The Ankle Syndesmosis Test You Must Know
Posted By: Andy Barker
More often than not they are mistake for lateral ankle injuries like an anterior talo-fibular ligament (ATFL) or calcaneofibular ligament (CFL).
And this is an big issue…
As the management of both syndesmosis injuries and lateral ankle injuries, is very different, particularly your acute management.
With a lower or even moderate grade ATFL or CFL injury you might promote early weight bearing and mobility exercise.
The complete opposite is needed for a syndesmosis injury.
When instability is present at the ankle syndesmosis (distal tibia-fibular joint), offloading the ankle is key, using a boot or crutches to allow the injury to settle, and more importantly, not make the syndesmosis injury worse.
It’s kind of funny that I writing about new grads missing these types of injuries…
Because I did exactly that as a new grad!
One of my most rememberable *%$@ ups as a newly qualified therapist was missing an ankle syndesmosis injury.
Worse than that…
At the time I did not even know what the ankle syndesmosis was!
Still to this day I don’t think it was even covered at Uni, or if it was it was glossed over.
This was not great for me as working in rugby at the time, syndesmosis injuries were very common and in many seasons they were more frequent than lateral ankle sprains and ruptures.
That experience left me wondering and questioning my knowledge and I set about learning everything I could about ankle syndesmosis injuries.
Over the years having managed dozens of these types of injuries, I have learnt more and more, and I hope this blog post helps you to better understand the ankle syndesmosis and especially syndesmosis special tests.
In this blog I will detail the ankle syndesmosis special test I used the most often and explain why this should always be the the first test you should use if you suspect an ankle syndesmosis injury.
Understanding The Anatomy Of The Ankle
I was alarmed the other day when I saw on social media how a couple of so called ‘guru’s’ were saying that anatomy is not important.
They were making the case that we learn all these attachments, innervations and rope learn this information for exams at Uni…
But a few weeks later forget them all, and don’t need to know them in that much detail…
So what’s the point.
Anatomy is the foundation of everything we do as therapists.
If you don’t know where certain structures are, what roles they do and how they work, it makes your job to assess, treat and rehab any injury much more difficult.
You can differentially diagnose a syndesmosis injury from an ATFL injury, just by palpating these structures.
But you can only do this if you know your ankle anatomy and where these structures are in the ankle.
You can diagnose a nerve injury in the lower leg, ankle or foot, but again you need to know what areas of the skin or which muscles and joint actions are innervated by which nerves.
Usually those that shout the loudest on social media make the most noise.
In the case of the gurus I saw shouting loudly about anatomy not being important…
They are 100% wrong, and I welcome any one to get in contact and try change my mind!
Let Your Patient Tell You Which Special Tests To Use
The best thing about your subjective assessment is that if you do it well, your patient will give you all the answers…
And in most cases actually tell you what to do in your objective assessment, and even what special tests to do!
Take the ankle.
The common mechanism for injury for a ATFL is plantarflexion and inversion.
This is very different to a syndesmosis injury in which the common mechanism of injury is dorsiflexion and external rotation.
These mechanisms are not just different…
But the complete opposite.
Unless you are dealing with a major ankle injury, like a fracture dislocation, when just about every structure in the ankle is damaged…
It is impossible for you to damage the syndesmosis with a mechanism of injury that involves inversion or plantar flexion.
It is equally as possible to sustain a lateral ankle injury with a dorsiflexion and external rotation mechanism of injury.
The syndesmosis joint is stressed and the integrity of the ligaments tested when the ankle is dorsiflexed and externally rotated, and this does not happen when a patient or athlete plantarflexes or inverts their ankle.
It can not…that’s fact.
So, if you do a good job with your subjective and attain how the ankle was injured, in most cases your patient will be able to tell you what happened and in turn, tell you what injury to suspect.
If you are clear on what injury to suspect you can be clear about what tests you need to include as part of your objective assessment and the specific special tests you will use.
The #1 Syndesmosis Test
If you suspect an ankle syndesmosis injury the first test you must do is the squeeze test.
When you squeeze together the tibia and fibula at the top of the lower leg these bones move closer together, whilst the tibia and fibula at the bottom part of the lower leg (the ankle syndesmosis), do the opposite and move apart.
Some movement and widening of the syndesmosis joint is normal, but if the syndesmosis ligaments are damaged there will be excessive widening at the joint and this test will be painful.
Pain with this test is considered a positive test for an ankle syndesmosis injury.
The squeeze test itself has been shown to be highly sensitive and specific to diagnosing syndesmosis injuries.
If you get a positive result with this test and the subjective assessment indicated a probable syndesmosis injury, then in most cases it is unnecessary to do any further special testing.
You have a mechanism of injury that fits this type of injury and a positive test, using the squeeze test that is evidenced to be both sensitive and specific to a syndesmosis injury.
Additional testing is unlikely to give you any further helpful information or testing results that are going to help you make a confident diagnosis.
If anything, it will just irritate your patient more and could actually make their injury worse, especially if you are assessing an acute ankle injury where instability is present.
Hope this helps
PS. If ankle assessments are something you would like to learn more about…then just let me know.
I can let you know some of the other tests I might use for ankle syndesmosis injuries, alongside the squeeze test, and what sort of presentations might warrant using these types of tests.
It is important to get the acute management of syndesmosis injuries right…
Or risk your patient or athletes symptoms not settling and be left with an unstable and painful ankle that just does not improve.
On the CPD call I’ll help you make sense of your ankle assessments and special tests to give you the confidence you need to assess these types of injuries well, to help you differentially diagnosis different ankle injuries, so you are sure you are treating the right thing.