PRP has been increasingly used in recent years to treat musculoskeletal injuries such as tendinopathy. While a number of studies have assessed the effectiveness of the therapy, researchers have primarily evaluated the clinical symptoms and functions of the treated patient. Furthermore, the studies have produced ambiguous and sometimes conflicting results, Arrigoni said.
As a result, the Italian team sought to evaluate the effectiveness of ultrasound-guided PRP injection of the supraspinatus tendon and compare it with medical and physical therapy alone. Patients were included in the study if they had a diagnosis of tendinosis or a focal tear of the supraspinatus tendon with a diameter of 1 cm or less. The researchers evaluated the success of each method based on morphological changes as seen on MRI and four years of follow-up.
Half of the 240 patients in the study were treated with ultrasound-guided PRP injection, while the other half received only medical and physical therapy. The hospital's blood transfusion department prepared the PRP. After being given local anesthesia with mepivacaine hydrochloride in the subacromial bursa, patients received one of two PRP injections under ultrasound guidance in the supraspinatus tendon. The second injection was provided 21 days later. Patients were immobilized with a soft brace for three days after injection.
Patients with a history of trauma or surgery during the four-year follow-up period were excluded, Arrigoni noted. MRI exams were performed on each patient before and four years after PRP injection, as well as on the group of patients who received medical and physical therapy.
Based on the MRI results, patients were classified as showing improvement, having stationary findings, or worsening. In addition, all patients were given a clinical and functional evaluation before therapy and after the four-year follow-up period. Pain was assessed using scores based on a visual analogue scale (VAS), while shoulder joint function was evaluated with Constant function scores.
"PRP injection in fact delays the degenerative changes of the tendons, and this is documented by the pain relief and functional improvement," Arrigoni said.