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Achilles tendinitis (also Achilles tenosynovitis or Achilles tendinopathy) is tendinitis of the Achilles tendon, generally caused by overuse of the affected limb and is more common among athletes training under less than ideal conditions. It should not be confused with xanthoma of the tendon, which is the accumulation of cholesterol in patients with familial hypercholesterolemia.
Development of Achilles' tendinitis depends on the type, frequency and severity of exercise or use; for example, rock climbers tend to develop tendinitis in their fingers, swimmers in their shoulders. It is a common injury, particularly in sports that involve lunging and jumping.
Swelling in a region of micro damage or partial tear can be detected visually or by touch. Increased water content and disorganized collagen matrix in tendon lesions may be detected by ultrasonography or magnetic resonance imaging.
Symptoms can vary from an ache or pain and swelling to the local area of the ankles, or a burning that surrounds the whole joint. With this condition, the pain is usually worse during and after activity, and the tendon and joint area can become stiffer the following day as swelling impinges on the movement of the tendon. Many patients report stressful situations in their lives in correlation with the beginnings of pain which may contribute to the symptoms.
The Achilles tendon does not have good blood supply or cell activity, so this injury can be slow to heal. The tendon receives nutrients from the tendon sheath or paratendon. When an injury occurs to the tendon, cells from surrounding structures migrate into the tendon to assist in repair. Some of these cells come from blood vessels that enter the tendon to provide direct blood flow to increase healing. With the blood vessels come nerve fibers. Researchers including Alfredson and his team in Sweden  believe these nerve fibers to be the cause of the pain - they injected local anaesthetic around the vessels and this decreased significantly the pain from the Achilles tendon.
Treatment is possible with ice, cold compression therapy, wearing heel pads to reduce the strain on the tendon, and an exercise routine designed to strengthen the tendon (see eccentric strengthening, below). Some people have reported vast improvement after applying light to medium compression around ankles and lower calf by wearing elastic bandages throughout the day. Using these elastic bandages while sleeping can reduce morning stiffness but care must be taken to apply very light compression during sleep. Compression can inhibit healing by hindering circulation. Seeing a professional for treatment as soon as possible is important, because this injury can lead to an Achilles tendon rupture with continued overuse. Other treatments may include non-steroidal anti-inflammatory drugs, such as ibuprofen, ultrasound therapy, manual therapy techniques, a rehabilitation program, and in rare cases, application of a plaster cast. Steroid injection is sometimes used, but must be done after very careful, expert consideration because it can increase the risk of tendon rupture. There has recently been some interest in the use of autologous blood injections; however the results have not been highly encouraging and there is little evidence for their use.
More specialised therapies include prolotherapy (sclerosant injection into the neovascularity) and extracorporeal shockwave therapy may have some additional benefit. The evidence is however limited.
Prevention of recurrence includes following appropriate exercise habits and wearing low-heeled shoes. Preventive exercises are aimed at strengthening the gastrocnemius and soleus muscles, typically by eccentric strengthening exercises. These involve repetitions of slowly raising and lowering the body while standing on the affected leg, using the opposite arm to assist balance and support if necessary, and starting with the heel in a hyperextended position. (Hyperextension is typically achieved by balancing the forefoot on the edge of a step, a thick book, or a barbell weight. so that the point of the heel is a couple of inches below the forefoot.) A physical therapist can prescribe safe exercise methods.
- Alfredson, H.; Ohberg, L.; Forsgren, S. (Sep 2003). "Is vasculo-neural ingrowth the cause of pain in chronic Achilles tendinosis? An investigation using ultrasonography and colour Doppler, immunohistochemistry, and diagnostic injections.". Knee Surg Sports Traumatol Arthrosc 11 (5): 334–8. doi:10.1007/s00167-003-0391-6. PMID 14520512.
- Christopoulos DG, Nicolaides AN, Szendro G, Irvine AT, Bull M, Eastcott HHG (1987). "Air-plethysmography and the effect of elastic compression on venous hemodynamics of the leg.". J Vasc Surg 5 (1): 148–59. PMID 3795381.
- Christopher C Nannini, MD (2012). "Achilles Tendon Rupture". emedicinehealth.com. Retrieved February 12, 2012.
- "JBJS | Limited Evidence Supports the Effectiveness of Autologous Blood Injections for Chronic Tendinopathies". jbjs.org. 2012. Retrieved February 12, 2012.
- R. J. de Vos*, P. L. J. van Veldhoven, M. H. Moen, A. Weir, J. L. Tol and N. Maffulli (2012). "Autologous growth factor injections in chronic tendinopathy: a systematic review". bmb.oxfordjournals.org. Retrieved February 12, 2012.
- Maffulli, N; Longo, UG, Denaro, V (Nov 3, 2010). "Novel approaches for the management of tendinopathy.". The Journal of bone and joint surgery. American volume 92 (15): 2604–13. doi:10.2106/JBJS.I.01744. PMID 21048180.
- G T Allison, C Purdam. Eccentric loading for Achilles tendinopathy — strengthening or stretching? Br J Sports Med 2009;43:276-279