Achilles Tendonitis Clinical Presentation

Achilles tendon injuries often occur in older recreational athletes (eg, athletes who are usually sedentary and deconditioned) but may also occur in younger well-conditioned athletes.

Determine any recent changes in activity level, training duration, running surface, or footwear.

Ask for previous history of calf pain or weakness.

If there is clinical suspicion of a partial or complete tear, inquire if there has been any history of quinolone use.

Achilles tendon injuries may be classified as follows:

Paratenonitis

Localized/burning pain during or following activity occurs.

As the disease progresses, onset of pain may occur earlier during activity, with decreased activity level, or even at rest.

In this condition, the paratenon itself is inflamed and thickened and is typically adherent to the underlying unaffected tendon. Under the microscope, there is capillary proliferation and infiltration of inflammatory cells within the paratenon.^[14]

Tendinosis

Usually, this injury is an asymptomatic, noninflammatory, degenerative disease process (mucoid degeneration).

The patient may complain of a sensation of fullness or a nodule in the back of the leg.

With tendinosis, there are thickened and yellowish areas of mucoid degeneration within the tendon itself. The tendon loses its normal coloration and striation patterns.

Hypocellularity, collagen disorganization, lack of inflammatory reaction, scattered vascular ingrowth, and intermittent areas of calcification or necrosis are hallmarks of this disease process.^{[14, 15]}

Pathology is usually found within the watershed area of the tendon.

Paratenonitis with tendinosis

Activity-related pain and diffuse swelling of the tendon sheath with nodularity is present.

Histologically and macroscopically, this entity combines findings found in both tendinosis and paratenonitis.^{[14, 15]}

Palpate the entire gastroc-soleus complex for tenderness, nodules, swelling, warmth, atrophy, and tendon defects with the patient in a prone position with feet off the table. Localization of the tenderness should be differentiated between musculotendinous (tennis leg), intrasubstance (Achilles tendon injury), and insertional (eg, Haglund deformity, pump bump). Nodules should be palpated for tenderness, boundaries, mobility, and size. Calf atrophy, determined by calf circumference as compared with the contralateral side, may provide information as to the chronicity of the disease process (acute vs chronic). "Gaps" or areas of tendon discontinuity are often signs of partial or complete tendon rupture.

Patients with paratenonitis typically present with warmth, swelling, and diffuse tenderness localized 2-6 cm proximal to the tendon's insertion. Crepitation may also be felt if peritenonitis presents acutely. As the condition becomes more chronic, symptoms may be provoked by decreased amounts of physical activity.

Tendinosis is often pain free. Typically, the only sign may be a palpable intratendinous nodule that accompanies the tendon as the ankle is placed through its range of motion (ROM). Occasionally, a thickening along the entire tendon may develop in chronic conditions.

Peritenonitis with tendinosis is diagnosed in patients with activity-related pain and swelling of the tendon sheath and tendon nodularity.

Perform a Thompson test to check for Achilles tendon rupture.

With the patient prone and the knee flexed, the calf is squeezed proximal to the affected area. If passive plantar flexion of the foot is achieved with this maneuver, the test is negative, and the Achilles tendon is at least partially intact. If no motion at the ankle is generated, the Thompson test is positive and a complete rupture of the tendon has occurred.

This test is important to perform because incomplete or complete ruptures may occur in patients with a history of paratenonitis, with or without tendinosis. With acute partial or complete tendon ruptures, patients often relate focal pain and swelling at the sight of injury.

Ascertain active and passive ROM and strength of the knee, ankle, and subtalar joints. Patients with overuse Achilles tendon injuries typically have decreased motion and strength in the ankle and/or subtalar joints.

Note the resting alignment and motion of the forefoot and ankle. Forefoot and heel varus, pronated feet, cavus feet, and tibia vara are known predisposing risk factors for this disease process.

Determine if evidence of neurovascular compromise is present.

Extrinsic causes of Achilles tendinitis include the following:^{[1, 2]}

• Overuse
• Increased intensity of activity
• Increased duration of training
• Stairs
• Hill climbing
• Poor conditioning
• Improper shoes
• Improper training surfaces
• Improper stretching exercises

Intrinsic Achilles tendinitis causes may include the following:^{[1, 2]}

• Age
• Tight Achilles tendon
• Varus heel
• Varus forefoot
• Cavus foot
• Tibia vara
• Medical diseases that may affect tendon tissue (eg, diabetes mellitus) and diseases requiring corticosteroid treatment (eg, lupus, asthma, transplants)