PRP for Hamstring Injuries

Does PRP Work for Hamstring Injuries?

PRP has demonstrated clinically meaningful evidence for two distinct hamstring conditions: acute Grade II (partial) hamstring muscle tears, where PRP injected into the injury site may accelerate return to sport; and chronic proximal hamstring tendinopathy, one of the most refractory running injuries, where PRP has shown significant improvement in pain and function in patients who have failed conservative management. The literature for acute hamstring strains shows mixed but generally positive results — faster return to sport when PRP is combined with a structured rehabilitation program — while the evidence for chronic proximal tendinopathy is consistently favorable in case series and clinical cohort studies.

At Maryland Orthopedic Specialists, our board-certified orthopedic physicians provide ultrasound-guided PRP therapy for hamstring injuries at our Bethesda and Germantown, MD offices, serving patients throughout Montgomery County and the greater Washington area.

The Hamstring Injury Spectrum

The hamstring muscle group comprises three muscles: the biceps femoris (long and short heads), the semimembranosus, and the semitendinosus. These muscles originate from the ischial tuberosity at the base of the pelvis, traverse the posterior thigh, and insert below the knee — crossing two joints and functioning in both hip extension and knee flexion. The dual-joint nature of the hamstrings makes them particularly vulnerable to strain during high-speed running, when the muscle is simultaneously lengthening under active eccentric load.

Hamstring injuries are the most common muscle injury in field sports, accounting for 12–16% of all athletic injuries. In elite soccer, Australian football, and sprinting sports, they represent the single most frequent injury type by incidence. The clinical and economic burden is substantial: athletes with hamstring injuries miss an average of 2–4 weeks of competition, and the re-injury rate is approximately 16–30% without comprehensive rehabilitation — among the highest recurrence rates of any sports injury.

Acute hamstring injuries are classified by severity:

• Grade I: Muscular strain with microscopic tearing; minimal functional deficit; full strength maintained; MRI shows peritendinous edema without macroscopic fiber disruption
• Grade II: Partial tear with macroscopic fiber disruption; significant pain and functional deficit; reduced strength; MRI demonstrates partial-thickness disruption with preserved muscle continuity
• Grade III: Complete rupture or proximal avulsion; significant weakness and functional loss; MRI shows full-thickness disruption; may require surgical repair (particularly proximal avulsions involving three tendons at the ischial tuberosity)

Proximal hamstring tendinopathy is a distinct clinical entity from acute muscle injury. It is a chronic degenerative condition affecting the tendinous origin of the hamstrings at the ischial tuberosity, typically presenting as deep buttock pain that is reproducibly aggravated by sitting for extended periods, running (especially uphill running and sprinting), and hip flexion. It most commonly affects long-distance runners and cyclists in the 40–60-year age range, though it can occur in younger athletes. Conservative management — including load management, progressive eccentric strengthening, and education — is the recommended first-line approach, but symptoms can persist for years in some patients, significantly limiting training capacity and quality of life.

Two Distinct PRP Applications

Acute Grade II Hamstring Tears

For acute Grade II hamstring tears, PRP is injected directly into the tear site under musculoskeletal ultrasound guidance, typically within 24–72 hours of injury during the proliferative phase of healing. At this stage, the injury site contains a hematoma (blood clot) and early inflammatory cells; the biological environment is primed for repair and most receptive to growth factor delivery.

The theoretical mechanism mirrors PRP's application in other soft tissue injuries: the concentrated platelets release PDGF, TGF-β1, IGF-1, FGF, and VEGF, which collectively recruit fibroblasts, stimulate satellite cell activation in the muscle, promote myogenic precursor proliferation, and support collagen matrix formation at the injury site. The goal is to amplify and accelerate a process that would occur naturally, compressing weeks of biological repair into a shorter timeframe.

Timing is critical. PRP injected during the acute inflammatory phase (days 0–3) provides growth factors when the healing cascade is most active. Injection during the remodeling phase (after day 14) may offer less benefit. This is one reason some published studies using delayed injection show attenuated effects compared to early-intervention studies.

Chronic Proximal Hamstring Tendinopathy

Like plantar fasciitis, proximal hamstring tendinopathy is fundamentally a degenerative condition. Histopathological studies of symptomatic proximal hamstring tendons demonstrate collagen disorganization, angiofibroblastic hyperplasia, increased ground substance, and absence of significant inflammatory infiltrate — the hallmarks of tendinosis. This pathology explains why anti-inflammatory approaches (corticosteroids, NSAIDs) provide limited long-term benefit and, in the case of repeated corticosteroid injection, carry real risks of tendon weakening and rupture at the enthesis.

PRP for proximal hamstring tendinopathy is reserved for patients who have failed at least 3 months of structured conservative management including:

• Activity modification and load management
• A progressive eccentric and heavy slow resistance (HSR) exercise program targeting the proximal hamstring
• Addressing biomechanical contributors (hip flexor tightness, running gait, saddle height in cyclists)
• Education about tendon loading principles

In this refractory population, PRP injected under ultrasound guidance directly into the degenerative zone at the ischial tuberosity origin provides growth factors to a tissue environment that has lost the ability to self-repair. Evidence from case series and retrospective studies shows significant improvements in pain (VAS, PROMIS Pain) and function (VISA-H, iHOT scores) at 3, 6, and 12 months.

Clinical Evidence: Literature Review

Study 1 — Fader et al., Muscles, Ligaments and Tendons Journal, 2014

Citation: Fader RR, Mitchell JJ, Traub S, et al. "Platelet-Rich Plasma Treatment Improves Outcomes for Chronic Proximal Hamstring Injuries in an Athletic Population." Muscles Ligaments Tendons J. 2014;4(4):461–466. URL: PMC4327356

This retrospective case series enrolled 18 consecutive athletes with clinically diagnosed and MRI-confirmed chronic proximal hamstring tendinopathy who had failed a minimum of 6 months of conservative management (activity modification, physical therapy, NSAIDs). All patients received a single ultrasound-guided PRP injection into the proximal hamstring origin, administered by a single sports medicine radiologist.

Key findings: At 6-month follow-up, 10 of 18 patients (56%) demonstrated 80% or greater improvement in their VAS pain score. The overall mean subjective improvement across all 18 patients was 63% (range 5–100%). The average VAS score pre-injection was 4.6; at 6 months post-injection, mean improvement was 63% from baseline. All 18 patients were available for follow-up. The only documented adverse effect was post-injection discomfort resolving within 72 hours in a single patient. The authors noted that this refractory patient population — athletes who had failed all conventional conservative measures — showed meaningful clinical improvement, supporting PRP as a viable option when eccentric exercise and rehabilitation have been exhausted.

Study 2 — Wetzel et al., Orthopedics, 2013

Citation: Wetzel RJ, Patel RM, Terry MA. "Platelet-Rich Plasma as an Effective Treatment for Proximal Hamstring Injuries." Orthopedics. 2013;36(1):e64–e70. DOI: 10.3928/01477447-20121217-20

This retrospective case series studied 15 athletes with chronic proximal hamstring tendinopathy and/or partial proximal hamstring tears who had failed traditional conservative treatment including physiotherapy and NSAIDs. Corticosteroid injections had been used in some cases but had not provided lasting relief. All patients received ultrasound-guided PRP injection into the hamstring origin.

Key findings: Clinically significant reductions in VAS pain scores were observed in the PRP group (P < .01). Nirschl Phase Rating Scale scores also improved significantly (P < .01) in the PRP cohort. In the matched traditional conservative treatment comparison group, neither VAS nor Nirschl scores showed statistically significant improvement. All athletes returned to their desired activity level following PRP treatment, with no major complications. The authors also noted — in the first evaluation of its kind — that patients who had previously received corticosteroid injection for this condition without lasting relief showed meaningful response to PRP, suggesting a distinct and complementary mechanism of action.

Study 3 — Hamid et al., American Journal of Sports Medicine, 2014

Citation: A. Hamid MS, Mohamed Ali MR, Yusof A, George J, Lee LPC. "Platelet-Rich Plasma Injections for the Treatment of Hamstring Injuries: A Randomized Controlled Trial." Am J Sports Med. 2014;42(10):2410–2418. DOI: 10.1177/0363546514541540

This single-blinded RCT enrolled 28 athletes (recreational through competitive) with Grade II hamstring injuries confirmed on MRI and randomized them to a single ultrasound-guided PRP injection plus standardized rehabilitation program versus rehabilitation program alone.

Key findings: The PRP group demonstrated a statistically significant reduction in time to return to play: 26.7 ± 7.0 days versus 42.5 ± 20.6 days in the control group (P = .02) — a difference of approximately 16 days. Significantly lower pain severity scores were observed in the PRP group throughout the study. No significant difference in pain interference scores was found between groups. No adverse events were reported. This remains one of the best-controlled individual RCTs of PRP for acute hamstring injuries and is frequently cited in subsequent systematic reviews as demonstrating clinically meaningful return-to-sport acceleration with PRP.

Study 4 — AOSSM 2023 Registry Data: LR-PRP for Proximal Hamstring Tendinopathy

Citation: Drexelius K, Imoe S, Orahovats A, Genuario J, Hunt K, Swanson B. "Patient Reported Outcomes Following Treatment with Leukocyte Rich Platelet Rich Plasma Injections for Proximal Hamstring Tendinopathy." Orthopaedic Journal of Sports Medicine. 2023;11(7 Suppl):S207. DOI: 10.1177/2325967123S00207

This retrospective analysis was drawn from a prospective PRP Data Registry, enrolling patients with documented proximal hamstring tendinopathy (PHT) who received ultrasound-guided leukocyte-rich PRP (LR-PRP) injections, all prepared using the Zimmer Biomet GPS III Platelet Concentration System. PRP was injected at a median volume of 3.2 mL (range 2.5–4 mL) per hamstring. Data were collected from September 2020 to August 2022, with follow-up at 2 weeks, 3 months, 6 months, and 1 year post-injection.

Key findings: Statistically significant improvements were observed in PROMIS Pain scores at all timepoints: 2 weeks (P = 0.036), 3 months (P = 0.003), 6 months (P = 0.007), and 1 year (P = 0.019). PROMIS Physical Function scores also improved significantly at 3 months (P = 0.030), 6 months (P = 0.015), and 1 year (P = 0.045). A strong positive correlation was identified between greater PRP volume injected and improved iHOT scores at 1 year (Pearson r = −0.90). Patient satisfaction with the injection increased across all timepoints. The authors concluded the data "adds to limited literature on LR-PRP for PHT" and supports its use for improving hip pain and function associated with proximal hamstring tendinopathy, noting that leukocyte-rich formulation specifically may be preferable for tendinopathic applications, where the inflammatory response from leukocyte content may enhance the biological stimulus for repair.

Evidence Synthesis: Systematic Reviews and Meta-Analyses (2020–2026)

Multiple systematic reviews and meta-analyses have pooled RCT data on PRP for acute hamstring injuries. A 2025 umbrella review published in PMC (PMID: PMC12966554) identified that across 8 systematic reviews, PRP significantly reduced re-injury risk versus controls (RR 0.84; 95% CI 0.76 to 0.92; I² = 0%), with high certainty of evidence. A 2026 British Journal of Sports Medicine meta-analysis of 6 RCTs (N = 277) found PRP reduced return-to-play time by a mean of 8.6 days (21.4 vs. 30.0 days; 95% CI −3.04 to −0.03; P = .045), particularly when image-guided injection was used. Adverse event rates and re-injury rates did not differ significantly from controls. The certainty of evidence was rated low to moderate, reflecting heterogeneity in PRP preparation, timing of injection, and rehabilitation co-interventions — underscoring that PRP for hamstring injuries should be viewed as one component of a comprehensive treatment program, not a standalone cure.

Re-Injury Prevention: Why PRP Alone Is Not Enough

The 30% hamstring re-injury rate in athletes represents one of the great clinical challenges in sports medicine. PRP provides a biological scaffold for tissue repair, but the structural and neuromuscular deficits that predispose to re-injury require targeted rehabilitation to address. A comprehensive return-to-sport program following PRP injection must include:

Progressive loading: Hamstring rehabilitation follows the principle of progressive tendon and muscle loading — beginning with isometric exercise, advancing to isotonic eccentric and concentric loading, and eventually heavy slow resistance training (Nordic hamstring curls, Romanian deadlifts with progressive load). This process cannot be rushed, regardless of how well the initial pain response to PRP proceeds.

Neuromuscular training: Re-injury risk is partly mediated by altered motor control and reduced proprioceptive feedback in the previously injured muscle. Targeted neuromuscular training (single-leg balance, agility drills, sport-specific movement patterns) addresses these deficits.

Sprint mechanics analysis: Biomechanical risk factors — excessive anterior pelvic tilt, insufficient hip extension, overstriding — are modifiable contributors to hamstring injury risk. A sprint mechanics assessment and targeted corrections should be part of any return-to-sport protocol for athletes.

Gradual return-to-play: Objective criteria for return to sport — full strength symmetry (injured versus uninjured limb), pain-free sprinting at maximal velocity, positive functional testing — should be met before competitive return, regardless of the calendar timeline.

PRP provides the biological groundwork. Rehabilitation determines structural integrity and long-term re-injury risk.

Patient Selection

• Grade II hamstring tear, athlete, ≤ 72 hours post-injury — Strongly appropriate — inject early during proliferative phase
• Grade II hamstring tear, recreational athlete, > 1 week post-injury — Appropriate; benefit may be attenuated; still reasonable
• Proximal hamstring tendinopathy, failed 3+ months conservative care including eccentric loading — Strongly appropriate for LR-PRP at ischial tuberosity origin
• Chronic PHT in runner or cyclist, sitting pain, bilateral symptoms — Appropriate; ensure eccentric program is in place before injection
• Grade III complete hamstring rupture / proximal avulsion, functional deficit — Surgical consultation is primary; PRP not indicated as standalone
• Grade I strain, no significant fiber disruption on MRI — Conservative care (rehabilitation alone) is appropriate first-line; PRP not indicated
• Active anticoagulation, platelet disorder — Evaluate eligibility individually

Treatment Protocol at Maryland Orthopedic Specialists

Acute Grade II Hamstring Tear Protocol

Timing: PRP injection within 24–72 hours of injury is optimal. At this stage, musculoskeletal ultrasound confirms the presence of a hematoma at the tear site and guides needle placement.

Guidance: Real-time musculoskeletal ultrasound. The probe is placed over the posterior thigh to visualize the area of fiber disruption and peritendinous edema. A single-needle or fenestration technique is used to deliver 3–5 mL of PRP into the hematoma and surrounding injured tissue.

NSAIDs: Discontinue NSAIDs immediately post-injury and avoid for 2 weeks post-injection, as they inhibit platelet activation and the prostaglandin-mediated healing response.

Post-injection rehabilitation (typical timeline):

• Days 0–5: Rest, ice, gentle ROM maintenance, avoid stretching into pain
• Week 1–2: Non-impact aerobic conditioning (pool walking, cycling with reduced resistance), gentle progressive ROM
• Week 2–4: Progressive strengthening — isometric, then isotonic hamstring exercises; core stabilization
• Week 4–6: Eccentric loading program begins; agility initiation (linear, controlled pace)
• Week 6–8: Sprint progression — linear sprinting at increasing intensity (70% → 85% → 95% maximal velocity); sport-specific drills
• Week 8–10: Return-to-sport testing (strength symmetry, functional tests); clearance for full competitive return if criteria met

Proximal Hamstring Tendinopathy Protocol

Guidance: Ultrasound-guided injection at the ischial tuberosity origin. Patient positioned prone. The probe identifies the tendinous origin of the biceps femoris and semimembranosus/semitendinosus and the area of degenerative signal change. Needle placed under direct visualization. 3–5 mL of LR-PRP injected with peppering technique through the degenerative zone.

Post-injection management: Avoid high-load hamstring activity and prolonged sitting on hard surfaces for 2 weeks. Resume eccentric loading program at week 3, progressing over 6–12 weeks. Expect a pain flare in the first 3–7 days post-injection — this is a normal biological response and not indicative of complication.

Follow-up: Clinical reassessment at 6–8 weeks. A second injection may be considered at 8–12 weeks in patients with partial response. Most patients with proximal hamstring tendinopathy who respond to PRP show meaningful improvement by 3 months and sustained improvement through 6–12 months.

Return-to-sport milestones: Full return to running: typically 10–16 weeks post-injection. Full return to speed work and competition: 16–24 weeks, contingent on continued rehabilitation compliance and clinical response.

Frequently Asked Questions