Achilles tendonitis is a clinical syndrome characterized by sharp, constant, and severe posterior ankle pain on plantar flexion of the ankle. Patients suffering from Achilles tendonitis will often splint the inflamed Achilles tendon by adopting a flat-footed gait to avoid plantar flexing the affected tendon. This dysfunctional gait may cause a secondary bursitis and tendonitis around the foot and ankle, which may serve to confuse the clinical picture and further increase the patient’s pain and disability. Pain on palpation of the insertion of the Achilles tendon on the calcaneus or at a point ˜5 cm above the calcaneus at the narrowest part of the Achilles tendon is a consistent finding in patients with Achilles tendonitis as is exacerbation of pain with active resisted plantar flexion. Patients suffering from Achilles tendonitis will also exhibit a positive creaking tendon test. This test is performed by having the patient sit on the edge of the examination table. The examiner then palpates the Achilles tendon while passively plantar flexing and dorsiflexing the ankle (Fig. 166.1). The test is positive if the examiner appreciates a creaking sensation. Untreated, Achilles tendonitis will result in increasing pain and functional disability calcium deposition around the tendon occurring, making subsequent treatment more difficult. Continued trauma to the inflamed tendon ultimately may result in tendon rupture (Fig. 166.2).

The onset of Achilles tendonitis usually is acute, occurring after overuse or misuse of the ankle joint. Inciting factors may include activities such as running and sudden stopping and starting, as when playing tennis. Improper stretching of the gastrocnemius and Achilles tendon before exercise as well as the use of quinolone antibiotics has also been implicated in the development of Achilles tendonitis, as well as acute tendon rupture.

Plain radiographs are indicated in all patients who present with posterior ankle pain (Fig. 166.3). 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 and/or ultrasound imaging of the ankle is indicated if Achilles tendonitis, rupture, or joint instability is suggested (Figs. 166.4 and 166.5). Color Doppler imaging may help identify neovascularity within the tendon, which is suggestive of acute tendinitis (Fig. 166.6). Radionuclide bone scanning is useful to identify stress fractures of the tibia not seen on plain radiographs. The injection technique described later serves as both a diagnostic and a therapeutic maneuver and can also be used to guide percutaneous tenotomy.

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 (Fig. 166.7). The Achilles tendon narrows during this downward course, becoming most narrow at ˜5 cm above its calcaneal insertion. It is at this narrowest point that tendonitis also may occur. A bursa is located between the Achilles tendon and the base of the tibia and the upper posterior calcaneus. This bursa also may become inflamed as a result of coexistent Achilles tendonitis and may confuse the clinical picture.

The benefits, risks, and alternative treatments are explained to the patient, and informed consent is obtained. The patient is then placed in the prone position with the patient’s ankle hanging off the edge of the table (Fig. 166.8). With the patient in the above position, a high-frequency linear ultrasound transducer is placed in a longitudinal plane with the inferior portion of the ultrasound transducer over the insertion of the Achilles tendon on the calcaneus, and an ultrasound survey scan is taken (Fig. 166.9). The linear Achilles tendon is identified at its insertion on the calcaneus (Fig. 166.10). When the insertion of the Achilles tendon is identified, the skin overlying the area beneath the ultrasound transducer is prepped with antiseptic solution. A sterile syringe containing 3.0 mL
of 0.25% preservative-free bupivacaine and 40 mg of methylprednisolone is attached to a 1½-inch, 22-gauge needle using strict aseptic technique. The needle is placed through the skin ˜1 cm above the superior border of the ultrasound transducer and is then advanced using an in-plane approach with the needle trajectory adjusted under real-time ultrasound guidance so that the needle tip rests against the site of tendinous insertion (Fig. 166.11). When the tip of needle is thought to be in satisfactory position, a small amount of solution is injected to ensure that the needle tip is not in the substance of the tendon (Fig. 166.12). After confirmation that the needle tip is outside the tendon, after careful aspiration, the contents of the
syringe are slowly injected. There should be minimal resistance to injection. The patient may note an exacerbation of his or her pain during the injection.