A problem-based approach in musculoskeletal ultrasonography: heel pain in adults

Abstract

Musculoskeletal ultrasonography (US) has unique advantages, such as excellent spatial resolution for superficial structures, the capability for dynamic imaging, and the ability for direct correlation and provocation of symptoms. For these reasons, US is increasingly used to evaluate problems in small joints, such as the foot and ankle. However, it is almost impossible to evaluate every anatomic structure within a limited time. Therefore, US examinations can be faster and more efficient if radiologists know where to look and image patients with typical symptoms. In this review, common etiologies of heel pain are discussed in a problem-based manner. Knowing the common pain sources and being familiar with their US findings will help radiologists to perform accurate and effective US examinations.

Keywords: Ankle; Foot; Heel; Pain; Ultrasonography; Ultrasound.

Fig. 1.. Anatomic locations of pain corresponding to common etiologies are illustrated on plantar surface (A) and medial surface (B) of the heel.

1, plantar fasciitis; 2, heel fat pad atrophy; 3, achilles tendinopathy; 4, tarsal tunnel syndrome; 5, tibialis posterior tendinopathy.

Fig. 2.. A 34-year-old woman with normal plantar fascia.

In the long-axis view, a normal, uniformly hyperechoic fibrillar echo pattern can be appreciated at the proximal portion of the plantar fascia. The thickness of the plantar fascia measured at the anteroinferior border of the calcaneus was smaller than 4 mm (double-headed arrow). Note the area of the anisotropy artifact (arrowheads) just distal to the insertion site and mid-portion, because of the normal curved course of the plantar fascia.

Fig. 3.. A 66-year-old woman with plantar fasciitis.

In the long-axis view of the proximal plantar fascia, fusiform thickening, hypoechogenicity of the superficial fibers, and perifascial hypoechogenicity (asterisk) are noted. The thickness of the plantar fascia in this case was greater than the 4-mm cut-off for diagnosing plantar fasciitis (double-headed arrow).

Fig. 4.. A 52-year-old woman with plantar fasciitis.

A. Long-axis view of the proximal plantar fascia, medial portion is shown. The plantar fascia appeared normal with a hyperechoic fibrillar appearance (white arrows). B. Long-axis view of the proximal plantar fascia, central portion is shown. The plantar fascia revealed decreased echogenicity (black arrows), with a perifascial hypoechoic area (asterisks) suggesting plantar fasciitis. C. Short-axis view of the proximal plantar fascia is shown. Localized hypoechoic changes (black arrows) are noted at the central portion of the plantar fascia accompanied by cortical erosion at the calcaneus (white arrowheads). The thickness of plantar fascia in this case was not greater than the 4-mm cut-off for diagnosing plantar fasciitis. Note the relatively normal-looking plantar fascia (white arrows) at medial portion.

Fig. 5.. A 70-year-old woman with plantar fibromatosis.

A. Short-axis view of the plantar fascia at the midfoot level shows a relatively well-defined hypoechoic lesion (white arrows) involving the superficial plantar fascia. Note that the lesion is located within the plantar fascia (black arrowheads). B. Long-axis view of the mass shows a spindle-shaped hypoechoic lesion (white arrows) involving the superficial one-half of the plantar fascia. The mass is protruding superficially, with the undersurface of the plantar fascia (black arrowheads) remaining flat.

Fig. 6.. A 48-year-old man with a chronic plantar fascial tear.

He had acute extreme pain at the plantar heel when he slammed on the brakes during a traffic accident 2 years ago. Long-axis view of the proximal plantar fascia shows marked thickening, blurred margin, and disruption of the normal fibrillar pattern (arrows). The abnormality of the plantar fascia is most pronounced at 2-3 cm distal to the calcaneal insertion, which is the typical site for a plantar fascial tear.

Fig. 7.. A 64-year-old woman with plantar heel pain.

Paired short-axis views of the plantar heel show discrete hypoechoic areas within the plantar heel fat pad overlying the plantar surface of the calcaneus. The marked hypoechoic areas (arrows) noted without compression (left-side image) were easily collapsed by minimal compression with the ultrasound transducer (right-side image).

Fig. 8.. A 62-year-old woman with plantar fasciitis and Baxter neuropathy, who had swelling and pain at the medial arch of the sole.

A. Anatomic location of pain in Baxter neuropathy, when compared to plantar fasciitis and heel fat pad atrophy is illustrated on the plantar surface of the foot. 1, plantar fasciitis; 2, heel fat pad atrophy; 3, Baxter neuropathy. B. The painful site of Baxter neuropathy is marked as a grey area on a schematic drawing of the posterior tibial nerve and its branches. 1, posterior tibial nerve; 2, medial calcaneal nerve; 3, medial plantar nerve; 4, lateral plantar nerve; 5, inferior calcaneal nerve (Baxter nerve). C. Long-axis view of the plantar fascia shows diffuse thickening and hypoechoic changes of the plantar fascia (arrows) near the calcaneal insertion. D. Short-axis view of the plantar midfoot level shows bright hyperechoic changes of the abductor digiti minimi (ADM) muscle when compared to the normal echo of the flexor digitorum brevis (FDB) muscle.

Fig. 9.. A 57-year-old woman with Achilles tendinopathy and paratenonitis.

A. Long-axis view of the left distal Achilles tendon shows attenuation of the normal fibrillar echotexture and diffuse hypoechogenicity and thickening of the Achilles tendon (black arrows). Note the irregularly shaped hypoechoic area, superficial to the Achilles tendon, suggestive of paratenonitis (double-headed white arrows). B. Short-axis view of the bilateral distal Achilles tendons shows diffuse swelling and hypoechoic changes of the left Achilles tendon (black arrows) with paratenon thickening (double-headed white arrows), in comparison to the right Achilles tendon (double-headed white arrows). C. Neovascularization is noted in the affected Achilles tendon.

Fig. 10.. A 67-year-old man with Haglund deformity.

A. Lateral ankle X-ray shows an abnormal bony protuberance (arrow) at the posterosuperior border of the calcaneus with multiple bone fragments. B. Long-axis view of the bilateral posterior heel shows insertional Achilles tendinopathy (black arrows) with calcifications, a bone fragment (white arrow), and retrocalcaneal bursitis (asterisk) at the affected heel. Note the normal-appearing Achilles tendon and collapsed bursa (curved arrow) on the contralateral side.

Fig. 11.. A 75-year-old man with a nearly complete tear of the tibialis posterior tendon.

A. Short-axis view of the tibialis posterior tendon shows nearly complete discontinuity of the tendon (arrows) at the retromalleolar level. B. Extended long-axis view along the tendon course shows the gap of the torn tendon, measured as 4.8 cm between the calipers. FDL, flexor digitorum longus; Nav, navicular.

Fig. 12.. A 12-year-old girl who was a ballet student with bilateral flexor hallucis longus tendinopathy, tenosynovitis, and snapping.

A. Short-axis view of the flexor hallucis longus tendon shows marked enlargement when compared to the adjacent flexor digitorum longus (FDL) tendon. B. Long-axis view of the flexor hallucis longus (FHL) tendon shows severe thickening and decreased echogenicity of the tendon with diffuse synovial hypertrophy (asterisk) in the tendon sheath. C. Typical foot and ankle position with full plantar flexion is shown when the ballet dancer is en pointe in pointe shoes. TP, tibialis posterior tendon; TN, tibial nerve.

Fig. 13.. A 60-year-old woman with an intraneural ganglion cyst at the tarsal tunnel.

Short-axis view (A) and long-axis view (B) of the right-side tarsal tunnel shows a well-defined anechoic mass inside of the tarsal tunnel, adjacent to the medial plantar nerve and superficial to the flexor hallucis longus (FHL) tendon. C. T2-weighted fat-suppressed magnetic resonance imaging reveals a cystic mass that had propagated along the course of the medial plantar nerve.

Fig. 14.. A 76-year-old woman with peroneal tendinopathy and split tear of the peroneus brevis.

Short-axis view of the peroneal tendons at the retromalleolar level shows enlarged peroneal tendons with a longitudinal split tear gap (arrow) at the peroneus brevis tendon, which is pushed anteriorly by the peroneus longus tendon toward the lateral malleolus. PB, peroneus brevis tendon; PL, peroneus longus tendon.

Fig. 15.. A 46-year-old woman with repeated ankle sprain and sinus tarsi syndrome.

A. Long-axis view of the calcaneocuboidal joint at the lateral heel shows a chronic avulsion fracture fragment (white arrow) at the calcaneus and a focal discontinuity (black arrow) of the calcaneocuboidal ligament. B. Oblique coronal scanning over the sinus tarsi shows hypoechoic changes in the sinus tarsi (asterisk), which is a finding of sinus tarsi syndrome. C. Hyperemia was noted in the sinus tarsi on Doppler ultrasonography.

Fig. 16.. A 47-year-old man with lateral foot pain caused by sural neuropathy. He had an ankle inversion injury several years ago.

A. A schematic illustration of the course of sural nerve at lateral heel and the patient’s symptomatic area is shown as a grey area. B. Paired short-axis view of the bilateral sural nerve at the level of the peroneal tubercle shows hypoechoic thickening of the right-side sural nerve (black arrow), when compared to the normal left-side sural nerve (white arrow). C. Long-axis view of the sural nerve shows fusiform thickening and hypoechoic changes of the sural nerve (black arrows).

Fig. 17.. A 46-year-old woman with calcaneal stress fracture.

A. Long-axis view of the calcaneal tuberosity at the posterior heel reveals cortical step-off (black arrow) with a small fracture fragment (white arrowhead). Note the small amount of effusion present in the retrocalcaneal bursa (asterisk). B. Lateral ankle X-ray taken after 3 weeks demonstrated a radio-opaque fracture line (black arrows) at the calcaneal tuberosity, which was not visible on an initial X-ray (not shown in the figure). A, Achilles tendon.