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

Bioinductive Collagen Implant Has Potential to Improve Rotator Cuff Healing: A Systematic Review

PURPOSE

To systematically review the literature to evaluate the clinical studies on bioinductive collagen implant (BCI) for the treatment of rotator cuff tears.

METHODS

A literature search of MEDLINE, Embase, and the Cochrane Library was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Clinical studies reporting BCI for rotator cuff tears were included. Quantitive and qualitative data were evaluated.

RESULTS

A total of 21 studies were included. In patients with full-thickness tears, 7 of the 8 studies with pre- to postoperative American Shoulder and Elbow Surgeons (ASES) scores demonstrated statistically significant improvements in mean pre- to postoperative ASES scores, with 75% to 100% of patients meeting the minimal clinically important difference. In those with partial-thickness tears, 7 of the 8 studies with pre- to postoperative ASES scores demonstrated statistically significant improvements in mean pre- to postoperative ASES scores, with 54.4% to 100% of patients meeting the minimal clinically important difference. For studies that quantified percent increases in tendon thickness, the reported increases ranged from 13% to 44% in full-thickness tears and 14% to 60% in partial-thickness tears. Six studies evaluated rotator cuff retears after BCI treatment in the full-thickness cohort, with rates reported ranging from 0% to 9%. Five studies evaluated rotator cuff retears after BCI treatment in the partial-thickness cohort, with rates reported ranging from 0% to 18%. Two of the included studies found that BCI was cost-effective due to the increased tendon healing, with cost savings of $5,338 to $13,061 per healed rotator cuff tendon.

CONCLUSIONS

The literature on rotator cuff tear augmentation with BCI has shown consistently reported good results. Additionally, there was evidence of low retear rates and consistently improved tendon thickness with BCI, with 2 randomized controlled trials showing improved tendon healing with BCI. However, there appears to be a higher rate of adhesive capsulitis reported.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I, III, and IV studies.

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 studies.

Platelet-Rich Plasma for Arthroscopic Rotator Cuff Repair: A 3-Arm Randomized Controlled Trial

BACKGROUND

Although there has been some amount of research into the use of platelet-rich plasma (PRP) after arthroscopic rotator cuff repair, most studies have not fully demonstrated its benefits. In addition, PRP formulations containing different concentrations of leukocytes have not been directly compared for rotator cuff repair.

PURPOSE/HYPOTHESIS

The purpose of this article was to determine whether arthroscopic rotator cuff repair combined with PRP injection, either leukocyte-rich PRP (LR-PRP) or leukocyte-poor PRP (LP-PRP), is superior to the control. The null hypothesis was that the addition of any PRP formulation would not result in outcomes superior to the control group.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Patients with full-thickness rotator cuff tears who underwent arthroscopic repair were assessed for eligibility. The included patients were randomized to 3 treatment groups: the LR-PRP, LP-PRP, and standard-care control groups. After the rotator cuff suture was fixed firmly, different groups of liquid PRP preparations prepared by centrifugation were injected into the tendon-to-bone interface. The functional outcomes were assessed using the University of California, Los Angeles (UCLA) score, the Constant score, the American Shoulder and Elbow Surgeons (ASES) score, the visual analog scale for pain during sleep and activity, and active range of motion at 3, 6, and 12 months after surgery. In addition, the visual analog scale score was obtained at weeks 2 and 6. Postoperative structural integrity was assessed by magnetic resonance imaging at 12 months using the Sugaya classification. Type III was considered partial retear, and types IV and V were considered complete retears. The safety of surgery was compared by the incidence of complications. The main analyses were performed in accordance with the intention-to-treat principle.

RESULTS

Of 150 patients initially randomized, the functional outcomes in 142 (46 LR-PRP, 47 LP-PRP, 49 control) and the structural integrity in 133 (40 LR-PRP, 46 LP-PRP, 47 control) were analyzed. There was no significant difference in the primary outcome of the UCLA score among the 3 groups (P = .169). The trends in functional outcomes and range of motion were similar for the 3 groups, with no significant differences among the groups at 12 months. However, within 6 months after surgery, the ASES score was better in the LR-PRP group than in the control group (3 months: 85.8 ± 4.1 vs 81.6 ± 8.7; P = .011; 6 months: 90.0 ± 5.4 vs 86.2 ± 6.8; P = .003). At 12 months after surgery, the overall retear rate, including partial and complete retears, was 8%. There were no significant differences in the rates of overall retear (P = .755) or complete retear (P = .633) among the 3 groups. The only surgical complication was postoperative stiffness, which occurred in 3% of patients, and the incidence did not significantly differ among the groups (P = .790).

CONCLUSION

The study did not reveal that shoulders treated with the LR-PRP or LP-PRP formulations had any superior functional or structural outcomes at 12 months compared with those of the control group. However, LR-PRP may offer better ASES scores than the control group up to 6 months after surgery, and its clinical benefit remains to be proven.

REGISTRATION

ChiCTR2100045039 (Chinese Clinical Trial Register).

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.

Biologic Augmentation of Rotator Cuff Repair: Current Concepts Review

Rotator cuff tears are common in an aging population. Thus far, primary repairs have shown high re-tear rates suggesting the need for improved healing modalities. Current augmentations of rotator cuff repairs include synthetic and biological scaffolds, surgical bone marrow venting, and infusing the repair with a variety of stem cells and growth factors aimed at restoring the native cellular structure and function of the repaired tissue. This current concepts review discusses the anatomy, physical presentation, diagnosis, and treatment of rotator cuff tears; biological adjuvants for rotator cuff repairs; and the current literature on outcomes after biologically augmented rotator cuff repairs. [Orthopedics. 202x;4x(x):xx-xx.].

Bone Marrow Stimulation for Arthroscopic Rotator Cuff Repair: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Bone marrow stimulation (BMS) has been proposed to augment healing at the time of arthroscopic rotator cuff repair (ARCR) by creating several bone marrow vents in the footprint of the rotator cuff, allowing mesenchymal stem cells, platelets, and growth factors to cover the area as a "crimson duvet."

PURPOSE

To perform a meta-analysis of randomized controlled trials (RCTs) to compare the outcomes after BMS and a control for those undergoing ARCR.

STUDY DESIGN

Meta-analysis; Level of evidence, 1.

METHODS

A literature search of 3 databases was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RCTs comparing BMS and a control for ARCR were included. Clinical outcomes were compared, and a P value <.05 was considered to be statistically significant.

RESULTS

A total of 7 RCTs with 576 patients were included. Overall, 18.8% of patients treated with BMS and 21.0% of patients treated with a control had a retear (I2 = 43%; P = .61). With BMS, the mean Constant score was 88.2, and with the control, the mean Constant score was 86.7 (P = .12). Additionally, there was no significant difference in the American Shoulder and Elbow Surgeons score (94.3 vs 93.2, respectively; P = .31) or visual analog scale score (0.9 vs 0.9, respectively; P = .89).

CONCLUSION

The level 1 evidence in the literature did not support BMS as a modality to improve retear rates or clinical outcomes after ARCR.

Partial-Thickness Rotator Cuff Tears: Current Concepts

» Partial-thickness rotator cuff tears (PTRCTs) are a common pathology with a likely high asymptomatic incidence rate, particularly in the overhead athlete.» The anatomy, 5-layer histology, and relationship to Ellman's classification of PTRCTs have been well studied, with recent interest in radiographic predictors such as the critical shoulder angle and acromial index.» Depending on the definition of tear progression, rates of PTRCT progression range from 4% to 44% and appear related to symptomatology and work/activity level.» Nearly all PTRCTs should be managed conservatively initially, particularly in overhead athletes, with those that fail nonoperative management undergoing arthroscopic debridement ± acromioplasty if <50% thickness or arthroscopic conversion repair or in situ repair if >50% thickness.» Augmentation of PTRCTs is promising, with leukocyte-poor platelet-rich plasma having the most robust body of supportive data. Mesenchymal signaling cell biologics and the variety of scaffold onlay augments require more rigorous studies before regular usage.

Leukocyte-Poor Platelet-Rich Plasma as an Adjuvant to Arthroscopic Rotator Cuff Repair Reduces the Retear Rate But Does Not Improve Functional Outcomes: A Double-Blind Randomized Controlled Trial

BACKGROUND

Whether the use of PRP as an adjuvant of rotator cuff repairs leads to improved tendon healing and better functional outcomes remains unclear in clinical evidence.

PURPOSE

The main purpose of this study was to assess whether the use of leukocyte-poor platelet-rich plasma (LP-PRP) as an adjuvant to arthroscopic rotator cuff repair (ARCR) decreases the rate of retears compared with a control group. The secondary objective was to analyze whether LP-PRP improves patient-reported outcomes.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

This was a double-blind randomized controlled trial at a single center. A consecutive series of 96 patients with rotator cuff tears <3 cm were enrolled and randomly allocated to the control group (double-row suture-bridge ARCR alone [n = 48]) and the PRP group (double-row suture-bridge repair, followed by 1 LP-PRP injection during surgery [n = 48]). The visual analog scale (VAS) for pain, the American Shoulder and Elbow Surgeons (ASES) score, the Single Assessment Numeric Evaluation (SANE), and the Pittsburgh Sleep Quality Index (PSQI) were administered preoperatively and at 6- and 12-month follow-up. Magnetic resonance imaging (MRI) was performed to evaluate tendon integrity at 6-month follow-up. Both patients and assessors were blinded to the intervention received during surgery.

RESULTS

The mean patient age was 56.1 ± 2.98 years. Of the 96 patients, 90 had MRI performed at 6 months after surgery (94% radiological follow-up). The retear rate in the PRP group was 15.2% (7/46 [95% CI, 6%-28%]), which was lower than that in the control group of 34.1% (15/44 [95% CI, 20%-49%]) (P = .037). Therefore, the risk ratio of ruptures in patients exposed to LP-PRP was 0.44 (95% CI, 0.2-0.9; P = .037). Overall, the ASES, VAS, SANE, and PSQI scores showed a statistical improvement after surgery (P < .001). There were no significant differences in functional scores between the groups. Most of the patients exceeded the minimal clinically important difference for the ASES, SANE, and VAS without significant differences between the groups.

CONCLUSION

In patients with rotator cuff tears <3 cm undergoing double-row suture-bridge repair, a 5-mL dose of LP-PRP injected at the tendon-bone interface significantly reduced the retear rate. However, the use of LP-PRP in terms of postoperative pain and patient-reported outcomes failed to show clinically meaningful effects.

REGISTRATION

NCT04703998 (ClinicalTrials.gov identifier).

Intra-Articular Platelet-Rich Plasma Injection After Anterior Cruciate Ligament Reconstruction: A Randomized Clinical Trial

Importance

Platelet-rich plasma (PRP) has been considered a promising treatment for musculoskeletal disorders. The effects of PRP on clinical outcomes of anterior cruciate ligament reconstruction (ACLR) are controversial.

Objective

To compare subjective outcomes and graft maturity in patients undergoing ACLR with and without postoperative intra-articular PRP injection.

Design, Setting, and Participants

This surgeon- and investigator-masked randomized clinical trial included patients treated at a national medical center in China who were aged 16 to 45 years and scheduled to undergo ACLR. Participants were enrolled between March 21, 2021, and August 18, 2022, and followed up for 12 months, with the last participant completing follow-up on August 28, 2023.

Interventions

Participants were randomized 1:1 to the PRP group (n = 60), which received 3 doses of postoperative intra-articular PRP injection at monthly intervals, or to the control group (n = 60), which did not receive postoperative PRP injection. Both groups had the same follow-up schedule.

Main Outcomes and Measures

The primary outcome was the mean score for 4 subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS4) (range, 0-100, with higher scores indicating better knee function and fewer symptoms) at 12 months postoperatively. Secondary outcomes were patient-reported outcomes, graft maturity (on magnetic resonance imaging), and physical examinations at 3, 6, and 12 months.

Results

Among the 120 randomized participants (mean [SD] age, 29.0 [8.0] years; 84 males [70%]), 114 (95%) were available for the primary outcome analysis. The mean KOOS4 scores at 12 months were 78.3 (SD, 12.0; 95% CI, 75.2-81.4) in the PRP group and 76.8 (SD, 11.9; 95% CI, 73.7-79.9) in the control group (adjusted mean between-group difference, 2.0; 95% CI, -2.3 to 6.3; P = .36). Secondary outcomes were not statistically significantly different between the 2 groups except for sports and recreation level and graft maturity at 6 months. Intervention-related adverse events included pain at the injection site and knee swelling after injection.

Conclusions and Relevance

In this randomized clinical trial among patients undergoing ACLR, the addition of postoperative intra-articular PRP injection did not result in superior improvement of knee symptoms and function at 12 months compared with no postoperative injection. Further studies are required to determine appropriate indications for PRP in musculoskeletal disorders.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR2000040262.

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.

Estrogen and testosterone supplementation improves tendon healing and functional recovery after rotator cuff repair

Failure of healing after rotator cuff repair (RCR) is common. The purpose of the current study was to evaluate the effect of systemic estrogen or testosterone supplementation on tendon healing after RCR. Seventy-two adult male mice were utilized for all experiments. The supraspinatus tendon was transected and repaired with 6-0 Prolene suture on the left shoulder of 51 animals. Mice were segregated into three groups postoperative: (1) vehicle group (VG; n = 18), (2) estrogen group (EST; n = 17), and (3) testosterone group (TST; n = 16). An unrepaired control group (unrepaired, n = 21) did not have surgery. Utilizing these animals, histological analysis, activity testing, biomechanical testing and RNA sequencing (RNA-seq) was performed. At 8 weeks post-RCR, TST, and EST supplementation improved the overall histologic structure of the repaired enthesis site. No differences in ultimate failure loads or stiffness were detected between VG, EST, and TST groups after biomechanical testing. RCR caused a reduction in wheel activity compared to unrepaired controls and supplementation with TST restored wheel activity. RNA-seq analysis indicated that estrogen and testosterone regulated different pathways associated with enthesis healing, including a suppression of inflammatory signaling. Supplementation with sex hormones improved the structure of the repaired tendon enthesis and significantly regulated expression of diverse pathways regulating multiple biological processes. Testosterone administration following RCR restored wheel activity without having a detrimental impact on biomechanical strength. Future human studies of sex hormone supplementation after RCR are warranted as supplementation in an animal model may improve tendon enthesis healing.

Massive and irreparable rotator cuff tear treatment by arthroscopic partial repair with long head of the biceps tendon augmentation provides better healing and functional results than partial repair only

BACKGROUND

The aim of this study was to compare the clinical and radiologic outcomes of 2 treatment methods for massive and irreparable rotator cuff tears (RCTs): partial repair (PR) and PR with long head of the biceps tendon (LHBT) augmentation. Biceps tendon augmentation is believed to promote better healing at the bone-tendon junction, leading to improved clinical and radiologic outcomes.

METHODS

This retrospective comparative study included patients with chronic, massive and irreparable RCTs involving both the supraspinatus (SSP) and infraspinatus muscles. Only patients with failure of nonoperative treatment and at least 1 year of follow-up between 2013 and 2018 were analyzed. The patients were divided into 2 groups based on the chosen treatment method. Irreparability was defined intraoperatively as the inability to achieve sustainable repair of the SSP after complete release, typically corresponding to a Goutallier classification of stage ≥ 3 and Patte classification of stage 3. The clinical assessment protocol involved measurements of range of motion and shoulder strength, as well as the Constant-Murley score (CMS) and Simple Shoulder Test score. Radiologic assessment comprised measurements of the acromiohumeral distance, Hamada classification, Sugaya classification, and Goutallier classification of both the SSP and infraspinatus.

RESULTS

The study included data from 60 patients (30 in each group) with a mean age of 62.5 years and a mean follow-up period of 34.5 months. The retear rate was 43.3% for PR with LHBT augmentation and 73.3% for PR alone (P = .036). During the final examination, statistically significant differences in favor of PR with LHBT augmentation were observed for the CMS (76.2 ± 10.9 vs. 70.9 ± 11.5, P = .034), Sugaya classification (3.5 ± 1.1 vs. 4.1 ± 0.9, P = .035), and acromiohumeral distance (5.8 ± 2 mm vs. 4.7 ± 1.3 mm, P = .021). There were no significant differences between the groups in range of motion, shoulder strength, Hamada classification, Simple Shoulder Test score, and postoperative Goutallier stage.

CONCLUSION

PR with LHBT augmentation for patients with irreparable, massive RCTs provides a lower retear rate and better humeral head centralization, as well as improved results measured by the CMS, compared with PR alone.

Leukocyte-poor platelet-rich plasma and leukocyte-rich platelet-rich plasma promote myoblast proliferation through the upregulation of cyclin A, cdk1, and cdk2

Muscle injuries are common among athletes and often treated with platelet-rich plasma (PRP). However, whether the leukocyte concentration affects the efficacy of PRP in treating muscle injuries remains unclear. This study investigated the effects of leukocyte-poor platelet-rich plasma (LP-PRP) and leukocyte-rich platelet-rich plasma (LR-PRP) on myoblast proliferation and the molecular mechanisms underlying these effects. Myoblasts were treated with 0.5% LP-PRP, 0.5% LR-PRP, 1% LP-PRP, or 1% LR-PRP for 24 h. The gene expression of the LP-PRP- and LR-PRP-treated myoblasts was determined using RNA sequencing analysis. Cell proliferation was evaluated using an bromodeoxyuridine (BrdU) assay, and cell cycle progression was assessed through flow cytometry. The expression of cyclin A, cyclin-dependent kinase 1 (cdk1), and cdk2 was examined using Western blotting. The expression of myoblast determination protein 1 (MyoD1) was examined through Western blotting and immunofluorescence staining. The LP-PRP and LR-PRP both promoted the proliferation of myoblasts and increased differential gene expression of myoblasts. Moreover, the LP-PRP and LR-PRP substantially upregulated the expression of cyclin A, cdk1, and cdk2. MyoD1 expression was induced in the LP-PRP and LR-PRP-treated myoblasts. Our results corroborate the finding that LP-PRP and LR-PRP have similar positive effects on myoblast proliferation and MyoD1 expression.

Editorial Commentary: Platelet-Rich Plasma Injections Produced a Significant Improvement in Most Patients With Rotator Cuff Tendinopathy

Platelet-rich plasma (PRP) is an autologous blood product containing a high concentration of platelets, growth factors, and cytokines, which basic science studies have shown may improve tendinopathy. However, there is controversy over its clinical efficacy with randomized controlled trials and subsequent meta-analysis finding mixed results when treating shoulder rotator cuff tendinopathy. The effect of leukocyte concentration on PRP has been shown to be paramount, with different concentrations being favored for different pathologies. In those with tendinopathy, it is unclear whether leukocyte-rich or leukocyte-poor PRP is superior. Recent research shows that PRP injections produced a significant improvement in most patients with rotator cuff tendinopathy. However, improvement in symptoms and functional outcomes is worse in patients who have a partial-thickness rotator cuff tear compared with isolated tendinopathy without a partial tear. PRP may be more advantageous than corticosteroids. Both function as anti-inflammatories, but PRP may be potentially anabolic, whereas as corticosteroids have a catabolic effect on tendons, which may reduce repairability if patients proceed with surgery. Additionally, there are higher infection rates if patients ultimately go on to surgery within 3 months after corticosteroid injections. Ultimately, we must refine the indications for best use for PRP shoulder injections and determine the 5 R's: right patient, right drug, right dose, right route, and right time. Finally, we must remember that patients can first try conservative management, including physical therapy.

Leukocyte and Platelet-Rich Plasma (L-PRP) in Tendon Models: A Systematic Review and Meta-Analysis of in vivo/in vitro Studies

Purpose

To perform a systematic review on the application of leukocyte- and platelet-rich plasma (L-PRP) in tendon models by reviewing in vivo/in vitro studies.

Methods

The searches were performed via electronic databases including PubMed, Embase, and Cochrane Library up to September 2022 using the following keywords: ((tenocytes OR tendon OR tendinitis OR tendinosis OR tendinopathy OR tendon injury) AND (platelet-rich plasma OR PRP OR autologous conditioned plasma OR leukocyte- and platelet-rich plasma OR L-PRP OR leukocyte-richplatelet-rich plasma Lr-PRP)). Only in vitro and in vivo studies that assessed the potential effects of L-PRP on tendons and/or tenocytes are included in this study. Description of PRP, study design and methods, outcomes measured, and results are extracted from the data.

Results

A total of 17 studies (8 in vitro studies and 9 in vivo studies) are included. Thirteen studies (76%) reported leukocyte concentrations of L-PRP. Four studies (24%) reported the commercial kits. In in vitro studies, L-PRP demonstrated increased cell proliferation, cell migration, collagen synthesis, accelerated inflammation, and catabolic response in the short term. In addition, most in vivo studies indicated increased collagen type I content. According to in vivo studies reporting data, L-PRP reduced inflammation response in 71.0% of studies, while it enhanced the histological quality of tendons in 67.0% of studies. All 3 studies reporting data found increased biomechanical properties with L-PRP treatment.

Conclusions

Most evidence indicates that L-PRP has some potential effects on tendon healing compared to control. However, it appears that L-PRP works depending on the biological status of the damaged tendon. At an early stage, L-PRP may accelerate tendon healing, but at a later stage, it could be detrimental.

Platelet-rich plasma use in meniscus repair treatment: a systematic review and meta-analysis of clinical studies

Background

There is conflicting clinical evidence whether platelet-rich plasma (PRP) therapies could translate to an increased meniscus healing rate and improved functional outcomes. The objective of this systematic review and meta-analysis was to compare the failure rate and patient-reported functional outcomes in meniscus repair augmented with and without PRP.

Methods

We comprehensively searched the PubMed, Web of Science, Medline, Embase, and Cochrane Library databases to identify studies that compared the clinical efficacy of meniscus repair performed with PRP versus without PRP. The primary outcome was the meniscus repair failure rate, while the secondary outcomes were knee-specific patient-reported outcomes, including the International Knee Documentation Committee (IKDC) score, Lysholm knee scale, visual analog scale, Tegner activity level score, Western Ontario and McMaster Universities Osteoarthritis Index score, Single Assessment Numeric Evaluation score, and Knee injury and Osteoarthritis Outcome Score. Furthermore, subgroup analyses were performed by stratifying the studies according to the PRP preparation technique to investigate the potential sources of heterogeneity among studies.

Results

Our meta-analysis included nine studies (two RCTs and seven non-RCTs) with 1164 participants. The failure rate in the PRP group was significantly lower than that in the non-PRP group [odds ratio: 0.64, 95% confidence interval (CI) (0.42, 0.96), P = 0.03]. Furthermore, the PRP group was associated with a statistically significant improvement in the visual analog scale for pain [Mean difference (MD): − 0.76, 95% CI (− 1.32, − 0.21), P = 0.007] and Knee injury and Osteoarthritis Outcome Score-symptom [MD: 8.02, 95% CI (2.99, 13.05), P = 0.002] compared with the non-PRP group. However, neither the IKDC score nor the Lysholm knee scale showed any differences between the two groups. In addition, the results of subgroup analyses favored PRP over platelet-rich fibrin matrix (PRFM) regarding the IKDC score.

Conclusions

Although meniscus repairs augmented with PRP led to significantly lower failure rates and better postoperative pain control compared with those of the non-PRP group, there is insufficient RCT evidence to support PRP augmentation of meniscus repair improving functional outcomes. Moreover, PRP could be recommended in meniscus repair augmentation compared with PRFM. PRFM was shown to have no benefit in improving functional outcomes.

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.

Current concepts on management of cuff tear

Among pathologies of the shoulder, rotator cuff tear is the most common. Diagnosis of cuff tear around mid twenties is unusual, but the prevalence increases significantly after the age of forty. The prevalence after the age of 60 is around 20-30%. A well recognised feature of cuff tear is being asymptomatic but, tear progression in asymptomatic is a known consequence. The spectrum of cuff tear ranges from partial, full thickness cuff tear with or without retraction. The mainstay of treatment for partial thickness cuff tear is systematic rehabilitation and for the full thickness cuff tear an initial rehabilitation is an accepted management. Failed rehabilitation for 3 months, acute traumatic tear, younger age, intractable pain, good quality muscle would be the indications for repair of a full thickness cuff tear. Though there are defined indications for surgical intervention in the full thickness rotator cuff tear, differentiating an asymptomatic tear that would not progress or identifying a tear that would become better with rehabilitation is an undeniable challenge for even the most experienced surgeon. Rehabilitation in cuff tear consists of strengthening the core stabilizers along with rotator cuff and deltoid muscles. In a symptomatic cuff tear that merits surgical intervention the objective is to do an anatomical foot print repair. In scenarios where the cuff is retracted, one has to settle for a medialised repair. As, a repair done in tension is more likely to fail than a tensionless medialised repair. The success rate of all these non anatomical procedures varies from series to series but it approximates around 60-80%. Augmenting cuff repair to enhance biological healing is a recent advance in rotator cuff repair surgery. The augmentation factors can be growth factors like PRP, scaffolds both auto and allografts. The outcome of these procedures from literature has been variable. As there are no major harmful effects, it can be viewed as another future step in bringing better outcomes to patients having rotator cuff tear surgery. Despite being the commonest shoulder pathology, the rotator cuff tear still remains as a condition with varied presenting features and a wide variety of management options. The goal of the treatment is to achieve pain free shoulders with good function. Correcting altered scapular kinematics by systematic rehabilitation of the shoulder would be the first choice in all partial thickness cuff tear and also as an initial management of full thickness cuff tears. Failure of rehabilitation would be the step forward for a surgical intervention. While embarking on a surgical procedure, correct patient selection, sound surgical technique, appropriate counselling about expected outcome are the most essential in patient satisfaction.

Leukocyte-Rich Platelet-Rich Plasma Has Better Stimulating Effects on Tenocyte Proliferation Compared With Leukocyte-Poor Platelet-Rich Plasma

BACKGROUND

Rotator cuff (RC) tendinopathy is one of the most common causes of shoulder pain. Platelet-rich plasma (PRP) has been frequently used in clinical scenarios, but its efficacy remains inconsistent.

PURPOSE

To investigate the different responses of human tenocytes from torn RCs to leukocyte-rich PRP (LR-PRP) and leukocyte-poor PRP (LP-PRP) in a 2-chamber coculture device.

STUDY DESIGN

Controlled laboratory study.

METHODS

PRP was prepared using different platelet and leukocyte concentrations according to 5 groups: (1) LR-PRP with 5000 platelets/µL, (2) LR-PRP with 10,000 platelets/µL, (3) LP-PRP with 5000 platelets/µL, (4) LP-PRP with 10,000 platelets/µL, and (5) control with only culture medium supplementation and without PRP stimulation. Platelet-derived growth factor-AB (PDGF-AB) and transforming growth factor-β1 (TGF-β1) were measured in LR-PRP and LP-PRP via enzyme-linked immunosorbent assay. Microscopy, water-soluble tetrazolium salt assay, and quantitative real-time polymerase chain reaction were used to investigate the morphology, proliferation, and gene expression of RC tenocytes exposed to different PRP formulations. Data were collected from at least 3 independent measurements. The results were analyzed via 1-way analysis of variance, followed by the post hoc Bonferroni test.

RESULTS

The ratio of leukocytes to 5000 platelets/µL was 29.5 times higher in LR-PRP than in LP-PRP (P < .05). In the 5000 platelets/µL groups, the levels of TGF-β1 and PDGF-AB were both significantly higher in LR-PRP versus LP-PRP (TGF-β1: 367.0 ± 16.5 vs 308.6 ± 30.3 pg/mL, respectively [P = .043]; PDGF-AB: 172.1 ± 1.8 vs 94.1 ± 4.2 pg/mL, respectively [P < .001]). Compared with the control group, RC tenocyte proliferation was 1.42 ± 0.01 and 1.41 ± 0.03 times higher in the LR-PRP groups with 5000 platelets/µL and 10,000 platelets/µL, respectively (P < .05). The expression of tenocyte-related genes was higher in tenocytes cultured in LR-PRP.

CONCLUSION

Both the LR-PRP groups with 5000 platelets/µL and 10,000 platelets/µL induced more growth factor release and increased RC tenocyte proliferation than did the LP-PRP groups.

CLINICAL RELEVANCE

In RC repair, LR-PRP may be better than LP-PRP for increasing the proliferation of tenocytes.

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.

Orthobiologics: Diagnosis and Treatment of Common Tendinopathies

Orthobiologics, including platelet-rich plasma, prolotherapy, and mesenchymal stem cells, are seeing increasing use in the treatment of osteoarthritis (OA), muscle injury, and tendinopathy. This article reviews the biology and applications of orthobiologics in tendons, muscles, and joints, and focuses on platelet-rich plasma (PRP). Clinical evidence-based literature related to the use of PRP in the treatment of rotator cuff injury, lateral epicondylosis, Achilles tendinopathy, plantar fasciitis, knee OA, and acute muscle injury are discussed.

Conditioned medium of human bone marrow-derived stem cells promotes tendon-bone healing of the rotator cuff in a rat model

Rotator cuff repair is a common surgery in sports medicine. During the surgery, torn tendon was re-fixed onto the bony surface. The majority of patients gain good results. However, re-tear occurs in some patients. The reason under this phenomenon is that the normal tendon-bone enthesis cannot be reconstructed. In order to strengthen the tendon-bone healing and promote enthesis regeneration, numerous manners are tested, among which stem cell related therapies are preferred. Stem cells, due to the ability of multi-lineage differentiation, are widely used in regenerative medicine. However, safety and ethics concerns limit its clinical use. Recent studies found that it is the secretome of stem cells that is biologically effective. On ground of this, we, in the current study, collected the conditioned medium of human bone marrow-derived stem cells (hBMSC-CM) and tested whether this acellular method could promote tendon-bone healing in a rat model of rotator cuff repair. By using histological, radiological, and biomechanical methods, we found that hBMSC-CM promoted tendon-bone healing of the rat rotator cuff. Then, we noticed that hBMSC-CM exerted an impact on macrophage polarization both in vivo and in vitro by inhibiting M1 phenotype and promoting M2 phenotype. Further, we proved that the benefit of hBMSC-CM on tendon-bone healing was related to its regulation on macrophage. Finally, we proved that, hBMSC-CM influenced macrophage polarization, which was, at least partially, related to Smad2/3 signaling pathway. Based on the experiments above, we confirmed the benefit of hBMSC-CM on tendon-bone healing, which relied on its immune-regulative property. Considering the accessibility and safety of acellular hBMSC-CM, we believe it is a promising candidate clinically for tendon-bone healing.