Achilles Tendonitis (1)

What is Achilles Tendonitis?

Often, and inaccurately, any pain around the Achilles is referred to as Achilles tendonitis. Achilles tendonitis refers to one specific and defined pathology of several which exist, and can co-exist. It is useful to divide the different problems of the Achilles tendon into those which affect the main “body” of the Achilles tendon (these conditions are tendonitis, tendonosis and rupture) and those conditions with affect the insertion of the Achilles tendon into the bone (insertional tendonosis of the Achilles tendon, a Hagglunds deformity).

What does Achilles Tendonitis look like?

The Achilles tendon itself structurally can be thought of almost like a horses tail with lots of longitudinal fibres running parallel to each other and packed very tightly. This is the substance of the Achilles tendon(2). Over a period of time, sometimes following multiple smaller injuries, areas of the body of the Achilles tendon can start to lose their normal well defined structure. In these areas the Achilles tendon itself becomes less well defined and the normal longitudinal fibres are less visible. This type of degenerative change within the Achilles tendon is known as tendonosis(1) and this usually results in a symmetrical swelling and area of localised pain in the tendon.The healthy, and unhealthy, Achilles tendon is surround circumferentially by a fine covering known as the paratenon(3). This layer looks something like a sausage skin and has various functions including lubrication and supplying blood to the tendon. When this layer becomes inflamed then the condition is known as Achilles tendonitis. It should be realised that both Achilles tendonitis as well as Achilles tendonosis may co-exist in the same Achilles tendon.