The study is a prospective double-blind randomized placebo-controlled trial. The study population is consisted of patients aged 18-65 years, who applied to the Department of Physical Medicine and Rehabilitation, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey and were diagnosed with rotator cuff tendinopathy and/or partial tear in the supraspinatus tendon (< 50%) by clinical and MRI examination, and met the inclusion criteria. The patients will be randomized into 3 groups using a closed envelope method; 1) Single PRP injection, 2) Single placebo injection, and 3) Two PRP injections applied 3 weeks apart. All injections will be performed into the subacromial space under ultrasound guidance. The same physical therapy program will be given to all groups and will be performed at least for 20 minutes daily.~The randomization will be done using the closed envelope method by a researcher who will not perform injections nor evaluate the patients, and to provide blindness, the injectors to be used will be covered with non-transparent tapes by the same investigator. The patients, the physician to make the evaluations, and the physician to perform injections will be blinded to the groups. The solution to be injected will be prepared by another researcher who is not blind. PRP injections will be prepared as follows;10 ml of venous blood taken from the patients will be put into the T-LAB® PRP kit (T-Biotechnology Laboratory, İstanbul, Turkey). The obtained blood will then be centrifuged at 3850 rpm for 8 minutes. Approximately 4 ml of the PRP obtained will be injected into the subacromial space using the lateral subacromial injection method under ultrasound guidance. The same amount of blood will be taken for the placebo injection group and after the same waiting time 4 ml of 0.9% saline will be injected using the same method.~Ultrasound guided lateral subacromial injection method will be used. For a safer and more efficient injection, all applications will be performed in the sagittal axis with the long axis in-plane technique, using the ultrasound device (Esaote® My Lab 70 XVision 6-18 Mhz linear probe). To obtain an optimal subacromial appearance with shoulder ultrasonography (USG), the patients will sit upright with their arms back, internally rotated, shoulder hyperextended and elbow flexed to 90° and forearm parallel to the floor. USG in-plane technique will be used in the subacromial region to confirm that the needle stays in the correct place as it is advanced.~Shoulder range of motion will be measured. The level of pain at rest, during motion and during the night will be evaluated with the visual analog scale (VAS). Constant Murley scale and Shoulder Pain and Disability Index (SPADI) will be used for functional evaluation. Quality of life will be assessed with Short-Form 36 (SF-36). Upper extremity muscle strength will be measured with the Isomed-2000® isokinetic device.~The participants in single-PRP injection and single-Placebo injection groups will be evaluated before the injection and 4 and 12 weeks later. Those in the two PRP injections group will be evaluated before the first injection, and 4 and 12 weeks after the second injection.
The aim of this study is to investigate the efficacy of single PRP injection compared with placebo and multiple PRP injections on pain, quality of life, shoulder function and muscle strength in the treatment of patients who have tendinopathy and/or partial tear in the rotator cuff.