Does application of moderately concentrated platelet-rich plasma improve clinical and structural outcome after arthroscopic repair of medium-sized to large rotator cuff tear? A randomized controlled trial

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.

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

OBJECTIVE

To analyze the efficacy and safety after the application of platelet-rich-plasma (PRP) as an adjuvant in arthroscopic rotator cuff repairs.

MATERIAL AND METHODS

A bibliographic search of the literature of prospective studies with level of evidence one or two was carried out from January 2004 to December 2021, including studies that compare the functional and re-tear results after arthroscopic cuff repair rotator with or without PRP.

RESULTS

A total of 281 articles were identified, of which 14 met the inclusion criteria. The overall re-rupture rate was 24%. In the PRP group, a decrease in the re-rupture rate and better functional results were demonstrated, although these differences were not significant.

CONCLUSIONS

Adjuvant treatment with PRP has shown promising results, although there is not yet enough evidence to provide a clear advantage for routine use in clinical practice.

[Translated article] Efficacy of platelet-rich plasma in rotator cuff repair: Systematic review and meta-analysis

OBJECTIVE

To analyse the efficacy and safety after the application of platelet-rich-plasma (PRP) as an adjuvant in arthroscopic rotator cuff repairs.

MATERIAL AND METHODS

A bibliographic search of the literature of prospective studies with level of evidence one or two was carried out from January 2004 to December 2021, including studies that compare the functional and re-tear results after arthroscopic cuff repair rotator with or without PRP.

RESULTS

A total of 281 articles were identified, of which 14 met the inclusion criteria. The overall re-rupture rate was 24%. In the PRP group, a decrease in the re-rupture rate and better functional results were demonstrated, although these differences were not significant.

CONCLUSIONS

Adjuvant treatment with PRP has shown promising results, although there is not yet enough evidence to provide a clear advantage for routine use in clinical practice.

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.

Arthroscopic Surgery Combined With Platelet-Rich Plasma Does Not Significantly Improve Pain, Function, Complications, and Retear Rate Compared With Arthroscopic Surgery Alone for Full-Thickness Rotator Cuff Tears: A Systematic Review and Meta-analysis

PURPOSE

To evaluate the effectiveness and safety of arthroscopic surgery combined with platelet-rich plasma (PRP) compared with arthroscopic surgery alone in the treatment of patients with full-thickness rotator cuff tears.

METHODS

The Cochrane Library, PubMed, Embase, Scopus, EBSCO, Web of Science, China National Knowledge Infrastructure, and Wanfang Database were systematically searched from inception to November 2023. Subject words combined with free words were used to collect randomized controlled trials focusing on arthroscopic surgery combined with PRP in the treatment of full-thickness rotator cuff tears. The assessment of evidence quality employed the Cochrane Collaboration risk of bias tool, and data analysis was performed using RevMan 5.3 software.

RESULTS

A total of 9 studies with 537 patients were included. The meta-analysis revealed that compared with the arthroscopic surgery alone group, the summary result of University of California Los Angeles score scores in the arthroscopic combined with PRP group was (mean difference [MD] = 1.08, 95% confidence interval [CI] 0.19∼1.97, P = .02), subgroup analysis of surgical suture method visual analog scale (VAS) single-row (MD = -1.00, 95% CI -1.50 to -0.50, P < .0001), VAS double-row (MD = -0.10, 95% CI -0.17 to -0.02, P = .02), and Constant-Murley score single-row (MD = 3.49, 95% CI 0.32∼6.66, P = .03), the difference was statistically significant, and the differences in VAS, Constant-Murley score, and Quick Disabilities of the Arm, Shoulder and Hand, complications, and retear rate were not statistically significant.

CONCLUSIONS

Patients undergoing arthroscopic repair combined with PRP treatment showed no difference in pain, function, complications, and retear rate compared with those treated with arthroscopic surgery alone.

LEVEL OF EVIDENCE

Level II, systematic review and meta-analysis of Level I and II evidence.

Semi-Bone Tunnel Technique Using Double-Row Suture Bridge Combined With Platelet-Rich Plasma Hydrogel for Rotator Cuff Repair in a Rabbit Model

BACKGROUND

The approach to managing the footprint area and reconstructing the tendon-bone interface (TBI) is critical for optimal healing.

PURPOSE

To evaluate the outcomes of the semi-bone tunnel (SBT) technique using a double-row suture bridge combined with platelet-rich plasma (PRP) hydrogel for rotator cuff repair in a rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 48 New Zealand White rabbits were divided into 4 groups. The supraspinatus tendons were severed at the footprint to create a rotator cuff tear model in the surgical groups. Rabbits were treated with the traditional onto-surface repair (control group), SBT technique (SBT group), and SBT technique combined with PRP hydrogel implantation (SBT+PRP group). The rabbits without surgery were the normal group. At 8 weeks after surgery, macroscopic observation, magnetic resonance imaging (MRI) and micro-computed tomography (μCT) examinations, histological evaluations, and biomechanical tests were performed to assess the curative effects of the given treatments.

RESULTS

The MRI results showed that the repaired supraspinatus tendon presented a uniform signal, minimal inflammatory response, and the lowest signal-to-noise quotient value in the SBT+PRP group. The μCT results suggested that the SBT technique did not reduce the local bone mineral density in the TBI area compared with the onto-surface repair technique. The histological staining results showed that the regenerated TBI in the SBT+PRP group had a 4-layer structure similar to the natural tissue. The highest values for biomechanical properties were observed in the SBT+PRP group, and there was no significant difference between the SBT+PRP group and normal group.

CONCLUSION

The SBT technique presented a better tendon-bone healing effect for rotator cuff tear in the rabbit model compared with the traditional onto-surface repair technique. The specimens in the SBT+PRP group had a similar TBI structure and biomechanical properties to the natural tissue.

CLINICAL RELEVANCE

The SBT technique can be an alternative surgical approach for rotator cuff repair, especially for moderate to large tears and cases requiring scaffold implantation.

Most Orthopaedic Platelet-Rich Plasma Investigations Don't Report Protocols and Composition: An Updated Systematic Review

PURPOSE

To systematically review the literature to assess the heterogeneity of platelet-rich plasma (PRP) preparation and composition reporting for the treatment of musculoskeletal/orthopaedic pathologies.

METHODS

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify Level I and Level II studies from 2016 to 2022 that evaluated the use of PRP therapy for musculoskeletal pathologies. The search phrase used was "platelet-rich plasma clinical studies." Studies were assessed based on their reporting of the PRP preparation methods and reporting of PRP composition.

RESULTS

One hundred twenty-four studies (in 120 articles) met inclusion criteria for analysis. Of these studies, 15 (12.1%) provided comprehensive reporting, including a clear, well-described, and reproducible preparation protocol that future investigators can follow. Thirty-three studies (26.6%) quantitatively reported the final PRP product composition.

CONCLUSIONS

Among the studies using PRP for the treatment of musculoskeletal/orthopaedic pathologies, less than 20% provided a clear, well-described, and reproducible PRP preparation protocol, and only one-fourth of studies reported on the final PRP product composition.

CLINICAL RELEVANCE

A diverse current reporting of PRP composition between studies provides a high heterogeneity of the term "PRP," which becomes a limitation for a comparison of studies using PRP.

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.

Rotator Cuff Augmentation: Its Role and Best Practices

Rotator cuff tears are a common source of pain and impairment in the shoulder. Healing of the rotator cuff tendons following repair has been associated with improved patient outcomes. While there have been many technical improvements in surgical techniques for rotator cuff repair, failure rates are still surprisingly high. Augmentation of these repairs has been shown to help with fixation biomechanics as well as healing rates. The described types of augments include autograft, allograft, xenograft, and synthetic options. This report reviews the commonly available types of augments and some of the outcomes associated with their use.

Platelet-rich plasma in the pathologic processes of tendinopathy: a review of basic science studies

Tendinopathy is a medical condition that includes a spectrum of inflammatory and degenerative tendon changes caused by traumatic or overuse injuries. The pathological mechanism of tendinopathy has not been well defined, and no ideal treatment is currently available. Platelet-rich plasma (PRP) is an autologous whole blood derivative containing a variety of cytokines and other protein components. Various basic studies have found that PRP has the therapeutic potential to promote cell proliferation and differentiation, regulate angiogenesis, increase extracellular matrix synthesis, and modulate inflammation in degenerative tendons. Therefore, PRP has been widely used as a promising therapeutic agent for tendinopathy. However, controversies exist over the optimal treatment regimen and efficacy of PRP for tendinopathy. This review focuses on the specific molecular and cellular mechanisms by which PRP manipulates tendon healing to better understand how PRP affects tendinopathy and explore the reason for the differences in clinical trial outcomes. This article has also pointed out the future direction of basic research and clinical application of PRP in the treatment of tendinopathy, which will play a guiding role in the design of PRP treatment protocols for tendinopathy.

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.

Orthobiologics: a review

PURPOSE

The use of biologic materials in orthopaedics (orthobiologics) has gained significant attention over the past years. To enhance the body of the related literature, this review article is aimed at summarizing these novel biologic therapies in orthopaedics and at discussing their multiple clinical implementations and outcomes.

METHODS

This review of the literature presents the methods, clinical applications, impact, cost-effectiveness, and outcomes, as well as the current indications and future perspectives of orthobiologics, namely, platelet-rich plasma, mesenchymal stem cells, bone marrow aspirate concentrate, growth factors, and tissue engineering.

RESULTS

Currently available studies have used variable methods of research including biologic materials as well as patient populations and outcome measurements, therefore making comparison of studies difficult. Key features for the study and use of orthobiologics include minimal invasiveness, great healing potential, and reasonable cost as a nonoperative treatment option. Their clinical applications have been described for common orthopaedic pathologies such as osteoarthritis, articular cartilage defects, bone defects and fracture nonunions, ligament injuries, and tendinopathies.

CONCLUSIONS

Orthobiologics-based therapies have shown noticeable clinical results at the short- and mid-term. It is crucial that these therapies remain effective and stable in the long term. The optimal design for a successful scaffold remains to be further determined.

Evidence for Utilization of Injectable Biologic Augmentation in Primary Rotator Cuff Repair: A Systematic Review of Data From 2010 to 2022

Background

Biologic healing after rotator cuff repair remains a significant challenge. Injectable biologic augmentation may improve tissue quality at the suture-tendon interface.

Purpose

To investigate the effect of injectable biologic supplementation in rotator cuff repair and to assess the quality and adherence to evolving reporting standards.

Study Design

Systematic review; Level of evidence, 3.

Methods

A systematic review was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included were 40 studies: 29 preclinical (in vivo animal models) and 11 clinical. Each clinical study was assessed for quality, risk of bias, and adherence to relevant MIBO (Minimum Information for Studies Evaluating Biologics in Orthopaedics) guidelines. The outcomes of interest were reported load to failure, load to gap, gap size, and stiffness in the preclinical studies, and healing rate and any patient-reported outcome measures in the clinical studies.

Results

Injectables reported included growth factors (eg, transforming growth factor-beta 3, erythropoietin), bone marrow-derived mesenchymal stem cells and adipose-derived mesenchymal stem cells (ADSCs), and other agents such as platelet-rich plasma (PRP) and hyaluronic acid. The most common findings for preclinical injectables were increased load to failure (16/29 studies; 55.2%) and improved collagen histological quality (11/29 studies; 37.9%). All 11 clinical studies (10 PRP, 1 ADSC) indicated no adverse events, with similar or improved patient-reported outcomes compared with repairs in the control groups. In 1 study utilizing an innovative delivery technique, a concentrated PRP globule with fibrin matrix was shuttled over a suture to maintain concentrated PRP at the repair site and demonstrated a significant decrease in retears (P = .03) at a 31-month follow-up. A matched-cohort study investigating augmentation with ADSCs demonstrated a significantly lower retear rate in the ADSC-augmented group than the control group at a 28-month follow-up (P < .001). On average, the clinical studies adhered to 66% of relevant MIBO reporting guidelines and had a low risk of bias.

Conclusion

Approximately 83% of preclinical studies found a positive biomechanical or histological effect, with no studies showing an overall negative effect. Clinically, utilization of innovative delivery techniques may reduce the risk of arthroscopic washout of PRP and improve retear rates. ADSCs were shown to reduce retear rates at a 28-month follow-up.

Transosseous-Equivalent/Suture Bridge Technique in Combination With Platelet-Rich Plasma Application Yield Optimal Clinical Outcomes in Arthroscopic Rotator Cuff Repair: A Bayesian Network Analysis of Randomized Controlled Trials

PURPOSE

To assess the clinical evidence defining the optimal combination of arthroscopic suture technique and platelet-rich products (PRP), and application for arthroscopic rotator cuff repair (ARCR).

METHODS

All level of evidence (LOE) I randomized controlled trials (RCT) focusing on arthroscopic suture technique and/or PRP application in ARCR were included. The exclusion criteria were LOE II or worse, studies with other interventions, studies reported none of the predetermined clinical outcomes; studies unable to extract any precise data; studies from the same patient group of included studies. A pair-wise meta-analysis and Bayesian network analysis were performed on each comparison. The intervention options were ranked by Bayesian network analysis.

RESULTS

27 studies comprising 1,947 individuals met the inclusion criteria. The application of transosseous equivalent/suture bridge repair (SB) with PRP (SB+PRP) significantly reduced retear rate (risk ratio [RR], 0.29; 95% confidence interval [CI], [0.15, 0.55].) and increased Constant-Murley score (mean difference, 1.90; 95% CI, [0.14, 3.74]), compared to SB repair. Single-row repair (SR) with PRP usage (SR+PRP) significantly reduced retear rate (RR, 0.27; 95% CI, [0.12, 0.55]) and pain visual analog scale (VAS) (mean difference: -0.84; 95% CI [-1.39, -0.46].), increased University of California, Los Angeles (UCLA) shoulder score (mean difference: 1.48; 95% CI [0.50, 2.58]) and Constant-Murley score (mean difference: 4.53; 95% CI [2.65, 6.38]), compared to SR repair. The ranking for outcomes demonstrated SB+PRP resulted in the best retear rate, UCLA shoulder score, with the second-best postoperative pain, Constant-Murley score, while SR+PRP resulted in the best postoperative pain, Constant-Murley score, with the second-best retear rate and UCLA score.

CONCLUSION

Arthroscopic rotator cuff repair utilizing SB+PRP yields optimal retear rate and UCLA shoulder score, with the second-best postoperative pain and Constant-Murley shoulder outcome score, while SR+PRP yields the best in these two parameters.

LEVEL OF EVIDENCE

Level I, Bayesian network analysis of level I RCT.

Strategies for promoting tendon-bone healing: Current status and prospects

Tendon-bone insertion (TBI) injuries are common, primarily involving the rotator cuff (RC) and anterior cruciate ligament (ACL). At present, repair surgery and reconstructive surgery are the main treatments, and the main factor determining the curative effect of surgery is postoperative tendon-bone healing, which requires the stable combination of the transplanted tendon and the bone tunnel to ensure the stability of the joint. Fibrocartilage and bone formation are the main physiological processes in the bone marrow tract. Therefore, therapeutic measures conducive to these processes are likely to be applied clinically to promote tendon-bone healing. In recent years, biomaterials and compounds, stem cells, cell factors, platelet-rich plasma, exosomes, physical therapy, and other technologies have been widely used in the study of promoting tendon-bone healing. This review provides a comprehensive summary of strategies used to promote tendon-bone healing and analyses relevant preclinical and clinical studies. The potential application value of these strategies in promoting tendon-bone healing was also discussed.

The Effect of PRP Augmentation of Arthroscopic Repairs of Shoulder Rotator Cuff Tears on Postoperative Clinical Scores and Retear Rates: A Systematic Review and Meta-Analysis

The aim of this review and meta-analysis is to assess recent clinical trials concerning the combination of operative treatment of rotator cuff tears and the administration of PRP and its effect on clinical scores and postoperative retear rates. The trials were used to compare the combination of PRP treatment and arthroscopic rotator cuff repair to arthroscopy alone. Twenty-five clinical trials were reviewed. A risk-of-bias assessment was made for all randomized clinical trials included, using the Cochrane collaboration’s tool as well as a quality assessment for all non-randomized studies utilizing the Newcastle−Ottawa scale. The PRP-treated patients showed statistically significant improvement postoperatively compared to control groups concerning the Constant−Murley (mean difference 2.46, 95% CI 1.4−3.52, p < 0.00001), SST (mean difference 0.32, 95% CI 0.02−0.63, p = 0.04), and UCLA (mean difference 0.82, 95% CI 0.23−1.43, p = 0.07) scores. A statistically significant decrease of retear rates in the PRP-treated patients, with a risk ratio of 0.78 (95% CI 0.65−0.94, p = 0.01), was found. We believe that the results presented have positive aspects, especially concerning the retear risk, but are yet inconclusive concerning clinical results such as shoulder pain and function.

Platelet-rich plasma does not improve clinical results in patients with rotator cuff disorders but reduces the retear rate. A systematic review and meta-analysis

PURPOSE

To assess whether the use of Platelet-rich plasma (PRP) produces a clinical benefit in patients with rotator cuff disorders, treated either conservatively or surgically.

METHODS

A systematic review was performed according to PRISMA guidelines on three databases (PubMed, Cochrane Library, Web of Science) to identify randomised controlled trials (RCTs) on the use of PRP in patients with rotator cuff disorders, treated either conservatively or surgically. A meta-analysis was performed on articles reporting results for Constant, UCLA, VAS, SST scores and retear rate. The RoB 2.0 and the modified Coleman Methodology Score were used to assess methodological quality.

RESULTS

A total of 36 RCTs (20 surgical, 16 conservative) were included, for a total of 2,443 patients. Conservative treatment showed high heterogeneity and no clear consensus in favour of PRP. The meta-analysis of the studies with surgical treatment showed no benefit in using PRP in any of the clinical outcomes, either at the short or medium/long-term follow-up. However, the retear rate was lower with PRP augmentation (p < 0.001). The overall quality of the studies was moderate to high, with the surgical studies presenting a lower risk of bias than the conservative studies.

CONCLUSION

The use of PRP as augmentation in rotator cuff surgical repair significantly reduces the retear rate. However, no benefits were documented in terms of clinical outcomes. PRP application through injection in patients treated conservatively also failed to present any clear advantage. While there are many studies in the literature with several RCTs of moderate to high quality, the high heterogeneity of products and studies remains a significant limitation to fully understanding PRP potential in this field.

LEVEL OF EVIDENCE

Level I.

Effect of Bone Marrow Aspirate Concentrate and Platelet-Rich Plasma Augmentation on the Rate of Revision Rotator Cuff Repair

Background:

The application of orthobiologics at the time of arthroscopic rotator cuff repair (RCR) has received an increasing amount of clinical interest despite a relative scarcity of human clinical studies on their efficacy.

Purpose:

To utilize a national administrative database to determine the association of bone marrow aspirate concentrate (BMAC) and platelet-rich plasma (PRP) applied at the time of RCR with revision surgery rates.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

The Mariner data set from the PearlDiver patient records repository was utilized to identify patients undergoing RCR using Current Procedural Terminology (CPT) code 29827. Patients receiving BMAC or PRP at the time of RCR were then identified using CPT coding. For comparison purposes, a matched cohort was created consisting of patients who underwent RCR without biologic augmentation in a 5:1 fashion for each biologic separately. Cases were matched according to age, sex, tobacco use, biceps tenodesis, distal clavicle excision, and subacromial decompression. All groups were then queried for revision RCR or conversion to reverse shoulder arthroplasty. Revision rates were compared utilizing a multivariate binomial logistic regression analysis. Adjusted odds ratios (ORs) and 95% CIs were calculated.

Results:

A total of 760 patients who underwent biologic augmentation during RCR were identified, including 646 patients in the PRP group and 114 patients in the BMAC group. They were compared with 3800 matched controls without documented biologic application at the time of surgery. Compared with matched controls, patients who received BMAC at the time of surgery experienced a significantly lower incidence of revision surgery at 2 years (OR, 0.36; 95% CI, 0.15-0.82; P = .015). There was no significant difference in revision rates between PRP and matched controls (OR, 0.87; 95% CI, 0.62-1.23; P = .183).

Conclusion:

The application of BMAC at the time of RCR was associated with a significant decrease in the incidence of revision surgery. There was no apparent effect of PRP on the incidence of revision surgery after primary RCR. Higher-level clinical studies considering surgical factors are needed to more clearly define the role of biologic adjuvants in RCR.

Platelet-rich Plasma in the Management of Shoulder Disorders: Basic Science and Implications Beyond the Rotator Cuff

Platelet-rich plasma (PRP) is an autologous mixture produced by centrifugal separation of whole blood. Understanding the clinical efficacy of PRP remains a challenge in the field of sports medicine, including the treatment of various shoulder conditions. Animal studies have examined the biologic actions of PRP on the rotator cuff tendon and shoulder capsule. Human studies have reported the outcomes of PRP in the management of subacromial impingement syndrome, rotator cuff tears, frozen shoulder, and glenohumeral osteoarthritis. These studies highlight the role of PRP in the nonsurgical management of these conditions and its utilization in the perioperative setting to augment tissue healing and optimize the surgical outcomes. The role of PRP as an adjunct therapy in patients undergoing rotator cuff repair has been in the spotlight during the last decade; however, a limited number of studies have examined the role of PRP in the management of non-rotator cuff shoulder conditions. This article aims to provide an overview of the biologic actions of PRP on shoulder tissues and to summarize the outcomes of PRP injection in patients with rotator cuff and non-rotator cuff disease of the shoulder. We sought to organize the existing literature and to provide recommendations on the use of PRP in various shoulder conditions, based on the existing evidence.

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.

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.

Changes From Baseline in Patient- Reported Outcomes at 1 Year Versus 2 Years After Rotator Cuff Repair: A Systematic Review and Meta-analysis

BACKGROUND

Most orthopaedic journals currently require reporting outcomes of surgical interventions for at least 2 postoperative years, but there have been no rigorous studies on this matter. Various patient-reported outcome (PRO) measures (PROMs) have been used to assess the status of the shoulder after rotator cuff repair (RCR).

HYPOTHESIS

We hypothesized that the mean shoulder-specific PROMs at 1 year improve substantially over baseline but that there is no clinically meaningful difference between the mean 1- and 2-year PROMs after RCR.

STUDY DESIGN

Meta-analysis; Level of evidence, 2.

METHODS

We conducted a systematic review of published randomized controlled trials (RCTs) and prospective cohort studies (level of evidence 1 and 2) reporting the shoulder-specific American Shoulder and Elbow Surgeons (ASES), the Constant, or the Western Ontario Rotator Cuff (WORC) Index scores at baseline, 1 year, and 2 years after RCR. The methodologic quality of studies was assessed. Also, the random effects meta-analyses of changes in PROMs for each of the first and second postoperative years were conducted.

RESULTS

Fifteen studies (n = 11 RCTs; n = 4 cohort studies) with a total of 1371 patients were included. Studies were highly heterogeneous, but no visual evidence of major publication bias was observed. The weighted means of the baseline PROMs were 46.2 points for the ASES score, 46.4 points for the Constant score, and 38.8 points for the WORC Index. The first-year summary increments were 41.1 (95% CI, 36.0-46.2) points for the ASES score, 34.2 (95% CI, 28.8-39.6) points for the Constant score, and 42.9 (95% CI, 37.3-48.4) points for the WORC Index. In contrast, the second-year summary increments were 2.3 (95% CI, 1-3.6) points for the ASES score, 3.2 (95% CI, 1.9-4.4) points for the Constant score, and 2 (95% CI, -0.1 to 4) points for the WORC Index.

CONCLUSION

All PROMs improved considerably from baseline to 1 year, but only very small gains that were below the minimal clinically important differences were observed between 1 year and 2 years after RCR. This study did not find any evidence for requiring a minimum of 2 years of follow-up for publication of PROs after RCR. Our results suggest that focusing on 1-year PROMs after RCR would foster more timely reporting, better control of selection bias, and better allocation of research resources.

Chitosan-platelet-rich plasma implants improve rotator cuff repair in a large animal model: Pilot study

Freeze-dried formulations of chitosan can be solubilized in platelet-rich plasma (PRP) to form injectable implants that are used as an adjunct treatment during surgical repair of the rotator cuff. The purpose of the current study was to assess chitosan-PRP implant residency, test safety, and assess efficacy over standard-of-care controls in a sheep model of rotator cuff repair. The infraspinatus tendon was transected unilaterally and immediately repaired with suture anchors in 22 skeletally mature ewes. In treatment groups, formulations containing chitosan, trehalose, and calcium chloride were solubilized with autologous leukocyte-rich PRP and injected at the tendon-bone interface and on top of the repaired site (1 mL or 2 mL doses). Implant residency was assessed histologically at 1 day. Outcome measures included MRI assessment at baseline, 6 weeks, and 12 weeks, histopathology and clinical pathology. Chitosan-PRP implants were resident at the injection site at 1 day and induced recruitment of polymorphonuclear cells. The tendon gap, which corresponds to the length of abnormally hyperintense tissue attached to the humeral head, was decreased by treatment with the 2 mL dose when compared to controls at 12 weeks on MRI images. Some histological features were improved by the 2 mL dose treatment compared to controls at 12 weeks. There was no treatment-specific effect on all standard safety outcome measures, which suggests high safety. This study provides preliminary evidence on the safety and efficacy of chitosan-PRP implants in a large animal model that could potentially be translated to a clinical setting.

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.

Leukocyte-Rich and Leukocyte-Poor Platelet-Rich Plasma in Rotator Cuff Repair: A Meta-analysis

To systematically review of randomized controlled trials(RCTs) to compared the effects of leukocyte-rich and leukocyte-poor platelet-rich plasma in arthroscopic rotator cuff repair. Two independent reviewers comprehensively searched PubMed, Embase, and Cochrane library databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Comparison of leukocyte-rich platelet-rich plasma or leukocyte-poor platelet-rich plasma in rotator cuff repair in a level I RCTs. Methodological quality assessment was carried out using Cochrane Review Manager 5.3 software. P<0.05 was considered statistically significant. Nine RCTs with 540 patients were included in this review. Meta-analysis showed that leukocyte-poor platelet-rich plasma in significantly reduced retear rate in rotator cuff repair [RR=0.56 95%CI (0.42,0.75); P＜0.05), and in clinical results, the constant score [MD=3.67, 95%CI (1.62,5.73); P=0.0005], UCLA score [MD=1.60, 95%CI (0.79,2.42); P=0.0001], ASES score [MD=2.16, 95%CI(0.12,4.20);P=0.04] were significantly improved. There was a significant result in favor of PRP for the Constant score [MD=-1.24, 95%CI(-1.50,-0.99); P＜0.00001], while SST scores were not significantly different among all groups [MD=0.21, 95%CI(-0.21,0.64); P=0.32]. In conclusion, leukocyte-poor platelet-rich plasma can improved the clinical function and reduced retear rate in arthroscopic rotator cuff repair. In contrast, the efficacy of leukocyte-rich platelet-rich plasma was not significantly improved with the exception of VAS score.

Augmentation of Rotator Cuff Healing With Orthobiologics

The limited regenerative capacity of the tendon-bone enthesis after surgical repair poses a significant challenge to achieving desired clinical outcomes. Biologic augmentation of the repair site has the potential to enhance the biomechanical and histological integrity of the enthesis, leading to lower retear rates and greater patient satisfaction. Platelet-rich plasma, stem cells and bone marrow aspirate concentrate, growth factors, biodegradable or biomimetic scaffolds, and amniotic products have been investigated in preclinical and, in some cases, clinical studies aimed at augmenting tendon-bone healing. Although many of these therapies have achieved some degree of success in improving structural, histological, and clinical outcomes after surgical tendon-bone enthesis repair, none have reliably and consistently lead to clinical improvement. High-quality randomized controlled clinical studies are needed to definitively evaluate the efficacy of these biologic therapies and ultimately determine which, if any, are capable of achieving a tendon-bone repair that is structurally noninferior to the native enthesis before injury.

Better Short-Term Outcomes After Rotator Cuff Repair in Studies With Poorer Mean Shoulder Scores and Predominantly Small to Medium-Sized Tears at Baseline: A Systematic Review and Meta-analysis

PURPOSE

To perform a meta-analysis to explore factors associated with clinical and structural short-term outcomes in randomized and nonrandomized prospective studies of rotator cuff repair.

METHODS

Medline, clinicaltrials.gov, and Mendeley were searched for literature published from January 2000 to December 2020 to identify randomized controlled trials (RCT) and nonrandomized prospective cohort studies (PCS) describing the outcome of surgical repair of full-thickness rotator cuff tears. Study quality was assessed by two independent reviewers. We calculated standardized mean difference (SMD) from baseline to follow-up in each trial arm, preferably at 12 months follow-up. Between-study heterogeneity of outcomes, small-study effects and rates of retear were assessed. Meta-regression was performed to estimate associations between prespecified variables and clinical and structural outcomes.

RESULTS

Outcomes in 64 RCT and 19 PCS trial arms were analyzed. Median age was 59 years. There was substantial between-study heterogeneity in clinical outcomes (SMD range: .42 to 6.44; I² = 93% in RCT, 88% in PCS) and summary estimates were not calculated. On the basis of multivariate analysis, better clinical outcome was associated with lower (worse) mean outcome value at baseline, smaller tear size, and lower proportion of large-massive tears (R² = 56 and 44%, respectively). Overall retear rate at median 13-month follow-up was 19.9% (interquartile range: 10-30). Higher mean age together with larger tear size and higher proportion of large-massive tears were associated with increased retear rates (R² = 33% and 58%, respectively). Clinical outcome was not significantly related to rate of retear.

CONCLUSIONS

Studies with lower mean outcome values at baseline and predominantly small- to medium-sized tears reported better clinical outcomes. Studies with higher mean age and a predominance of large-massive tears had significantly increased retear rates, but retear rates were not associated with clinical outcome.

LEVEL OF EVIDENCE

Level II, meta-analysis of level I and II 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.

The Role of Nanomaterials and Biological Agents on Rotator Cuff Regeneration

The rotator cuff is a musculotendon unit responsible for movement in the shoulder. Rotator cuff tears represent a significant number of musculoskeletal injuries in the adult population. In addition, there is a high incidence of retear rates due to various complications within the complex anatomical structure and the lack of proper healing. Current clinical strategies for rotator cuff augmentation include surgical intervention with autograft tissue grafts and beneficial impacts have been shown, but challenges still exist because of limited supply. For decades, nanomaterials have been engineered for the repair of various tissue and organ systems. This review article provides a thorough summary of the role nanomaterials, stem cells and biological agents have played in rotator cuff repair to date and offers input on next generation approaches for regenerating this tissue.

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.

Significant Improvement in Shoulder Function and Pain in Patients Following Biologic Augmentation of Revision Arthroscopic Rotator Cuff Repair Using an Autologous Fibrin Scaffold and Bone Marrow Aspirate Derived From the Proximal Humerus

Purpose

To clinically evaluate patients who underwent a biologic augmentation technique in revision arthroscopic rotator cuff repair using an autologous fibrin scaffold and concentrated stem cells isolated from bone marrow aspirate (BMA) obtained from the proximal humerus.

Methods

This is a retrospective review of prospectively collected data from patients who underwent biologic augmentation of revision arthroscopic rotator cuff repair using an autologous fibrin scaffold and BMA obtained from the proximal humerus between 2014 and 2015. Minimum follow-up was 12 months. Outcome measures were collected preoperatively and postoperatively including range of motion as well as American Shoulder and Elbow Surgeons Shoulder Form, Simple Shoulder Test, single assessment numeric evaluation, and visual analog score. In addition, BMA samples of each patient were assessed for the number of nucleated cells and colony-forming units. Regression analysis was performed to investigate whether the number of nucleated cells and colony-forming units had an influence on outcome and failure.

Results

Ten patients who underwent biologic augmentation of revision arthroscopic rotator cuff repair using an autologous fibrin scaffold and concentrated BMA obtained from the proximal humerus between 2014 and 2015 were included. The mean follow-up time was 30.7 (range: 12-49) months. Four patients were revised at final follow-up. Postoperative clinical scores improved significantly: American Shoulder and Elbow Surgeons (28.1 ± 5.4 to 60.9 ± 9.0; P < .01), single assessment numeric evaluation (6.6 ± 2.3 to 65.1 ± 10.9; P < .01), visual analog scale (7.2 ± 0.9 to 3.1 ± 0.9; P < .01), and Simple Shoulder Test (1.6 ± 0.5 to 10.3 ± 5.7; P < .01). Postoperative range of motion increased significantly with regard to flexion (97.0 ± 13.6 to 151.0 ± 12.2; P < .01) and abduction (88.0 ± 14.0 to 134.0 ± 15.1; P = .038) but not with external rotation (38.0 ± 5.7 to 50.5 ± 6.5; P = .16). Less pain was correlated to an increased number of nucleated cells (P = .026); however, there was no correlation between failure rate and number of nucleated cells (P = .430).

Conclusions

Patients who underwent biologic augmentation of revision arthroscopic rotator cuff repair using an autologous fibrin scaffold and concentrated BMA demonstrated a significant improvement in shoulder function along with reduction of pain. However, the overall revision rate for this procedure was 40%.

Level of Evidence

Level IV, therapeutic case series.

Chitosan-Platelet-Rich Plasma Implants Improve Rotator Cuff Repair in a Large Animal Model: Pivotal Study

The purpose of this study was to assess the safety and efficacy of chitosan-platelet-rich plasma (PRP) hybrid implants used as an adjunct to surgical rotator cuff repair in a pivotal Good Laboratory Practice (GLP)-compliant study. The infraspinatus tendon was transected in 48 skeletally mature ewes and repaired with a transosseous-equivalent (TOE) technique. In the two treatment groups, a chitosan-PRP solution was injected at the footprint between the tendon and the bone and on top of the repaired site (2 mL or 3 mL doses, n = 12 per group). To further assess chitosan safety, a chitosan-water solution was injected at the same sites (3 mL, n = 12). Outcome measures included Magnetic Resonance Imaging (MRI) assessment and clinical pathology at 3 months and 6 months and histopathology at 6 months. The tendon gap was decreased at 3 months on MRI images and certain histopathological features were improved at 6 months by chitosan-PRP treatment compared to controls. The group treated with chitosan-water was not different from controls. Chitosan-PRP treatment induced no negative effects in the sheep, which suggests high safety. This study provides further evidence on the safety and efficacy of chitosan-PRP for rotator cuff repair augmentation, which could eventually be used in a clinical setting.

The Statistical Fragility of Platelet-Rich Plasma in Rotator Cuff Surgery: A Systematic Review and Meta-analysis

BACKGROUND

The practice of evidence-based medicine relies on objective data to guide clinical decision-making with specific statistical thresholds conveying study significance.

PURPOSE

To determine the utility of applying the fragility index (FI) and the fragility quotient (FQ) analysis to randomized controlled trials (RCTs) evaluating the utilization of platelet-rich plasma (PRP) in rotator cuff repairs (RCRs).

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

RCTs pertaining to the utilization of PRP in surgical RCRs published in 13 peer-reviewed journals from 2000 to 2020 were evaluated. The FI was determined by manipulating each reported outcome event until a reversal of significance was appreciated. The associated FQ was determined by dividing the FI by the sample size.

RESULTS

Of the 9746 studies screened, 19 RCTs were ultimately included for analysis. The overall FI incorporating all 19 RCTs was only 4, suggesting that the reversal of only 4 events is required to change study significance. The associated FQ was determined as 0.092. Of the 43 outcome events reporting lost to follow-up data, 13 (30.2%) represented lost to follow-up >4.

CONCLUSION

Our analysis suggests that RCTs evaluating PRP for surgical RCRs may lack statistical stability with only a few outcome events required to alter trial significance. Therefore, we recommend the reporting of an FI and an FQ in conjunction with P value analysis to carefully interpret the integrity of statistical stability in future comparative trials.

CLINICAL RELEVANCE

Clinical decisions are often informed by statistically significant results. Thus, a true understanding of the robustness of the statistical findings informing clinical decision-making is of critical importance.

Retear rates after rotator cuff surgery: a systematic review and meta-analysis

Background

Rotator cuff retear (RCR) is one of the main postoperative drawbacks. RCR can be considered a multifactorial issue, which causes are related either to biological than biomechanical factors. The aim of this study was to define the incidence of RCR after surgical treatment at different time points and to identify the main factors influencing the postoperative rotator cuff (RC) healing.

Methods

A systematic review and meta-analysis were performed following the PRISMA guidelines. A comprehensive search of the literature was carried out in July 2020, using PubMed and Cochrane Library databases. Only level 1 and 2 clinical evidence studies were included. Studies were included if patients with preoperative repairable full-thickness RC tears were treated surgically, and if studies reported postoperative RCR confirmed by imaging diagnostic. The association between timing of retear and follow-up time points were investigated using an inverse-variance method of pooling data. A subgroup meta-analysis was performed using the DerSimonian and Laird method for the estimation of the between-study variance, i.e., τ². The association between retear rate after surgery and patients’ age, preoperative tear size, fatty infiltration, postoperative rehabilitation protocol, surgical techniques, and RC repairs was determined by expressing the effect measure in terms of odds ratio (OR) with 95% confidence interval (CI). The Mantel-Haenszel method with 95% CIs was used.

Results

Thirty-one articles were included in this study. The percentage of RCR after surgery was 15% at 3 months follow-up, 21% at 3–6 months follow-up, 16% at 6–12 months follow-up, 21% at 12–24 months follow-up, 16% at follow-up longer than 24 months. The main factors influencing RC healing are both patient-related (i.e., age, larger tear size, fatty infiltration) and not patient-related (i.e., postoperative rehabilitation protocol, surgical techniques, and procedures).

Conclusions

Postoperative RC healing is influenced by patient-related and non-patient-related factors. Further high-level clinical studies are needed to provide highly relevant clinical results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04634-6.

Platelet-Rich Product Supplementation in Rotator Cuff Repair Reduces Retear Rates and Improves Clinical Outcomes: A Meta-analysis of Randomized Controlled Trials

PURPOSE

The purpose of this study was to conduct a comprehensive systematic review and meta-analysis to investigate the clinical and imaging outcomes of all 4 types of platelet-rich therapies (pure platelet-rich plasma [P-PRP], leukocyte and platelet-rich plasma, pure platelet-rich fibrin, and leukocyte and platelet-rich fibrin) in rotator cuff repairs.

METHODS

A systematic literature search was performed to identify rotator cuff tears comparing any of the 4 types of platelet-rich products (PRP) to a control in rotator cuff repair. Data extracted from the studies included retear rates diagnosed with imaging studies, as well as outcome scores such as Constant, American Shoulder and Elbow Surgeons (ASES), University of California Los Angeles (UCLA), Simple Shoulder Test (SST), and visual analog scale (VAS). Meta-analyses compared postoperative outcome scores and retear rates between the control and study groups.

RESULTS

Seventeen studies were included in the meta-analysis. When pooling data from all studies, retear rate for the treatment group was 19.3%, compared to 25.4% for the control group (odds ratio [OR] 0.59, P = .0037). When stratified based on PRP type, only P-PRP resulted in a significant reduction in retear rate (OR 0.26, P = .0005). Overall, treatment with PRP significantly improved Constant scores when compared to controls (mean difference [MD] 2.41, P =.0027), as well as VAS scores (MD -0.12, P = .0014), and SST scores (MD 0.41, P = .0126). There was no significant difference in ASES scores (MD 0.37, P = .7762) or UCLA scores (MD 0.76, P =0.2447) between treatment and controls when pooling data from all studies.

CONCLUSIONS

This analysis demonstrates significant reductions in retear rates when rotator cuff repair is augmented with PRP. P-PRP appears to be the most effective formulation, resulting in significantly improved retear rates and clinical outcome scores when compared with controls.

Basic Research on Tendon Repair: Strategies, Evaluation, and Development

Tendon is a fibro-elastic structure that links muscle and bone. Tendon injury can be divided into two types, chronic and acute. Each type of injury or degeneration can cause substantial pain and the loss of tendon function. The natural healing process of tendon injury is complex. According to the anatomical position of tendon tissue, the clinical results are different. The wound healing process includes three overlapping stages: wound healing, proliferation and tissue remodeling. Besides, the healing tendon also faces a high re-tear rate. Faced with the above difficulties, management of tendon injuries remains a clinical problem and needs to be solved urgently. In recent years, there are many new directions and advances in tendon healing. This review introduces tendon injury and sums up the development of tendon healing in recent years, including gene therapy, stem cell therapy, Platelet-rich plasma (PRP) therapy, growth factor and drug therapy and tissue engineering. Although most of these therapies have not yet developed to mature clinical application stage, with the repeated verification by researchers and continuous optimization of curative effect, that day will not be too far away.

Application of Platelet-Rich Plasma in Arthroscopic Rotator Cuff Repair: A Systematic Review and Meta-analysis

Background:

It is unclear how and which factors affect the clinical efficacy of platelet-rich plasma (PRP) applied during arthroscopic rotator cuff repair.

Purpose:

To evaluate the clinical efficacy of PRP for arthroscopic repair of full-thickness rotator cuff tear and investigate the factors that affect its clinical efficacy.

Study Design:

Systematic review; Level of evidence, 1.

Methods:

We searched Cochrane Library, EMBASE, MEDLINE, and OVID to identify randomized controlled trials (RCTs) of patients who received PRP treatment and arthroscopic rotator cuff repair (PRP group) versus controls (no-PRP group). The primary outcomes included retear rate, Constant-Murley score, University of California Los Angeles (UCLA) score, short-term American Shoulder and Elbow Surgeons (ASES) score, visual analog scale (VAS) score for pain, and adverse events.

Results:

A total of 14 RCTs were included in this systematic review. Significant improvement in Constant-Murley, UCLA, and VAS pain scores were found in the PRP group during short-term, midterm, and long-term follow-up. The PRP group had a significantly decreased retear rate (risk ratio [RR], 0.57 [95% CI, 0.42 to 0.78]; P = .0003), especially for long-term follow-up (RR, 0.38 [95% CI, 0.17 to 0.83]; P = .02), large to massive tears (RR, 0.58 [95% CI, 0.42 to 0.80]; P = .0008), use of leukocyte-poor PRP (RR, 0.50 [95% CI, 0.33 to 0.76]; P = .001), and intraoperative application of PRP (RR, 0.57 [95% CI, 0.42 to 0.79]; P = .0007). No significant difference between the 2 groups was found in the incidence of adverse events (RR, 1.34 [95% CI, 0.83 to 2.15]; P = .23) or in ASES scores at short-term follow-up (weighted mean difference, 1.04 [95% CI, –3.10 to 5.19]; P = .62).

Conclusion:

The results of this review indicated that arthroscopic rotator cuff repair with PRP significantly reduced the long-term retear rate and shoulder pain and provided improved long-term shoulder function in patients. Intraoperative application of PRP, use of leukocyte-poor plasma, and large to massive tear size contributed to a significantly decreased retear rate for rotator cuff repair combined with PRP.

The Effect of Platelet-Rich Plasma Leukocyte Concentration on Arthroscopic Rotator Cuff Repair: A Network Meta-analysis of Randomized Controlled Trials

BACKGROUND

It is unclear whether leukocyte-poor (LP) or leukocyte-rich (LR) varieties of platelet-rich plasma (PRP) as an adjuvant to arthroscopic rotator cuff repair (ARCR) result in improved tendon healing rates.

PURPOSE

To perform a network meta-analysis of the randomized controlled trials in the literature to ascertain whether there is evidence to support the use of LP- or LR-PRP as an adjunct to ARCR.

METHODS

The literature search was based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Randomized controlled trials comparing LP- or LR-PRP with a control alongside ARCR were included. Clinical outcomes, including retears and functional outcomes, were compared using a frequentist approach to network meta-analysis, with statistical analysis performed using R. The treatment options were ranked using the P-score.

RESULTS

There were 13 studies (868 patients) included, with 9 studies comparing LP-PRP with a control and 4 studies comparing LR-PRP with a control. LP-PRP was found to significantly reduce the rate of retear and/or incomplete tendon healing after fixation, even among medium-large tears; it also improved outcomes on the visual analog scale for pain, Constant score, and University of California Los Angeles score. LP-PRP had the highest P-score for all treatment groups. LR-PRP did not result in any significant improvements over the control group, except for visual analog scale score for pain. However, post hoc analysis revealed that LP-PRP did not lead to significant improvements over LR-PRP in any category.

CONCLUSION

The current study demonstrates that LP-PRP reduces the rate of retear and/or incomplete tendon healing after ARCR and improves patient-reported outcomes as compared with a control. However, it is still unclear whether LP-PRP improves the tendon healing rate when compared with LR-PRP.

Current Biological Strategies to Enhance Surgical Treatment for Rotator Cuff Repair

Rotator cuff tear is one of the most common shoulder problems encountered by orthopedic surgeons. Due to the slow healing process and high retear rate, rotator cuff tear has distressed millions of people all around the world every year, especially for the elderly and active athletes. This disease significantly impairs patients' motor ability and reduces their quality of life. Besides conservative treatment, open and arthroscopic surgery contributes a lot to accelerate the healing process of rotator cuff tear. Currently, there are many emerging novel treatment methods to promote rotator cuff repair. A variety of biological stimulus has been utilized in clinical practice. Among them, platelet-rich plasma, growth factors, stem cells, and exosomes are the most popular biologics in laboratory research and clinical trials. This review will focus on the biologics of bioaugmentation methods for rotator cuff repair and tendon healing, including platelet-rich plasma, growth factors, exosomes and stem cells, etc. Relevant studies are summarized in this review and future research perspectives are introduced.

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.

Stemless Total Shoulder Arthroplasty With Orthobiologic Augmentation

Total shoulder arthroplasty (TSA) has evolved over the years and is used for a variety of indications, with arthritis being the most common. Stemless TSA is a unique bone-preserving design that can eliminate rotational malalignment. Additionally, recent literature has found utility in the use of biological mesh and a platelet-rich plasma injection to improve healing. The purpose of this article is to outline the process of TSA using a stemless system and how to incorporate the use of amnion matrix and platelet-rich plasma into the surgical technique.

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).

Biologics to Improve Healing in Large and Massive Rotator Cuff Tears: A Critical Review

Large and massive rotator cuff tears have the highest risk of retear. Common biologic modalities that can potentially reduce the retear rate and improve healing include platelet-rich plasma (PRP), scaffolds, and mesenchymal stem cells (MSCs). PRP has been studied for its role in improving rotator cuff healing and results of randomized controlled trials and meta-analyses show mixed results. Most studies in large and massivge tears show that PRP decreases the retear rate, but the connection between structural integrity and clinical outcomes is still unknown. Extracellular matrix (ECM) and synthetic scaffolds can increase healing in augmentation and bridging repair. Acellular dermal allografts have shown better healing rates and outcomes than xenografts in meta-analyses. Synthetic scaffolds augmented with bone marrow-derived stem cells have only been studied in vitro but are promising for the combination of mechanical stability and induction of a biological response. Superior capsule reconstruction is an exciting type of interposition graft reconstruction that has shown favorable early clinical outcomes for large and massive tears. Bone marrow-derived stem cells and adipose-derived stem cells improve the biomechanical characteristics of tendon repair and enhance the histological findings of the healing process in animal studies. However, evidence from human studies is lacking, especially in patients with large and massive tears. In summary, there are many biological options to augment rotator cuff repair in patients with large and massive tears. Due to mixed results and a lack of standardization in high-quality studies, we cannot recommend PRP at this time as an adjunct to rotator cuff repair. Both ECM and synthetic scaffolds, as well as SCR, can be used, especially in situations where native tendon is compromised, and additional mechanical augmentation is needed. Stem cells have been the least studied to date, so it is difficult to give recommendations for or against their use at this time.

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.

Preliminary Clinical Outcomes Following Biologic Augmentation of Arthroscopic Rotator Cuff Repair Using Subacromial Bursa, Concentrated Bone Marrow Aspirate, and Platelet-Rich Plasma

Purpose

To evaluate the clinical outcomes of patients who underwent arthroscopic rotator cuff repair augmented using subacromial bursa, concentrated bone marrow aspirate (cBMA), and platelet-rich plasma.

Methods

Sixteen patients were included in the study who underwent arthroscopic rotator cuff repair augmented using subacromial bursa, cBMA, and platelet-rich plasma from January 2018 to July 2018 and had a minimum 1-year follow-up. American Shoulder and Elbow Surgeons (ASES), Simple Shoulder Test, Constant-Murley, and Single Assessment Numerical Evaluation (SANE) scores were collected preoperatively and at terminal follow-up. To determine the clinical relevance of ASES scores, the minimal clinically important difference, substantial clinical benefit, and the patient acceptable symptomatic state thresholds were used. In vitro cellular proliferation of subacromial bursa (nucleated cells/gram) and cBMA (nucleated cells and colony-forming units/cc) samples was evaluated and correlated to clinical outcomes scores.

Results

Mean follow-up was 12.6 ± 1.8 months (range 12-19 months). Patients achieved significant improvement in ASES (45.8±22.5_pre vs 88.5 ± 14.6_post, Δ44.7 ± 20.7; P = .001), Simple Shoulder Test (4.3 ± 3.2_pre vs 10.4 ± 1.6_post, Δ5.7 ± 3.9, P = .002), Constant-Murley (44.3 ± 18.2_pre vs 83.6 ± 17.5_post, Δ37.2 ± 21.8; P = .001), SANE (13.3 ± 10.7_pre vs 86.3 ± 17.5_post, Δ71.9 ± 22.9; P = .001), and pain scores (5.0±2.8_pre vs 1.1 ± 1.6_post, Δ3.5±2.5, P = .001) at final follow-up. With regards to ASES score, 93.8% of patients achieved the minimal clinically important difference, 93.8% the substantial clinical benefit, and 62.5% reached or exceeded the patient acceptable symptomatic state criteria. There was a significant positive correlation of nucleated cell count of cBMA with postoperative SANE score (r = 0.707; P = .015) and delta in ASES score (r = 0.727; P = .011). All other correlations were found to be nonsignificant (P > .05, respectively).

Conclusions

Patients undergoing arthroscopic rotator cuff repair augmented using the Mega-Clot with bursa technique achieved significant improvement in functional outcomes at a minimum 1-year follow-up, with 93.8% of patients reaching substantial clinical benefit.

Level of Evidence

Level IV, therapeutic case series.