A Phase 2 interventional study of Platelet-Rich Plasma (PRP) Injections and Centrifuge in Osteoarthritis, Articular Cartilage and Musculoskeletal Disorders, sponsored by University of California, San Francisco. Active, not recruiting at 1 site in United States. Open to participants aged 18 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-08.
Sponsored by University of California, San Francisco · Phase 2, Interventional, and Treatment
This is a randomized, double-blind, placebo-controlled phase 2 study with a secondary crossover phase at the end of the initial trial to ensure all subjects receive one PRP injection. The goal is to identify what proteins change in the blood following repeated intraarticular knee PRP injections in patients with knee osteoarthritis. The objective is to determine the protein changes resulting from a single autologous PRP injection (5 mL) in comparison to a normal saline control.
About 60 subjects will take part in this study by two age groups at UCSF into the following arms: Arm A: PRP injection; Arm B: normal saline injection control. The study aims to demonstrate what benefits PRP has on knee osteoarthritis and methods to best achieve biologic effects. Subjects with a diagnosis of knee osteoarthritis ages 18-45 and 46-70 years old presenting to a University Based sports medicine clinic will be screened for potential eligibility. Subjects who meet all qualifying requirements will be recruited from UCSF's orthopedic and primary care clinics.
Subjects will be on study for up to 26 weeks Screening: up to 14 days Treatment: injection of PRP or normal saline; subjects can cross over at week 12 to a PRP if originally in the control injection group Follow-up: 2 weeks post-baseline injection, 12 weeks postbaseline, (14 weeks if crossover patient), 26 weeks.
This is a randomized, double-blind, placebo-controlled trial with a secondary crossover phase at the end of the initial trial to ensure all subjects receive one PRP injection. The randomization will be stratified by two age groups (ages 18-45 yrs. and 46-70 yrs).Screening and medical chart data will be reviewed to determine subject eligibility.
Platelet rich plasma (PRP) falls under transfusion medicine which has been FDA approved. Seeking to identify biological pathways by which PRP acts in a degenerative condition like knee osteoarthritis. The study compares the immediate and delayed variations in blood and synovial fluid biomarkers following PRP knee intraarticular injections in younger and older patients with knee osteoarthritis. The differences in blood biomarkers between ages of Knee osteoarthritis (KOA) patients are being investigated in this study. Intra-individual variations in some blood proteins will deviate (e.g., be larger or lower) from a normal saline control between week two and week twelve following the 5 mL PRP injection.
The unblinded research evaluation will evaluate the first batch of the first 20 blood and synovial fluid samples to ensure that the tests provide the desired results and data outcomes.
The visits consist of the Baseline visits (Week 0), the Week 2 visit, and the Week 12 visit and for half of the participants an optional 14 Week visit. These are in person visits. There are three remote visits at Week 26, Week 52 and Week 104.
Participation is estimated to take 2-2.5 hours for each visit over 6 months. The time it takes for each participant to attend an on-site visit is approximately 2-2.5 hours in total each time. The knee injection takes approximately 45 minutes for blood or knee fluid donation and preparation of the PRP. This injection occurs 1-2 times, depending on randomization arm). Subjects will complete surveys at the 3-4 timepoints, estimated to take 30 minutes per timepoint (or total); perform functional testing which is walking 40 meters back and forth quickly, sitting and standing for 30 seconds, and climbing stairs for 3 minutes and have the activity monitor put on (15 minutes). Subject will complete study questionnaires at the beginning of each visit (30 minutes). In addition, participants are asked to engage in physical therapy ideally once a week for 10 weeks although this will be documented as it is standardized but not required for the study.
If subjects are assigned to the Placebo Arm (Arm B), subjects will be informed that of receiving the placebo (normal saline injection) rather than the PRP injection. Subject will be offered the option of crossing over to receive a PRP injection. If a subject agrees to have a PRP injection, researchers will collect research blood (about 60cc or 4 tablespoons) and fluid from the knee joint space. If the subject decides to receive the PRP injection, the researchers will collect research blood (approximately 20ml or 1.5 tablespoons) and fluid from the knee joint space (45 minutes). The subject will fill out a questionnaire (30 minutes) and perform tasks to test their function (45 minutes). At the baseline appointment, subjects will receive an activity monitor to use for one week. The activity monitor should be returned on the week 14 visit.
Week 14 on site visit - If subjects are given a PRP injection at 12 weeks, subjects will have a two-week follow-up visit. The researchers will collect research blood (about 20ml or 2 tablespoons) and fluid from the knee joint space. Subjects will complete a questionnaire, and tasks testing the subject's function. Subjects will go home with an activity monitor that subjects will be asked to wear for 1 week. The activity monitor should be returned. Subjects will be asked to keep a diary to record symptoms and pain medication intake following injections. The participants will be interviewed and have their diaries reviewed on follow up visits.
4,398 studies on the registry are indexed under Osteoarthritis; 582 are open to participants now.
This study's planned enrollment of 60 is below the median of 70 across 3,440 interventional studies indexed under Osteoarthritis.
Browse Osteoarthritis studies →University of California, San Francisco is the lead sponsor of 2,132 studies on the registry; 375 are open to participants now.
Of its 262 completed or terminated interventional studies of FDA-regulated products, 196 (75%) have results posted.
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Exclusion Criteria
1. Patients will be excluded if:
i. Acute myocardial Infarction (within 5 days of any planned study procedure); ii. Unstable angina; iii. Uncontrolled arrhythmia causing symptoms or hemodynamic compromise; iv. Recurrent syncope; v. Active endocarditis; vi. Acute myocarditis or pericarditis; vii. Symptomatic severe aortic stenosis; viii. Uncontrolled heart failure; ix. Acute (within 3 months) pulmonary embolus or pulmonary infarction; x. Thrombosis of lower extremities; xi. Suspected dissecting aneurysm; xii. Uncontrolled asthma; xiii. Pulmonary edema; xiv. Room air desaturation at rest ≤85%; xv. Respiratory failure; xvi. Acute non-cardiopulmonary disorders that may affect exercise performance or be aggravated by exercise (ie infection, renal failure, thyrotoxicosis); and xvii. Mental impairment leading to inability to cooperate.
A vacutainer vial containing 50 mL of peripheral blood will be processed immediately to create PRP using a previously optimized two-step centrifugation protocol viii. First, the whole blood will be centrifuged at 500 x g for 8 minutes at 4°C. The plasma will be collected above the buffy coat using a sterile pipette, placed into a separate sterile tube, and centrifuged a second time at 700 x g for 17 minutes at 12° C. The top 70% will be collected as the PPP and the bottom 30% will be resuspended as the PRP. PPP will be aliquoted into cryovials for storage at -80 °C. Approximately 6 mL of PRP will be produced from each 50 mL vial of whole blood. Five mL will be allocated for administration to patients and the remaining one mL will be aliquoted into cryovials for storage at -80 °C. The syringe containing PRP will be covered with Aluminum foil, such that the investigator cannot tell what fluid is to be injected.
Drug: Platelet-Rich Plasma (PRP) Injections · Device: Centrifuge
A placebo injection of 6 mL of 0.9% saline will be prepared by the unblinded research assistant in an adjacent room. The syringed will be prepared in a 10 mL syringe and covered with Aluminum foil, such that the investigator performing the injection cannot tell if there is PRP or saline to be injected.
Drug: Platelet-Rich Plasma (PRP) Injections · Drug: Control saline injection
Bloods will be drawn prior to the PRP injection, and repeated at 2 weeks, 12 weeks, possibly 14 weeks for crossover patients follow up visits. Under aseptic technique with a surgical drape/curtain in place to block the study subject's view of the knee. Syringes will be covered with aluminum foil and subjects will have a cover over their eyes, so that neither subjects nor the clinical investigator will know if the injection delivered is PRP injection or a normal saline injection
Also known as: platelet-rich growth factors (GFs), platelet-rich fibrin (PRF) and platelet concentrates (PCs)
The Eppendorf Centrifuge is used to make the PRP. In our opinion, the centrifuge is a nonsignificant risk device. The centrifuge, sterile vials for blood collection and PRP injection syringes do not present a potential risk for serious health, safety or welfare of a subject. It is not needed to support or sustain human life. It is not of substantial importance in diagnosis, curing, mitigating or treating disease for the health, safety and welfare of the patients. There are no potential for serious risk to the health, safety or welfare of a subject.
Also known as: Microcentrifuge tubes, Eppendorf tubes
A placebo injection of 6 mL of 0.9% saline will be prepared by the unblinded research assistant in an adjacent room. The syringed will be prepared in a 10 mL syringe and covered with Aluminum foil, such that the investigator performing the injection cannot tell if there is PRP or saline to be injected.
Identify Protein Changes in Platelet Rich Plasma (PRP)
The protein changes from a single autologous PRP injection (5 mL) vs normal saline control, using proteomic analysis of' venous blood samples. For proteomic analysis of Platelet poor plasma (PPP) and PRP, the samples will undergo quantitative mass spectrometry, with higher numbers indicating more proteins and lower numbers meaning less proteins.
Time frame: 2 weeks
To determine the Intra-individual change in specific proteins in the peripheral blood
Changes in specific proteins in the blood will be different (e.g., higher or lower) after the 5 mL PRP injection compared to a normal saline control using proteomic analysis. PPP and PRP samples will undergo quantitative mass spectrometry, with higher numbers indicating more proteins and lower numbers meaning less proteins.
Time frame: 12 weeks
To determine the Protein Changes in the synovial vluid
Using proteomic analysis of the synovial fluid at the knee, compare the protein alterations caused by an autologous PRP dose (5 mL) to the normal saline control. For proteomic analysis of synovial fluid, the samples will undergo quantitative mass spectrometry, with higher numbers indicating more proteins and lower numbers meaning less proteins.
Time frame: 2 weeks and 12 weeks
Examine Differences by Age
Protein alterations in blood and synovial fluid following knee injections. For each arm, investigator will compare groups of young people (18-45 years old) and older people (46-70 years old) independently.
Time frame: 2 weeks and 12 weeks
Change in Visual Analog Pain Scores
Pain will be measured using the Visual Analog Pain Scores, the score ranges from 0-10, zero indicating no pain and 10 being the worst pain ever.
Time frame: 2 weeks, 12 weeks and 26 weeks
Changes in Knee Injury and Osteoarthritis Outcome Scores (KOOS scores)
Knee Injury and Osteoarthritis Outcome Scores (KOOS scores), the score ranges from 0-100, with 0 representing extreme knee problems and 100 representing no knee problems.
Time frame: 2 weeks, 12 weeks and 26 weeks
Plan to share: No
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University of California, San Francisco