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Jumper’s Knee – Patella tendinopathy

Over the years we have seen a lot of people with knee problems. Many of them with problems of the patellar tendon. They have had many treatments including, cortisone, physical therapy, rest, some of the them wear big braces on their knees. They are doing a consult with me because they are still looking for help. Can Platelet Rich Plasma Therapy help them? After an email or a phone call we assesses the person’s situation. If we feel they are a realistic candidate for treatment, they come in for a consultation where we can do an examination and come up with a healing program.

  • 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. PRP utilizes the blood’s platelets and their healing and tissue repair factors.

Patellar tendinopathy is commonly referred to by the more lay terms as “Jumper’s Knee” or “Tennis Knee” because this type of chronic injury is seen obviously in jumping athletes and tennis players. The term basketball knee may also apply as this injury is caused by wear and tear of playing basketball on hard surfaces. So too tennis players. Most tennis players play on the painted cement court.

Women make for a larger percentage of patellar tendinopathy than previous thought.

This is not a male problem.

A June 2022 paper (1) writes: “Patellar tendinopathy is one of the most common musculoskeletal problems associated with sport. While commonly perceived as a predominantly male problem, recent epidemiological studies revealed that it also affects a large number of sport-active women . . . Women represent only a minority of patients studied for this topic (this paper) showed a gender blindness in sports medicine when investigating a common problem like patellar tendinopathy.”

Various treatment options

When knee pain begins, most people self-treat via instructions from the internet. They will ICE and  COMPRESS the knee with tape or braces. Some will ELEVATE their knee when laying down or sitting in a chair. Much fewer will REST. By now you will probably recognize the familiar RICE anagram or Rest, Ice, Compression, and Elevation as the first line of knee pain treatments along with anti-inflammatory medications found “over-the-counter.”

As the person’s knee worsens they will make their first doctors appointment. Here their doctor may advise them to Rest, Ice, Compress and elevate again. This time the doctor may offer the person a stronger medication. Still failing to resolve their knee pain, the doctor then may move onto stronger medication, a cortisone injection, or physical therapy. Some people will get all these treatments.

For clinicians to maximize the efficacy of conservative treatment options for their patients, they must understand the most up-to-date literature evaluating the potential benefit of taping, bracing, and injections as adjunctive treatments for maximizing treatment success

A June 2020 study (2) from Stanford University focused on additional treatment options for the two most common causes of front of the knee pain, patellofemoral pain syndrome, and patellar tendinopathy. The researchers wrote: “Conservative management is the first-line treatment for these conditions. For clinicians to maximize the efficacy of conservative treatment options for their patients, they must understand the most up-to-date literature evaluating the potential benefit of taping, bracing, and injections as adjunctive treatments for maximizing treatment success.”

Here they discuss tape, brace, and Prolotherapy, PRP and Stem Cell injections

  • Recent studies of bracing and taping have found them to be helpful for patients in the short-term management of pain and improving function.
  • Injections remain a commonly used treatment for musculoskeletal conditions; however, the evidence for their use in patellofemoral pain and patellar tendinopathy is limited. The use of platelet-rich plasma (PRP), sclerosing (sometimes referred to as Prolotherapy), or stem cell injections is an exciting new area in the treatment of patellar tendinopathy.

I point out this study because many of the people that come into our office have heard something similar in their orthopedist’s office. Wear a brace if it helps, there is no evidence that PRP or stem cells can help you. So the first thing many of the people who eventually come to visit is ask is, “Is there any research on PRP or stem cells for patellofemoral pain syndrome, and patellar tendinopathy?”

I also want to point out that these same people who come visit us are people who have been on anti-inflammatories, wrap up their legs in ace bandages, ice, may have had a cortisone injections and nothing is really helping. They are here because for some of them are willing to take a chance on PRP or stem cells.

Physical therapy and exercise for Patellar tendinopathy

A May 2022 study (3) suggests that “Despite a dearth of studies on preventative interventions for athletes with Patellar tendinopathy, resistance training may be a useful prophylactic method. Eccentric, heavy slow and isometric resistance training have been found to be feasible and clinically beneficial in-season. There are a lack of studies showing that extracorporeal shock wave therapy offers any additional benefit over resistance training in competing athletes. Patellar strapping and taping may offer short-term pain relief during training and competition.”

Platelet-rich plasma injection in the treatment of patellar tendinopathy

A May 2022 paper (2)  compared PRP injection with other ‘active treatment’ interventions (‘Non-PRP’ injection and ‘No-injection’ treatments) or ‘No-active treatment’ interventions. To do this the researchers examined eight published studies. They suggest “assessment of these studies revealed that there were no significant differences in pain relief, functional outcomes, and quality of life in the short, medium, and long term between PRP injection and Non-PRP injection interventions. Similarly, comparison of PRP injection to the No-active treatment intervention showed no differences in short- and medium-term pain relief. However, when PRP injection was compared to the No-injection treatment intervention extracorporeal shock wave therapy , the former was found to be more effective in terms of pain relief in the medium term and long term and functional outcomes in the medium term and long term. Conclusions: “In terms of pain relief and functional outcomes, the PRP injection did not provide significantly greater clinical benefit than Non-PRP injections in the treatment of patellar tendinopathy. However, in comparison with ESWT, there was a significant benefit in favor of PRP injection.”

Is PRP no better than a placebo? “IT’S UNCLEAR.”

One of the problems in understanding if PRP works for patellar tendinopathy is that empirically, doctors have seen good results. However, there is very little research to support this. In May 2022 a paper in The Journal of family practice (3) wrote:

Does platelet-rich plasma (PRP) injections improve patellar tendinopathy symptoms?  “IT’S UNCLEAR. High-quality data have not consistently established the effectiveness of platelet-rich plasma (PRP) injections to improve symptomatic recovery in patellar tendinopathy, compared to placebo (strength of recommendation A), based on 3 small randomized controlled trials. The 3 small randomized controlled trials included only 111 patients, total. One found no evidence of significant improvement with PRP compared to controls. The other 2 studies showed mixed results, with different outcome measures favoring different treatment groups and heterogeneous results depending on follow-up duration.”

PRP is effective for patellar tendinopathy

However an April 2022 (5) also reviewed the previous research and said this: “Four studies investigated the efficacy of PRP injection on various outcome measures of patellar tendinopathy. All the selected studies reported a significant positive impact of PRP injection on patellar tendinopathy symptoms.” The researchers also noted “significantly improved” pain and functional scores at the  6- and 12-month follow-up assessments. Another study “reported that PRP accelerated the recovery compared to dry needling in a short-term follow-up. However, this benefit dissipated over time.” Further PRP showed better outcomes in short-term, medium-term, and long-term follow-ups compared to normal saline injection. The researchers here as well concluded there is not enough published research, stating: “However, because of the limited number of studies and the disparities in the study populations and protocols, it is not possible to make a firm conclusion on the efficacy of these injection methods, and these results should be inferred with care.”

PRP research on patellar tendinopathy

There is limited research as well in the role of PRP in helping patients with patellar tendinopathy. However a 2017 study (4) stated: “These limited studies are encouraging and indicate that PRP injections have the potential to promote the achievement of a satisfactory clinical outcome, even in difficult cases with chronic refractory tendinopathy after previous classical treatments have failed.” One of the studies reviewed was a study from researchers in the Netherlands. In this study, outcomes of patients with patellar tendinopathy treated with platelet-rich plasma injections (PRP) were evaluated to determine whether certain characteristics, such as activity level or previous treatment affected the results. What they found was: “After PRP treatment, patients with patellar tendinopathy showed a statistically significant improvement. In addition, these improvements can also be considered clinically meaningful.”

A 2014 study in The American journal of sports medicine (5) offered these results and assessments:

  • “Chronic patellar tendinopathy is one of the most common overuse knee disorders. Platelet-rich plasma (PRP) appears to be a reliable nonoperative therapy for chronic patellar tendinopathy.”

In this study a total of 28 athletes (17 professional, 11 semiprofessional) with chronic patellar tendinopath refractory to nonoperative management were prospectively included for ultra-sound guided pure PRP injections into the site of the tendinopathy. The same treating physician at a single institution performed 3 consecutive injections 1 week apart, with the same PRP preparation used. Tendon healing was assessed with MRI at 1 and 3 months after the procedure.


  • Patients showed significantly improved at the 2-year follow-up.
  • Twenty-one of the 28 athletes returned to their presymptom sporting level at 3 months (range, 2-6 months) after the procedure.
  • Follow-up MRI assessment showed improved structural integrity of the tendon at 3 months after the procedure and complete return to normal structural integrity of the tendon in 16 patients (57%).
  • Seven patients did not recover their presymptom sporting level (among them, 6 were considered treatment failures): 3 patients returned to sport at a lesser level, 1 patient changed his sport activity (for other reasons), and 3 needed surgical intervention.


In this study, application of 3 consecutive ultrasound-guided PRP injections significantly improved symptoms and function in athletes with chronic patellar tendinopathy and allowed fast recovery to their pre-symptom sporting level. The PRP treatment permitted a return to a normal architecture of the tendon as assessed by MRI.

A July 2018 study (6) wraps it up succinctly. The study author wrote: “Patellar tendons seem to benefit from PRP injections.”

As stated at the top of this article. We have been offering regenerative medicine injections for more than 23 years. Empirical and in office data shows a benefit for many. Will these treatments work for everyone? No. Email me with the form below so we can assess whether or not these treatments would be viable for you.

UCLA doctors present a case history

Doctors at UCLA presented this September 2021 case history (6). It tells the story of a 19-year-old FEMALE Division-1 collegiate soccer player who came to the training room with a slowly developing and worsening onset right front knee pain. According to the case: “The pain started while she was doing rehabilitation following a right anterior cruciate ligament (ACL) reconstruction using a contralateral patellar tendon autograft. She has point tenderness over her right medial proximal patellar tendon, and she describes pain that worsens with repetitive loading of her knee during activities such as squats and running. She is diagnosed with patellar tendonitis via diagnostic ultrasound and starts physical therapy with a specific focus on eccentric and concentric loading of the quadriceps. She fails to improve following 3 months of compliant physical therapy and is frustrated by her continued pain. ” The patients was recommended to PRP injections. “Using ultrasound guidance, the athlete underwent a patellar tendon LP-PRP injection without the use of local anesthetic. She was restricted from lower body activities for 2 weeks to allow tissue recovery. She then resumed her rehabilitation program with a focus on eccentric loading in addition to her post-ACL reconstruction exercise regimen. At 15-month follow-up, she was ready to play in the season opener for her collegiate team.”

But is there any research?

A December 2018 study examined the role of mesenchymal stem cells in the treatment of tendinopathies.(2) The investigators of this study wrote: “Although (research) attention was mainly focused on their (the stem cell’s) ability to differentiate (change into needed repair cells) and to directly participate to the regeneration process in the past, mesenchymal stem cells have more recently been demonstrated to have further and probably more important therapeutic functions in response to injury like immune modulation and trophic (promoting cellular growth) activities. That is why that they have been defined as “drugstores”. Indeed, they can home in on sites of inflammation or tissue injury and they start to secrete immunomodulatory and trophic agents such as cytokines and growth factors aimed to re-establish physiological homeostasis in response to that environment. (In simpler terms act as an anti-inflammatory and pro-healing agent). So, either as direct player in the process or/and bioactive molecules “drugstores”, mesenchymal stem cells may enhance tissue repair and regeneration and thereby restore normal joint homeostasis.” This research does suggest further studies to validate these positive findings.

A well referenced and cited study from 2012 (3) followed eight mid-20s aged athletes with chronic patellar tendon degeneration. These patients received bone marrow stem cell therapy. The stem cells were taken from the patient’s iliac bone crest and injected into the problem knee. These patients were then followed for 5 years to measure the long-term results of the treatment. Here were the published results:

  • “At 5-year followup, statistically significant improvement was seen for most clinical scores.
  • Seven of eight patients said they would have the procedure again if they had the same problem in the opposite knee and were completely satisfied with the procedure.
  • Seven of 8 patients thought that the results of the procedure were excellent. According to our results, (bone marrow stem cells should be) considered as a potential therapy for those patients with chronic patellar tendinopathy refractory to nonoperative treatments.”


1 Mondini Trissino da Lodi C, Landini MP, Asunis E, Filardo G. Women Have Tendons… and Tendinopathy: Gender Bias is a “Gender Void” in Sports Medicine with a Lack of Women Data on Patellar Tendinopathy—A Systematic Review. Sports Medicine-Open. 2022 Dec;8(1):1-8.
2 Sisk D, Fredericson M. Taping, Bracing, and Injection Treatment for Patellofemoral Pain and Patellar Tendinopathy [published online ahead of print, 2020 Jun 4]. Curr Rev Musculoskelet Med. 2020;10.1007/s12178-020-09646-8. doi:10.1007/s12178-020-09646-8
3 Burton I. Interventions for prevention and in-season management of patellar tendinopathy in athletes: A scoping review. Physical Therapy in Sport. 2022 Mar 7.

2 Barman A, Sinha MK, Sahoo J, Jena D, Patel V, Patel S, Bhattacharjee S, Baral D. Platelet-rich plasma injection in the treatment of patellar tendinopathy: a systematic review and meta-analysis. Knee surgery & related research. 2022 Dec;34(1):1-5.
3 Wolfenden E, Vukelic B, DeMarco M, Knox J, Ose D. Does platelet-rich plasma improve patellar tendinopathy symptoms? J Fam Pract. 2022 May;71(4):188-189. doi: 10.12788/jfp.0402. PMID: 35730711.

5 Nuhmani S, Ahsan M, Bari MA, Malhotra D, Al Muslem WH, Alsaadi SM, Muaidi QI. Patellar Tendinopathy—Does Injection Therapy Have a Role? A Systematic Review of Randomised Control Trials. Journal of clinical medicine. 2022 Apr 3;11(7):2006.
6 Fahy KE, Miller EM, Kobayashi Y, Gottschalk AW. Efficacy of Platelet-Rich Plasma on Symptom Reduction in Patellar Tendinopathy. The Ochsner Journal. 2021;21(3):232.


2 Abat F, Alfredson H, Cucchiarini M, Madry H, Marmotti A, Mouton C, Oliveira JM, Pereira H, Peretti GM, Spang C, Stephen J, van Bergen CJA, de Girolamo L. Current trends in tendinopathy: consensus of the ESSKA basic science committee. Part II: treatment options. J Exp Orthop. 2018 Sep 24;5(1):38. doi: 10.1186/s40634-018-0145-5. PMID: 30251203; PMCID: PMC6153202.
3 Pascual-Garrido C,et al. Treatment of chronic patellar tendinopathy with autologous bone marrow stem cells: a 5-year-followup. Stem Cells Int. 2012;2012:953510. doi: 10.1155/2012/953510. Epub 2011 Dec 18.
4. Gosens T, Den Oudsten BL, Fievez E, van ‘t Spijker P, Fievez A. Pain and activity levels before and after platelet-rich plasma injection treatment of patellar tendinopathy: a prospective cohort study and the influence of previous treatments.Int Orthop. 2012 Apr 27. [Epub ahead of print]
5. Charousset C, Zaoui A, Bellaiche L, Bouyer B. Are multiple platelet-rich plasma injections useful for treatment of chronic patellar tendinopathy in athletes? a prospective study. The American journal of sports medicine. 2014 Apr;42(4):906-11.
6 Filardo G, Di Matteo B, Kon E, Merli G, Marcacci M. Platelet-rich plasma in tendon-related disorders: results and indications. Knee Surgery, Sports Traumatology, Arthroscopy. 2018 Jul;26(7):1984-99. — 1613

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