Achilles tendinopathy especially among individuals who participate in repetitive action sports. n Palpation: Palpate the Achilles for tendon thickness (most commonly in the distal two-thirds of the tendon (33)) as well as for temperature, crepitus, tenderness and nodules. n Movement: Thoroughly assess dorsiflexion and plantarflexion of the ankle joints and the mobility of the subtalar joint both actively and passively. In Kvist’s study, 60% of the athletes had impaired dorsiflexion and subtalar joint movement (34).

Special tests There are two special tests. First, the toe raise – or the calf raise – which can be performed to assess the strength of the calf muscles because calf muscle weakness will cause abnormal biomechanics in the Achilles. Clement et al (32) highlighted that 41 out of 109 runners had weakness in their calf muscles and had an increased risk of developing Achilles tendinopathy (32). The second validated method of assessing pain and function of the Achilles tendon (35) is the Victorian Institute of Sport Assessment questionnaire for Achilles tendinopathy – the VISA–A.

Differentials As the symptoms are non-specific, there are a few conditions that present in the same way. These include Achilles tendinitis, paratendinitis, partial or complete rupture, retrocalcaneal bursitis, Achilles bursitis and referred pain. The crucial difference is that the pathophysiology in Achilles tendinopathy does not involve inflammation, so non-steroidal anti- inflammatory drugs will not alleviate symptoms like they do for the other conditions. The onset of the symptoms also helps differentiation, for example sudden onset of severe pain suggests Achilles rupture. Further investigations are needed to confirm the diagnosis.

INVESTIGATIONS Öhberg et al (28) found neovascularisation in all their symptomatic Achilles tendinopathy specimens, but none in asymptomatic normal tendons. Due to the significance of such neovascularisation, power Doppler and colour Doppler have been used extensively in other studies and

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in clinical practice. Ultrasound scans have also been used to demonstrate sonographic differences in normal and pathological tendons. Data from many studies suggest that deterioration of neovascularisation is associated with an improved clinical prognosis, so ultrasound is an ideal tool for grading, capable of showing the disappearance of neovascularisation during ankle dorsiflexion. This further supports the mechanism whereby eccentric exercise permanently damages the neovascularisation process and accompanying formation of new nerves (30). Since the publication of Alfredson et al’s (36) results, eccentric loading exercises are the mainstay of conservative management of this tendinopathy.

Other diagnostic modalities include

tendon biopsy and magnetic resonance imaging (MRI). Aström et al (37) showed that tendon biopsy detected all cases of tendinopathy and MRI and ultrasound had comparable good detection rates. Another study (38) produced similar results, with ultrasound detecting 23 out of 34 cases of Achilles tendinopathy, and MRI detecting 19 out of 34. In this study, ultrasound had a higher positive predictive value (0.65) than MRI (0.56), in contrast to a lower negative predictive values of 0.68 and 0.94, respectively.

While many studies demonstrate the occurence of neovascularisation in symptomatic Achilles tendinopathy, there are varying opinions about the absolute presence of neovascularisation. This may be because of differences in methodology and the types of participants examined in such studies.

INVESTIGATIONS FOR ACHILLES TENDINOPATHY

n Ultrasound n Tendon biopsy n Magnetic resonance imaging

Figure 6: Ultrasound image of thickening of Achilles tendon

Figure 7: Colour Doppler ultrasound scan showing neovascularisation of Achilles tendon

ULTRASOUND IN ACHILLES TENDINOPATHY Features found on ultrasound Achilles tendinopathy can manifest in several ways on ultrasound, showing features such as: n diffuse or focal tendon thickening (Fig. 6) n loss of the parallel contours n changes in reflectivity n neovascularisation (Fig. 7). It is generally agreed (30,39,40) that the main distribution of tendon thickening is in the distal two-thirds of the tendon, but Gibbon et al (41) showed that tendon thickening was more common in the proximal two-thirds of the tendon. The

A DECADE TO ACCURATELY DESCRIBE TENDON PATHOLOGY AND MINIMISE THE MISUSE OF OTHER DESCRIPTIVE TERMS

TENDINOPATHY – THIS UMBRELLA TERM HAS BEEN SUCCESSFULLY USED FOR OVER

sportEX medicine 2010;45(Jul):23-30