Achilles Tendon Rupture Diagnosis and Treatment Primer

With the Achilles tendon rupture Kobe Bryant sustained in the game last night this is a good time to talk about how a primary care or emergency physician can tell if a patient has an Achilles tendon rupture.  This can sometimes be a challenging diagnosis, but most of the time it is relatively easy to tell if a patient has a complete Achilles tendon rupture. Achilles tendon rupture is more common in men than in women, is most common in the 30’s though can occur at any age, and is usually though not always quite painful.  The history is helpful.  Most people who sustain an Achilles rupture feel like they were kicked or hit in the back of the ankle/heel area, and sometimes hear or feel a loud pop.  Typically the mechanism of injury is a forceful or violent push-off on the affected foot, though a direct blow to the Achilles or a fall onto the affected foot can also cause Achilles tendon rupture.

Clinically there are three tests we can use that make the diagnosis of an Achilles tendon rupture likely.  The most sensitive test is the calf squeeze test, also called the Robert’s test.  In this test you lie prone (on your belly) with your feet hanging off the exam table.  The examiner squeezes the calf and if the Achilles tendon is intact the foot moves the foot downward, i.e. plantar flexes.  If the Achille’s tendon is completely ruptured the foot does not move downward. This  test is reported to have a 96% sensitivity, meaning it is negative in only 4% of cases of Achilles rupture.  Most of these cases are probably in older injuries where some degree of healing may have occurred.

The second test is called the knee flexion test, or Matles test.  In this test the patient is also lying prone and they are asked to actively (using their own leg muscles) flex the knees to 90 degrees. If the Achilles tendon is intact the foot naturally remains in a slightly plantar flexed position throughout the movement. If the foot falls to neutral or less flexion it is a sign of Achilles tendon rupture.  This test has a sensitivity of 88%. It has the advantage that even in older injuries it tends to remain abnormal because healing tends to result in a longer Achilles tendon.

The least sensitive clinical test is simple palpation of the Achilles tendon, feeling carefully for a disruption of the tendon itself.  Sensitivity of this is reported to be 73% and is less sensitive the older the injury.

Remarkably in some cases the Achilles tendon is not very tender, and the injury may not be terribly painful.  Diagnostic testing for Achilles tendon rupture include ultrasound and MRI imaging, though MRI is certainly more commonly done in most settings today because of the increased accuracy that is less technician dependent.

Although treatment over the last few years has generally been surgical, recent evidence suggests that non-surgical treatment with modern physical therapy modalities can be a good alternative for some individuals. Surgical repair is more often used in younger and more active patients and tends to result in earlier return to full activity.  The belief that rerupture rates are lower with surgical repair and that better functional outcomes favor surgical care have been challenges recently.  A large meta-analysis of 10 studies using functional rehabilitation and early range of motion showed similar rates or rerupture, lower rates of complications other than rerupture, but longer periods of time to return to work (19.6 days longer off work on average).

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