PRP for Achilles Tendinopathy

Does PRP Help Achilles Tendinopathy?

PRP can be an effective treatment for chronic midportion Achilles tendinopathy, particularly in patients who have undergone an adequate trial of conservative care — including eccentric loading programs — without sufficient improvement. Midportion Achilles tendinopathy shows the most consistent clinical response to PRP in the published literature, and the treatment is most effective when used as a complement to, rather than a replacement for, a structured tendon loading program. At Maryland Orthopedic Specialists in Bethesda and Germantown, Maryland, our board-certified orthopedic physicians offer PRP for Achilles tendinopathy as part of a comprehensive, individualized treatment plan for patients throughout Montgomery County.

Understanding Achilles Tendinopathy

Achilles tendinopathy is one of the most common and most frustrating lower extremity overuse conditions encountered in orthopedic practice. It affects approximately 2–3% of runners and up to 9% of recreational athletes, and it is not limited to athletes — significant rates of Achilles tendinopathy are documented in sedentary middle-aged adults as well. The Achilles tendon is the largest tendon in the body and serves as the primary force transmitter for the calf muscle complex during walking, running, and jumping; its repeated loading requirements make it particularly susceptible to cumulative stress injury.

Clinically, it is important to distinguish between the two primary anatomical presentations of Achilles tendinopathy, as they differ in pathology, prognosis, and treatment response:

• Midportion Achilles tendinopathy occurs 2–6 cm proximal to the calcaneal insertion — the "watershed zone" of the tendon, which has the poorest blood supply. This is the more common presentation and the one with the strongest evidence base for PRP.
• Insertional Achilles tendinopathy occurs at or near the bone-tendon junction and is frequently associated with Haglund's deformity or enthesopathy. It is generally more resistant to all forms of treatment, including PRP, and the evidence for PRP at this location is less compelling.

The pathology of Achilles tendinopathy follows the continuum model described by Cook and Purdam: beginning as a reactive tendinopathy in response to acute overload, progressing through a failed repair phase, and ultimately reaching a degenerative state characterized by disorganized collagen architecture, intratendinous neovascularization (Kager's fat pad proliferation), and evidence of failed healing. Risk factors include training errors (sudden increases in mileage or intensity), inappropriate footwear, biomechanical factors (excessive pronation), male sex, increasing age, and concurrent metabolic conditions such as diabetes and hyperlipidemia.

The Rationale for PRP in Achilles Tendinopathy

The biological rationale for PRP in Achilles tendinopathy is particularly compelling because the condition's primary pathophysiological driver — failed healing in a hypovascular tissue environment — is precisely the deficit that PRP is designed to address.

The midportion of the Achilles tendon, unlike most tissues in the body, has limited intrinsic blood supply, which is why it is the most common site of both tendinopathy and spontaneous rupture. In a healthy tendon, platelet activation at sites of microtrauma initiates a cascade of growth factor release that coordinates the inflammatory, proliferative, and remodeling phases of tissue repair. In a degenerative tendon, this cascade is chronically dysregulated — the tissue is locked in a failed repair cycle, producing disorganized type III collagen rather than the mechanically superior type I collagen that characterizes healthy tendon.

PRP delivers supraphysiological concentrations of relevant growth factors directly to this hypovascular environment. Of particular importance for tendon repair, TGF-β1 stimulates tenocyte proliferation and type I collagen synthesis. PDGF drives cell migration and angiogenesis. VEGF promotes the formation of new capillary networks that can improve the long-term vascular supply to the affected area. Together, these factors aim to restart and redirect the repair response that the degenerative tendon can no longer mount on its own.

An important clinical distinction: PRP is injected peritendinously (around the tendon) rather than intratendinously (into the tendon substance itself) for Achilles tendinopathy. Intratendinous injection of any substance carries a risk of structural weakening and is not standard practice for chronic tendinopathy management.

Clinical Evidence: Literature Review

The evidence for PRP in Achilles tendinopathy is nuanced, with some trials showing benefit and others showing equivalence to placebo — a finding that has important implications for patient selection and protocol design.

de Vos RJ, et al. — JAMA, 2010

Citation: de Vos RJ, Weir A, van Schie HT, et al. Platelet-rich plasma injection for chronic Achilles tendinopathy: a randomized controlled trial. JAMA. 2010;303(2):144–149. DOI: 10.1001/jama.2009.1986

This is the largest and most frequently cited RCT of PRP specifically for chronic Achilles tendinopathy. The trial enrolled 54 patients with chronic midportion Achilles tendinopathy (symptoms > 2 months) and randomized them to either a single ultrasound-guided PRP injection or a saline injection. Critically, both groups simultaneously performed a standardized, supervised eccentric calf-loading program — one of the most effective evidence-based conservative treatments for Achilles tendinopathy. The primary outcome was the VISA-A questionnaire score (a validated disease-specific outcome measure) at 24 weeks. The finding: there was no statistically significant difference between the PRP and saline groups at 24 weeks.

This result warrants careful interpretation rather than dismissal. Both groups improved substantially from baseline — an outcome that reflects the well-established efficacy of eccentric loading. The most plausible explanation for the null finding is that when optimal conservative care (eccentric loading) is provided to both groups, PRP does not add measurable benefit in this specific context. The trial does not answer the more clinically relevant question of whether PRP helps patients who have already failed an eccentric loading program — which is the population most commonly presenting for PRP evaluation. The study also used a single injection, and injection formulation and leukocyte content were not reported. The takeaway from de Vos et al. is not that PRP is ineffective for Achilles tendinopathy, but that PRP may not augment outcomes when combined with concurrent eccentric loading in an RCT setting — and that patient selection and protocol design are critical determinants of treatment success.

Monto RR — Foot and Ankle Clinics, 2011

Citation: Monto RR. Platelet-rich plasma and Achilles tendon repair. Foot and Ankle Clinics. 2011;16(3):537–545.

This retrospective study evaluated the use of PRP as an augmentation strategy in Achilles tendon repair surgery, examining outcomes in patients who underwent tenorrhaphy with PRP augmentation versus standard repair alone. Patients in the PRP-augmented group demonstrated significantly better functional outcomes and higher AOFAS (American Orthopaedic Foot and Ankle Society) scores compared to controls, with results sustained and maintained at 2-year follow-up. This study addresses a different population than conservative non-surgical PRP (surgical versus non-operative context), but it provides histological and functional evidence that PRP can meaningfully augment Achilles tendon healing — specifically in the context of promoting tendon-to-tissue integration and structural remodeling after repair.

Sanchez M, et al. — Foot & Ankle International, 2003

Citation: Sanchez M, Anitua E, Azofra J, et al. Plasma rich in growth factors to treat an Achilles tendon avulsion. Foot & Ankle International. 2003;24(5):430–435.

This early case series evaluated the structural effects of PRGF (plasma rich in growth factors, a precursor formulation to modern PRP) in Achilles tendon injuries. Post-treatment histological analysis revealed evidence of improved collagen organization — specifically, a shift toward more regular, parallel collagen fiber arrangement resembling normal tendon tissue, compared to the disorganized fibrillar structure typical of degenerative tendinopathy. While the small sample size and case series design preclude definitive conclusions, the histological findings provide mechanistic support for the hypothesis that PRP promotes genuine structural remodeling of tendon tissue, not merely symptomatic relief.

PATH-2 Trial — Bone & Joint Journal, 2024

Citation: Alsousou J, et al. Platelet-rich plasma in Achilles tendon rupture: two-year follow-up of a randomized placebo-controlled trial. Bone & Joint Journal. 2024. DOI: 10.1302/1358-992X.2024.12.003

The PATH-2 trial deserves specific mention here because it is the most recent and one of the most rigorously designed trials involving the Achilles tendon and PRP — but it addresses an entirely different condition: acute Achilles tendon rupture, not chronic tendinopathy. The trial found no benefit of a single PRP injection over placebo in patients who had sustained an acute complete Achilles tendon rupture treated non-operatively. These results should not be extrapolated to the management of chronic midportion Achilles tendinopathy. Acute rupture and chronic tendinopathy are fundamentally different pathological processes at different stages of tissue biology — the optimal interventions, timing, and expected responses are not comparable. PRP is not recommended at Maryland Orthopedic Specialists for acute Achilles tendon rupture based on current evidence.

An Honest Assessment

The evidence for PRP in Achilles tendinopathy is more mixed than for knee osteoarthritis or lateral epicondylitis, and patients deserve a candid summary. PRP shows the most consistent benefit for midportion Achilles tendinopathy that has failed an adequate course of conservative care, particularly when eccentric loading has been performed for at least 8–12 weeks without sufficient improvement. In this population — patients with chronic, treatment-resistant tendinopathy — PRP represents a reasonable next step before considering more invasive interventions such as prolotherapy, percutaneous needle tenotomy, or surgical debridement.

PRP is not appropriate for, and has not shown benefit in, acute Achilles tendon rupture. Evidence for insertional Achilles tendinopathy is less robust. Results with PRP alone (without concurrent or subsequent loading programs) appear inferior to PRP combined with supervised eccentric exercise. At Maryland Orthopedic Specialists, we prescribe a post-injection eccentric loading protocol as standard practice, and we counsel patients that the combination of PRP and structured rehabilitation is more likely to produce meaningful, sustained improvement than either approach in isolation.

Who Is a Good Candidate for PRP?

• Chronic midportion Achilles tendinopathy (> 3 months) — Acute Achilles tendon rupture (complete or partial)
• Failed 8–12 weeks of eccentric loading program — Active infection or cellulitis at injection site
• Ultrasound-confirmed tendinosis at midportion — Insertional tendinopathy (weaker evidence, evaluated case-by-case)
• Willing to participate in post-injection rehab program — Platelet dysfunction or thrombocytopenia
• Athletes seeking to avoid surgical debridement — Current anticoagulant therapy (evaluated individually)
• Tendinopathy without full-thickness intratendinous tear — Systemic inflammatory disease in active flare

Treatment Protocol at Maryland Orthopedic Specialists

Diagnosis and Imaging All patients with suspected Achilles tendinopathy undergo clinical evaluation including assessment of pain location, severity, functional limitations, and prior treatment history. Diagnostic musculoskeletal ultrasound is performed to:

• Confirm the diagnosis and anatomical location (midportion vs. insertional)
• Grade the degree of tendinosis (structural disorganization, hypoechogenicity, tendon thickening)
• Identify any partial intratendinous tears
• Assess neovascularization with Doppler imaging
• Guide and confirm appropriate injection placement

The PRP Procedure

1. Blood is drawn from a peripheral vein (30–60 mL).
2. The sample is centrifuged to concentrate the platelet-rich plasma layer.
3. Under real-time ultrasound guidance, the PRP is injected peritendinously — surrounding the diseased midportion of the tendon — rather than into the tendon substance itself.
4. Peritendinous delivery is the standard approach for Achilles tendinopathy; intratendinous injection is avoided due to risk of structural compromise.

Post-Injection Protocol

• 48 hours of relative rest; avoid running and high-impact activity.
• Avoid NSAIDs for 2 weeks post-injection.
• Walking is permitted as tolerated from day one.
• Begin or resume eccentric calf-raise program at 2–4 weeks post-injection, progressing per a physical therapist's guidance.
• Follow-up at 6 weeks to assess symptoms, ultrasound findings, and readiness to advance loading.

Number of Injections Most patients receive one injection initially. A second injection at 6–8 weeks may be considered in partial responders. Bilateral or severe tendinopathy may require a staged approach.

Timeline to Results

• Mild improvement may be noted at 4–6 weeks.
• Meaningful pain reduction and improved function typically emerge at 8–12 weeks.
• Maximum benefit is expected at 3–6 months.
• Duration: 12 months or longer in responders who complete the rehabilitation protocol.

Frequently Asked Questions