Platelet-rich plasma and the shoulder: clinical indications and outcomes

Is platelet-rich plasma a new solution for shoulder adhesive capsulitis? A systematic scoping review of the literature

Background

Platelet-rich plasma (PRP) has shown promising results for adhesive shoulder capsulitis (AC) in pre-clinical models. The aim of this review is to investigate the clinical outcomes of using PRP in AC.

Materials and Methods

We conducted a systematic scoping review of the literature using bibliographic databases from inception until the 9th of January 2022 [PubMed, Web of Science, Scopus, and CENTRAL]. Randomized studies were included if they investigated the use of PRP in human patients with a diagnosis of AC. Authors performed individual study quality assessments using the RoB 2 tool.

Results

We screened a total of 470 results and 6 were included in the final synthesis. Studies included data of 578 patients with 263 patients receiving PRP (45.5%). All studies used PRP as part of non-operative treatment. PRP was compared to another intervention in all six studies. Four of these studies found PRP to be more effective. No major adverse effects were reported in any study.

Conclusion

PRP is a safe treatment option that can be added to the investigative treatment arsenal of AC. Despite showing some favorable results, several limitations and patient-centered questions remain to be addressed by future studies.

Level of Evidence

IV.

A systematic review of randomized control trials looking at functional improvement of rotator cuff partial thickness tears following platelet-rich-plasma injection: a comparison of glenohumeral joint vs. subacromial bursa vs. intratendinous injection locations

Background

Prior research has demonstrated that platelet-rich plasma (PRP) has shown promising results in the treatment of knee osteoarthritis, lateral epicondylitis, and rotator cuff disease. However, there is a lack of standardization with PRP regarding its use for partial thickness rotator cuff tears (PTRCTs). The primary objective of this review is to assess the location of PRP injections in the shoulder, and how it corresponds to shoulder functional outcomes in PTRCTs.

Methods

Data sources included randomized controlled trials (RCTs) conducted between January 2010 and September 2021 with the terms PRP, partial thickness rotator cuff tears, intra-articular injections, subacromial injections, and intratendinous injections. Major inclusion criteria: partial thickness rotator cuff tears only, functional outcome scores pre-injection and post-injection, minimum 2-month follow-up time, and nonsurgical PRP injections only. Major exclusion criteria: PRP used as an adjunct therapy, full-thickness rotator cuff tears, and surgical intervention before treatment.

Results

A total of 8 RCTs were included which utilized PRP injected into the shoulder for PTRCTs. Studies were grouped by the location of the injection with the following breakdown: 1 glenohumeral joint, 4 subacromial bursa, and 3 intratendinous as the site of injection of PRP. Intra-articular PRP showed a 46.2% improvement (P < .05) in the Disabilities of the Arm, Shoulder, and Hand score at 12-month follow-up, however PRP compared to physical therapy had no statistical difference. For subacromial injections, one study showed no statistical difference between hyaluronic acid and PRP vs PRP, but both groups showed improvement compared to normal saline at 3, 6, and 12 months (P < .05). For intratendinous injections, PRP was found to be superior in the Shoulder Pain and Disability Index scores at 66.1% improvement (P < .05) at 3 months and 71.6% at 6 months (P < .05) after two PRP injections when compared to dry needling. Another study showed a statistically significant difference in ASES score when combining LP-PRP injection intratendinous and subacromial bursa when compared to corticosteroid at 3 months. Furthermore, at 6-month follow-up, the PRP group showed significant improvement in the Oxford Shoulder Score compared to a subacromial bursa corticosteroid group 53.8% vs 31.7% (P < .01).

Conclusion

Based on our review of current literature, there is inconclusive evidence of the ideal location to inject PRP when partial rotator cuff tear is present. Despite PRP showing improved functional outcomes in patients diagnosed with PTRCT regardless of the injection site, more research is needed to figure out the optimal concentration of PRP, frequency of injection, and who are ideal candidates when utilizing PRP for PTRCTs.

Regenerative Medicine Solutions for Rotator Cuff Injuries in Athletes: Indications and Outcomes

Rotator cuff (RC) injuries include a wide range of pathologic states. Athletes are perhaps the most susceptible to RC injuries ranging from tendinopathy to partial or full-thickness tears, due to functional overload and repetitive movements, causing abstention from sports for long periods. Regenerative medicine keeps giving us multiple choices to fight the disability caused by these pathologies. A literature search was performed, and findings related to the structure-function of rotator cuff units, pathophysiology of injuries, regenerative medicine treatments, and future strategies were outlined. Platelet-rich plasma (PRP) has a greater number of articles and clinical trials, accompanied by stem cells progenitor, prolotherapy, and new approaches such as microfragmented adipose tissue and exosomes. RC injuries in athletes can cause pain, functional impotence, and the risk of recurrence, and can lead them to stop playing sports. Regenerative medicine offers a range of treatments, but some of them need further studies to underline their actual validity.

Kangfuxin Accelerates Extraction Socket Healing by Promoting Angiogenesis Via Upregulation of CCL2 in Stem Cells

Kangfuxin (KFX) shows potential in wound healing, but its role in socket healing is unclear. This research finds increased bone mass, mineralization, and collagen deposition in KFX-treated mice. Mouse bone marrow mesenchymal stem cells, human periodontal ligament stem cells (hPDLSCs), and human dental pulp stem cells (hDPSCs) are treated with KFX under osteogenic induction. RNA-sequencing reveals upregulated chemokine-related genes, with a threefold increase in chemokine (C-C motif) ligand 2 (Ccl2). The conditioned medium (CM) of hPDLSCs and hDPSCs treated with KFX promotes endothelial cell migration and angiogenesis. Ccl2 knockdown abolishes CM-induced endothelial cell migration and angiogenesis, which can be reversed by recombinant CCL2 treatment. KFX-treated mice showed increased vasculature. In conclusion, KFX increases the expression of CCL2 in stem cells, promoting bone formation and mineralization in the extraction socket by inducing endothelial cell angiogenesis. © 2023 American Society for Bone and Mineral Research (ASBMR).

Novel Orthobiologic Preparation and Regenerative Rehabilitation of a Complex Shoulder Injury in a Competitive Adolescent Female Athlete

Background

Platelet-rich plasma (PRP) and prolotherapy have resulted in promising outcomes in patients with various types of shoulder injuries. However, there is a lack of preliminary evidence supporting preparation of PRP production, timely application of these therapies and regenerative rehabilitation protocols. The purpose of this case report is to describe the distinct method including orthobiologic preparation, tissue-specific treatment and regenerative rehabilitation of an athlete with a complex shoulder injury.

Case Presentation

A 15y/o competitive female wrestler with a complex shoulder injury presented to the clinic after unsuccessful conservative rehabilitation. Unique methods were incorporated to optimize PRP production, specific tissue healing and regenerative rehabilitation. Multiple injuries required different orthobiologic interventions at different time frames, in order to promote optimal healing and stability of the shoulder.

Outcomes

The described interventions resulted in successful outcomes including pain, disability, full return to sport, and regenerative tissue healing confirmed with diagnostic imaging.

Level of Evidence

5.

Platelet-Rich Plasma Injections Are at Least Equivalent to Corticosteroid Injections for Adhesive Capsulitis: A Systematic Review of Prospective Cohort Studies

PURPOSE

To evaluate the role of platelet-rich plasma (PRP) for adhesive capsulitis (AC) as compared with other injectables.

METHODS

A literature search of the PubMed and Embase online databases was performed to identify articles evaluating injection therapy for the treatment of AC. The inclusion criteria included prospective studies comparing PRP against alternative injectables with a minimum of 15 patients in each treatment arm and a minimum 12-week follow-up period. Pain scores, range of motion, and function scores were the primary outcomes assessed.

RESULTS

Five articles comparing PRP with corticosteroid or saline solution injections met the inclusion criteria. A total of 157 patients were treated with PRP, with a follow-up duration ranging from 3 to 6 months. All 5 studies showed statistically significant improvements in pain scores, motion, and function scores in patients receiving PRP, corticosteroid, and saline solution injections. However, PRP was consistently superior on intergroup analyses in all but 1 study. In 4 studies, pain and function scores favored PRP over control at final follow-up (range in mean difference, -2.2 to 0.69 for visual analog scale pain score [n = 5] and -50.5 to -4.0 for Shoulder Pain and Disability Index score [n = 3]), whereas 3 studies found greater improvement in shoulder motion after PRP (range in mean difference, 0.7° to 34.3° for forward flexion and -2.3° to 20.4° for external rotation [n = 4]). One study found no significant difference between PRP and corticosteroid injections but noted that the results were comparable.

CONCLUSIONS

According to a limited number of prospective studies, PRP injections for AC are at least equivalent to corticosteroid or saline solution injections and often lead to improved pain, motion, and functional outcomes at 3- to 6-month follow-up. Given the small number of studies, with design heterogeneity, there is insufficient evidence to routinely recommend PRP for AC. However, the results are promising and do support considering PRP as an adjunct treatment option for AC, especially for patients refractory and/or averse to corticosteroids or alternative treatment modalities.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Assessment of a Synergistic Effect of Platelet-Rich Plasma and Stem Cell-Seeded Hydrogel for Healing of Rat Chronic Rotator Cuff Injuries

Outcomes after repair of chronic rotator cuff injuries remain suboptimal. Type-1 collagen-rich tendon hydrogel was previously reported to improve healing in a rat chronic rotator cuff injury model. Stem cell seeding of the tendon hydrogel improved bone quality in the same model. This study aimed to examine whether there was a synergistic and dose-dependent effect of platelet-rich plasma (PRP) on tendon-bone interface healing by combining PRP with stem cell-seeded tendon hydrogel. Human cadaveric tendons were processed into a hydrogel. PRP was prepared at two different platelet concentrations: an initial concentration (initial PRP group) and a higher concentration (concentrated PRP group). Tendon hydrogel was mixed with adipose-derived stem cells and one of the platelet concentrations. Methylcellulose, as opposed to saline, was used as a negative control due to comparable viscosity. The supraspinatus tendon was detached bilaterally in 33 Sprague-Dawley rats (66 shoulders). Eight weeks later, each detached tendon was repaired, and a hydrogel mixture or control was injected at the repair site. Eight weeks after repair, shoulder samples were harvested and assigned for biomechanical testing (n = 42 shoulders) or a combination of bone morphological and histological assessment (n = 24 shoulders). Biomechanical testing showed significantly higher failure load and stiffness in the concentrated PRP group than in control. Yield load in the initial and concentrated PRP groups were significantly higher than that in the control. There were no statistically significant differences between the initial and concentrated PRP groups. The addition of the highly concentrated PRP to stem cells-seeded tendon hydrogel improved healing biomechanically after chronic rotator cuff injury in rats compared to control. However, synergistic and dose-dependent effects were not seen.

Effectiveness of subacromial injections in rotator cuff lesions: systematic review and meta-analysis protocol

INTRODUCTION

Subacromial injections are therapeutic options for rotator cuff injuries, with consistent results not well established yet for each drug applied. The objective of this systematic review and meta-analysis is to analyse the effectiveness of the substances used in subacromial injections for the treatment of rotator cuff injuries and shoulder impingement syndrome, considering the functional gain and pain improvement of the shoulder.

METHODS AND ANALYSIS

Beginning in November 2022, we will perform a detailed search using the MEDLINE/PubMed, EMBASE, Cochrane Central Register of Controlled Trials and LILACS databases. Relevant grey literature (reference lists, conference abstracts and academic papers) will also be included.Two reviewers will independently screen and extract the information from the literature. Bias and quality of the included studies will be evaluated using the risk of bias assessment tool provided by the Cochrane Collaboration. Statistical analyses will be performed using Review Manager V.5.4 software.

ETHICS AND DISSEMINATION

Approval and patient informed consent are not required because we will only include published literature. The results of this research will be disseminated in a peer-reviewed journal and likely through other scientific events.

PROSPERO REGISTRATION NUMBER

CRD42020199292.

Double-Row Repair With Platelet-Rich Plasma Optimizes Retear Rates After Small to Medium Full-Thickness Rotator Cuff Repair: A Systematic Review and Network Meta-analysis of Randomized Controlled Trials

PURPOSE

To compare the different interventions described in the literature for the surgical treatment of small and medium complete rotator cuff tears.

METHODS

A systematic review of randomized controlled trials of small-medium, full-thickness rotator cuff tears published since 2000 was performed. Clinical characteristics, re-tear rates, range of motion (ROM), and patient-reported outcomes (PRO) data were collected. Interventions were compared via arm-based Bayesian network meta-analysis in a random-effects model. Interventions were ranked for each domain (re-tear risk, pain, ROM, and PROs) via surface under the cumulative ranking curves.

RESULTS

A total of 18 studies comprising 2046 shoulders (47% females, mean age 61 ± 3 years, mean follow-up 21 ± 5 months) were included. Interventions that ranked highest for minimizing re-tear risk included arthroscopic single-row repair (A+SR) or double-row repair (A+DR) with or without platelet-rich plasma (PRP). Open repair and A+SR repair with acromioplasty (ACP) ranked highest for pain relief. Interventions that ranked highest for ROM improvement included open repair, PT, and A+DR with or without ACP. Interventions that ranked highest for PROs included arthroscopic footprint microfracture with or without SR, open repair, and A+SR with or without ACP.

CONCLUSIONS

Based on a network meta-analysis of level 1 studies, arthroscopic rotator cuff repair with a SR or DR construct demonstrates similar retear rates, PROs, and clinical outcomes. The highest-ranking treatment for minimizing retears was arthroscopic repair with DR constructs and PRP augmentation, although open repair and arthroscopic SR remain reliable options with excellent clinical outcomes. Addition of PRP to DR constructs trended toward a 56% decreased risk of retear as compared to DR repair alone. Although no single treatment emerged superior, several interventions offered excellent clinical improvements in pain, ROM, and PROs that exceeded minimal clinically important difference thresholds.

LEVEL OF EVIDENCE

I, systematic review and meta-analysis of level I studies.

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.

Intradiscal injection for the management of low back pain

Low back pain (LBP) is a common clinical problem and a major cause of physical disability, imposing a prominent socioeconomic burden. Intervertebral disc degeneration (IDD) has been considered the main cause of LBP. The current treatments have limited efficacy because they cannot address the underlying degeneration. With an increased understanding of the complex pathological mechanism of IDD, various medications and biological reagents have been used for intradiscal injection for the treatment of LBP. There is increasing clinical evidence showing the benefits of these therapies on symptomatic relief and their potential for disc repair and regeneration by targeting the disrupted pathways underlying the cause of the disease. A brief overview of the potential and limitations for these therapies are provided in this review, based on the recent and available data from clinical trials and systematic reviews. Finally, future perspectives are discussed.

Follow-up on a Biological Revision Technique for Large, Recurrent, Retracted, Rotator Cuff Tears

INTRODUCTION

Revision of large recurrent rotator cuff tears by simple repair has a structural failure rate of 40% to 90%. The author presents a minimum 2-year follow-up study of revision rotator cuff reconstructions using a bridging patch graft composed of autogenous biceps tendon saturated with concentrated autologous iliac bone marrow, to determine how the technique compares to the reported outcome of simple repair as a treatment alternative.

METHODS

The principal entrance criterion was a symptomatic rotator cuff retear with retraction creating a 3- to 5-cm defect. Twenty-five consecutive patients (with an average age of 62 years) were enrolled. Twenty-two (88%) were available for follow-up at 24 to 120 months (mean 68 months) for interview and examination. Questionnaires using Constant, American Shoulder and Elbow Surgeons, and University of California at Los Angeles (UCLA) Shoulder scores were completed. In the terminal 15 patients, the presence of viable marrow mesenchymal cells fixed to the tendon graft at the time of implantation was determined by histological verification. Rotator cuff integrity was evaluated by ultrasonography examination. The Wilcoxon rank-sum test was used to compare nonparametric preoperative with postoperative questionnaire outcome scores.

RESULTS

Twenty of 22 patients (91%) demonstrated an intact tendon construct. Two of 22 patients (9%) demonstrated structural failure. Viable mesenchymal cells were identified on all graft specimens in high concentration. All patients showed improved results: The mean Constant score increased from 13 to 76; American Shoulder and Elbow Surgeons from 17 to 81; UCLA from 6 to 29 (P < 0.001).

DISCUSSION

The autogenous graft/marrow technique consistently and successfully reconstructed a large, recurrent rotator cuff tear in a clinical setting where the primary cuff repair had failed. The observation that an autogenous tendon graft saturated with concentrated marrow has the biological potential to reconstruct a difficult soft-tissue defect in the shoulder strongly implies its potential as a reconstructive tool for other soft-tissue defects.

Platelet-Rich Plasma in Arthroscopic Rotator Cuff Repair: Clinical and Radiological Results of a Prospective Randomized Controlled Trial Study at 10-Year Follow-Up

PURPOSE

The aim of the study is to compare, at 10-year follow-up, the clinical and radiological outcomes of arthroscopic rotator cuff repair with or without the addition of platelet-rich plasma (PRP) over the tendon-bone interface at the end of the surgical procedure.

METHODS

Of 53 patients recruited in the study, and randomly divided into 2 groups (PRP = 26; control = 27), 38 were re-evaluated at least 10 years after the index procedure. The clinical evaluation was carried out through: University of California at Los Angeles (UCLA) Shoulder Score, Visual Analogue Scale (VAS), Simple Shoulder Test, Constant-Murley Score (CMS), Single Assessment Numerical Evaluation (SANE), American Shoulder and Elbow Surgeons (ASES) and isometric strength in abduction, forward flexion and external rotation. Musculoskeletal ultrasonography had been used to evaluate the integrity of the repaired cuff.

RESULTS

A number of 38 (71%) patients (PRP = 17; control = 21) with a median age of 71 [64.75-76.50] years have been evaluated. Satisfaction at follow-up is high (90%), without statistically significant difference between the two groups. We report good and excellent clinical results in both groups (PRP vs control): CMS (81.62 [72.47-85.75] vs 77.97 [69.52-82.55] points), UCLA (34 [29.00-35.00] vs 33 [29.00-35.00] points), VAS (0.34 [0.00-1.85] vs 0.70 [0.00-2.45] cm). It was not possible to find a statistically significant difference for the variables analyzed, except for ASES and SANE. On average, 37% of the operated patients had a re-rupture at the ultrasound examination, regardless of the treatment group (P = 1.00). Compared with the previous radiological control at the 2-year follow-up, new retears occurred in 6% of the patients who received PRP treatment, whereas in the control group the percentage raises to 14% (P = .61).

CONCLUSION

The clinical and radiological outcomes at the 10-year follow-up show a substantial uniformity of results between the 2 groups. The minor differences that had been observed at 2-year follow-up disappeared at long term. Patients' satisfaction is still high 10 years after surgical treatment.

LEVEL OF EVIDENCE

Level II, randomized controlled trial, treatment study.

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.

The Effect of Intradiscal Platelet-Rich Plasma Injection for Management of Discogenic Lower Back Pain: A Meta-Analysis

Objective

Although several researches of animal and human subjects have yielded promising results regarding intradiscal injection of platelet-rich plasma (PRP) for the management of intervertebral disc (IVD) pathologies, small sample sizes and unstandardized graft preparation procedures hampered these research efforts. Therefore, we conducted a meta-analysis to evaluate the effectiveness of intradiscal PRP injection for the treatment of discogenic lower back pain.

Methods

The PubMed, SCOPUS, Embase, and Cochrane Library databases were systematically searched for relevant studies published from January 01, 1980 to December 14, 2020. The keywords used for the search were (platelet-rich plasma) AND (intradiscal OR back pain OR lumbar spine OR discogenic). Filters were used to select studies with human participants; all study designs were included.

Results

After the systematic review, three articles, including one randomized control trial and two prospective observational studies, were included in the final analysis. Analysis of changes in visual analogue scale (VAS) scores showed that VAS scores were significantly reduced two and six months after intradiscal PRP injection (two months: standardized mean difference [SMD] = −0.837, 95% CI = −1.158 to −0.516, P < 0.001; six months: SMD = −1.430, 95% CI = −2.209 to −0.652, P < 0.001), but not after one month (SMD = −0.661, 95% CI = −1.346 to 0.023, P = 0.058). Regarding changes in Owestry Disability Index (ODI), ODI scores were significantly reduced after six months (SMD = −0.964, 95% CI = −1.885 to −0.043, P = 0.040).

Conclusion

Intradiscal PRP injections are effective in relieving pain and improving disabilities caused by discogenic lower back pain. However, the pain-reducing effect significantly manifests two or six months after the injections, but not after one month.

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

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

Platelet-rich plasma-enhanced osseointegration of decellularized bone matrix in critical-size radial defects in rabbits

Background

Bone defects represent a common orthopedic condition. With its vast array of donor sources, xenogeneic bone shows considerable potential as a bone defect repair material but may also be associated with immune rejection and reduced osteogenic capacity. Thus, reducing the risks for immune rejection of xenogeneic bone, while improving its osseointegration, are key technical challenges.

Methods

Decellularized bone matrix scaffolds (DBMs) were fabricated by thorough ultrasonic vibration and subjection to chemical biological agents to remove cells and proteins. The DBMs were then mixed with platelet-rich plasma (PRP) under negative pressure. Growth factor concentrations of PRP, as well as the microstructures and biomechanical properties of the system, were examined. Furthermore, osseointegration capacities in the critical-size radial defect rabbit model were verified.

Results

Complete decellularization of the scaffold and limited reductions in mechanical strength were observed. Moreover, the obtained PRP demonstrated various growth factors. Radiographic evaluation and histological analysis verified that more new bone formation occurred in the DBM mixed with PRP group at 6 and 12 weeks after implantation compared with both the blank group and the DBM without PRP group.

Conclusions

Thorough physical and chemical treatments can reduce the probability of immune rejection of DBMs. The novel composite of DBMs mixed with PRP can serve as a promising bone regeneration material.