Someone will email an MRI of their hamstring problem. They will talk about their microtearing in their hamstring tendons and their pain and soreness with certain movements, especially sitting. They have had a cortisone injection and anti-inflammatories. They have rested it and rested it and it is still not improving. Over the years we have seen many patients with hamstring injuries and we have helped many achieve their treatment goals. Let’s look at the research.
The hamstrings comprise a group of muscles at the back of the thigh. Among the muscle group is the semitendinosus muscle, semimembranosus muscle and the long and short head of the biceps femoris. The semitendinosus muscle, semimembranosus muscle and the long head of the biceps femoris hamstrings attach to the pelvis at the ischial tuberosity, the bony prominences sometimes referred to as “sit bones.” So named because they are the bones we do sit on. They are also often referred to as the Proximal hamstrings (the center hamstrings) because of their attachment or insertion at this “center” point.
Hamstring reinjury rates are high
A February 2022 paper (11) writes: “Hamstring strain injuries are common among athletes and often require rehabilitation to prepare players for a timely return to sport performance while also minimizing reinjury risk. Return to sport is typically achieved within weeks of the injury; however, subsequent athlete performance may be impaired, and reinjury rates are high. Improving these outcomes requires rehabilitation practitioners (eg, athletic trainers and physical therapists) to understand the causes and mechanisms of hamstring strain injury, know how to perform a thorough clinical examination, and progress loading to the site of injury safely and effectively.”
Wear and tear, partial tear, full hamstring tear treatments
When we get emails into the office about hamstring injuries it is usually from someone who has a full devastating tear or a recent acute partial tear, or someone who has been suffering from a “nagging,” hamstring problem. A confirmed complete rupture would require surgery to get an athlete back to his/her sport. A partial acute tear, or, wear and tear damage can be treated non-surgically.
When someone contacts our office with the “nagging” type injury, they have already searched the internet for a series of remedies and aids that may help them “get through it.” Unfortunately many of the suggested treatments they have read about, Rest, Ice, wraps, tapes, compression sleeves, only do so much to help them. None of these treatments are actually designed to heal a hamstring. They are designed to provide comfort and address symptoms. At this point the hamstring sufferer will then seek out further treatment. A course of physical therapy may be recommended. Many people find this helpful. As mentioned earlier in this article there is also recommendations to stronger prescription strength non-steroidal anti-inflammatory medications and corticosteroid injections.
Treatment with cortisone or PRP?
PRP treatments involve collecting a small amount of your blood and spinning it in a centrifuge to separate the platelets from the red cells. The collected platelets are then injected back into the injured area to stimulate healing and regeneration.
As hamstring injury is usually accompanied by inflammation, cortisone is often suggested as a treatment. There are times cortisone may be called for, we very, very rarely see a patient where we would suggest cortisone. In our office we specialize in regenerative medicine, treatments that rebuild tissue. Cortisone removes inflammation, it does not rebuild tissue.
An April 2019 study (1) compared the effectiveness of pain relief in patients with grade 2 proximal hamstring injury (typically a partial tear that causes you to limp, have some muscle swelling, and soreness to the touch), treated with platelet-rich plasma (PRP) or corticosteroid injection.
In a group of 56 patients:
- 32 received PRP
- 24 received steroid injections
At 1 week post-injection follow-up, 23 patients (71.9%) from the PRP group and 11 patients (45.8%) from the steroid group showed positive response, (as measured by VAS pain scale).
At 4 weeks post-injection, 23 patients (71.9%) from the PRP group and 13 patients (54.2%) from the steroid group showed positive response, (as measured by VAS pain scale).
The research concluded: “The PRP group had shown more favorable response compared to steroid group at 1 week post-injection, which suggests that PRP therapy can be considered as a conservative treatment choice for grade 2 proximal hamstring injuries with better short-term pain relief based on limited pilot data.”
A January 2022 paper (12) writes: “The effect of platelet-rich plasma (PRP) treatment on recovery in acute hamstring injuries is controversial. Previous study results are inconsistent, and a standardized therapeutic approach has not been established yet.” In this study the doctors assessed the treatment effect using a combination of hematoma aspiration and muscle strain PRP injection in partial hamstring muscle tears (grade 2 strains) in athletes.
- Athletes were treated conservatively, and with a combination of ultrasound-guided hematoma aspiration and PRP muscle strain injection.
- The outcome, including return-to-play (in days) and recurrence rate, was compared retrospectively between both groups (conservative vs aspiration/PRP).
Results: Fifty-five athletes (28 treated conservatively, 27 with hematoma aspiration/PRP injection) were included. Average return-to-play time (mean) was 32.4 days in the conservative group and 23.5 days in the aspiration/PRP group. Recurrence rate of the hamstring strain was 28.6% (8/28) in the conservative treatment group and less than 4% (1/27) in the aspiration/PRP group.
Conclusions: “Athletes with grade 2 hamstring strains treated with a combination of hematoma aspiration and PRP injection had a significantly shorter return-to-play and a lower recurrence rate compared with athletes receiving conservative treatment.”
NFL players with acute hamstring injuries return to play faster after PRP injections
An April 2020 study (2) found that the addition of PRP injections to nonoperative treatment for acute partial musculotendinous hamstring injuries will lead to a shortened return to play in National Football League (NFL) players. Here is the summary:
- A total of 108 NFL players had MRI evidence of a hamstring injury, and of those, 69 athletes sustained grade 2 injuries.
- Thirty players received augmented treatment with PRP injections and 39 players underwent nonoperative treatment alone.
- Average time missed in those treated with PRP injections was 22.5 days, 18.2 practices, and 1.3 games.
- In those who did not receive PRP injections, time missed was 25.7 days, 22.8 practices and 2.9 games.
Chronic hamstring injuries in athletes
A 2015 study (3) from the University of Colorado declared: “The results of our study indicate that ultrasound guided platelet rich plasma injection at the ischial tuberosity for chronic recalcitrant hamstring tendinitis is an effective reliable treatment modality when traditional conservative treatment fails. Some cases can certainly be treated conservatively and achieve successful results, but other cases do not respond as well to these modalities, and the literature suggests either a corticosteroid injection or operative repair as the next possible step. Our results support the prior results . . . that PRP would be a logical, and less invasive, option for treating proximal hamstrings tendinopathy, specifically those that have failed traditional conservative treatment. Platelet rich plasma injection provides improvement in functional outcomes, while providing pain relief. ”
An April 2022 study (10) published different results. The researchers accessed 108 previously published studies on hamstring injuries to conclude: “Several strategies exist to prevent hamstring injury and address known risk factors. Eccentric strengthening reduces injury incidence and improves hamstring strength, fascicle length, H/Q ratio (the measurement of torque in the hamstring muscle group), and limb asymmetry, while stretching-based interventions can be implemented to improve flexibility. These results provide valuable insights to athletes, trainers, coaches, and therapists seeking to optimize hamstring training and prevent injury.
In a study of 90 male participants, A July 2022 paper (9) evaluating the efficacy of early versus delayed introduction of lengthening (ie, eccentric strengthening) exercises in addition to an established rehabilitation program on return to sport duration for acute hamstring injuries found: “Accelerating the introduction of lengthening exercises in the rehabilitation of hamstring injury in male athletes did not improve the time to return to sport nor the risk of reinjury.”
Hamstring injuries may need more than one treatment or single injection – Why PRP may not work
There is research, as pointed out in this article that PRP can help hamstring injuries. There is also research that suggests it will not. In our twenty plus years of treating patients with regenerative medicine techniques, we have seen many patients where PRP injections have failed. Why did they fail? Mostly it was not enough treatment. What does this mean? Typically when someone goes to an orthopedist for hamstring injury and it is agreed upon by doctor and patient to give PRP a try, the treatment will most likely consist of a single injection to a single spot at the hamstring attachment. This is not the optimal way to offer PRP.
In August 2020 researchers (4) announced that they will be conducting a new study on PRP that will take the next few years. Here is how they are testing the effectiveness of PRP. One injection.
“Currently, there are controversies regarding the clinical use of platelet-rich plasma (PRP) for the treatment of acute hamstring injury. . . This study is a single-center double-blind randomized placebo-controlled trial.”
Here is the study guidelines: Sixty-eight patients will be randomized to receive under ultrasound guidance either a single injection of PRP or normal saline. All patients will undergo a standardized hamstring rehabilitation program under the supervision of a sports physiotherapist. The results of this study will provide insights into the effect of PRP in muscle and may help to identify the best PRP application protocol for muscle injuries.
One shot of PRP will usually not extend much or any benefit. Treatment with PRP needs to be more comprehensive
The chances are these researchers will find similar results to other researchers who found one injection of PRP to be not effective. For instance, here are the findings of an earlier study on one shot PRP for hamstring injuries. In this study,(5) the researchers looked at the effectiveness of a single platelet-rich plasma (PRP) injection in reducing the return to sport duration in male athletes, following an acute hamstring injury. The findings? “(This study’s) findings indicate that there is no benefit of a single PRP injection over intensive rehabilitation in athletes who have sustained acute, MRI positive hamstring injuries. Intensive physiotherapy led rehabilitation remains the primary means of ensuring an optimal return to sport following muscle injury.”
Many times we will get an email from someone with chronic hamstring problems seeking stem cell therapy for their injury. A main reason for seeking stem cell therapy to the patient is that they already tried PRP and it did not work for them. Why would it not work for them? Many of these people received a single PRP injection. The single PRP injection is a treatment type that we typically see as not effective for many people. We will suggest to patients that, realistically, to achieve the type of healing they are looking for, 2 – 3 treatments may be required. This was confirmed by research in a March 2019 paper in the Journal of science and medicine in sport.(6)
In this study, doctors tested the efficacy of an ultrasound-guided platelet-rich plasma (PRP) injection in the treatment of patients with proximal hamstring tendinopathy.
- The patient was given “a single PRP injection under ultrasound guidance.” Following the injection, pain, function and sporting activity were measured via the Victorian Institute of Sport Assessment-Proximal Hamstring Tendons (VISA-H) questionnaire, administered before injection and at 8-weeks follow-up.
- 69% of patients reported no change in their ability to undertake sport or other physical activity at 8-weeks follow-up. Conclusion: “Patients with proximal hamstring tendinopathy receiving a PRP injection did not improve on clinical outcomes at 8-weeks follow-up.”
Does this mean a single PRP treatment will not help? No, not at all. Even in this the above study 69% of the people said that they had no improvement, 31% had a different outcome. In a study, published in the Journal of Ultrasound Medicine, (7) doctors offered these more positive findings:
The researchers of this study compared the effects of ultrasound-guided platelet-rich plasma (PRP) and whole blood (WB) injections in patients with chronic hamstring tendinopathy. Again this was a single injection. In our office we have seen consistently better results when a second or third treatment was offered.
- The doctors performed a prospective double-blind randomized controlled trial, PRP or WB was injected under ultrasound guidance into the proximal hamstring tendon in a group of patients with clinically suspected hamstring tendinosis. Questionnaires were administered before injection and 2, 6, and 12 weeks and 6 months after injection. Pain and function outcomes were measured.
Results: The whole blood (WB) group showed greater improvements in pain and function over the PRP group before 12 weeks, whereas the PRP group showed improved outcomes over whole blood (WB) at 6 months. “Both PRP and whole blood groups showed improvements in all outcome measures at 6 months. The PRP group showed significant improvements in 6-month pain and function scores.”
PRP speeds up rehab
Accelerating the rehab process following an acute hamstring injury is one of the main reasons people reach out to us following hamstring injury. These people tells us that they are already in physical therapy and that they were told by their therapist that the should look into PRP therapy to help accelerate the healing process. In agreement with our own clinical observations, a study in the American Journal of Sports Medicine (8) reported these results:
- Twenty-eight patients diagnosed with an acute hamstring injury were randomly allocated to autologous PRP therapy combined with a rehabilitation program or a rehabilitation program only. The primary outcome of this study was time to return to play. In addition, changes in pain severity and pain interference scores over time were examined.
- Patients in the PRP group achieved full recovery significantly earlier than controls. The mean time to return to play was up to 15 days sooner for the PRP group vs the control group. Significantly lower pain severity scores were observed in the PRP group throughout the study. A single autologous PRP injection combined with a rehabilitation program was significantly more effective in treating hamstring injuries than a rehabilitation program alone.
We have been offering regenerative medicine injections for more than 22 years. We have helped many people with hamstring problems. Can PRP or stem cell therapy be an option for you? Use the contact form below so we can assess your candidacy for treatment.
Do you have questions? Ask Dr. Darrow
Marc Darrow, MD., JD. is the medical director and founder of the Darrow Stem Cell Institute in Los Angeles, California. With over 23 years experience in regenerative medicine techniques and the treatment of thousands of patients, Dr. Darrow is considered a leading pioneer in the non-surgical treatment of degenerative Musculoskeletal Disorders and sports related injuries. Dr. Darrow has co-authored and continues to co-author leading edge medical research including the use of bone marrow derived stem cell therapy for shoulder, hip, knee and spinal disorders.
Marc Darrow, MD. JD., discusses the treatment philosophy of the Darrow Stem Cell Institute. Transcript of video
A leading provider of stem cell therapy, platelet rich plasma and prolotherapy
11645 WILSHIRE BOULEVARD SUITE 120, LOS ANGELES, CA 90025
Stem cell and PRP injections for musculoskeletal conditions are not FDA approved. We do not treat disease. We do not offer IV treatments. There are no guarantees that this treatment will help you. Prior to our treatment, seek advice from your medical physician.
Neither Dr. Darrow, nor any associate, offer medical advice from this transmission. This information is offered for educational purposes only. The transmission of this information does not create a physician-patient relationship between you and Dr. Darrow or any associate. We do not guarantee the accuracy, completeness, usefulness or adequacy of any resource, information, product, or process available from this transmission. We cannot be responsible for the receipt of your email since spam filters and servers often block their receipt. If you have a medical issue, please call our office. If you have a medical emergency, please call 911.
1 Park PY, Cai C, Bawa P, Kumaravel M. Platelet-rich plasma vs. steroid injections for hamstring injury—is there really a choice?. Skeletal radiology. 2019 Apr 1;48(4):577-82.
2 Bradley JP, Lawyer TJ, Ruef S, Towers JD, Arner JW. Platelet-Rich Plasma Shortens Return to Play in National Football League Players With Acute Hamstring Injuries. Orthopaedic journal of sports medicine. 2020 Apr 17;8(4):2325967120911731.
3 Fader RR, Mitchell JJ, Traub S, Nichols R, Roper M, Dan OM, McCarty EC. Platelet-rich plasma treatment improves outcomes for chronic proximal hamstring injuries in an athletic population. Muscles, ligaments and tendons journal. 2014 Oct;4(4):461.
4 Hamid MS, Hussein KH, Salim AM, Puji A, Yatim RM, Yong CC, Sheng TW. Study protocol for a double-blind, randomised placebo-controlled trial evaluating clinical effects of platelet-rich plasma injection for acute grade-2 hamstring tear among high performance athletes. BMJ open. 2020 Aug 1;10(8):e039105.
5 Hamilton B, Tol JL, Almusa E, Boukarroum S, Eirale C, Farooq A, Whiteley R, Chalabi H. Platelet-rich plasma does not enhance return to play in hamstring injuries: a randomised controlled trial. British journal of sports medicine. 2015 Jul 1;49(14):943-50.
6 Levy GM, Lucas P, Hope N. Efficacy of a platelet-rich plasma injection for the treatment of proximal hamstring tendinopathy: A pilot study. Journal of science and medicine in sport. 2019 Mar 1;22(3):247-52.
7 Davenport KL, Campos JS, Nguyen J, Saboeiro G, Adler RS, Moley PJ. Ultrasound‐Guided Intratendinous Injections With Platelet‐Rich Plasma or Autologous Whole Blood for Treatment of Proximal Hamstring Tendinopathy: A Double‐Blind Randomized Controlled Trial. Journal of Ultrasound in Medicine. 2015 Aug;34(8):1455-63.
8 A Hamid MS, Mohamed Ali MR, Yusof A, George J, Lee LP. Platelet-rich plasma injections for the treatment of hamstring injuries: a randomized controlled trial. The American journal of sports medicine. 2014 Oct;42(10):2410-8.
9 Vermeulen R, Whiteley R, van der Made AD, van Dyk N, Almusa E, Geertsema C, Targett S, Farooq A, Bahr R, Tol JL, Wangensteen A. Early versus delayed lengthening exercises for acute hamstring injury in male athletes: a randomised controlled clinical trial. British journal of sports medicine.:bjsports-2020.
10 Rudisill SS, Varady NH, Kucharik MP, Eberlin CT, Martin SD. Evidence-based hamstring injury prevention and risk factor management: A systematic review and meta-analysis of randomized controlled trials. The American Journal of Sports Medicine. 2022 Apr 6:03635465221083998.
11 Hickey JT, Opar DA, Weiss LJ, Heiderscheit BC. Hamstring Strain Injury Rehabilitation. Journal of Athletic Training. 2022 Feb;57(2):125-35.
12 Trunz LM, Landy JE, Dodson CC, Cohen SB, Zoga AC, Roedl JB. Effectiveness of Hematoma Aspiration and Platelet-rich Plasma Muscle Injections for the Treatment of Hamstring Strains in Athletes. Medicine and science in sports and exercise. 2022 Jan 1;54(1):12-7.