79% participant retention after 1 year

This is a randomized controlled clinical trial to investigate the effectiveness, safety and tolerability of platelet-rich plasma (PRP) injections for treatment of patellar tendinopathy in adults 18-50 years of age. Subjects will be randomly assigned to three parallel treatment groups:

1. Leukocyte-rich PRP injection + exercise
2. Leukocyte-poor PRP injection + exercise
3. Saline injection + exercise (control) Primary endpoints are (1) the number (rate) and severity of adverse events as reported by both patients and study physicians during the first 12 weeks after initiation of treatment, (2) patient-rated tolerability of treatment; (3) the change in function (VISA score) and treatment success (global improvement scale) over six months of a post-injection exercise protocol.

Inclusion Criteria:

• Male or female ≥ 18 and ≤ 50 years of age at Enrollment Visit
• Documentation of a clinical diagnosis of patellar tendinopathy, grade-IIIB Blazina stage, confirmed on ultrasound
• Previously tried an exercise program of at least six weeks duration
• Fluent in official language of study site
• Written informed consent obtained from subject
• Normal values on screening laboratory panels (CBC, PT, PTT, INR, serum creatine, ALT, ALP, AST, bilirubin, albumin)

Exclusion Criteria:

• For women of child-bearing potential, positive pregnancy test at enrollment visit
• Major surgery in the past three months
• Surgery on the symptomatic knee
• Bleeding disorder
• Systemic inflammatory disease
• Arthritis or degenerative knee condition
• Recent fluoroquinolone use
• Subjects who have any requirement for the use of systemic steroids or immunosuppressants
• Subjects who are known to be HIV positive
• Uncooperative patient, or patients who are incapable of following directions or who are predictably unwilling to return for follow-up examinations
• Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data