Achilles Bursitis – The Clinical Syndrome
Achilles bursitis is being seen with increasing frequency in clinical practice as jogging has increased in popularity. The Achilles tendon is susceptible to the development of bursitis at its insertion on the calcaneus and at its narrowest part at a point approximately 5 cm above its insertion. The Achilles tendon also is subject to repetitive motion injury that may result in microtrauma, which heals poorly because of the tendon’s avascularity. Running is often implicated as the inciting factor of acute Achilles bursitis. Bursitis of the Achilles tendon frequently coexists with Achilles tendinitis, creating additional pain and functional disability. Calcium deposition around the Achilles bursa may occur if the inflammation continues, making subsequent treatment more difficult.
What are the Symptoms of Achilles Bursitis?
The onset of Achilles bursitis is usually acute, occurring after overuse or misuse of the ankle joint. Inciting factors include activities such as running and sudden stopping and starting as when playing tennis. Improper stretching of the gastrocnemius and Achilles tendons before exercise has been implicated in the development of Achilles bursitis, acute tendinitis, and tendon rupture. The pain of Achilles bursitis is constant and severe and is localized in the posterior ankle. Significant sleep disturbance is often reported. The patient may attempt to splint the inflamed Achilles bursa by adopting a flat-footed gait to avoid plantar flexion of the affected foot. Patients with Achilles bursitis experience pain with resisted plantar flexion of the foot. A creaking or grating sensation may be palpated when passively plantar flexing the foot because of coexistent tendinitis. As mentioned previously, a chronically inflamed Achilles tendon may suddenly rupture with stress or during vigorous injection procedures to treat Achilles bursitis.
How is Achilles Bursitis diagnosed?
Plain radiographs are indicated in all patients with posterior ankle pain. Based on the patient’s clinical presentation, additional tests, including complete blood cell count, erythrocyte sedimentation rate, and antinuclear antibody testing, may be indicated. Magnetic resonance imaging (MRI) and ultrasound imaging of the ankle is indicated if joint instability is suspected and to help clarify the diagnosis. Color Doppler imaging is useful in identification of tendinitis of the Achilles tendon. Radionucleotide bone scanning is useful to identify stress fractures of the tibia not seen on plain radiographs. The following injection technique serves as a diagnostic and therapeutic maneuver.
Achilles bursitis generally is identified easily on clinical grounds. Because tendinitis frequently accompanies Achilles bursitis, the specific diagnosis may be unclear. Stress fractures of the ankle also may mimic Achilles bursitis and tendinitis and may be identified on plain radiographs, MRI, or radionucleotide bone scanning.
Initial treatment of the pain and functional disability associated with Achilles bursitis should include a combination of nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors and physical therapy. Local application of heat and cold may be beneficial. The patient should be encouraged to avoid repetitive activities responsible for the evolution of the bursitis, such as jogging. For patients who do not respond to these treatment modalities, the following injection technique with a local anesthetic and steroid may be a reasonable next step.
For injection, the patient is placed in the prone position with the affected foot hanging off the end of the table. The foot is gently dorsiflexed to facilitate identification of the margin of the tendon to aid in avoiding injection directly into the tendon. The tender points at the tendinous insertion or at its narrowest part approximately 5 cm above the insertion are identified and marked with a sterile marker.
Proper preparation with antiseptic solution of the skin overlying these points is carried out. A sterile syringe containing 2 mL of 0.25% preservative-free bupivacaine and 40 mg of methylprednisolone is attached to a 25-gauge, 1½-inch needle using strict aseptic technique. With strict aseptic technique, the previously marked points are palpated. The needle is carefully advanced at this point alongside the tendon through the skin and subcutaneous tissues, with care taken not to enter the substance of the tendon. The contents of the syringe are gently injected while slowly withdrawing the needle. Minimal resistance to injection should be felt. If significant resistance to injection is noted, the needle tip is probably in the substance of the Achilles tendon and should be withdrawn slightly until the injection proceeds without significant resistance. The needle is removed, and a sterile pressure dressing and ice pack are placed at the injection site. Ultrasound guidance may improve the accuracy of needle placement and decrease the incidence of needle-related complications.
Complications and Pitfalls
The possibility of trauma to the Achilles tendon from the injection itself is ever present. Tendons that are highly inflamed or previously damaged are subject to rupture if they are directly injected. This complication can be greatly decreased if the clinician uses gentle technique and stops injecting immediately if significant resistance to injection is encountered. Approximately 25% of patients report a transient increase in pain after this injection technique, and patients should be warned of this possibility.
The Achilles tendon is the thickest and strongest tendon in the body, but it also is 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. The Achilles tendon narrows during this downward course, becoming most narrow approximately 5 cm above its calcaneal insertion. Tendinitis and bursitis may occur at this narrowest point. The previously mentioned injection technique is extremely effective in the treatment of pain secondary to the causes of posterior ankle pain. Coexistent tendinitis and arthritis may contribute to posterior ankle pain and may require additional treatment with a more localized injection of a local anesthetic and depot steroid.
The injection technique is a safe procedure if careful attention is paid to the clinically relevant anatomy in the areas to be injected. The use of physical modalities, including local heat and gentle range-of-motion exercises, should be introduced several days after the patient undergoes this injection technique for ankle pain. Vigorous exercises should be avoided because they would exacerbate the symptoms. Simple analgesics and NSAIDs may be used concurrently with this injection technique.