Ultrasound-Guided Injection Technique for Retrocalcaneal Bursitis Pain
Retrocalcaneal bursitis is a common cause of posterior heel pain. The retrocalcaneal bursa, which is also known as the subtendinous calcaneal bursa, lies between the Achilles tendon and its insertion on the calcaneus (Fig. 167.1). The bursa serves to cushion and facilitate sliding of the Achilles tendon over the calcaneus. The bursa is subject to inflammation from a variety of causes with acute trauma to the ankle and repetitive microtrauma being the most common. Acute injuries to the bursa can occur from direct blunt trauma to the posterior ankle kicks while playing sports as well as from overuse injuries including running on uneven or soft surfaces or jobs that require repeated plantar flexion of the ankle. If the inflammation of the bursa is not treated and the condition becomes chronic, calcification of the bursa with further functional disability may occur. Gout and other crystal arthropathies may also precipitate acute retrocalcaneal bursitis as may bacterial, tubercular, or fungal infections.
The patient suffering from retrocalcaneal bursitis most frequently presents with the complaint of pain in the posterior heel, which may radiate into the posterior ankle. The patient may find walking downstairs, standing on tiptoes, and kneeling increasingly difficult. Physical examination of the patient suffering from retrocalcaneal bursitis will reveal point tenderness over the posterior ankle. If there is significant inflammation, rubor and calor may be present and the entire area may feel boggy or edematous to palpation. At times, massive effusion may be present, which can be quite distressing to the patient. Active plantar flexion of the affected ankle will often reproduce the patient’s pain. Sudden release of resistance to active plantar will markedly increase the pain. If calcification or gouty tophi of the bursa and surrounding tendons are present, the examiner may appreciate crepitus with active extension of the ankle, and the patient may complain of a catching sensation when moving the affected ankle, especially on awaking. Often, the patient will not be able to sleep on the affected side. Occasionally, the retrocalcaneal bursa may become infected, with systemic symptoms, including fever and malaise, as well as local symptoms, with rubor, calor, and dolor being present.
Plain radiographs are indicated in all patients who present with ankle pain to rule out occult ankle pathology (Fig. 167.2). Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging or ultrasound imaging of the affected area may also confirm the diagnosis and help delineate the presence of other bursitis including coexistent Achilles bursitis, calcific tendonitis, tendinopathy, triceps tendonitis, or other ankle pathology (Figs. 167.3 and 167.4). Rarely, the inflamed bursa may become infected, and failure to diagnose and treat the acute infection can lead to dire consequences.
CLINICALLY RELEVANT ANATOMY
The retrocalcaneal bursa lies between the Achilles tendon and the base of the tibia and the posterior calcaneus (Fig. 167.5). The bursa is subject to the development of inflammation after overuse, misuse, or direct trauma as is the Achilles bursa, which lies posterior to the Achilles tendon at its insertion on the calcaneus. The Achilles tendon is the thickest and strongest tendon in the body yet is also very susceptible to rupture. The common tendon of the gastrocnemius muscle, the Achilles tendon, begins at midcalf and continues downward to attach to the posterior calcaneus, where it may become inflamed (see Figs. 167.1 and 167.5). The Achilles tendon narrows during this downward course, becoming most narrow ˜5 cm above its calcaneal insertion. It is at this narrowest point that tendonitis also may occur. Tendonitis, especially at the calcaneal insertion, may mimic retrocalcaneal bursitis and may make diagnosis difficult.