Thompson Test Achilles Tendon In Injury Test

Introduction to the Thompson Test (Calf Squeeze Sign )

The Thompson Test or the Thompson Test or the Calf Squeeze Sign is one of the most commonly performed tests to examine the Achilles tendon. It is a crucial tool in assessing those with posterior ankle pains or inability to walk since they may be a sign of an impending Achilles tendon rupture. Often referred to as the ‘’simplest and best’’ test, this test is routinely used in assessments of orthopedic and sports medicine.

The Achilles tendon is the largest, toughest, and probably the longest tendon in the human body and is involved in walking, running and jumping. Hence, its functional condition management is very vital to physiotherapists, while diagnosing any possible injury. To quickly ascertain whether the Achilles tendon is ruptured or not the doctors use the Thompson Test.

Purpose of the Thompson Test: Diagnosing Achilles Tendon Rupture
 

The main use of Thompson Test is therefore, to help identify a complete or partial Achilles tendon rupture. The gastrosoleus muscle is an important component of plantar flexion of foot and is attached to the calcaneus by means of achilles tendon. A rupture usually occurs in forceful movements such as when an individual is pushing off during a race or jumping.

Symptoms of individuals with Achilles tendon rupture may be in the form of a pop, unable to walk or loss of strength in the affected leg. Early identification of this rupture is important since failure to repair it in time may result in chronic dysfunction or poor prognosis even when surgical repairs are undertaken.

Anatomy Of Calf Muscle for  Thompson Test

The structures relating to the Thompson Test are mainly situated in the posterior lower leg including the Achilles Tendon and muscles and bones surrounding the area.

Achilles Tendon: The Achilles tendon links the calf muscles (gastrocnemius & soleus) to the calcaneus – the heel bone. It helps in plantar flexion which is very essential in walking/running in flexing the foot from the ankle.

Gastrocnemius and Soleus Muscles: These muscles constitute most of the bulk of the calf and the muscles join together to form the Achilles tendon. The gastrocnemius comprises two heads – medial and lateral and gets its origin from femur while soleus originates from tibia as well as the fibula. Altogether they produce the force which helps to perform the movement of plantar flexion.

Calcaneus (Heel Bone): Achilles tendon attaches itself into the plantar surface of the calcaneus at its posterior region. This insertion point brings out the forces developed by the calf muscles as they make movements during locomotion.

Plantaris Muscle: A small muscle which is present beside the Achilles tendon and can be involved in the action of plantarflexion though it is non-essential for the functioning of the Achilles.

Indications for the Thompson Test

The Thompson Test is mainly recommended when the doctor has high possibilities of an Achilles tendon rupture or injury. The test should not be done in patients with posterior ankle pain, obvious gap in the tendon or weakness in plantar flexion.

Suspected Achilles Tendon Rupture

In fact, the Thompson Test is applied most frequently to detect a possible rupture of the Achilles tendon. A strain usually happens when there is a stretch in the calf muscle, this is characterized by a loud popping sound with weakness and inability to walk and push off with the affected leg. One can therefore be quickly ruled out or confirmed by this test if a rupture is suspected.

Post-Trauma Assessment

For individuals who have sustained lower leg injury especially in sporting activities that involve running and jumping the Thompson Test is useful to determine any damage on the Achilles tendon. For example if the scan obtained is inconclusive immediate evaluation enables the next imaging investigation like MRI or the surgical procedure to be planned.

Posterior ankle pain:

It can be the manifestation of a wide number of disorders and conditions and therefore its delegates and differential diagnosis are very extensive.

If the patient complains of pain in the back of the ankle joint, the so-called Thompson Test will help to identify pathology of the Achilles tendon over other causes, including calcaneal bursitis, posterior tibial tendonitis, or referred pain due to nerve entrapment.

Post-Surgical Monitoring

Common tests are normal after Achilles tendon repair; however, the Thompson Test can be employed in the subsequent investigations to determine the begins to regain function. It is especially valuable during the rehabilitation stage, deciding when patients should get back in the activity.

How to Perform the Thompson Test: Step-by-Step Guide

Patient Positioning

Patient should be face downwards on the examination table and the feet of the patient should be off the table. This position helps to leave the foot and the ankle to be as relaxed as possible so that the examiner can determine the condition of the Achilles tendon.

The specific leg which is impaired must be more exposed and the patient has to minimize moving other parts of his body.

Therapist Positioning

The physiotherapist should position himself or herself to the side of the patient and at the level of the patient’s calf.

The therapist uses the right hand and places it on the mid lower third of the affected limb over the gastrocnemius and soleus muscles.

Performing the Test

The therapist compresses the calf muscles gently and this results in contraction of the muscles. Under normal circumstances this contraction brings about tension in the achilles tendon resulting in passive plantar flexion of the foot.

If the achilles tendon is still functional then, the foot should plantar flex or point in the downward direction because of the squeeze in the calf.

However, when the foot cannot be moved off the ground or there is no plantar flexion, the test is positive which means it is a complete rupture of the Achilles tendon.

Observation and Key Findings of Thompson Test

Positive Test: A positive result obtained when there is no plantar flexion in the ankle when the calf is squeezed this means that the Achilles tendon is separated and unable to pull the foot back up.

Negative Test: Negative result where, the foot plantar flexes normally then it means the Achilles tendon is normal.

Differential Diagnosis with the Thompson Test

The Thompson Test is exclusively for evaluating the status of Achilles tendon but other conditions that should be considered are; Some of these include:

• Posterior Tibial Tendon Dysfunction: Inner side of the ankle pain and swelling may mimic Achilles tendon injuries common in the sporting fields. This condition can be further separated employing special tests toward the posterior tibial tendon.
• Calcaneal Bursitis: Inflammation of the bursae close to the Achilles’ insertion will cause pain in the posterior ankle but it will not compromise the strength of the Achilles tendon.
• Plantar Fasciitis: This condition produces heel pain especially with the initial steps in the morning; the pain can rarely be mistaken for Achilles tendon pathology.
• Achilles Tendonitis: Pain due to a partial tear or chronic inflammation of the Achilles tendon is similar; however, some ankle plantarflexion will probably be distinguishable by the Thompson Test.

Related Tests to the Thompson Test

Several other tests are often performed in conjunction with the Thompson Test to enhance diagnostic accuracy:

• Matles Test (Knee Flexion Test): This test is used in evaluating individuals that may have sustained an Achilles tendon rupture by looking at the foot that is placed in a 90 degree angle with the knee. Basically, absence of plantarflexion on the leg affects at the site of the rupture is an indication of a ruptured tendon.
• Simmonds’ Test (Achilles Tendon Gap Test): In this test, the examiner tries to feel for a hole or padx in the area of the superior Achilles tendon and this also confirms that there has been a rupture.
• MRI or Ultrasound: Facility of clinical diagnosis of AT rupture is supplemented with the help of imaging techniques like MRI or ultrasound in order to identify the severities of the injury.

Latest Research on the Thompson Test

Some of the most recent studies conducted in the field have focused on the efficiency of the Thompson Test in real practice, including its diagnostic reliability. Some of the investigations show that the test is sensitive to complete Achilles tendon rupture, though it may not be very effective when it comes to partial tears or other types of tendon injuries. Hence, it’s suggested that clinicians use the Thompson Test along with other imaging techniques like ultrasound or MRI in the cases when the results are not clear.

Improved Sensitivity with Dynamic Ultrasound: Research by investigators has revealed that the dynamic ultrasound helps to improve sensitivity of Thompson Test because of visualization of the Achilles tendon contractile function in real time.

Post-Injury Rehabilitation and Follow-Up: Other works focused on the use of the Thompson Test in follow-up examination after the operation, and also noted that this is a simple and effective tool in evaluation of recovery after Achilles tendon repair.

Conclusion

Thompson Test has been described as a precious piece of equipment in the diagnosis of Achilles tendon ruptures, thanks to the fact that it provides fast and efficient means to evaluate tendon status. In fact, for physiotherapists performing the test correctly and knowing more details about the test becomes important more so when the patient is an athlete or has undergone through trauma. However, the test is most valuable when performed hand in hand with other clinical examination and relevant imaging.