INJURY DIAGNOSIS TENDINOPATHY INTRATENDINOUS TISSUE

n Collagen degeneration and thinning n Scattered vascular ingrowth n Hypercellularity n Increased interfibrillar glycosaminoglycans n Interfibrillar mucoid patches and vacuoles n Lipid accumulation

PARATENDINOUS TISSUE

n Mucoid degeneration n Fibrosis n Vascular proliferation n Degeneration of main body of tendo achilles n Peritendinous crepitans (adhesions)

Grey and amorphous appearance Tendon thickening (diffuse, fusiform or nodular) Figure 4: Histopathological signs of tendinopathy

The degeneration is either mucoid or lipoid, microscopically characterised by thinning of collagen fibres, interfibrillar mucoid patches and vacuoles, or an intratendinous accumulation of lipids, respectively (20). These degenera- tive changes are a constant feature of Achilles tendon rupture, emphasising that tendinosis is an important precur- sor and cause of tendon rupture (22). The peritendinous tissue can

be involved in the early stages of tendinopathy and can show histological signs of mucoid degeneration, fibrosis and vascular proliferation, either alone or in combination with degeneration of the main body of the tendo Achilles (23). Paratenon involvement occasionally presents as ‘peritendinous crepitans’ and is due to adhesions between the tendon and the paratenon (10). The occurrence of these histopathological changes results in macroscopic alterations in the appearance of the affected portion of the tendon, whereby the tendon begins to appear grey and amorphous from a previously normal glistening white appearance. In addition, there is diffuse, fusiform or nodular thickening of the tendon (24).

Pain is the main symptom of Achilles tendinopathy. However the pain mechanism is not completely understood. It was traditionally thought that pain originated from associated inflammation or from separation of collagen fibres. Although these mechanisms were widely accepted in the past, numerous studies have now provided data that are inconsistent with either theory (25). An in vivo microdialysis study by Alfredson recently identified an abnormal

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increase in glutamate levels in patients with painful Achilles tendinopathy (26). However, this biochemical finding needs to be correlated with histopathological findings and pain in Achilles tendinopathy before glutamate can be pinpointed as the real cause of the pain.

CLINICAL FEATURES Achilles tendinopathy usually presents as morning stiffness, swelling and pain in the mid-portion of the tendon. The pain is usually exacerbated by eccentric loading exercises (4). Studies have shown that the duration of symptoms in Achilles tendinopathy patients can vary from a few months

to a few years (27). It has been suggested that the pain in the early stages is bearable and does not affect daily activities, so patients only seek medical attention if the pain severely affects ability to carry out daily activities as the disease progresses (28). The pain is thought to be related to vasculo–neural growth in the tendon (29), however there is some evidence to show that the degree of neovascularisation does not correlate with the severity of symptoms (30). Symptomatic Achilles tendons are

caused by an abnormality in the kinetic chain of the lower limb, therefore the hips, back, knees, ankles and both Achilles should be examined. It is important to understand the origin of the abnormal biomechanics because this helps determine the target joint for intervention.

EXAMINING THE ACHILLES As with other orthopaedic physical examinations, it is generally agreed that the Achilles should be examined by looking, feeling and moving (31) (Fig. 5]. n Inspection: Observe the Achilles from the sides and dorsal aspects for local erythema and swelling. Compare both Achilles (20). Inspect the foot for malalignment, for over-pronation, forefoot varus and pes planus. Over- pronation was present in 61 of 109 runners in a study by Clement et al (32) and was reported to predispose

LOOK FEEL MOVE

Figure 5: Examining the Achilles 25

n Inspect the Achilles from the sides and back. Compare the Achilles of both legs.

n Is there any redness or swelling? n Is there any malalignment of the foot, or over-pronation? n Is there varus of the forefoot or pes planus?

n Can you feel any areas of thickness, especially around the distal two-thirds of the tendon?

n Does the skin feel hot? n Is there any tenderness? n Can you feel any crepitus or nodules?

n Are dorsiflexion and plantarflexion of the ankle joint as you would expect?

n Does the subtalar joint move correctly (actively and passively)?