PRP + Hyaluronic Acid (HA) for Knee Osteoarthritis

Boulder Biologics offers combined platelet-rich plasma (PRP) and hyaluronic acid (HA) injections for selected patients with symptomatic knee osteoarthritis (OA). This is an autologous/viscosupplementation strategy intended to improve pain and function by combining:

  • HA: a viscoelastic lubricating polymer that can improve joint mechanics and may reduce symptoms in some patients (viscosupplementation).

  • PRP: an autologous platelet concentrate designed to modulate the intra-articular biologic environment through growth factor/cytokine signaling rather than direct tissue replacement.

Clinical evidence suggests that PRP+HA may provide greater symptom improvement than PRP alone or HA alone in certain knee OA populations, though response varies and outcomes cannot be guaranteed. (1-5)

 

Why combine PRP and HA?

1) Complementary mechanisms

Hyaluronic acid is a major component of synovial fluid; intra-articular HA injections aim to improve lubrication and viscoelasticity and may reduce pain in some patients. PRP provides platelet-derived signaling molecules that may influence inflammation and tissue homeostasis.

Combination protocols are theorized to provide both biomechanical support (HA) and biologic modulation (PRP). Prospective and randomized studies have reported improved clinical outcomes (pain/function scores) in PRP+HA groups compared with PRP-only or HA-only comparators. (1,2,4,5)

2) Potential reduction in post-injection flare

Some studies report that PRP+HA may reduce adverse reactions compared with PRP alone, potentially through HA’s effects on the intra-articular environment and viscoelastic buffering, although this is not guaranteed and depends on formulation and technique. (4)

 

What does the clinical evidence show?

The following peer-reviewed clinical studies (randomized trials and prospective cohorts) report that PRP+HA can improve pain and function in knee OA, with some reporting superiority over either PRP or HA alone:

Randomized controlled trial (mild–moderate knee OA) comparing HA, PRP, and PRP+HA: PRP+HA produced favorable outcomes vs single-agent arms in that trial design. (1)

Randomized clinical study of PRP, HA, PRP+HA, and placebo reported improvement across groups, with PRP+HA showing benefit in multiple endpoints reported by the authors. (2)

Prospective study (PRP + “hybrid” HA) demonstrated clinical improvement in Kellgren–Lawrence II–III OA over follow-up. (3)

Arthroscopy prospective cohort reported PRP+HA was superior to PRP or HA alone for inflammation-related measures and for pain/function outcomes in their dataset. (4)

A Scientific Reports RCT found that PRP + crosslinked HA produced greater pain reduction at 6 months than PRP alone in KL grade 2 OA. (5)

Interpretation for patients: The overall evidence supports PRP+HA as a reasonable option for symptom reduction and functional improvement in selected patients with knee OA, especially in early-to-moderate disease. Evidence is not uniform across all studies; protocols differ (number of injections, HA type, PRP formulation), and individual responses vary. (1-5)

 

Who is a candidate?

PRP+HA is typically considered for patients who:

  • Have symptomatic knee OA (often mild–moderate radiographic disease, depending on clinical picture)

  • Have persistent symptoms despite conservative measures (activity modification, physical therapy, weight optimization, bracing, and/or medications as appropriate)

  • Want to pursue a non-surgical option and understand that results vary

Patients with advanced, end-stage OA may still pursue injections for symptom management, but the probability of robust improvement may be lower than in early disease.

 

How the procedure is performed

Step 1: Clinical evaluation

We confirm diagnosis, review imaging (X-ray/MRI as appropriate), and discuss whether PRP alone, HA alone, or PRP+HA is most appropriate.

Step 2: PRP preparation

Blood is drawn and processed using a controlled centrifugation protocol. PRP formulation is selected based on the indication (knee OA) and patient-specific factors, with attention to platelet dose and leukocyte/red blood cell content (PRP is not one uniform product).

Step 3: Injection technique

Injections are performed using sterile technique with ultrasound guidance when appropriate to improve accuracy. HA and PRP may be administered sequentially in the same session, depending on the protocol used.

Step 4: Post-procedure expectations

  • Some soreness or pressure is common for 24–72 hours.

  • Symptom improvement, when it occurs, is typically gradual over weeks to months.

  • We provide individualized aftercare guidance and activity modification recommendations.

Safety and Contraindications

Most adverse events reported in these studies are mild and self-limited (post-injection soreness, swelling). Serious adverse events are uncommon when sterile technique and appropriate patient selection are used. (4,5)

 PRP+HA may not be appropriate for patients with:

  • Active local or systemic infection

  • Uncontrolled bleeding disorders or anticoagulation issues (case-specific)

  • Known allergy to a specific HA preparation or excipients

  • Severe acute inflammatory flare where injection is not clinically appropriate

These considerations are reviewed during consultation.

 

FDA regulatory disclosure

  • PRP is an autologous blood product prepared from the patient’s own blood.

  • Hyaluronic acid products used for viscosupplementation are typically regulated as devices/drug-device combinations depending on the product.

 Importantly, PRP has not been approved by the U.S. Food and Drug Administration (FDA) as a drug/biologic for the treatment of knee osteoarthritis, and clinical use is based on physician judgment, current scientific evidence, and individualized patient evaluation. No claims are made regarding guaranteed outcomes, cartilage regeneration, or disease modification.

 

References

1.     Lana JF, Weglein A, Sampson SE, et al. Randomized controlled trial comparing hyaluronic acid, platelet-rich plasma and the combination of both in the treatment of mild and moderate osteoarthritis of the knee. J Stem Cells Regen Med. 2016;12(2):69–78. doi:10.46582/jsrm.1202011. PMID:28096631. 

2.     Yu W, Xu P, Huang G, Liu L. Clinical therapy of hyaluronic acid combined with platelet-rich plasma for the treatment of knee osteoarthritis. Exp Ther Med. 2018;16(3):2119–2125. doi:10.3892/etm.2018.6412. PMID:30186448. 

3.     Papalia R, Zampogna B, Russo F, et al. The combined use of platelet rich plasma and hyaluronic acid: prospective results for the treatment of knee osteoarthritis. J Biol Regul Homeost Agents. 2019;33(2 Suppl 1):21–28. PMID:31168999. 

4.     Xu Z, He Z, Shu L, et al. Intra-articular platelet-rich plasma combined with hyaluronic acid injection for knee osteoarthritis is superior to platelet-rich plasma or hyaluronic acid alone in inhibiting inflammation and improving pain and function. Arthroscopy. 2021;37(3):903–915. doi:10.1016/j.arthro.2020.10.013. PMID:33091549. 

5.     Sun SF, Lin GC, Hsu CW, et al. Comparing efficacy of intraarticular single crosslinked hyaluronan (HYAJOINT Plus) and platelet-rich plasma (PRP) versus PRP alone for treating knee osteoarthritis. Sci Rep. 2021;11(1):140. doi:10.1038/s41598-020-80333-x. PMID:33420185.