The goal of this clinical trial is to test if Plateth-rich plasma would provide improved pain relief and function in patients with rotator cuff tendinopathy compared to standard treatment of corticosterone injections.

Researchers will compare a control group of patients treated with a corticosterone injection with a case group of patients treated with Plateth-rich plasma injection.

The purpose of this study is to perform a double-blind randomized controlled trial, comparing PRP with corticosteroids to provide pain relief and improve function in patients with rotator cuff tendinopathy. The hypothesis of this study is that PRP would provide improved pain relief and function in patients with rotator cuff tendinopathy compared to standard treatment of CS injections.

Rotator cuff tendinopathy represents the most common pathology of the shoulder and is the main reason for outpatient consultation for pathologies related to the shoulder girdle. First-line treatment for rotator cuff tendinopathy usually consists of activity modification, stretching and strengthening exercises, oral anti-inflammatory medications. When these initial measures are not effective, a second line of treatment consists of local infiltrations with corticosteroids. However, most of the studies evaluating the effectiveness of corticosteroids in patients with rotator cuff tendinopathy show that the clinical results are usually short-lived.

In this sense, platelet-rich plasma (PRP) emerges as a promising alternative due to its ability to release pro-regenerative growth factors (FsC) and cytokines at the lesion site. Platelet Rich Plasma is considered a minimal handling product. Specifically, at the Hospital Italiano de Buenos Aires (HIBA), platelet-rich plasma has been used for more than 10 years for different musculoskeletal conditions, both on an outpatient basis or as an adjuvant to different surgical procedures.

Several small cohort studies and randomized controlled trials have examined the clinical benefit of PRP for treating patients with rotator cuff tendinopathy, however their results have been confounded by small patient samples, lack of a control group, variable or insufficient data from the PRP preparations and short-term follow-up.

The purpose of this study is to perform a double-blind randomized controlled trial, comparing PRP with corticosteroids to provide pain relief and improve function in patients with rotator cuff tendinopathy. The hypothesis of this study is that PRP would provide improved pain relief and function in patients with rotator cuff tendinopathy compared to standard treatment of CS injections.

Hypothesis

In patients with rotator cuff tendinopathy, PRP subacromial injections produce significantly greater improvement in shoulder pain and function than standard treatment with corticosteroid subacromial injection.

Primary objective To evaluate in patients with rotator cuff tendinopathy whether a subacromial infiltration with PRP produces a significant improvement in pain (measured through the visual analogue scale (VAS) for pain) compared to a control group treated with standard corticosteroid therapy.

Secondary objective To assess whether the use of PRP applied as a subacromial infiltration in patients with rotator cuff tendinopathy improves the functional results (measured using the American Shoulder and Elbow Surgeons (ASES) score) and Constant's score, compared to a control group that underwent subacromial infiltration with corticosteroids.

To assess whether the use of PRP applied as a subacromial infiltration in patients with rotator cuff tendinopathy improves sleep disorders (measured using the Pittsburgh score) compared to a control group that underwent subacromial infiltration with corticosteroids.

Confirm that platelet-rich plasma is a procedure safe by systematically recording adverse effects and complications associated with its use.

To accomplish the objectives, a randomized controlled clinical trial will be conducted, with an intervention group (patients that will receive PRP) and control group (patients that will receive corticosterone), usual treatment, blind for the treatment received by the patient and for clinical and radiological evaluation. The entire study will be carried out at the Hospital Italiano de Buenos Aires headquarters.

Eligible patients will be enrolled in the study by giving their informed consent.

Preparation of platelet-rich plasma

For the PRP group, a leukocyte-poor preparation from a prepackaged kit (RegenLab, Lausanne, Switzerland) will be used. According to the manufacturer's manual, 10 ml of venous blood will be drawn into a blood collection tube containing a sodium citrate anticoagulant and a proprietary separating gel (thixotropic gel) to isolate the red and white blood cells from the PRP. Samples will be centrifuged at 1500g for 5 minutes to produce approximately 7 mL of 80% platelets at 1.6x concentration. The manufacturer reports a filtration of 99.7%, 87 to 89%, 70 to 75%, and 96.5% of red blood cells, white blood cells, mononuclear cells, and granulocytes, respectively. The supernatant is then resuspended by inverting the tube several times and withdrawn into a separate 5 mL syringe for subacromial injection.

This procedure will be performed 2 times in each patient. The product from the first kit will be injected into the patient. Instead, the product from the second kit will be used to evaluate the final composition of the PRP. These specific measurements will include the final average of platelets, leukocytes and erythrocytes, and the specific formula of leukocytes and growth factors.

Statistical analysis raised Quantitative variables will be presented as mean and standard deviation or median and interquartile interval according to the observed distribution. Categorical variables will be presented as proportions. The 95% confidence intervals will be calculated for each of the estimators.

The comparison of continuous data between two groups will be analyzed with the t test if the distribution of the variables is normal or with the Mann-Withney-Wilcoxon test if it is not. The analysis of categorical data will be carried out with the chi-square test. Statistical analysis will be performed with STATA MP version 16 (Stata Corporation, College Station, TX). A p value less than 0.05 will be considered statistically significant.

Sample size To calculate the sample size, the expected values of the variable "pain" represented by the VAS, which is the main outcome variable, are used. The minimal clinically relevant difference (MCID) was previously described in the setting of rotator cuff disease as 1.5 points with a standard deviation of 2.41 points on a 10-point scale for shoulder pain. A type I error probability of 5% and a power of 90% will be used. Using these parameters in a superiority formula, a sample size of 45 patients per group was calculated. Considering the possibility of a loss to follow-up of 10% of the patients per group, 50 patients per group will be included, with a total final sample of 100 patients.

Randomization

All included patients will be randomized after obtaining informed consent. Each patient will be randomly assigned a treatment arm using the online randomizer (http://protocolos.hospitalitaliano.org.ar) to treatment arms 1 (control) or 2 (intervention)

Ethical considerations

Participation in the study will be in all cases voluntary and certified by the informed consent process. The study will be carried out in full accordance with current national and international regulations: Declaration of Helsinki of the World Medical Association, Provision 6677/10 of ANMAT, and the Standards of Good Clinical Practices ICH E6.

The proposed intervention does not frequently present adverse events and there are known contraindications for its application. The procedure will be paid for by the financing of the study, it will not imply any cost to the patient or their health coverage. The costs of monitoring and periodic evaluations will be borne by the study investigators.

All study data will be treated with the utmost confidentiality, with restricted access only to authorized personnel for the purposes of the study in accordance with current legal regulations National Law on Protection of Personal Data 25,326 (Habeas Data Law.

Damage or complications

The coverage for the risk of Institutional Malpractice is attached, of the Clinical Trial that will be contracted to carry out the following study once approved by the Ethics Committee. In the same Coverage is granted to the claim or claims that occur due to any injury, illness or death of Patients, caused or alleged to have been caused by the administration of medicinal products indicated in the Investigation Protocol, by acts of Medical Praxis committed during the execution of the Clinical Trial (negligence, incompetence, imprudence and non-observance of duties). In this multidisciplinary work, 2 Orthopedics and Hemotherapy services will be included. Each service will be responsible for the costs of interventions free of charge and with overtime.

In the case of the preparation of the PRP, will be carried out free of charge and the person in charge will be Dr. Pablo Camino Hemotherapy service plant doctor.

Luciano Rossi doctor of the Shoulder Pathology team of the Orthopedics and Traumatology Service of the Italian Hospital of Buenos Aires will carry out the infiltrations The rehabilitation will be carried out with the standard HIBA kinesiology protocol for patients with chronic rotator cuff tendinopathy and will be carried out by the rehabilitation team of the HIBA Kinesiology service.

Inclusion Criteria:

• symptomatic rotator cuff tendinopathy (confirmed by ultrasound).
• At least 3 months of failed conservative treatment (decreased activity, anti-inflammatories, kinesiology for at least 3 months before diagnosis).

Exclusion Criteria:

• Refusal to participate or informed consent
• Previous shoulder surgery,
• Partial or total tears of the rotator cuff,
• Patients with shoulder osteoarthritis
• Advanced fatty infiltration of the rotator cuff muscles
• Systemic or rheumatoid arthritis,
• Uncontrolled diabetes,
• Acute or chronic infections of the shoulder to be operated on
• Ongoing cancer chemotherapy therapies
• Sepsis, septic arthritis, osteomyelitis or other ongoing infectious processes;
• Patients with autoimmune diseases;
• Pregnants

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At the time of blood collection, patients will be placed in a hemotherapy extraction chair with a screen that will prevent the patient from seeing their arm at the time of blood collection.