Chapter 28
Pain in the Achilles Region

Investigations 

Plain X-ray is of limited value in patients with recent-onset pain in the Achilles region but, if symptoms are longstanding, X-ray may reveal a Haglund's deformity, a prominent superior projection of the calcaneus that is associated with overuse tendinopathy and which may also be a precipitating factor in retrocalcaneal bursitis. Posterior impingement can be shown on plain X-ray using functional views (see p. 550). Also, X-ray may reveal calcification in the tendon itself (Fig. 28.3).

(e) Passive movement—muscle stretch (soleus). The patient stands upright and keeps the knee flexed. The foot must remain in a neutral position

(f) Functional tests. These can be used to reproduce pain, if necessary, or to test strength. Tests include double leg and single leg calf raises, hops, eccentric drops (illustrated) and lunge

(g) Palpation—prone. Palpate the site of pain. Palpate the tendon and paratenon while the tendon moves to determine which structure is involved. Palpate the gastrocnemius, soleus and retrocalcaneal bursa

(h) Special test—Simmond's calf squeeze test for Achilles tendon rupture. The practitioner squeezes the fleshy part of the calf. The test is positive if the foot fails to plantarflex

Fig. 28.3 Calcification in the insertion of the Achilles tendon. This finding does not have any impact on management—the patient is managed according to the symptoms of tendinopathy (see p. 541)

Fig. 28.4 Various imaging appearances in patients with Achilles tendinopathy. Note that in all cases the histopathology revealed the same abnormality—tendinosis—which represents tendon degeneration, not inflammation (a) Ultrasound appearance showing mild morphological abnormality

(b) Ultrasound appearance showing a large area of morphological abnormality (REPRODUCED WITH PERMISSION FROM JACOBSON JA AND VAN HOLSBEECK MT. MUSCULOSKELETAL ULTRASONOGRAPHY. ORTHOPAEDIC CLINICS OF NORTH AMERICA 1998, P. 148)

(c) MRI appearance showing mild morphological abnormality

In symptomatic patients, both ultrasound and MRI (Fig. 28.4) often reveal abnormal signal in the Achilles tendon that generally correspond with the histopathology of tendinosis (5) (6)(tendon degeneration) described below (pp. 540–1). It has been suggested that imaging appearance is clearly related to symptoms and that investigation can differentiate between various abnormalities of the Achilles tendon (i.e. tendinosis, paratenonitis, partial tear). While this is sometimes the case, there are many instances where it is not. Importantly, there are no prospective studies proving that imaging can distinguish subtle pathological states.(7)  Furthermore, abnormal appearances on imaging of the Achilles tendon may occur in asymptomatic patients.(8)

In clinical practice, we suggest ultrasound or MRI be used as part of the evaluation of the patient with persistent Achilles tendon pain to determine whether or not there is evidence of tendinopathy. The radiologist should not be expected to make a histological diagnosis (i.e. paratenonitis, ‘tendinitis', tendinosis). We suggest the clinician attach less weight to imaging results than to history and examination findings. 

(d) MRI appearance showing a large area of morphological abnormality (REPRODUCED WITH PERMISSION OF STOLLER DW. MRI IN ORTHOPAEDICS AND SPORTS MEDICINE 2ND EDN. LIPPINCOTT, WILLIAMS AND WILKINS 1996, P. 256)