Achilles tendinitis, or tendinosis, is a condition affecting the Achilles tendon, which causes pain and discomfort at the structure's region. It is primarily caused by an inflammation of the adjacent sheath, the paratenon.
Achilles tendinitis is a condition induced by inflammation of the paratenon next to the Achilles tendon and leads to pain at the back of the heel. It is mainly induced by strain and pressure exerted to the back of the foot when walking, running or performing any type of intense physical exercise that involves this particular region.
The condition may manifest in two ways: the insertional type, which affects individuals who are not particularly active, and the non-insertional one. Insertional tendinitis is a result of the tendon's damage in the location where it is joined to the heel bone. Non-insertional tendinitis, on the other hand, involves the middle part of the tendon and is diagnosed in younger individuals who engage in physical activity of any type.
Achilles tendinitis is not solely caused by an injury to the tendon; it involves a more complicated etiologic path, including both intrinsic factors that predispose to a tendon injury amongst others, and extrinsic factors that further stress the tendons.
As far as the intrinsic factors are concerned, Achilles tendinitis has been associated with a plethora of other diseases, such as chronic kidney failure  , collagen deficiencies, autoimmune diseases such as systemic lupus erythematous and rheumatoid arthritis, thyroid and parathyroid dysfunction, gout, tibia vara, an O blood type and a prior family history of Achilles tendinitis    .
On the other hand, various extrinsic factors contribute to the final clinical picture and morbidity. The consumption of steroid drugs are believed to render the tendon more susceptible to damage  , quinolones also have a damaging and toxic effect on the tendon's structure   and, naturally, extreme physical activity causes excessive stress on the tendon    . There are particular circumstances when physical activity actually threatens the tendon's wellbeing: inadequate warm-up prior to intense exercise, jumping, running, stair climbing, shoes that are not designed to support intense exercise and stretching beyond a reasonable extent.
Achilles tendinitis mainly affects people who engage in frequent and excessive physical activity. Although the actual incidence of the disease has not been calculated yet, it is believed that 1 million athletes suffer from the condition annually. More specifically, this type of tendinitis is most common amongst track runners, dancers, gymnasts and tennis players (descending frequency).
A certain geographical discrepancy has also been observed. Only 6 new cases per 100,000 individuals have been reported in Scotland, whereas in Denmark, the number is 37 new cases per 100,000 . Men suffer from Achilles tendon injuries at a higher rate than women, almost 6 times more frequently. It appears that most cases of tendinitis are not diagnosed amongst professional athletes, but amongst people who engage in strenuous activity without adequate warm-up.
Achilles tendinitis does not refer to a single condition of the respective tendon, but to a variety of conditions with different pathophysiologic background and clinical characteristics. The classification model presently followed dictates the categorization of Achilles tendinitis depending on the specific location that has sustained damage, as opposed to the exact type of damage sustained.
In general, the aforementioned tendon can suffer various types of injuries, each of which can be outlined with the use of a different pathophysiologic route. The predominant histopathological alterations that are observed in a tendon include an elevated cellular proliferation, collagen disarray, neovascularization and an abnormally large quantity of ground substance   .
Based on the specific location on which an injury has been inflicted and the aforementioned histopathological changes, three types of Achilles tendinitis can be described:
Although the condition can lead to restricted mobility in its initial phase, it has a very good prognosis.
Achilles tendinitis leads to a characteristic clinical picture. The primary symptom is pain and tenderness at the location of the tendon, namely at the back of the heel. Initially, pain can be felt while engaging in various types of physical activity that involve motions of the feet; as the condition remains undiagnosed or mistreated, the condition is exacerbated and may lead to symptoms experienced while resting. Pain can be felt upon awakening in the morning, typically becomes worse with movement and is accompanied by edema and tenderness at the site of the tendon. Crepitation that can be palpated may also be caused, as a result of tendon fibrosis   , alongside enlarged regional lymph nodes.
Achilles tendinitis is mainly diagnosed clinically. There are no specific tests or pathognomonic findings: the workup procedure involves a standard complete blood count, in order to detect markers of inflammation or rule out abnormalities that may cause the same clinical picture, coagulopathy-focused tests, an ESR (erythrocyte sedimentation rate) and tests ordered to eliminate arthritis. Imaging modalities can be employed if necessary.
Achilles tendinitis is a condition with no etiologic treatment, that is approached supportively in order to minimize pain, edema and inflammation of the tendon. Various methods have been proposed and are applied, depending on the particular characteristics of each case. These include:
There are various measures to prevent the onset of Achilles tendinitis. If a person has never suffered from the condition before, prevention centers around strengthening the tendon and delaying its potential degeneration, which is expected to occur as a person ages. One should be physically active and follow a correct workout schedule, that involves adequate warm-up and stretching time, in order to maintain flexible tendons that can become stronger  .
On the other hand, patients who suffer from the chronic type of Achilles tendinitis are advised to wear appropriate shoes, orthotic devices to correct gait abnormalities that may induce tendon traumatization and no high heel shoes. An exercise program that involves gradual intensity buildup is recommended . Physical activity should also feature special exercises to strengthen the gastrocnemius muscles, especially when the condition has been caused by a degenerative alteration to the tendons.
Achilles tendinitis is a condition that affects the Achilles tendon, namely the tendon that lies at the back of the heel and served as the lever, in order to pull the heel upwards. This tendon is involved in every movement the heel performs: walking, jumping, dancing and practically every type of physical exercise, intense or not, exerts pressure on the tendon. Although this structure is designed to bear an extreme amount of weight, its frequent use and strain can lead to damage, either in the form of inflammation or rupture.
Achilles tendinitis is a term used to describe any type of damage the Achilles tendon may sustain. It is primarily caused by intense physical exercise, activity without the appropriate warm-up and stretching exercises or engaging in intense activity after having remained immobile for a long time. The aging process further aggravates the condition: aged tendons have degenerated fibers, something which makes it more likely for this structure to be injured.
Tendon injuries manifest in a characteristic way. A person will feel pain at the back of the heel that worsens with exercise or may accompany them even when they rest. This location may be felt as sluggish, tender and swollen. The patients usually wake up in the morning to feel the pain present at the Achilles tendon's location. This condition is diagnosed mainly by the symptoms a patient mentions and the physical examination.
There is no definitive answer concerning which therapeutic measure is most beneficial to the individuals affected by Achilles tendinitis; various methods are applied. These include physical therapy, which is the core of the therapeutic approach, anti-inflammatory medications, acupuncture, shock therapy and, in some extreme cases, even surgery.