Patellar Tendinopathy: The Efficacy of Injection Treatments


Patellar tendinopathy is a common overuse injury of the patella tendon frequently seen in running and jumping sports. Many of us will be aware of the pathophysiology, where repeated episodes of microtrauma cause strain on the patella tendon and microscopic damage develops in the tendon tissues. As many as 53% of athletes retire from their sports due to this injury, highlighting the importance of knowledge and up to date research in such an area to provide optimal treatment (van Ark et al, 2011).  A multi-factorial approach is ideally taken with such a pathology and a variety of different treatments are used; commonly rest, NSAIDS, stretching, eccentric training, and injection treatments (van Ark et al, 2011). The utilisation of injection therapy has recently gained popularity and a number of studies have investigated the clinical benefits and pathological results of the various injection options. This article will discuss new research on the efficacy of injection treatments for patellar tendinopathy.

Patellar Tendinopathy


What Does The New Research Say?

Van Ark et al (2011) recently published a systematic review comparing 7 different injection treatments and discussed their rationale and effectiveness in treating patellar tendinopathy. Overall, they concluded the use of injection treatments seem promising, however it is difficult to draw firm conclusions due to the small number of studies which are not only of low quality, but present conflicting views on the rationale and methodological approach of such treatments.

 The Different Injection Options

Steroid Injections

  • Ultrasound imaging shows that steroids can reduce inflammation and oedema in a tendon, but cannot repair degenerative changes (Fredberg et al, 1998).
  • Fredberg et al (2004), Kongsgaard et al (2009) and Capasso et al (1997) each conducted a RCT on the use of steroid injections on patella tendinosis which all demonstrated improvements in pain scores in the short term (3/12), however improvements deteriorated in the long term (6/12) and in some cases even relapsed to their initial pain scores after 4 weeks.
  • This lack of long term improvement is possibly attributed to its lack of effect upon tissue regeneration, and is thus targeting the symptoms, and not the cause of the pain.
  • To add insult to injury (pun intended), adverse effects including slowing and weakening of collagen synthesis leading to a higher risk of tendon rupture has been shown with the use of repeated steroid injections
  • It would be remiss of us at this point to not mention the work from Coombes, Bisset and Vicenzino (2010) who showed in the management of tendinopathy that any potential short term improvements in function following corticosteroid injections are reversed in the longer term.

Sclerosing Injections

  • As assumed from previous research, neovascularisation seen in tendinopathy is attributed to increased pain.
  • Sclerosis, the act of injecting a chemical irritant (e.g. polidocanol) into the tendon, is thought to destroy the neovessles and accompanying nerves, thus ridding the patient of pain.
  • Alfredson and Ohberg (2005) noted significant reductions in pain during activity, and increases in knee function up to 4/12 post treatment.
  • They failed to investigate the long term effects, and more quality research is needed to justify the use of such treatment.

Aprotinin Injections

  • Aprotinin is a protein which inhibits the enzyme ‘metalloprotease’ that breaks down protein which makes up tendon tissue.
  • Capasso et al (1997) and Orchard et al (2008) found varying results with the Aprotinin injection and in some instances, provided better pain relief then steroid injections. They concluded Aprotinin injections are better used as a second line treatment.
  • Both studies however were of low methodological quality and although the results look promising, it is difficult to draw any valid conclusions with regards to its effect upon patella tendinosis.
  • Furthermore, some sports medicine practitioners are reluctant to use aprotinin injections secondary to potential for anaphylaxis (Orchard et al., 2008).

Platelet Rich Plasma (PRP) Injections

  • Platelet rich plasma (PRP) is blood plasma enriched with platelets containing growth factors, and is utilised to stimulate soft tissue healing with low healing potential.
  • Volpi et al (2007), Kon et al (2009) and Filardo et al (2010) investigated the use of PRP injections combined with varying exercise and stretching programmes. They showed significant reductions in pain and, in some cases, an improvement in regeneration of the tendon tissue.
  • However, with low methodological quality due to lack of control groups and lack of standardisation of the subjects included in the studies, we again cannot make confident conclusions on its immediate and long term effects.
Sports Physiotherapist | Sports Physiotherapy | Physical Therapy

 Take Home Messages

  • In the early, inflammatory stages of patella tendonitis, steroid injections may be beneficial for reducing the inflammation and oedema. Whilst this may lead in the short term to greater pain relief and quicker return to activity the long term implications of these injections must be considered.
  • In the later  degenerative stages of tendinopathy, injection treatments targeting tendon regeneration, such as PRP, should be considered. We can maximise such treatment by combining the injection with an appropriate exercise training program which includes eccentric exercises loading the patellar tendon to improve tendon regeneration.
  • There is a dearth of quality research on injection therapies for patellar tendinopathy; and many clinical decisions are made via past experience and anecdotal evidence.

What Are Your Thoughts?

What are your experiences with injection therapy and patellar tendinopathy? I would love you to let me know in the comments or catch me on Facebook or Twitter.

Also, if you are after more information about exercises helpful in the management of patellar tendinopathy; check this out. (affiliate link)

About The Author

This is a great guest post from Frances McKirdy. Fran graduated from Nottingham University in England with a BSc (Hons) in Physiotherapy. Her knowledge and experience comes from a rounded background in cardiopulmonary, orthopaedic, neurological and musculoskeletal physiotherapy. Having a keen interest in sport rehabilitation, she is currently working in Singapore specializing in musculoskeletal disorders, sports injuries, and post-operative rehabilitation. She has also experience working as the physiotherapist at the Denmark football festival for the U18 squad from England and for several rugby teams. Her approach to treatment is evidence based and individualized; ensuring her rehabilitation is effective and recovery time is optimised. Outside of her work, she is also a keen sports-woman with a wide sporting background in athletics, wakeboarding, running, netball and touch rugby.


Alfredson, H. Ohberg, L. (2005) Neovascularisation in chronic painful patellar tendinosis– promising results after sclerosing neovessels outside the tendon challenge the need for surgery. Knee Surg Sports Traumatol Arthrosc; 13: 74–80.

Capasso G, Testa V, Maffulli N. (1997) Aprotinin, corticosteroids and normosaline in the management of patellar tendinopathy in athletes: a prospective randomized study.  Sports Exerc Injury; 3 :111–15.

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Fredberg, U. Bolvig, L. Pfeiffer-Jensen, M. (2004) Ultrasonography as a tool for diagnosis, guidance of local steroid injection and, together with pressure algometry, monitoring of the treatment of athletes with chronic jumper’s knee and Achilles tendinitis: a randomized, double-blind, placebo-controlled study.  Scand J Rheumatoll; 33: 94-101.

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Kongsgaard, M. Kovanen, V. Aagaard, P.  (2009) Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. Scand J Med Sci Sports; 19: 790 – 802 .

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Orchard J, Massey A, Rimmer J, Hofman J, Brown R. Delay of 6 weeks between aprotinin injections for tendinopathy reduces risk of allergic reaction. Journal of Science and Medicine in Sport 2008;11(5):473-480.

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