Practitioner Seed # 3: Differential Diagnosis

It can be like finding a needle in a haystack!

 

Diagnosing  the patient in front of you as a new graduate can prove to be an arduous task. Your pattern recognition system is in its infancy.

You are frantic in that first assessment, attempting to process and combine subjective details, objective tests,  remain alert to the presence of any psychosocial factors, understand your patients goals & aspirations, all while building rapport and gaining buy in!

Even with 16 years of experience this can be a challenge!

However…………..

It is with experience that you begin to develop your pattern recognition and execute a more streamlined approach with your questioning and test battery.

This is where a thorough assessment is paramount!

AND

This is the one time as a student or new grad, that you might need to ‘Rote’ learn a logical flow of tests, to ensure that you don’t miss anything.

Once you are led down a certain hypothetical pathway, it’s important to complete a set of quick ‘clearing tests’ to ensure that you are not missing something.

Essentially you are trying to prove your hypothesis wrong in what we know as the:

Differential Diagnoses

Unfortunately, the human condition is not that simple and multiple diagnoses can be present simultaneously.

This is where the experienced clinician will identify the ‘Primary’ or the ‘Driver’ that is a potential causative impairment or pathology in the overall health disorder.

During field based, pivoting and Contact sports, we have seen a rise in syndesmosis (High ankle) injuries. Whether contact sport has changed – Athletes are bigger, faster, stronger, changes to tackling technique-  OR we are better at differentially diagnosing from the typical Inversion ankle sprain?

Maybe a bit of both!

Lets consider the different presentations:

Syndesmosis Sprain v Inversion Ankle Sprain

Mechanism:

SS: Contact with planted foot and opponent falls across leg, foot externally rotates.

v

IAS: Non contact, cutting or landing from jump (sometimes on oppo foot) and ankle collapses into inversion +/- plantarflexion.

Pain Location:

SS: Above ankle if AITFL involved, which can extend up the shin into interosseous membrane, posterior pain if PITFL is involved. May also have some medial pain if deltoid ligament is implicated. IMPORTANT TO CHECK THIS!

v

IAS: Pain over lateral ligament complex +/- medial ankle joint pain – (As a result of the medial joint compression from the inversion)

 

Clinical Tests:

SS: Calder et al indicated +ve squeeze test (instability 9.5x more likely), palpation of AITFL & associated deltoid ligament injury (instability 11 times more likely).  In practice we find use of the end range dorsiflexion/ rotation test to be a really good at diagnosing syndesmosis injuries, although not at establishing severity/ instability.

v

IAS: Palpation tenderness over lateral ligaments +/- Medial joint tenderness (But no deltoid laxity!),  positive anterior drawer/ talar tilt – Pain, laxity and abnormal end feel.

 

Check out this algorithm for diagnosing syndesmosis instability (Calder et al)

 

Functional: 

SS: In the vast majority of cases, player will struggle to play on. Upon assessment they will have difficulty with producing force, running, hopping etc

v

IAS: Player may be able to continue with supportive taping if low grade, and minimal ankle joint surface/ medial gutter involvement.

So now you should feel more confident in being able to differentially diagnose an everyday ankle sprain from a syndesmosis injury.

This is one differential diagnosis that you don’t want to miss as the difference in healing rates and return to play timelines vary considerably.

Stay tuned for future instalments on how you can be systematic when planning a rehabilitation interval, and predict injury timelines, when you are new to this caper!

 

 

 

Reference:

Calder, J. D., Bamford, R., Petrie, A., & McCollum, G. A. (2016). Stable versus unstable grade II high ankle sprains: a prospective study predicting the need for surgical stabilization and time to return to sports. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 32(4), 634-642.