Is platelet-rich plasma an ideal biomaterial for arthroscopic rotator cuff repair? A systematic review and meta-analysis of randomized controlled trials

Platelet-derived exosomes alleviate tendon stem/progenitor cell senescence and ferroptosis by regulating AMPK/Nrf2/GPX4 signaling and improve tendon-bone junction regeneration in rats

BACKGROUND

Tendon stem/progenitor cell (TSPC) senescence contributes to tendon degeneration and impaired tendon repair, resulting in age-related tendon disorders. Ferroptosis, a unique iron-dependent form of programmed cell death, might participate in the process of senescence. However, whether ferroptosis plays a role in TSPC senescence and tendon regeneration remains unclear. Recent studies reported that Platelet-derived exosomes (PL-Exos) might provide significant advantages in musculoskeletal regeneration and inflammation regulation. The effects and mechanism of PL-Exos on TSPC senescence and tendon regeneration are worthy of further study.

METHODS

Herein, we examined the role of ferroptosis in the pathogenesis of TSPC senescence. PL-Exos were isolated and determined by TEM, particle size analysis, western blot and mass spectrometry identification. We investigated the function and underlying mechanisms of PL-Exos in TSPC senescence and ferroptosis via western blot, real-time quantitative polymerase chain reaction, and immunofluorescence analysis in vitro. Tendon regeneration was evaluated by HE staining, Safranin-O staining, and biomechanical tests in a rotator cuff tear model in rats.

RESULTS

We discovered that ferroptosis was involved in senescent TSPCs. Furthermore, PL-Exos mitigated the aging phenotypes and ferroptosis of TSPCs induced by t-BHP and preserved their proliferation and tenogenic capacity. The in vivo animal results indicated that PL-Exos improved tendon-bone healing properties and mechanical strength. Mechanistically, PL-Exos activated AMPK phosphorylation and the downstream nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPX4) signaling pathway, leading to the suppression of lipid peroxidation. AMPK inhibition or GPX4 inhibition blocked the protective effect of PL-Exos against t-BHP-induced ferroptosis and senescence.

CONCLUSION

In conclusion, ferroptosis might play a crucial role in TSPC aging. AMPK/Nrf2/GPX4 activation by PL-Exos was found to inhibit ferroptosis, consequently leading to the suppression of senescence in TSPCs. Our results provided new theoretical evidence for the potential application of PL-Exos to restrain tendon degeneration and promote tendon regeneration.

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).

Understanding Fibrous Tissue in the Effective Healing of Rotator Cuff Injury

The rotator cuff is a crucial group of muscles and tendons in the shoulder complex that plays a significant role in the stabilization of the glenohumeral joint and enabling a wide range of motion. Rotator cuff tendon tears can occur due to sudden injuries or degenerative processes that develop gradually over time, whether they are partial or full thickness. These injuries are common causes of shoulder pain and functional impairment, and their complex nature highlights the essential role of the rotator cuff in shoulder function. Scar formation is a crucial aspect of the healing process initiated following a rotator cuff tendon tear, but excessive fibrous tissue development can potentially lead to stiffness, discomfort, and movement limitations. Age is a critical risk factor, with the prevalence of these tears increasing among older individuals. This comprehensive review aims to delve deeper into the anatomy and injury mechanisms of the rotator cuff. Furthermore, it will inspect the signaling pathways involved in fibrous tissue development, evaluate the various factors affecting the healing environment, and discuss proactive measures aimed at reducing excessive fibrous tissue formation. Lastly, this review identifed gaps within existing knowledge to advance methods for better management of rotator cuff tendon injuries.

Arthroscopic rotator cuff repair combined with platelet-rich plasma products can reduce the rate of retearing and improve clinical outcomes: A meta-analysis of randomized controlled trials

BACKGROUND

Although several studies on the potential benefits of protein-rich plasma (PRP) therapy for rotator cuff injuries have been published, the results have been conflicting. Therefore, this study aimed to determine whether PRP is beneficial for the prevention of retears after arthroscopic rotator cuff repair (ARCR).

METHODS

Two reviewers conducted independent literature searches based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials (RCTs) comparing a PRP treatment group with a control group were included. The quality of evidence was assessed using the Cochrane Collaboration Risk of Bias Tool. Clinical outcomes were compared using the risk ratio (RR) for dichotomous variables and weighted mean difference (WMD) for continuous variables. Statistical significance was set at P < .05.

RESULTS

This review included 21 RCTs (1359 patients). Significant results were noted in favor of PRP treatment compared with controls based on retearing rates (16.5% vs 23.6%, respectively; P = .002) and the Constant score in the short term (WMD: 1.98; 95% confidence interval [CI], 0.27-3.70; I2 = 0%; P = .02), medium term and long term (WMD: 2.56 [95% CI: 1.57-3.55]; I2 = 2%; P < .001); the University of California, Los Angeles score in the short term (WMD: 1.14 [95% CI: 0.43-1.85]; I2 = 25%; P = .002) but not in the medium and long term (WMD: 0.66 [95% CI: -0.16 to 1.48]; I2 = 57%; P = .11); and the visual analog scale score in the short term (WMD: -0.63 [95% CI: -0.83 to-0.43]; I2 = 41%; P < .001), medium and long term (WMD: -0.12 [95% CI: -0.19 to-0.05]; I2 = 0%; P = .008). There was no significant difference in American Shoulder and Elbow Surgeons scores between the treatment and control groups in the short term (WMD: -0.48 [95% CI: -2.80 to 1.85]; I2 = 22%; P = .69) or medium and long term (WMD: 0.92 [95% CI: -1.56 to 3.39]; I2 = 40%; P = .47).

CONCLUSION

Intraoperative use of PRP reduces the risk of rotator cuff repair failure, improves clinical outcomes, and reduces recurrence rates.

Effect of Platelet-Rich Plasma Dosing for Healing after Arthroscopic Cuff Repair Compared with Surgery Alone: A Systematic Review and Meta-Analysis

INTRODUCTION

Platelet-rich plasma (PRP) has been used for arthroscopic rotator cuff repairs (aRCR), but no studies have addressed the impact of platelet concentration. The primary aim was to evaluate whether the PRP cell concentration has an effect on tendon healing after aRCR compared with surgery alone. The secondary aim was to assess the functional and pain outcomes.

MATERIALS AND METHODS

A systematic review was performed with searches in the MEDLINE (PubMed), Scopus, Web of Science, and Cochrane (Central) databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Metanalytic procedures were performed for randomized controlled trials (RCTs), and a subgroup analysis was used for studies with target (approximately 10 6 cells·μL -1 ) or below-target PRP cellular concentrations (app. 5 × 10 5 cells·μL -1 ) regarding the primary outcome of tendon healing.

RESULTS

This review included 10 studies (8 RCTs) with 342 patients in the aRCR + PRP group and 344 patients with isolated aRCR. The risk of bias was low to intermediate (6/4, respectively). Meta-analysis of the RCT revealed that the aRCR + high-concentration PRP group had an approximately 3.9-fold higher chance of healing than the non-PRP group (odds ratio, 3.89; 95% confidence interval, 1.78-8.44; P = 0.0007). No significant difference in healing was found between the aRCR + low-concentration PRP and non-PRP groups (odds ratio, 2.21; 95% confidence interval, 0.66-7.45; P = 0.2). The Constant-Murley score and University of California Los Angeles scores were significantly improved in the aRCR + PRP groups with more than 12 months of follow-up, and no significant differences were found consistently for the American Shoulder and Elbow Society and visual analog scale scores.

CONCLUSIONS

This study highlights that a PRP cell concentration close to the target (10 6 cells·μL -1 ) of patients with aRCR may improve their healing and functional outcomes and that dosing may be potentially useful in therapy.

Evaluation of Spin Bias in Systematic Reviews and Meta-analyses of Rotator Cuff Repair With Platelet-Rich Plasma

BACKGROUND

The use of platelet-rich plasma (PRP) in orthopaedics continues to increase. One common use of PRP is as an adjunct in rotator cuff repair surgery. Multiple systematic reviews and meta-analyses have summarized the data on PRP use in rotator cuff repair surgery. However, systematic reviews and meta-analyses are subject to spin bias, where authors' interpretations of results influence readers' interpretations.

PURPOSE

To evaluate spin in the abstracts of systematic reviews and meta-analyses of PRP with rotator cuff repair surgery.

STUDY DESIGN

Systematic review; Level of evidence, 3.

METHODS

A PubMed and Embase search was conducted using the terms rotator cuff repair and PRP and systematic review or meta-analysis. After review of 74 initial studies, 25 studies met the inclusion criteria. Study characteristics were documented, and each study was evaluated for the 15 most common forms of spin and using the AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews, Version 2) rating system. Correlations between spin types and study characteristics were evaluated using binary logistic regression for continuous independent variables and a chi-square test or Fisher exact test for categorical variables.

RESULTS

At least 1 form of spin was found in 56% (14/25) of the included studies. In regard to the 3 different categories of spin, a form of misleading interpretation was found in 56% (14/25) of the studies. A form of misleading reporting was found in 48% (12/25) of the studies. A form of inappropriate extrapolation was found in 16% (4/25) of the studies. A significant association was found between misleading interpretation and publication year (odds ratio [OR], 1.41 per year increase in publication; 95% CI, 1.04-1.92; P = .029) and misleading reporting and publication year (OR, 1.41 per year increase in publication; 95% CI, 1.02-1.95; P = .037). An association was found between inappropriate extrapolation and journal impact factor (OR, 0.21 per unit increase in impact factor; 95% CI, 0.044-0.99; P = .048).

CONCLUSION

A significant amount of spin was found in the abstracts of systematic reviews and meta-analyses of PRP use in rotator cuff repair surgery. Given the increasing use of PRP by clinicians and interest among patients, spin found in these studies may have a significant effect on clinical practice.

Efficacy of platelet-rich plasma and platelet-rich fibrin in arthroscopic rotator cuff repair: A systematic review and meta-analysis

OBJECTIVE

Basic scientific studies have demonstrated positive effects of platelet-rich therapies, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF), on tendon repair. However, clinical evidence indicating improved prognosis is controversial. In this study, we aimed to determine whether augmentation of arthroscopic rotator cuff repair with PRP and PRF improves outcomes compared to arthroscopic repair alone.

LITERATURE SURVEY

PubMed, Embase, and Cochrane library databases were comprehensively searched for randomized controlled trials (RCTs) published until June 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. No language restriction was applied.

METHODOLOGY

The primary outcomes were the rate of repeat tears after arthroscopic rotator cuff repair (retear rate) and clinical function scores (Constant-Murley Score, University of California, Los Angeles Score), and the extracted data were assessed for quality. Statistical analyses were performed using Review manager 5.3, and p < .05 was considered statistically significant.

SYNTHESIS

Ten RCTs with 628 patients were included. The results showed that augmenting surgery with PRP reduces retear rates compared to surgery alone (risk ratio [RR] = 0.40, 95% confidence interval [CI] 0.23-0.69, p = .001), whereas PRF has no effect on retear rates (p = .92). Regarding clinical function, PRP improves Constant-Murley scores (mean difference [MD] = 2.03, 95% CI 0.13-3.93, p = .04) and University of California, Los Angeles scores (MD = 1.30, 95% CI 0.36-2.24, p = .007), whereas PRF improves only Constant-Murley scores (MD = 3.93, 95% CI 1.50-6.36, p = .002). However, these differences were small and below the minimum clinically important difference threshold.

CONCLUSIONS

This study showed that compared to arthroscopic rotator cuff repair alone, the application of PRP in arthroscopic rotator cuff repair reduces retear rate and improves clinical function scores, whereas the application of PRF has no clinically meaningful benefit. The small number and heterogeneity of studies as well as methodological limitations and risk of bias limit confidence in the true effect.

The effect of augmenting suture material with magnesium and platelet-rich plasma on the in vitro adhesion and proliferation potential of subacromial bursa-derived progenitor cells

Background

Connective tissue subacromial bursa-derived progenitor cells (SBDCs) have been suggested as a potent biologic augment to promote healing of the repaired rotator cuff tendon. Maximizing the amount of retained progenitor cells at the tendon repair site is essential for ensuring an optimal healing environment, warranting a search for proadhesive and proliferative adjuvants. The purpose was to evaluate the effect of magnesium (Mg), platelet-rich plasma (PRP), and a combination of both adjuvants on the in vitro cellular adhesion and proliferation potential of SBDCs on suture material commonly used in rotator cuff surgery.

Methods

SBDCs were isolated from subacromial bursa samples harvested during rotator cuff repair and cultured in growth media. Commercially available collagen-coated nonabsorbable flat-braided suture was cut into 1-inch pieces, placed into 48-well culture dishes, and sterilized under ultraviolet light. Either a one-time dose of 5 mM sterile Mg, 0.2 mL of PRP, or a combination of both adjuvants was added, while a group without treatment served as a negative control. Cellular proliferation and adhesion assays on suture material were performed for each treatment condition.

Results

Augmenting the suture with Mg resulted in a significantly increased cellular adhesion (total number of attached cells) of SBDCs compared to PRP alone (31,527 ± 19,884 vs. 13,619 ± 8808; P < .001), no treatment (31,527 ± 19,884 vs. 21,643 ± 8194; P = .016), and combination of both adjuvants (31,527 ± 19,884 vs. 17,121 ± 11,935; P < .001). Further, augmentation with Mg achieved a significant increase in cellular proliferation (absorbance) of SBDCs on suture material when compared to the PRP (0.516 ± 0.207 vs. 0.424 ± 0.131; P = .001) and no treatment (0.516 ± 0.207 vs. 0.383 ± 0.094; P < .001) group. The combination of Mg and PRP showed a significantly higher proliferation potential compared to PRP alone (0.512 ± 0.194 vs. 0.424 ± 0.131; P = .001) and no treatment (0.512 ± 0.194 vs. 0.383 ± 0.094; P < .001). There were no significant differences in the remaining intergroup comparisons (P > .05, respectively).

Conclusion

Augmenting suture material with Mg resulted in a significantly increased cellular adhesion of SBDCs compared to untreated suture material, as well as augmentation with PRP alone or a combination of both adjuvants. Further, Mg with or without PRP augmentation achieved a significant increase in the cellular proliferation of SBDCs on suture material compared to untreated sutures and augmentation with PRP alone. Application of Mg may be a clinically feasible approach to optimizing the use of SBDCs as a biological augment in rotator cuff repair, while combined augmentation with PRP may harness the full potential for optimized tissue recovery due to the high concentration of PRP-derived growth factors.

Biotherapeutic Applications of Platelet-Rich Plasma in Regenerative Medicine

BACKGROUND

Platelet-rich plasma (PRP), a blood-based product containing platelets and growth factors, is being utilized to treat numerous non-hemostatic disorders. Studies have explored the use of PRP to provide rapid repair, healing, and recovery from various injuries; some studies mentioned the effectiveness of PRP as compared with other forms of treatment like the use of hyaluronic acid. Commercially available PRP systems are available now, and each varies from one another depending on how it is prepared, thus causing variations in platelet concentration and growth factor content. These variations also implicated different therapeutic applications.

METHODS

The paper reviews the various applications of PRP, including factors to consider before using PRP therapy, and provides an extensive list of PRP applications.

RESULTS

The administration of PRP as a standalone treatment or as a co-therapy results in observed positive outcomes. However, there is a lack of standardization for PRP preparation, increasing the risks for heterogeneity and bias amongst results.

CONCLUSION

The use of PRP is indeed an option for regenerative therapy, but more research is needed before it can fully be recommended as a primary treatment modality.

Current Progress of Platelet-Rich Derivatives in Cartilage and Joint Repairs

In recent years, several types of platelet concentrates have been investigated and applied in many fields, particularly in the musculoskeletal system. Platelet-rich fibrin (PRF) is an autologous biomaterial, a second-generation platelet concentrate containing platelets and growth factors in the form of fibrin membranes prepared from the blood of patients without additives. During tissue regeneration, platelet concentrates contain a higher percentage of leukocytes and a flexible fibrin net as a scaffold to improve cell migration in angiogenic, osteogenic, and antibacterial capacities during tissue regeneration. PRF enables the release of molecules over a longer period, which promotes tissue healing and regeneration. The potential of PRF to simulate the physiology and immunology of wound healing is also due to the high concentrations of released growth factors and anti-inflammatory cytokines that stimulate vessel formation, cell proliferation, and differentiation. These products have been used safely in clinical applications because of their autologous origin and minimally invasive nature. We focused on a narrative review of PRF therapy and its effects on musculoskeletal, oral, and maxillofacial surgeries and dermatology. We explored the components leading to the biological activity and the published preclinical and clinical research that supports its application in musculoskeletal therapy. The research generally supports the use of PRF as an adjuvant for various chronic muscle, cartilage, and tendon injuries. Further clinical trials are needed to prove the benefits of utilizing the potential of PRF.

Allogeneic Dermal Fibroblasts Improve Tendon-to-Bone Healing in a Rabbit Model of Chronic Rotator Cuff Tear Compared With Platelet-Rich Plasma

PURPOSE

To compare the effects of allogeneic dermal fibroblasts (ADFs) and platelet-rich plasma (PRP) on tendon-to-bone healing in a rabbit model of chronic rotator cuff tear.

METHODS

Thirty-two rabbits were divided into 4 groups (8 per group). In 2 groups, the supraspinatus tendon was detached and was left as such for 6 weeks. At 6 weeks after creating the tear model, we performed transosseous repair with 5 × 10⁶ ADFs plus fibrin injection in the left shoulder and PRP plus fibrin in the right shoulder. The relative expression of the COL1, COL3, BMP2, SCX, SOX9, and ACAN genes was assessed at 4 weeks (group A) and 12 weeks (group B) after repair. Histologic and biomechanical evaluations of tendon-to-bone healing at 12 weeks were performed with ADF injection in both shoulders in group C and PRP injection in group D.

RESULTS

At 4 weeks, COL1 and BMP2 messenger RNA expression was higher in ADF-injected shoulders (1.6 ± 0.8 and 1.0 ± 0.3, respectively) than in PRP-injected shoulders (1.0 ± 0.3 and 0.6 ± 0.3, respectively) (P = .019 and P = .013, respectively); there were no differences in all genes in ADF- and PRP-injected shoulders at 12 weeks (P > .05). Collagen continuity, orientation, and maturation of the tendon-to-bone interface were better in group C than in group D (P = .024, P = .012, and P = .013, respectively) at 12 weeks, and mean load to failure was 37.4 ± 6.2 N/kg and 24.4 ± 5.2 N/kg in group C and group D, respectively (P = .015).

CONCLUSIONS

ADFs caused higher COL1 and BMP2 expression than PRP at 4 weeks and showed better histologic and biomechanical findings at 12 weeks after rotator cuff repair of the rabbit model. ADFs enhanced healing better than PRP in the rabbit model.

CLINICAL RELEVANCE

This study could serve as a transitional study to show the effectiveness of ADFs in achieving tendon-to-bone healing after repair of chronic rotator cuff tears in humans.

Evidence analysis on the utilization of platelet-rich plasma as an adjuvant in the repair of rotator cuff tears

BACKGROUND

Platelet-rich plasma has been gaining popularity as an agent for biological augmentation either as the sole treatment modality or as an adjunct to surgical repair. There is substantial discrepancy in the results of the published meta-analyses; and the true efficacy and role of using autologous platelet-rich plasma (PRP) at the time of rotator cuff repair is still ambiguous.

AIM

To performed this systematic overview on the overlapping meta-analyses that analyzed autologous PRP as an adjuvant in the repair of rotator cuff tears and identify the studies which provide the current best evidence on this subject and generate recommendations for the same.

METHODS

We conducted independent and duplicate electronic database searches in PubMed, Web of Science, Scopus, Embase, Cochrane Database of Systematic Reviews, Reference Citation Analysis and the Database of Abstracts of Reviews of Effects on September 8, 2021 to identify meta-analyses that analyzed the efficacy of PRP as an adjuvant in the repair of rotator cuff tears. Methodological quality assessment was made using Oxford Levels of Evidence, AMSTAR scoring and AMSTAR 2 grades. We then utilized the Jadad decision algorithm to identify the study with the highest quality to represent the current best evidence to generate the recommendation.

RESULTS

Twenty meta-analyses fulfilling the eligibility criteria were included. The AMSTAR scores of the included studies varied from 6-10 (mean: 7.9). All the included studies had critically low reliability in their summary of results due to their methodological flaws according to AMSTAR 2 grades. Significant heterogeneity was observed in the reporting of VAS, function outcome scores (long-term UCLA score, ASES score, SST score), operative time and long-term re-tear rates. Recent meta-analyses are more supportive of the role of intra-operative administration of PRPs at the bone-tendon interface in improving the overall healing and re-tear rates, functional outcome and pain. The initial size of the tear and type of repair performed do not seem to affect the benefit of PRPs. Among the different preparations used, leucocyte poor (LP)-PRP possibly offers the greatest benefit as a biological augment in these situations.

CONCLUSION

Based on this systematic overview, we give a level II recommendation that intra-operative use of PRPs at the bone-tendon interface can augment the healing rate, reduce re-tears, enhance functional outcome and mitigate pain in patients undergoing arthroscopic rotator cuff repair. LP-PRP possibly offers the greatest benefit in terms of healing rates, as compared with other platelet preparations.

Efficacy of Platelet-Rich Plasma Injection in the Management of Rotator Cuff Tendinopathy: A Review of the Current Literature

Platelet-rich plasma (PRP) is being projected as a newer and superior treatment option for rotator cuff tendinopathy. With the first use of PRP in trauma and orthopedics dating back only to 1998, its advent into the field is relatively recent. Thus, data on long-term efficacy, large cohort studies, or large randomized controlled trials are fairly limited. Moreover, owing to the absence of standardized methods of platelet extraction and lack of consensus on the ideal concentration of platelets in PRP, data comparison from different studies is difficult. Things are complicated by the fact that it is also not clear whether a single injection of PRP is therapeutic or if multiple serial injections are needed to produce the desired effects. The literature on efficacy and pain relief is also obtained from studies with low sample sizes and short follow-ups. The dropout rate and noncompliance rate were also found to be high in some studies. Thus, the data is often not clinically significant and may also be biased due to the non-standardized inclusion and exclusion criteria of the studies. Though multiple studies have suggested good pain control with PRP injection, many studies have found that PRP injection therapy may not be any better than the physical therapy regimen prescribed to patients with rotator cuff tendinopathy. Also, the data on the efficacy of PRP on shoulder function and shoulder range of motion is at variance. This submission aims to evaluate the efficacy and use of PRP in the management of rotator cuff tendinopathy.

Functional and radiologic results of the crimson duvet procedure in rotator cuff treatment: a randomized controlled clinical trial

BACKGROUND

Rotator cuff tears are one of the more frequent pathologies of the shoulder. Arthroscopic techniques and biologic augmentation have been developed to improve the rate and quality of healing. The crimson duvet procedure (CDP) theoretically provides mesenchymal stem cells through microfracture treatment of the footprint. The aim of this research was to evaluate the effect of CDP in patients who had undergone arthroscopic surgery for complete rotator cuff repair.

METHODS

A prospective randomized clinical trial was performed in a total of 123 patients, consisting of 59 women and 64 men, with a mean age of 58 years. We included patients with a clinical and radiologic diagnosis of a complete rotator cuff tear. All patients were treated with arthroscopic rotator cuff repair. In group 1, the surface of the footprint was débrided; in group 2, the footprint underwent microfracture. The primary outcome was the nonhealing rate, which was detected by magnetic resonance imaging (MRI) or ultrasonography, and the secondary outcome was the functional result. A Sugaya classification of I to III was considered to indicate healing. For clinical evaluation, the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) and Constant scores were evaluated, along with the range of motion. The functional evaluation was performed preoperatively and at 6 months and 1 year postoperatively. The radiologic (MRI or ultrasonography) evaluation was performed at 6 months. Neither the patients nor the radiologists and physical therapists who performed the postoperative evaluations were informed of the random selection.

RESULTS

We observed a healing rate of 85.11% in the control group and 93.7% in the CDP group, which was not significant (P = .19). However, a significant improvement in function was observed in all patients. The ASES score improved from 68.9 (SD 13.8) preoperatively to 92.2 at 6 months and to 96.4 (SD 6.2) at 12 months (P < .05), but no difference was observed between the groups. A similar level of improvement was observed in the Constant score.

CONCLUSION

The arthroscopic repair of complete rotator cuff tears presents good and excellent clinical results in most patients. Nevertheless, nonhealing occurs at a rate that depends mainly on the age of the patient and the size of the tear. The addition of CDP did not improve the functional results or the healing rate.

Limited evidence for biological treatment measures for cartilage and tendon injuries of the shoulder

PURPOSE

To critically review the available literature on the usage of biologics to treat cartilage and tendon injuries of the shoulder.

METHODS

Four different databases were searched in January 2020 for studies reporting data on bone marrow stimulation, autologous chondrocyte implantation, platelet-rich plasma, autologous concentrated serum, and bone marrow aspirate concentrate for the treatment of cartilage and/or tendon injuries of the shoulder. Prospective, retrospective, cohort and case-control studies as well as case series, systematic reviews and laboratory studies (involving human tissue) were included. Cadaveric or animal studies were excluded. Findings were summarized and an expert opinion on trends was provided.

RESULTS

Although there is limited literature available on biologics in cartilage lesions of the shoulder, the advancement from micro- to nanofracture, that is well established for the treatment of cartilage lesions in the knee, may be the next step in the treatment of shoulder lesions as well. The high rate of failure and therefore the complexity of tendon healing following rotator cuff repair has led to a rising interest in biologic augmentation such as platelet-rich plasma and stem cells to enhance tendon-bone-healing and to decrease the prevalence of failure. Despite the increase in publications, there exists a huge heterogeneity of content, quality, and quantity of among studies and their processing methods reporting the use of platelet-rich plasma in rotator cuff repair.

CONCLUSION

Conclusions from individual studies cannot be generalized. Currently, no evidence supports that platelet-rich plasma provides clinical benefits in rotator cuff repair. Similar is reported for microfracture in rotator cuff repair, however, despite no clinical benefits, microfracture has shown to reduce the appearance of structural failures. Although some evidence exists for the use of stem cells form bone marrow aspirate concentrate, results from large case series are still lacking.

LEVEL OF EVIDENCE

Level V.

Platelet-Rich Plasma Augmentation of Arthroscopic Rotator Cuff Repair Lowers Retear Rates and Improves Short-Term Postoperative Functional Outcome Scores: A Systematic Review of Meta-Analyses

Purpose

The purpose of this study is to conduct a systematic review of meta-analyses of rotator cuff repair using platelet-rich plasma (PRP) to identify whether PRP improves clinical function and rate of tendon retears. We will (1) conduct a systematic review of the current meta-analyses of rotator cuff repair using platelet-rich plasma available in the literature, (2) evaluate the quality of these meta-analyses using the Preferred Reporting Items for Systematic Review (PRISMA) methodology, (3) identify whether PRP improves clinical function and rate of tendon retears, and develop guidance to improve future studies in this area.

Methods

We carried out a systematic review of previous meta-analyses published on the clinical outcomes of PRP used in the treatment of rotator cuff tears. We performed a comprehensive search of PubMed, Medline, Cochrane, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Embase databases, using various combinations of the commercial names of each PRP preparation and “rotator cuff” (with its associated terms), looking specifically at human meta-analysis studies involving the repair of the rotator cuff tendon surgically in the English language. Data validity was assessed and collected on clinical outcomes. Following this, a meta-analysis was undertaken.

Results

Thirteen meta-analyses met the inclusion and exclusion criteria. All were considered of similar quality with Oxman-Guyatt index of 9 and PRISMA score of more than 24. A total of 1,800 patients with an average follow up of 12 to 36 months. The use of PRP for arthroscopic rotator cuff tear, when compared with controls, leads to a lower number of retears, improved short-term postoperative scores, and functional outcome. The following postoperative scores were reported: Constant: 12, Simple Shoulder Test: 10, ASES (American Shoulder and Elbow Surgeons): 9, UCLA (University of California, Los Angeles) 11, SANE (Single Assessment Numeric Evaluation) 1, VAS (visual analog scale): 6, and Retears: 13. Subgroup analysis showed that leukocyte content and gel application make no difference in the effectiveness of PRP. VAS score subgroup analysis showed short-term pain relief.

Conclusions

Our study shows that PRP is effective in reducing retears after rotator cuff repair and improving functional outcome scores and reducing short-term pain.

Level of Evidence

Level III, systematic review of Level I-III studies.

Platelet-Rich Plasma Has Better Results for Retear Rate, Pain, and Outcome Than Platelet-Rich Fibrin After Rotator Cuff Repair: A Systematic Review and Meta-analysis of Randomized Controlled Trials

PURPOSE

To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) in the literature to ascertain the extent to which platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) improved patient outcomes in arthroscopic rotator cuff repair.

METHODS

Two independent reviewers performed the literature search based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, with a third author resolving any discrepancies. RCTs comparing PRP or PRF to a control in rotator cuff repair were included. Quality of evidence was assessed using the Cochrane Collaboration risk of bias tool. Clinical outcomes were compared using the risk ratio for dichotomous variables and the mean difference for continuous variables. A P value <.05 was deemed statistically significant.

RESULTS

Included in this review are 23 RCTs with 1440 patients. PRP resulted in significantly decreased rates of retear (15.9% versus 29.0%, respectively; P < .0001). Significant results were noted in favor of PRP compared with control based on the Constant score (83.9 versus 81.2, respectively; P = .0006); the University of California, Los Angeles score (31.1 versus 30.2; P < .00001); the American Shoulder and Elbow Surgeons score (87.3 versus 84.5; P = .04); and the visual analog scale score (1.3 versus 1.6; P = .01). PRF resulted in an improved Constant score (80.1 versus 80.0, respectively; P = .04) compared with control.

CONCLUSIONS

The current evidence shows that using PRP in arthroscopic rotator cuff repair can improve pain levels and functional outcome scores while reducing the retear rate after surgery. PRF injection, on the other hand, improves only the Constant score.

LEVEL OF EVIDENCE

II; systematic review and meta-analysis of level I and II evidence.

Diagnosis and Management of Partial Thickness Rotator Cuff Tears: A Comprehensive Review

Partial thickness rotator cuff tears (PRCTs) are a challenging disease entity. Optimal management of PRCTs continues to be controversial. Although advances in magnetic resonance imaging and ultrasonography have aided in early diagnosis, arthroscopic evaluation remains the benchmark for diagnosis. Conservative treatment is often the first line of management for most patients; however, evidence suggests that surgical intervention may limit tear progression and the long-term sequelae. Surgical decision making is driven by factors such as age, arm dominance, etiology, activity level, tear thickness, and tear location. Many surgical options have been described in the literature to treat PRCTs including arthroscopic débridement, transosseous, in situ repair techniques, and tear completion and repair. Biologic supplements have also become an attractive alternative to aid in healing; however, the long-term efficacy of these modalities is largely unknown. This article will provide a detailed review of the etiology and natural history of PRCTs, as well as diagnosis, and current management to guide clinical decision-making and formulate an algorithm for management of PRCTs for the orthopaedic surgeon.

The Evolution of Arthroscopic Rotator Cuff Repair

Over the past 30 years, arthroscopic rotator cuff repair (ARCR) has evolved to become the gold standard in treating rotator cuff pathology. As procedural concepts of ARCR continue to improve, it is also continually compared with the open rotator cuff repair as the historical standard of care. This review highlights the evolution of ARCR, including a historical perspective; the anatomic, clinical, and surgical implications of the development of an arthroscopic approach; how arthroscopy improved some of the problems of the open approach; adaptations in techniques and technologies associated with ARCR; future perspectives in orthobiologics as they pertain to ARCR; and lastly, the clinical improvements, or lack of improvements, with all of these adaptations.

Systematic Review of Platelet-Rich Plasma for Rotator Cuff Repair: Are We Adhering to the Minimum Information for Studies Evaluating Biologics in Orthopaedics?

Background

The therapeutic efficacy of orthobiologic therapies for rotator cuff repair is difficult to evaluate owing to reporting inconsistences. In response, the Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO) guidelines were developed to ensure standard reporting on orthobiologic therapies.

Purpose

To systematically review clinical studies evaluating platelet-rich plasma (PRP) for full-thickness rotator cuff repair and adherence to MIBO guidelines.

Study Design

Scoping review; Level of evidence, 4.

Methods

A search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed, EMBASE, and the Cochrane Library databases. Inclusion criteria were clinical studies reporting on rotator cuff tears (≥1 cm) surgically repaired with PRP. Patient demographics, biologic intervention, and adherence to the MIBO guidelines were systematically reviewed.

Results

A total of 19 studies (1005 patients) were included in this review. Across all studies, 58.5% of the MIBO checklist items for PRP were reported. Out of 47 checklist items, 19 were reported in over 85% of studies, whereas 22 were reported in less than half of studies. Details of whole-blood processing and characteristics, as well as PRP processing and characteristics, were reported inconsistently, and no study provided adequate information to enable the precise replication of preparation protocols for PRP.

Conclusion

This systematic review highlights the current reporting deficiencies within the scientific literature of important variables for evaluating PRP for full-thickness rotator cuff repair. There was widespread variability among published studies that evaluate PRP for this application and, more specifically, studies were limited by inconsistent universal reporting of whole-blood and PRP processing and postprocessing characteristics. To improve our understanding of biologic efficacy and to promote repeatability, stricter adherence to the MIBO guidelines is necessary. We propose that the checklist limitations be addressed and that modification of the MIBO guidelines be considered to improve the reporting of individual components within certain categories.

Can platelet-rich plasma injections provide better pain relief and functional outcomes in persons with common shoulder diseases: a meta-analysis of randomized controlled trials

Background

To evaluate the efficacy of autologous platelet-rich plasma (PRP) injections in the treatment of common shoulder diseases.

Methods

The PubMed, Medline, and Central databases and trial registries were searched from their inception to October 2020 for randomized controlled trials of autologous PRP injections for shoulder diseases versus placebo or any control intervention. Preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed in the selection, analysis, and reporting of findings. The primary outcome was pain intensity (visual analog scale), and secondary outcomes were changes in function and quality of life (QoL).

Results

A total of 17 randomized controlled trials of PRP versus control were analyzed. From 8–12 weeks to ≥1 year, PRP injections were associated with better pain relief and functional outcomes than control interventions. PRP injections were also associated with greater QoL, with an effect size of 2.61 (95% confidence interval, 2.01–14.17) at medium-term follow-up. Compared with placebo and corticosteroid injections, PRP injections provided better pain relief and functional improvement. In subgroup analyses, trials in which PRP was prepared by the double centrifugation technique, the platelet concentration in the PRP was enriched ≥5 times, leucocyte-rich PRP was used, or an activating agent was used before application reported the most effective pain relief at 6–7 months.

Conclusions

PRP injections could provide better pain relief and functional outcomes than other treatments for persons presenting with common shoulder diseases. PRP injections have a greater capacity to improve shoulder-related QoL than other interventions.

Repair Tension During Arthroscopic Rotator Cuff Repair is Correlated With Preoperative Tendon Retraction and Postoperative Rotator Cuff Integrity

PURPOSE

This study aimed to examine the correlation of repair tension during arthroscopic rotator cuff repair (ARCR) with preoperative factors and to evaluate whether measuring tension during ARCR is effective for predicting rotator cuff integrity after ARCR.

METHODS

Patients who underwent ARCR from May 2014 to June 2017 were enrolled in this study. Inclusion criteria were patients with medium or larger-sized tears and with a minimum of 6 months' follow-up. Patients with a partial repair were excluded. Intraoperative repair tension was measured according to Davidson's method. Correlation of repair tension with preoperative factors was evaluated with Pearson and Spearman correlation coefficient tests. Logistic regression analysis was performed on intraoperative factors, including repair tension, to identify independent predictors of retear after ARCR. Receiver operating characteristic (ROC) curve was used to determine the cutoff value of repair tension for retear.

RESULTS

One-hundred twenty patients met the inclusion criteria. Mean repair tension was 26.6 ± 12.6 N, and retear was found in 29 shoulders (24.2%). Among the preoperative factors, tear size in the mediolateral (P < .001) and anteroposterior (P < .001) directions, DeOrio and Cofield's classification (P <0.001), geometric classification (P <.001), and fatty infiltration of supraspinatus (P = .006) and infraspinatus (P = .003) were significantly correlated with repair tension. However, multivariable logistic regression analysis identified only tear size in the mediolateral direction as an independent predictor of repair tension (P = .036). Logistic regression analysis showed that repair tension (P = .02) and geometric classification (P < .001) are significant factors affecting rotator cuff integrity after ARCR. ROC curve analysis showed the cutoff value of repair tension of large to massive tears for retear to be 35.6 N.

CONCLUSION

This study demonstrated that intraoperative repair tension is strongly correlated with tear size in the mediolateral direction based on preoperative magnetic resonance imaging and that measuring tension during ARCR is effective for predicting rotator cuff integrity after ARCR.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Microfragmented Adipose Tissue With Adjuvant Platelet-Rich Plasma Combination Therapy for Partial-Thickness Supraspinatus Tear

A 50-year-old male presented with acute, sharp, right shoulder pain. Ultrasound of the right shoulder revealed a partial thickness tear of the supraspinatus. After conservative management failed to provide any relief, he was treated with microfragmented adipose tissue (MFAT) injection followed by platelet-rich plasma (PRP) at 14 weeks. At the 28-week follow-up, he showed significant improvement in pain and mobility with a resolution of the tear on ultrasound. While PRP has been shown to confer some protection against retears, very few studies have investigated the efficacy of MFAT use in rotator cuff pathology. In this case, we used a combination of MFAT and PRP to successfully treat a partial thickness supraspinatus tear. These agents may function in a synergistic manner, with MFAT providing a cell scaffold and PRP modulating the cellular environment to optimize healing. Further studies are needed to better understand the mechanism of this treatment modality in treating similar conditions.

The clinical efficacy of leukocyte-poor platelet-rich plasma in arthroscopic rotator cuff repair: a meta-analysis of randomized controlled trials

BACKGROUND

The efficacy of platelet-rich plasma (PRP) in the arthroscopic treatment of rotator cuff injury has been reported in the literature. However, conclusions have been inconsistent and more often related to differences in the types of PRP used. Therefore, to minimize these differences, we performed a meta-analysis of only studies investigating leukocyte-poor PRP to evaluate whether PRP promotes and improves the effects of arthroscopic rotator cuff repair.

METHODS

A comprehensive search of the PubMed, Embase, and Cochrane Library databases was conducted to evaluate the efficacy of leukocyte-poor PRP in arthroscopic rotator cuff repair. The available data were extracted, and the methodologic quality of the included studies was evaluated by the Cochrane risk-of-bias assessment tool.

RESULTS

In total, 10 randomized controlled trials involving 742 patients were included. The results of the meta-analysis showed that treatment with leukocyte-poor PRP performed better than the control treatment in relieving postoperative pain in the short-term (mean difference [MD], -0.57; 95% confidence interval [CI], -0.79 to -0.35; P < .0001) and medium- and long-term (MD, -0.18; 95% CI, -0.34 to -0.03; P = .02) follow-up groups. However, the changes in the MD in the visual analog scale score were below the minimal clinically important difference. Regarding the Constant shoulder (MD, 3.35; 95% CI, 1.68-5.02; P < .0001) and University of California, Los Angeles (MD, 1.73; 95% CI, 0.94-2.52; P < .0001) scores, statistically significant differences were found in favor of leukocyte-poor PRP over the control treatment. However, the changes in the MD in both the Constant and University of California, Los Angeles scores were below the minimal clinically important difference. Moreover, during medium- and long-term follow-up, the retear rate in the leukocyte-poor PRP group was lower than that in the control group regardless of the rotator cuff tear size (small and medium [<3 cm] [risk ratio (RR), 0.64; 95% CI, 0.43-0.97; P = .03] vs. medium and large [>3 cm] [RR, 0.51; 95% CI, 0.34-0.77; P = .001]) and surgical repair method (single-row repair [RR, 0.61; 95% CI, 0.43-0.87; P = .007] vs. double-row suture bridge repair [RR, 0.57; 95% CI, 0.38-0.84; P = .005]).

CONCLUSION

According to our study, leukocyte-poor PRP can significantly reduce the postoperative retear rate in the medium and long term regardless of the tear size and the method used for rotator cuff repair. However, the use of leukocyte-poor PRP failed to show clinically meaningful effects in terms of postoperative pain and patient-reported outcomes.

Polymorphisms and alterations in gene expression associated with rotator cuff tear and healing following surgical repair: a systematic review

BACKGROUND

Rotator cuff tears (RCTs) are a common cause of shoulder disability, yet both conservative and surgical treatment strategies can lead to poor results in some patient populations. Enhanced understanding of the genetic processes associated with RCTs can assist in the development of more effective management options and help predict individual responses to surgical treatment. This systematic review analyzes the current literature on the genetic footprint associated with RCTs and interprets these findings to enhance the current understanding of RCT pathogenesis, potential treatment regimens, and prognostic biomarkers of outcomes after surgical repair.

METHODS

A systematic search of the Embase, PubMed, and Web of Science electronic databases was performed. Medical Subject Headings (MeSH) and Emtree index terms were formulated from the concept terms "rotator cuff tear," "genetics," and "human," and synonyms of these concepts were applied to the Web of Science search. Articles were screened against predefined inclusion and exclusion criteria. Eligible studies compared gene expression patterns and genetic polymorphisms between cases (with RCTs) and controls (without RCTs). Quality assessment was performed with studies being rated as high, moderate, or poor quality. A modified best-evidence synthesis was applied, and studies were determined to be of strong, moderate, or limited evidence.

RESULTS

The search identified 259 articles. Of these studies, 26 were eligible for review. Two studies were considered poor quality; 15 studies, moderate quality; and 9 studies, high quality. Analysis of these articles found that RCTs were associated with alterations in genes that code for the extracellular matrix, cell apoptosis, immune and inflammatory responses, and growth factor pathways. In particular, there was strong evidence of a significant association between RCTs and the genes MMP3, TNC, and ESRRB. Strong evidence of an association between BMP5 upregulation and successful healing after surgical repair was also found.

CONCLUSION

This review provides strong evidence of an genetic association with RCTs. The genotype and gene expression patterns detailed within this review can assist in deciphering the biological mechanisms resulting in RCTs, as well as predicting an individual's response to surgical repair. Future research could investigate whether manipulating these genes-or their associated signaling pathways-could assist in RCT healing and whether genetic biomarkers could be used clinically to predict patient outcomes after surgical repair of RCTs.

The efficacy of platelet-rich plasma in arthroscopic rotator cuff repair: A protocol of randomized controlled trial

BACKGROUND

Platelet-rich plasma (PRP), an autologous platelet concentrate (contain a large number of growth factors), has been widely investigated in healing and rebuilding the bone and tendon tissue. The objective of this prospective randomized research is to study and then compare the long-term effectiveness of the repair of arthroscopic rotator cuff without and with the platelet-rich plasma. It is assumed that there is no difference in the clinical results between patients receiving the repair of arthroscopic rotator cuff and the patients who do not receive PRP enhancement.

METHODS

This current study is a prospective, single-center, controlled, and randomized experiment. This study was reviewed and permitted via the institutional review committee of our hospital. All the patients will receive the written informed consent in order to involve in our clinical experiment. Patients were selected from the patients who received the repair of arthroscopic rotator cuff. Patients who meet the following conditions will be included in this study: ages ranges from 18 to 55; patients with complete tear of rotator cuff confirmed during operation; the patients agreed to wear the abduction stent for 4 weeks after operation; the preoperative count of platelet count is >150,000. All patients were evaluated at follow-up and baseline for the scores of Constant-Murley (CM) and American Shoulder and Elbow Surgeons (ASES), the numerical rating scale (NRS), and retear rate. The analysis is implemented with the SPSS 16.0 (SPSS Inc., Chicago, IL), the significance level remain at P < .05.

CONCLUSIONS

The results of this study will provide useful new information on whether PRP is effective in the arthroscopic rotator cuff repair patients.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry6108).

Effects of applying platelet-rich plasma during arthroscopic rotator cuff repair: a systematic review and meta-analysis of randomised controlled trials

Because of its healing properties, platelet-rich plasma (PRP) has been applied to the bone-tendon interface during arthroscopic rotator cuff repair to improve surgical outcomes. However, its effects remain ambiguous. Therefore, we conducted this systematic review and meta-analysis to assess the effects of PRP on retear rate and functional outcomes. Randomised control trials were identified and extracted. Data collection was completed on 15 February 2020. The results are expressed as the risk ratio (RR) for the categorical variables and weighted mean difference for the continuous variables, with 95% confidence intervals (CIs). Analyses were performed using RevMan 5.3 software. Seven randomised controlled trials published from 2013 to 2018, with 541 patients in total, were included. The results revealed a significant decrease in retear rate [RR 0.38, 95% CI (0.22, 0.68), P = 0.0009). Furthermore, a significant improvement was observed regarding short-term Constant score [mean difference = 3.28, 95% CI (1.46, 5.11), P = 0.0004), short-term University of California at Los Angeles activity score [mean difference = 1.60, 95% CI (0.79, 2.42), P = 0.0001], and short-term visual analogue scale score [mean difference =  - 0.14, 95% CI (- 0.23, - 0.05), P = 0.002]. This systematic review indicates the efficacy of PRP when applied to the bone-tendon interface during arthroscopic rotator cuff repair.

A possible injectable tissue engineered nucleus pulposus constructed with platelet-rich plasma and ADSCs in vitro

BACKGROUND

Injectable tissue engineered nucleus pulposus is a new idea for minimally invasive repair of degenerative intervertebral disc. The platelet-rich plasma (PRP) and adipose-derived stromal cells (ADSCs) could be harvested from autologous tissue easily. PRP contains numerous autologous growth factors and has reticulate fibrous structure which may have the potential to make ADSCs differentiate into nucleus pulposus-like cells. The goal of this study was to explore the feasibility of constructing a possible injectable tissue engineered nucleus pulposus with PRP gel scaffold and ADSCs.

METHODS

After identification with flow cytometry, the rabbit ADSCs were seeded into PRP gel and cultured in vitro. At the 2nd, 4th, and 8th week, the PRP gel/ADSCs complex was observed by macroscopy, histological staining, BrdU immunofluorescence, and scanning electron microscopy. The glycosaminoglycans (GAG) in the PRP gel/ADSCs complex were measured by safranin O staining with spectrophotometry. In PRP gel/ADSCs complex, gene expression of HIF-1α, aggrecan, type II collagen were tested by RT-PCR. The injectability of this complex was evaluated.

RESULTS

Macroscopically, the complex was solidified into gel with smooth surface and good elasticity. The safranin O dye was almost no positive staining at 2nd week; however, the positive staining of extracellular matrix was enhanced obviously at 4th and 8th week. The HE staining and SEM demonstrated that the cells were well-distributed in the reticulate scaffold. BrdU immunofluorescence showed that ADSCs can survive and proliferate in PRP gel at each time points. The level of GAG at 4th week was higher than those at 2nd week (P < 0.05), and significant difference was also noted between 4th and 8th week (P < 0.05). HIF-1α, aggrecan, type II collagen gene expression at 4th week were much more than those at 2nd week (P < 0.05), and significant differences were also noted between 4th and 8th week (P < 0.05). The flow rate of complex was 0.287 mL/min when passed through the 19-gauge needle with the 100 mmHg injection pressure.

CONCLUSIONS

Our preliminary findings suggest that the PRP gel make it possible for rabbit ADSCs differentiated into nucleus pulposus-like cells after coculture in vitro. According to the results, it is a better feasible method for construction of autologous injectable tissue engineered nucleus pulposus.

Influence of Acromial Morphologic Characteristics and Acromioclavicular Arthrosis on the Effect of Platelet-Rich Plasma on Partial Tears of the Supraspinatus Tendon

OBJECTIVE. The purposes of this study were to determine the medium-term effect of ultrasound-guided infiltration of platelet-rich plasma (PRP) on partial tears of the supraspinatus tendon (SST) and to identify prognostic indicators of an unfavorable outcome. SUBJECTS AND METHODS. Over a period of 4 years, patients with a partial SST tear smaller than 1.5 cm referred for ultrasound-guided PRP infiltration (1 mL) for shoulder pain lasting more than 3 months were recruited consecutively. MRI was used to analyze the type of acromion and presence of acromioclavicular (AC) arthrosis. Primary (size of the tear and associated bursitis) and secondary (mobility and pain) results were collected at 3 months. RESULTS. The study included 128 patients (66 men, 62 women; mean age, 48.3 years; range, 20-59 years). At 3 months, favorable evolution of the tear repair was recorded in 71.1% (91/128) of patients and resolution of bursitis in 66.7% (42/63). Changes in tear size had large effect sizes (Cohen d ≥ 1.16), as did pain and shoulder mobility (Cohen d ≥ 0.95). The strongest predictors of unfavorable evolution of tear and bursitis were type 3 acromion and types 1 and 2 acromion with AC arthrosis (p < 0.001; β = 20.412). CONCLUSION. Ultrasound-guided PRP infiltration of partial tears of the SST relieves pain and improves shoulder mobility, but its effect on the size of the tear is influenced by the morphologic characteristics of the acromion and the presence of AC arthrosis. The effect of PRP is insufficient in patients with a type 3 acromion or severe AC arthrosis.

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.