Achilles Tendon Rupture

Courtny Johnson, D.P.M., M.S.H.S.

Basic Information

Definition

Achilles tendon rupture is a disruption of the continuity of the Achilles tendon that most often results from the combination of mechanical stress and intratendinous degeneration.

ICD-10CM CODES
S86.0	Unspecified injury of Achilles tendon
S86.012	Achilles tendon rupture left
S86.011	Achilles tendon rupture right
M66.871	Non traumatic Achilles tendon rupture right
M66.872	Non traumatic Achilles tendon rupture left

Epidemiology & Demographics

Incidence

In the general population, Achilles tendon ruptures occur in 7 per 100,000 individuals. Recreational activities are the immediate cause of more than 80% of Achilles tendon ruptures.

Peak Incidence

30- to 40-year age group

Predominant Age

30- to 55-year age group

Risk Factors

General risk factors include recreational athletes, stop-and-go sports (e.g., basketball, tennis, and soccer), preexisting Achilles tendinopathy, increase in duration or intensity of running, advanced age, male gender, and poor running mechanics. Fluoroquinolone antibiotics have been associated with Achilles tendon ruptures, with an incidence of 12 per 100,000. This is more likely to occur in first-time users of fluoroquinolones and usually occurs within the first 90 days of therapy. Other risk factors can be categorized into intrinsic and extrinsic.

Intrinsic risk factors include Achilles tendinopathy and biomechanics, such as overpronation or underpronation, pes planus, pes cavus, limb length discrepancy, and foot misalignment. Rheumatologic disorders such as systemic lupus erythematosus, rheumatoid arthritis, and gout can cause collagen degeneration, inflammation, crystallization, and calcification of tendons, which causes them to weaken and predisposes them to rupture.

Clinical Presentation

A classic presentation for acute Achilles tendon rupture is a middle-aged male who participates in strenuous activities involving sudden pivoting on a foot or rapid accelerating as in recreational sports. A snapping/popping sensation of the tendon may be described by some patients, followed by an acute onset of severe pain in the posterior ankle. Patients who also attempt new strenuous activities without proper training and stretching or who typically lead a sedentary lifestyle are more likely to experience some kind of Achilles tendinopathy, including ruptures. It is important to note that pain is not always an initial presenting symptom.

Physical Findings

A palpable delve in the posterior distal third of the Achilles tendon may be appreciated with increased dorsiflexion of the ankle. Depending on the severity of the rupture pain, ecchymosis and diffuse edema may be noted. The patient may present with an antalgic gait and the inability to perform a single heel raise on the injured limb secondary to weakened plantar flexion power.

Etiology/Mechanism of Injury

Indirect trauma is most often associated with Achilles tendon ruptures, which typically fall under three categories: mechanical, vascular, and poor tissue quality.

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Mechanical: Involves variations of a rapid loading process on an already tensed tendon such as a sudden dorsiflexion of the ankle with the knee extended while an eccentric load is applied.
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Vascular: Located 2 to 6 cm proximal to the Achilles tendon insertion is a known area of hypovascularity.
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Poor tissue quality: Refers to the common notion that prior tendon degeneration is required to weaken the tendon before it is ruptured. This often occurs in the form of repetitive microtrauma from improper training techniques.

Diagnosis

Differential Diagnosis

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Achilles tendinopathy (tendinosis vs. tendonitis)
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Retrocalcaneal bursitis
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Ankle sprain
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Calcaneal avulsion fracture
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Partial rupture of gastrocnemius
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Plantaris rupture
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Partial rupture of gastrocnemius
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Os trigonum syndrome
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Calcaneal apophysitis

Workup

A thorough history and physical examination, along with a high clinical suspicion, is key to distinguishing Achilles tendon ruptures from other Achilles tendinopathies. The clinical history in most presentations is very specific, and the physical examination is usually diagnostic. The following is a list of specific clinical tests and imaging modalities.

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Simmonds-Thompson’s test (Fig. E1): Also known as the “calf squeeze test,” it is an accurate means of detecting Achilles tendon ruptures. The patient is placed in a prone position with the affected limb hanging off the examination table with the knee flexed. While squeezing the gastrocnemius, the clinician evaluates for the presence or absence of ankle plantar flexion. If ankle plantar flexion is absent, the test is said to be positive and indicative of Achilles tendon rupture.

FIG.E1

Tests for rupture of the Achilles tendon.¹

All tests are performed with the patient lying prone with his or her feet extending over the end of the examination table. The patient’s asymptomatic side serves as a control (for each test, a patient with an intact Achilles tendon is depicted on the left, compared with a patient with a ruptured Achilles tendon on the right). (1) Palpable gap in tendon (top): The clinician gently palpates the course of the tendon, searching for gaps, which if present usually lie between 2 and 6 cm from the calcaneus.² (2) Calf squeeze test (Simmonds–Thompson test, middle): The clinician gently squeezes the patient’s calf in its middle third and just below the place of widest girth, observing the ankle for movement. If the tendon is intact, the ankle should plantarflex. Absence of movement or minimal movement is a positive response. The normal plantar flexion of the ankle results from compression of the soleus muscle, which bows the Achilles tendon posteriorly.³ (3) Knee flexion test (Matles test, bottom): The clinician observes the position of the patient’s ankles as the patient flexes both knees to 90 degrees (the knees may be flexed individually or simultaneously). The ankle remains slightly plantar flexed if the tendon is intact; slight dorsiflexion or a neutral position of the ankle is the positive response. Thompson described the calf squeeze test in 1962,² pointing out that the test could be performed with the patient prone or kneeling on a chair. Simmonds described the identical test in 1957.⁴ Matles described the knee flexion test in 1975.⁵

From [1] Maffulli N: The clinical diagnosis of subcutaneous tear of the Achilles tendon: a prospective study in 174 patients, Am J Sports Med 26[2]:266–270, 1998; [2] Thompson TC, Doherty JH: Spontaneous rupture of tendon of Achilles: a new clinical diagnostic test, J Trauma 2:126–129, 1962; [3] Scott BW, Chalabi AA: How the Simmonds–Thompson test works, J Bone Joint Surg Br 74B[2]:314–315, 1992; [4] Simmonds FA: The diagnosis of the ruptured Achilles tendon, Practitioner 179[1069]:56–58, 1957; [5] Matles AL: Rupture of the tendon Achilles, Bull Hosp Jt Dis 36[1]:48–51, 1975.
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Matles test (knee flexion test): The test is an additional physical examination finding utilized to assess Achilles tendon ruptures. The patient is placed in the prone position with the knees flexed at 90 degrees. If the injured foot falls in a neutral or dorsiflexed position instead of a plantar flexed position when compared to the contralateral limb, the test of the injured limb is positive for Achilles tendon rupture.

Imaging Studies

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Ultrasound imaging may be used to assess Achilles tendinopathy and is considered by some the first-line imaging modality. Ultrasound provides clinicians with a practical means of evaluating Achilles tendinopathy and ruptures at the bedside.
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MRI (Fig. E2) is often utilized to further evaluate Achilles tendinopathy, especially ruptures. Discontinuity of the Achilles tendon can be seen on T2-weighted images, where the signal in the tendon is increased at the area of rupture and the tendon diameter is increased. MRI provides greater anatomic detail as well as greater accuracy in detecting partial Achilles tendon tears. MRI has proved to be superior to ultrasound in defining ruptures histologically.

FIG.E2

Complete Achilles tendon rupture, managed nonoperatively with 6 weeks of ankle casting in plantar

Treatment

Initial treatment should consist of the PRICE protocol (protection of the injured limb, rest, ice, compression to reduce swelling, and elevation). Adequate analgesics for at-home use can include acetaminophen and/or nonsteroidal antiinflammatory drugs.

The typical course of immobilization of the injured limb ranges from a minimum of 8 to 12 weeks. Over the past few years there has been a trend in nonoperative management of Achilles tendon ruptures that include accelerated protocol to rehabilitation. These accelerated protocols have been shown to improve outcomes of nonoperative Achilles tendon management. These protocols have the patient non–weight bearing in a posterior splint or equinus short leg cast with crutches for 2 weeks. A controlled ankle motion walker with special sequential heel wedges then follows this for the next 4 weeks of non–weight bearing with crutches. After 4 to 6 weeks the patient may return to regular shoe gear, with a heel wedge modification for an additional 2 months. During this period it is recommended that patients start resistance exercises, proprioception and gait retraining, and sport retraining.

Surgical Treatment

If surgical intervention is warranted, it should be done within 7 to 14 days of the injury. Proper timing of surgical repair is imperative to postsurgical recovery. The inflammatory phase of wound healing occurs within the first 7-14 days following an acute Achilles tendon rupture. During this phase, vascularity to the injured tendon increases, aiding in postoperative healing.

The primary goal of surgical treatment of Achilles tendon rupture is to reestablish ankle plantar flexion. This is usually achieved when there is an end-to-end apposition of the damaged Achilles tendon. Several surgical techniques exist to repair the ruptured Achilles tendon, which include percutaneous repair and open operative techniques. Percutaneous repair has shown to be advantageous, with decreased operative times and decreased postoperative deep infections. Other open surgical procedures can involve lengthening and flap-down methods to bridge the gap in the tendon. Multiple biologic grafts are available to augment and reinforce the rupture site. After surgery, 10 to 12 weeks of immobilization followed by rehabilitation is recommended.

Referral

Acute and/or complete Achilles tendon ruptures warrant surgical intervention. Acute complete Achilles tendon ruptures are more likely to have better postoperative outcomes if addressed within 14 days of initial injury. Orthopedic or podiatric surgical consultation should be obtained for symptomatic acute or chronic Achilles tendinopathy or ruptures.

Pearls & Considerations

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Patients who experience Achilles tendon ruptures may present with or without pain and may still maintain their ability to ambulate or flex their ankles. If pain is present, it usually occurs 2 to 6 cm proximal to the Achilles tendon insertion on the calcaneus.
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When evaluating Achilles tendinopathy, palpate the course of the Achilles tendon with particular attention to any edema, ecchymosis, or palpable delve or discontinuity of the tendon.
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A positive Thompson’s test is an accurate means for assessing Achilles tendon ruptures.
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Acute Achilles tendon ruptures should be treated within 14 days. Surgical intervention has been shown to decrease re-rupture rates when compared to nonsurgical treatment options.

Prevention

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Previous tendinopathy or previous Achilles tendon ruptures are known risk factors and are associated with up to 10% of re-rupture rates.
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Physical therapy as well as physical rehabilitation protocol should be maintained following both operative and nonoperative therapies. Eccentric and concentric exercise should be continued on a regular basis following Achilles tendon ruptures and particularly before engaging in any vigorous exercise.
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The patient should reduce his or her training intensity during fluoroquinolone use and anabolic steroid use.

Ferri – Achilles Tendon Rupture