Most patients with Achilles tendonopathy do not need investigations to make the diagnosis (which is normally made clinically) or to plan treatment.
A tendonopathic swelling is usually easy to identify clinically with the aid of the arc test. Occasionally it may be felt appropriaite to clarify the nature of such a swelling, especially if the patient has an underlying condition known to produce tendon swellings, such as gout or xantholasmas.
Plain films may show calcification in the body of the tendon, but is rarely useful.
Ultrasound and MRI are both accurate methods of diagnosing Achilles tendon rupture and can be used to clarify inconclusive clinical examination with the calf squeeze and Matles tests. Hypoechoic signal on ultrasound and high signal on MRI are corelated with areas of abnormal histopathology. Retrocalcaneal bursitis also shows well on ultrasound and MRI. Mitchell's (2009) review of the use of ultrasound is useful and clear.
Colour Doppler imaging shows areas of neovascularisation and can be used to guide injections of sclerosants. However, neovascularisation can also be seen in 29-35% of asymptomatic tendons in physically active people (Sengkerij 2009, Hirschma 2010). Sengkerij (2009) demonstrated high interobserver reliability for colour Doppler imaging (ICCC 0.85). However, there was a poor correlation with VISA-A scores.
If surgery is planned it may be useful to have information about the extent of tendonopathy and therefore the amount of surgery that may be needed. Ultrasound and MRI are both useful for this, although there is no good evidence that they change intended surgery and the effect may be mainly to back-up the surgeon's intended plan. Nicholson (2007) reported that patients with insertional tendonopathy who had degenerative changes in the tendon on MRI were 6-8 times more likely to require surgery than those who had only thickening. However, most of their non-surgically treated patients did not have any imaging.
A few patients have evidence of a significant underlying arthropathy or enthesopathy which may require rheumatology investigations and/or consultation.
Plain lateral radiography will show calcification and spurs.
A number of techniques have been used to demonstrate the extra bone of a Haglund's deformity, particularly the Fowler-Philip angle and parallel pitch lines. However, Lu (2007) measured the Fowler/Philip angle and assessed parallel pitch lines in 37 with symptomatic Haglund deformities and 40 asymptomatic heels. There was no difference in the mean Fowler/Philip angle (60deg in the patients, 62 deg in the controls). Parallel pitch lines were positive in 57% of patients and 42% of controls (not significant). 57% of patients had spurs compared with 5% of controls, and 78% had Achilles calcification compared with 12% of controls. Neither measurement was of any value in diagnosing a Haglund's deformity or in measuring the amount of bone to be removed.
Parallel pitch lines. Inferior line tangential to the posterior prominence and the inferior margin of the calcaneocuboid joint. Superior line parallel to inferior line beginning at posterior margin of subtalar joint. Bone above superior line is abnormal.
Fowler-Philip angle. Inferior line tangential to the posterior prominence and the inferior margin of the calcaneocuboid joint. Superior line tangential to posterior calcaneal surface. Normal 44-69deg
Radiographic measurements of Haglund's deformity. Lu (2007) showed neither to be useful in differentiating symptomatic from asymptomatic heels