected by the method of footprint preparation. Bone drilling and preserving the native fibrocartilage at the tendon attachment site improved tissue quality and mechanical strength of bone-tendon interface in an animal model.

Arthroscopic Revision of Medial Rotator Cuff Failure Augmented With a Bioabsorbable Patch

When revising failed double-row and suture-bridge rotator cuff repairs medial failures represent a potential feature. In the presence of a compromised healing environment, patch augmentation becomes a logical adjunct from a mechanical and biological point of view. A reproducible step-by-step revision technique is described that reinforces the weak central cuff area with an absorbable synthetic scaffold.

The Impact of Re-tear on the Clinical Outcome after Rotator Cuff Repair Using Open or Arthroscopic Techniques - A Systematic Review

Background:

It is generally accepted that rotator cuff repair gives satisfactory results in the long term, although most studies have so far shown a fairly high rate of structural failure or re-tear. The purpose of this review study is to assess whether failure of the repaired cuff to heal could negatively affect the functional outcome.

Methods:

This article includes an extensive Internet PubMed based research in the current English-language literature including level I to level V studies as well as systematic reviews.

Results:

According to this extended study research, the results are mixed; certain reports show that patients with a healed rotator cuff repair have improved function and strength compared to those with structural failure, whereas other studies support the generally perceived concept that tendon re-tear does not lead to inferior clinical outcome.

Conclusion:

Further high-level prospective studies with larger numbers of patients and longer follow up are needed to overcome the current debate over function between healed and failed rotator cuff repairs.