Keeping active is an incredibly important part of life to improve health and fitness, and to prevent chronic diseases like diabetes and heart disease . However, tendon injuries can cause debilitating pain in professional and recreational athletes which may result in reduced activity levels . One of the more common tendon conditions is Achilles tendinopathy .
What is tendinopathy?
Tendons connect muscles to bone in order to transmit forces that help us move . They are incredibly strong and are made up of very organised, well-aligned fibres called collagen . In fact, the Achilles tendon is loaded with up to 12 times it’s body weight when running !
Tendinosis (or tendinopathy) is the term used to denote degenerative changes in the tendon structure, which typically involve disorganisation of these fibres and microtears [5, 6]. This can occur with or without pain . This can be slow to heal due to the relatively poor blood supply to tendons [2, 5].
What causes Achilles tendinopathy?
Achilles tendinopathy is commonly seen in runners or sports involving lots of running , due to increased load going through the tendon. This is because the Achilles tendon connects the calf muscles to the heel bone to allow for the push off required when running . It most commonly occurs in the middle of the tendon, but can also affect where the tendon connects to the bone .
Typically, tendons respond well to consistent loading (i.e. the duration and intensity of running), but they hate drastic changes in load [7, 8]. This causes the tendon structure to become disorganised and inefficient as it cannot handle the increased load. For example, someone who has not run for 3 months who decides to run 30km in a week is at a high risk of developing tendon pain.
Other risk factors for the development of Achilles tendinopathy are :
- Weak calf muscles
- Ankle instability
- Flat feet
- Taking certain antibiotics
- Taking corticosteroids
Of note, 6% of sedentary people (i.e. minimal tendon loading) will suffer from Achilles tendinopathy in their life . This is thought to be due to the effect metabolic diseases have on the tendon, its ability to repair and pain mechanisms [9, 10]. This includes diabetes, insulin resistance, obesity and high cholesterol [9, 11, 12].
What are the symptoms?
Achilles tendinopathy is characterised by :
- Pain on loading the tendon (e.g. running)
- Morning stiffness in the Achilles tendon, often improves as the tendon warms up
- Swelling of the Achilles tendon
- Decreased strength/power due to pain
What about rupturing the tendon?
Tendinopathy is a risk factor for tendon rupture, due to the disease within the tendon rendering it weaker . However, as previously mentioned, tendons can have structural abnormalities without symptoms. For this reason, most Achilles tendon ruptures occur in people without previous pain. Most ruptures occur in middle-aged men doing explosive or unexpected movements . As with tendinopathy, certain medications can also increase the risk of rupture .
How is tendinopathy treated?
Tendons like to be loaded on a consistent basis, within their capacity. The mainstay of treatment for Achilles tendinopathy is therefore optimal loading exercises [7, 16, 17]. This often means initially reducing activity (as overload is usually the issue) and slowly building this capacity over the following weeks . Other adjuncts in the early stage include icing and anti-inflammatories, although these provide more short term relief . From there, calf strengthening exercises can also be added to assist the musculotendinous unit . Management may also involve correction of biomechanics, for example those with chronic ankle instability, as appropriate footwear can help offload the tendon and alleviate symptoms . It must be noted, however, that this is a condition that often takes months to resolve, even with the best treatment.
There are further medical interventions available for Achilles tendinopathy which can be used when symptoms are not controlled by a thorough trial of a loading program. These include certain medications, patches, shock wave therapy and injections. Recently, there has been more robust evidence supporting the role of platelet-rich plasma (PRP) injections in treating resistant forms of tendinopathy [20, 21], but it must be used with an appropriate rehabilitation program. It is also important to adequately control blood sugars, weight and cholesterol levels if these are an issue, particularly in sedentary tendinopathy [9, 11]. Recently the use of steroid injections has fallen out of favour, as there is growing evidence that these weaken the tendon and increase risk of rupture in the long-term .
Achilles tendon pain can be diagnosed and managed by sports doctors, physiotherapists and sports podiatrists.
1. Carroll S, Dudfield M. What is the relationship between exercise and metabolic abnormalities? A review of the metabolic syndrome. Sports medicine 2004;34(6):371-418
2. Rio E, Moseley L, Purdam C, et al. The pain of tendinopathy: physiological or pathophysiological? Sports medicine 2014;44(1):9-23
3. Kujala UM, Sarna S, Kaprio J. Cumulative incidence of achilles tendon rupture and tendinopathy in male former elite athletes. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine 2005;15(3):133-5
4. Khan KM, Cook JL, Bonar F, Harcourt P, Astrom M. Histopathology of common tendinopathies. Update and implications for clinical management. Sports medicine 1999;27(6):393-408
5. Maffulli N, Sharma P, Luscombe KL. Achilles tendinopathy: aetiology and management. Journal of the Royal Society of Medicine 2004;97(10):472-6
6. Maffulli N, Khan KM, Puddu G. Overuse tendon conditions: time to change a confusing terminology. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association 1998;14(8):840-3
7. Cook JL, Rio E, Purdam CR, Docking SI. Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research? British journal of sports medicine 2016;50(19):1187-91
8. O'Neill S, Watson PJ, Barry S. A Delphi Study of Risk Factors for Achilles Tendinopathy- Opinions of World Tendon Experts. International journal of sports physical therapy 2016;11(5):684-97
9. Gaida JE, Alfredson L, Kiss ZS, Wilson AM, Alfredson H, Cook JL. Dyslipidemia in Achilles tendinopathy is characteristic of insulin resistance. Medicine and science in sports and exercise 2009;41(6):1194-7
10. Jewson JL, Lambert EA, Docking S, Storr M, Lambert GW, Gaida JE. Pain duration is associated with increased muscle sympathetic nerve activity in patients with Achilles tendinopathy. Scandinavian journal of medicine & science in sports 2017;27(12):1942-49
11. Ranger TA, Wong AM, Cook JL, Gaida JE. Is there an association between tendinopathy and diabetes mellitus? A systematic review with meta-analysis. British journal of sports medicine 2016;50(16):982-9
12. Tilley BJ, Cook JL, Docking SI, Gaida JE. Is higher serum cholesterol associated with altered tendon structure or tendon pain? A systematic review. British journal of sports medicine 2015;49(23):1504-9
13. van Sterkenburg MN, van Dijk CN. Mid-portion Achilles tendinopathy: why painful? An evidence-based philosophy. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA 2011;19(8):1367-75
14. Hess GW. Achilles tendon rupture: a review of etiology, population, anatomy, risk factors, and injury prevention. Foot Ankle Spec 2010;3(1):29-32
15. Sode J, Obel N, Hallas J, Lassen A. Use of fluroquinolone and risk of Achilles tendon rupture: a population-based cohort study. Eur J Clin Pharmacol 2007;63(5):499-503
16. Rio E, Kidgell D, Purdam C, et al. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. British journal of sports medicine 2015;49(19):1277-83
17. Kongsgaard M, Qvortrup K, Larsen J, et al. Fibril morphology and tendon mechanical properties in patellar tendinopathy: effects of heavy slow resistance training. The American journal of sports medicine 2010;38(4):749-56
18. Kubo K, Ikebukuro T, Yata H, Tsunoda N, Kanehisa H. Time course of changes in muscle and tendon properties during strength training and detraining. J Strength Cond Res 2010;24(2):322-31
19. Alfredson H, Ohberg L, Zeisig E, Lorentzon R. Treatment of midportion Achilles tendinosis: similar clinical results with US and CD-guided surgery outside the tendon and sclerosing polidocanol injections. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA 2007;15(12):1504-9
20. Miller LE, Parrish WR, Roides B, Bhattacharyya S. Efficacy of platelet-rich plasma injections for symptomatic tendinopathy: systematic review and meta-analysis of randomised injection-controlled trials. BMJ Open Sport Exerc Med 2017;3(1):e000237
21. Fitzpatrick J, Bulsara MK, O'Donnell J, McCrory PR, Zheng MH. The Effectiveness of Platelet-Rich Plasma Injections in Gluteal Tendinopathy: A Randomized, Double-Blind Controlled Trial Comparing a Single Platelet-Rich Plasma Injection With a Single Corticosteroid Injection. The American journal of sports medicine 2018;46(4):933-39
22. Mohamadi A, Chan JJ, Claessen FM, Ring D, Chen NC. Corticosteroid Injections Give Small and Transient Pain Relief in Rotator Cuff Tendinosis: A Meta-analysis. Clinical orthopaedics and related research 2017;475(1):232-43