In order to adequately treat an ankle sprain and reduce the risk of recurrence, it is of the utmost importance to properly identify the deficits present and to be able to do a follow-up with reliable measurements.
By Michael Bertrand-Charette, Pt, MSc, PhD Candidate
Ankle sprains are among the most common musculoskeletal injuries [1-3]. Although many people quickly regain function, others will remain with deficits that increase their risk of ankle sprains in the future. In fact, up to 33% of people will report a sensation of instability in their ankle and this sensation can last up to 3 years after the sprain before it is no longer perceived . Moreover, this peripheral injury seems to have a more central effect, since even the uninjured limb shows a decrease in performance during bilateral assessment using a valid and reliable test . In order to adequately treat these patients and reduce the risk of recurrence, it is therefore of the utmost importance to properly identify the deficits present and to be able to do a follow-up with reliable measurements.
However, what would be the best test for this assessment and what does it really assess?
To answer this first question, a quick literature review is all you need. We easily come to the conclusion that several systematic reviews have established that the Star Excursion Balance Test (SEBT) is a valid (it really assesses ankle instability) and reliable (it is mostly free from measurement errors that could affect the results) test [6-10]. In short, the SEBT can discriminate between unstable ankles and healthy ankles. Moreover, it is a relatively easy-to-use test as little equipment and training are required to perform it. For those who are unfamiliar with this test, it involves fixing measuring tapes on the ground in a star-shaped form and asking the patient to stand on the involved ankle in the center of this star. The patient must then use its other lower limb to reach as far as they can [11,12]. A short version of the test is also available and appears to have similar psychometric properties .
For the second question, it is a little less clear. Indeed, it is well known that proprioception is altered following ankle sprains [14-16]. But do we really know what “proprioception” means? If you ask your colleagues, some of them might answer: “Yes, of course.” However, chances are they will use the term proprioception to describe deficits found both following a simple grade I ankle sprain and deficits secondary to a cerebellar stroke. Some will find that I exaggerate, others will probably agree with me.
We will therefore define this term. Proprioception is defined as a group of senses including the senses (1) of limb position and movement (also called kinesthesia), (2) of tension or force, (3) of effort and (4) of balance [17,18]. Given this definition, it is not surprising that some clinicians and researchers tend to use for all kinds of deficits/pathologies. Moreover, proprioception involves various sensory receptors, the proprioceptors, found in several structures throughout the body (for example, in muscles, tendons, fascias, joint capsules, ligaments and skin around joints) [18,19]. Now that we have a common definition of proprioception, do you still believe the SEBT only assesses ankle proprioception? If we analyze this test, we notice that it will indeed require information from the proprioceptors around the ankle. However, the SEBT is not limited to ankle somatosensation. It requires an adequate control of the knee, the hip, stabilizers, etc., requiring a timely integration of the information from the sensory receptors with movement planning and execution .
If this assessment during a functional movement, which requires a precise integration of information from different sensory receptors in order to plan a movement and its execution  is not proprioception per se, then what is it? This is where we will introduce the concept of motor control. Motor control is the ability to regulate or direct the mechanisms essential to movement . This means that movement is an interaction between the individual, the task and the environment.
Knowing that, it is therefore important as clinicians to use the right terms to describe the deficits found during the initial assessment of your patient and to use the appropriate tests to assess these deficits. For example, it is possible that you specifically want to assess somatosensation (i.e. proprioception involving the detection of movement or reproduction of movement, thus using information from proprioceptors ). On the other hand, you might want to assess the more global function of your patient to reflect his or her motor control and somatosensory processing during a functional task . To help clinicians in their clinical decision-making process, a recent systematic review proposed a classification of proprioceptive tests to quickly identify what is being assessed (outcome) during specific tests .
-Somatosensation: Joint Position Sense , Threshold for Perception of Passive Movement ;
-Motor control: Star Excursion Balance test [11,12], Hop Tests [22,23], Biodex Stability System , Limit of Stability , Balance Error Scoring System , Time to Stabilisation .
The results of this systematic review suggest that the SEBT should be used to assess a patient’s motor control following a sprain. Indeed, the test is valid, accurate and responsive. However, if a physical therapist specifically wants to assess somatosensation, it would be more interesting to use the Joint Position Sense (passive-to-passive joint position replication; see Boyle & Negus 1998  for more information).
In conclusion, it is important to clearly identify your patient’s primary deficit (somatosensation or motor control). This will guide you in your clinical-decision process to ensure optimal follow-up while selecting the most appropriate interventions to optimize your patient’s rehabilitation. Afterwards, it is up to you to use a precise terminology when discussing with other therapists to have a real understanding of the case you are referring to and it will provide an accurate clinical description of your patient. For more information, you can read the open access systematic review in the BMJ Open Sport & Exercise Medicine .
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