Comparative Efficacy of Platelet-Rich Plasma (PRP) Injection Versus PRP Combined with Vitamin C Injection for Partial-Thickness Rotator Cuff Tears: A Randomized Controlled Trial

Comparison of the effect of platelet rich plasma injection with the combination of platelet rich plasma and vitamin C on partial thickness rotator cuff tears

Clinical trial with a control group, with parallel groups, double-blind, randomized, phase 2 on 110 patients. Simple random tables created by computer were used for randomization.

To prepare PRP, a 20 ml venous blood sample was collected from each patient and injected into a tube containing an anticoagulant (sterile sodium citrate tubes). The blood was then centrifuged at 1500 rpm for 10 minutes. Following centrifugation, the plasma located above the red blood cells was carefully transferred to a new sterile tube. The second round of centrifugation lasted for 10 minutes at a speed of 2500 rpm, and the supernatant (approximately 5–6 ml) was removed so that about 3 ml of plasma along with the cell sediments remained at the bottom of the tube. In the next step, through vortexing, we made the platelet suspension in the remaining plasma in the form of a suspension with an approximate concentration of 5 times the platelet baseline and used it with or without vitamin C for injection into the patients.

Entry conditions: Patients who, according to the clinical examination of an orthopedic specialist doctor and MRI results, according to Elman's classification system, have partial rotator cuff tears of the 1st and 2nd stage located in supraspinatus. Non-entry conditions: Rotator cuff tears secondary to fracture Prior surgical repair or revision arthroscopy

Patients will be randomly assigned to one of two groups: normal saline + PRP or vitamin C + PRP.

Visual Analog Scale (VAS); Constant score; American Shoulder and Elbow Surgeons (ASES) score

Decision to implement changes in the intervention

All patients who met the inclusion criteria were included in the study after providing informed consent. To evaluate the anterior-posterior tear size, scores 1 and 2 were considered in the MRI findings (score 1, less than 5 mm, and score 2, 5–10 mm) . The participants were randomly divided into two groups, A, normal saline + PRP, and B, vitamin C + PRP, by a simple random method and simple random tables created by a computer. The injection of the therapeutic compound was performed under ultrasound guidance in the subacromial space for two consecutive periods at intervals of 3 weeks. Notably, both injections were performed by the same orthopedic specialist and via the same injection method. Group A was treated with 1.5 ml of normal saline and 1.5 ml of PRP, and group B received 1.5 ml of vitamin C and 1.5 ml of PRP.

Despite obtaining informed consent from the participants in the study, they remain unaware of their assigned treatment intervention group. The preparation of platelet-rich plasma (PRP) is conducted by a hematologist at the Comprehensive Center for Stem Cells and Regenerative Medicine. The hematologist combines the PRP obtained from the patients with either normal saline or vitamin C. Moreover, the hematologist is aware of the treatment intervention for each participant as they record patient names alongside the respective treatment type. Furthermore, syringes containing the therapeutic combinations (normal saline + PRP and vitamin C + PRP) are conventionally labeled as A or B, with the hematologist knowledgeable about how to designate each according to the therapeutic intervention type. Subsequently, the orthopedic specialist responsible for administering the therapeutic combination remains blinded to the specific type of intervention.