Biological Strategies to Enhance Rotator Cuff Healing

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).

Human umbilical cord mesenchymal stem cells overexpressing RUNX1 promote tendon-bone healing by inhibiting osteolysis, enhancing osteogenesis and promoting angiogenesis

BACKGROUND

Rotator cuff injury (RCI) is a common shoulder injury, which is difficult to be completely repaired by surgery. Hence, new strategies are needed to promote the healing of tendon-bone.

OBJECTIVE

We aimed to investigate the effect of human umbilical cord mesenchymal stem cells (hUC-MSCs) overexpressing RUNX1 on the tendon-bone healing after RCI, and to further explore its mechanism.

METHODS

Lentiviral vector was used to mediate the overexpression of RUNX1. RUNX1-overexpressed UCB-MSCs (referred to as MSC-RUNX1) were co-cultured with osteoclasts, and TRAP staining was performed to observe the formation of osteoclasts. Then MSC-RUNX1 was cultured in osteogenic differentiation medium, Alizarin red staining was conducted to detect osteogenic differentiation. The expression of markers of osteogenesis and osteoclast was detected by RT-qPCR. EA. hy926 cells were co-cultured with MSC-RUNX1. Transwell assay was used to detect the migration, and the expression of angiogenesis related-genes VEGF and TGF-β was detected by RT-qPCR. The rat rotator cuff reconstruction model was established and MSCs were injected at the tendon-bone junction. Biomechanical test and micro-CT scanning were performed, and HE, Masson and Alcian Blue staining were used for histological evaluation of tendon-bone healing. TUNEL and PCNA immunofluorescence (IF) staining were performed to evaluate apoptosis and proliferation at the tendon-bone healing site. The levels of TNF-α, IL-6 and IL-8 in serum were detected by ELISA. The expression of CD31 and Endomucin that related to angiogenesis was detected by IF. Safranin O-fast and TRAP/CD40L immunohistochemical staining were used to assess the levels of osteoclasts and osteoblasts at the tendon-bone healing site.

RESULTS

hUC-MSCs overexpressing RUNX1 inhibited osteoclast formation and promoted osteogenic differentiation. MSC-RUNX1 could promote the migration and tube formation of EA. hy926 cells, and up-regulate the levels of VEGF and TGF-β. Model mice treated with MSC-RUNX1 partially restored the biomechanical indexes. Treatment of MSC-RUNX1 obviously increased the bone density, accompanied by the formation of new bone. In vivo experiments showed that MSC-RUNX1 treatment could promote tendon-bone healing and inhibit inflammatory response in rats. MSC-RUNX1 treatment also promoted angiogenesis at the tendon-bone healing site, while inhibiting osteoclast formation and promoting osteogenic differentiation.

CONCLUSION

hUC-MSCs overexpressing RUNX1 can inhibit the formation of osteoclasts and differentiation of osteoblasts, promote angiogenesis and inhibit inflammation, thereby promoting tendon-bone healing after RCI.

Personalized, Predictive, Participatory, Precision, and Preventive (P5) Medicine in Rotator Cuff Tears

Rotator cuff (RC) disease is a common musculoskeletal disorder of the shoulder entailing pain, with reduced functionality and quality of life. The main objective of this study was to present a perspective of the current scientific evidence about personalized, predictive, participatory, precision, and preventive approaches in the management of RC diseases. The personalized, predictive, participatory, precision and preventive (P5) medicine model is an interdisciplinary and multidisciplinary approach that will provide researchers and clinicians with a comprehensive patrimony of knowledge in the management of RC diseases. The ability to define genetic predispositions in conjunction with the evaluation of lifestyle and environmental factors may boost the tailoring of diagnosis and therapy in patients suffering from RC diseases.

Biomimetic strategies for tendon/ligament-to-bone interface regeneration

Tendon/ligament-to-bone healing poses a formidable clinical challenge due to the complex structure, composition, cell population and mechanics of the interface. With rapid advances in tissue engineering, a variety of strategies including advanced biomaterials, bioactive growth factors and multiple stem cell lineages have been developed to facilitate the healing of this tissue interface. Given the important role of structure-function relationship, the review begins with a brief description of enthesis structure and composition. Next, the biomimetic biomaterials including decellularized extracellular matrix scaffolds and synthetic-/natural-origin scaffolds are critically examined. Then, the key roles of the combination, concentration and location of various growth factors in biomimetic application are emphasized. After that, the various stem cell sources and culture systems are described. At last, we discuss unmet needs and existing challenges in the ideal strategies for tendon/ligament-to-bone regeneration and highlight emerging strategies in the field.

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.

Genetic factors in rotator cuff pathology: potential influence of col 5A1 polymorphism in outcomes of rotator cuff repair

Background

Investigations in genetics have provided valuable information about the correlation between gene variants and tendinopathy. Single Nucleotide Polymorphisms of COL5A1 gene are reported to be involved in Achilles tendinopathy, chronic degenerative tendon changes at the elbow, and other tendinopathies. The influence of Single Nucleotide Polymorphisms of COL5A1 was previously analyzed in rotator cuff disease with confounding results. Moreover, the rs12722 polymorphism in COL5A1 gene has been implicated in the aetiology of musculoskeletal soft tissue injuries in several association studies. This study aims to analyse the possible influence of rs12722 polymorphism in COL5A1 in the outcomes of rotator cuff repair.

Methods

Seventy-nine patients were included in the study. DNA was extracted from 1.2 ml of venous blood and genotyped for COL5A1 SNPs rs12722. Rotator cuff muscle strength and range of motion (ROM) in anterior elevation, external and internal rotation of the shoulder were evaluated.

Results

Patients presenting COL5A1 SNP rs12722 CC showed a ROM of passive external rotation statistically significantly higher compared to patients with CT genotype and TT genotype.

Conclusions

COL5A1 SNP rs12722 may influence the functional outcomes of RCRs, even though further studies are required to confirm these preliminary results.

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.

Genetics of rotator cuff tears: no association of col5a1 gene in a case-control study

Background

The incidence of RC tears increases with aging, affecting approximately 30 to 50% of individuals older than 50 years, and more than 50% of individuals older than 80 years. Intrinsic factors (age or gender), extrinsic factors (sports activity or occupation), and biological factors were identified in the onset and progression of RC tears. The attention in the study of aetiology of RC tendinopathy has shifted to the identification of gene variants. Genes encoding for proteins regulating the concentration of pyrophosphate in the extracellular matrix and genes encoding for fibroblastic growth factors, defensin beta 1 and estrogen-related receptor-beta were analyzed. However, only in one study the role of variants of collagen type V alpha 1 (col5a1) gene in RC tears was assessed. The objective of this study was to determine whether a col5a1 DNA sequence variant, rs12722 (C/T) was associated with rotator cuff (RC) tears in a case-control study.

Methods

The study included 93 Caucasian patients undergoing surgery for RC tears and 206 patients with no history and sign of RC disease as evaluated by MRI. Patients were divided into two groups. Group 1 included patients with RC tear diagnosed on clinical and imaging grounds and confirmed at the time of surgery. Group 2 (control group) included patients without history or clinical symptoms of RC disorders and with a MRI negative for RC disease. DNA was obtained from approximately 1.2 ml of venous blood using the MagCore extractor system H16 with a MagCore Genomic DNA Large Volume Whole Blood Kit (RBC Bioscience Corp., Taiwan). All study participants were genotyped for SNPs rs12722.

Results

We first estimated that our study had 92% power at p < 0.05 to detect a genetic effect size of 2.05 in the RT tears (93 individuals) and healthy population (206 individuals) cohorts, assuming a minor allele frequency for col5a1 variant rs12722 of 0.5707 in the Italian population (gnomAD frequency). No significant difference in allele and genotype frequencies was observed between RT tears patients and healthy controls. Similarly, no significant association was seen between the RT tears and healthy controls participants in the combined genotype distributions.

Conclusion

In conclusion, no correlations between the SNP rs12722 of col5a1 gene and RC tears susceptibility was found.

Platelet-Rich Plasma Derived Growth Factors Contribute to Stem Cell Differentiation in Musculoskeletal Regeneration

Stem cell treatment and platelet-rich plasma (PRP) therapy are two significant issues in regenerative medicine. Stem cells such as bone marrow mesenchymal stem cells, adipose-derived stem cells and periodontal ligament stem cells can be successfully applied in the field of tissue regeneration. PRP, a natural product isolated from whole blood, can secrete multiple growth factors (GFs) for regulating physiological activities. These GFs can stimulate proliferation and differentiation of different stem cells in injury models. Therefore, combination of both agents receives wide expectations in regenerative medicine, especially in bone, cartilage and tendon repair. In this review, we thoroughly discussed the interaction and underlying mechanisms of PRP derived GFs with stem cells, and assessed their functions in cell differentiation for musculoskeletal regeneration.

Rotator cuff rehabilitation: current theories and practice

A fully functioning, painless shoulder joint is essential to maintain a healthy, normal quality of life. Disease of the rotator cuff tendons (RCTs) is a common issue that affects the population, increasing with age, and can lead to significant disability and social and health costs. RCT injuries can affect younger, healthy patients and the elderly alike, and may be the result of trauma or occur as a result of chronic degeneration. They can be acutely painful, limited to certain activities or completely asymptomatic and incidental findings. A wide variety of treatment options exists ranging from conservative local and systemic pain modalities, to surgical fixation. Regardless of management ultimately chosen, physiotherapy of the RCT, rotator cuff muscles and surrounding shoulder girdle plays an essential role in proper treatment. Length of treatment, types of therapy and timing may vary if therapy is definitive care or part of a postoperative protocol. Allowing time for adequate RCT healing must always be considered when implementing ROM and strengthening after surgery. With current rehabilitation methods, patients with all spectrums of RCT pathology can improve their function, pain and quality of life. This manuscript reviews current theories and practice involving rehabilitation for RCT injuries.

Use of grafts in rotator cuff re-rupture

INTRODUCTION AND OBJECTIVES

Rotator cuff re-ruptures appear in 38-65% of cases. In order to reduce this rate, many studies have been performed using different types of biomaterial for purely mechanical aims (re-inforce the suture) and/or biological agents (growth factor transporterts). The aim of this study is to review 22 cases treated with xenografts and analyse various current alternatives.

MATERIALS AND METHODS

A descriptive and retrospective study was conducted using the variables of age, sex, laterality, time of surgery, involvement in MRI, number of anchors, and final mobility results on the Constant and the University of California Los Angeles (UCLA) validated scales.

RESULTS

The study included 22 patients, with a mean age of 51.7±4.6 years. A mean of 2 anchors were used and 13 patients were treated with a porcine intestinal submucosa implant, 6 with equine pericardium, and 3 with porcine dermis. Final results were: 37.6±13 points for the Constant test, and 16.9±3.9 points on the UCLA scale. The follow up was 36±10.2 months.

CONCLUSIONS

In our experience, xenografts could provide good functional results and they would be a surgical alternative to tendon transfers in cases of massive tears. Further studies should be conducted with other biomaterials.

Deltoid muscle tropism does not influence the outcome of arthroscopic rotator cuff repair

BACKGROUND

Several different factors have been identified as causes of failure of rotator cuff (RC) repair. However, no studies focused on the role of the deltoid muscle. The aim of this study was to investigate the role of the deltoid tropism in the outcomes of arthroscopic RC repair procedures.

MATERIALS AND METHODS

Nine male (45 %) and 11 female (55 %) patients who underwent arthroscopic RC repair were included in the study. The mean age was 63.5 ± 8.1 years (range 50-74 years), and the follow-up averaged 1.9 ± 1.3 years (range 1-5 years) after surgery. Clinical outcomes were assessed using the modified University of California, Los Angeles (UCLA) shoulder rating scale, Wolfgang criteria shoulder score and Oxford shoulder score (OSS). Functional outcomes were evaluated considering active and passive range of motion of the shoulder and muscle strength. The deltoid tropism was measured pre-operatively and post-operatively using T2-weighted transverse MRI images.

RESULTS

No statistically significant correlation was found between the thickness of each portion of the deltoid muscle (vD, lD and dD) and the UCLA shoulder rating scale, Wolfgang shoulder score and OSS. At the same time, no statistically significant relationship was detected between the thickness of each portion of the deltoid muscle (vD, lD and dD) and the functional outcomes.

CONCLUSIONS

The deltoid tropism does not influence the results of arthroscopic RC repair. Early RC repair may prevent the reduction in the tropism of the deltoid muscle. Nevertheless, further prospective randomized studies with larger samples are necessary to clarify the role of deltoid tropism in the outcomes of arthroscopic RC repair procedures.

Regeneration of Full-Thickness Rotator Cuff Tendon Tear After Ultrasound-Guided Injection With Umbilical Cord Blood-Derived Mesenchymal Stem Cells in a Rabbit Model

Rotator cuff tendon tear is one of the most common causes of chronic shoulder pain and disability. In this study, we investigated the therapeutic effects of ultrasound-guided human umbilical cord blood (UCB)-derived mesenchymal stem cell (MSC) injection to regenerate a full-thickness subscapularis tendon tear in a rabbit model by evaluating the gross morphology and histology of the injected tendon and motion analysis of the rabbit's activity. At 4 weeks after ultrasound-guided UCB-derived MSC injection, 7 of the 10 full-thickness subscapularis tendon tears were only partial-thickness tears, and 3 remained full-thickness tendon tears. The tendon tear size and walking capacity at 4 weeks after UCB-derived MSC injection under ultrasound guidance were significantly improved compared with the same parameters immediately after tendon tear. UCB-derived MSC injection under ultrasound guidance without surgical repair or bioscaffold resulted in the partial healing of full-thickness rotator cuff tendon tears in a rabbit model. Histology revealed that UCB-derived MSCs induced regeneration of rotator cuff tendon tear and that the regenerated tissue was predominantly composed of type I collagens. In this study, ultrasound-guided injection of human UCB-derived MSCs contributed to regeneration of the full-thickness rotator cuff tendon tear without surgical repair. The results demonstrate the effectiveness of local injection of MSCs into the rotator cuff tendon.

SIGNIFICANCE

The results of this study suggest that ultrasound-guided umbilical cord blood-derived mesenchymal stem cell injection may be a useful conservative treatment for full-thickness rotator cuff tendon tear repair.

Progress in cell-based therapies for tendon repair

The last decade has seen significant developments in cell therapies, based on permanently differentiated, reprogrammed or engineered stem cells, for tendon injuries and degenerative conditions. In vitro studies assess the influence of biophysical, biochemical and biological signals on tenogenic phenotype maintenance and/or differentiation towards tenogenic lineage. However, the ideal culture environment has yet to be identified due to the lack of standardised experimental setup and readout system. Bone marrow mesenchymal stem cells and tenocytes/dermal fibroblasts appear to be the cell populations of choice for clinical translation in equine and human patients respectively based on circumstantial, rather than on hard evidence. Collaborative, inter- and multi-disciplinary efforts are expected to provide clinically relevant and commercially viable cell-based therapies for tendon repair and regeneration in the years to come.

Arthroscopic repair of partial-thickness and small full-thickness rotator cuff tears: tendon quality as a prognostic factor for repair integrity

BACKGROUND

The healing failure rate is high for partial-thickness or small full-thickness rotator cuff tears.

PURPOSE

To retrospectively evaluate and compare outcomes after arthroscopic repair of high-grade partial-thickness and small full-thickness rotator cuff tears and factors affecting rotator cuff healing.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Included in the study were 55 consecutive patients (mean age, 57.9 ± 7.2 years) who underwent arthroscopic repair for high-grade partial-thickness (n = 34) and small full-thickness (n = 21) rotator cuff tears. The study patients also underwent magnetic resonance imaging (MRI) preoperatively and computed tomography arthrography (CTA) at least 6 months postoperatively, and their functional outcomes were evaluated preoperatively and at the last follow-up (>24 months). All partial-thickness tears were repaired after being converted to full-thickness tears; thus, the repair process was almost the same as for small full-thickness tears. The tendinosis of the torn tendon was graded from the MRI images using a 4-point scale, and the reliabilities were assessed. The outcomes between high-grade partial-thickness tears that were converted to small full-thickness tears and initially small full-thickness tears were compared, and factors affecting outcomes were evaluated.

RESULTS

The inter- and intraobserver reliabilities of the tendinosis grade were good (intraclass correlation coefficient, 0.706 and 0.777, respectively). Failure to heal as determined by CTA was observed in 12 patients with a high-grade partial-thickness tear (35.3%; complete failure in 4 and partial failure in 8) and in 3 patients with a small full-thickness tear (14.3%; complete failure in 1 and partial failure in 2). The patients with high-grade partial-thickness rotator cuff tears showed a higher tendinosis grade than did those with small full-thickness tears (P = .014), and the severity of the tendinosis was related to the failure to heal (P = .037). Tears with a higher tendinosis grade showed a 7.64-times higher failure rate (95% CI, 1.43-36.04) than did those with a lower tendinosis grade (P = .013). All functional outcome scores improved after surgery (all P < .001); however, there was no difference between groups.

CONCLUSION

The high-grade partial-thickness rotator cuff tears showed more severe tendinosis compared with the small full-thickness tears in this study. Contrary to previous impressions that tear size or fatty infiltration is the factor that most influences healing, tendinosis severity assessed by preoperative MRI was the only factor associated with failure to heal, given the numbers available for analysis, in patients with partial-thickness and small full-thickness rotator cuff tears. Surgeons should pay more attention to tendon quality during repair surgery or rehabilitation in smaller rotator cuff tears, especially in high-grade partial-thickness tears with severe tendinosis.

Role of serum fibrinogen levels in patients with rotator cuff tears

Although rotator cuff (RC) tendinopathy is a frequent pathology of the shoulder, the real understanding of its aetiopathogenesis is still unclear. Several studies showed that RC tendinopathy is more frequent in patients with hyperglycemia, diabetes, obesity, or metabolic syndrome. This paper aims to evaluate the serum concentration of fibrinogen in patients with RC tears. Metabolic disorders have been related to high concentration of serum fibrinogen and the activity of fibrinogen has been proven to be crucial in the development of microvascular damage. Thus, it may produce progression of RC degeneration by reducing the vascular supply of tendons. We report the results of a cross-sectional frequency-matched case-control study comparing the serum concentration of fibrinogen of patients with RC tears with that of a control group of patients without history of RC tears who underwent arthroscopic meniscectomy. We choose to enrol in the control group patients with pathology of the lower limb with a likely mechanic, not metabolic, cause, different from tendon pathology. We found no statistically significant differences in serum concentration of fibrinogen when comparing patients with RC tears and patients who underwent arthroscopic meniscectomy (P = 0.5). Further studies are necessary to clarify the role of fibrinogen in RC disease.