Shoulder Assessments – The 3 BIG ACJ Mistakes

Posted By: Andy Barker

So the Acromioclavicular or ACJ is a relatively simple joint.

It’s a plane synovial joint that has very little movement…

It joins the clavicle or collarbone to the acromion (shoulder)…

It has no direct muscles attachments…

And only two ligaments – the acromioclavicular ligament on the top, and the coracoclavicular ligament (conoid and trapezoid ligament together) below.

Yet ACJ injuries can be tricky to manage.

They can take an age to settle down…

And are at high risk of re-injury and aggravating particularly with patients or athletes that have manual jobs, lift weights and particularly athletes involved in contact sport.

It is also an injury that are often misdiagnosed, usually as glenohumeral joint (GHJ) injury or even a muscular problem like an issue with the upper trap or levator scapulae.

I’ve seen this first hand in elite sport and I got caught out with a professional rugby player myself, who at first appeared to have a simple ACJ injury…

But it turned out to be a whole lot worse!

He had got injured in a game making a tackle (direct impact to his shoulder).

He managed through to the end of the game and reported his injury afterwards.

We were able to settle his symptoms quickly and get him back ‘fit’ and playing in the next game.

However, he continued to struggle and even given our best efforts, modifying his training and contact, and the daily treatment and rehab he was getting, something was just not right.

Where You Are Going WRONG With The Shoulder
I sent him for an MRI and he actually had a small distal clavicle fracture, at the distal end, right next to the ACJ.

We had sent him for an x-ray after his initial injury, but this was clear and given he initially had all the signs of a ACJ injury, we managed it that way.

However, on reflection there were a couple of signs I could of picked up on earlier, that might have suggested it was not just a simple ACJ injury.

I am going to share those with you, plus another tip, to help you avoid a similar mistake to me…

And help you nail your shoulder assessment so you can correctly diagnose an ACJ injury and know how to rule out other issues in the shoulder.

Rule Out A Fracture

Firstly, if there is evidence of high impact trauma and your patient or athlete has any bony tenderness to the ACJ or the two bones that make up the joint, the clavicle and or acromion, it is smart to rule out a fracture.

The mechanism of injury for a fracture to the ACJ, clavicle or acromion can be the same (direct impact or fall on to the shoulder/outstretched hand), so it makes logical sense and good practice to rule out a fracture with any possible bony injury.

It is also not uncommon to get injuries to both the ACJ and a fracture to the acromion, clavicle or both.

With regards to a fracture, bony deformity of the clavicle or acromion is a tell tale fracture sign, as is crepitus on palpation, which are largely not present with an isolated ACJ injury (note you will often see a raised distal end of the clavicle with an ACJ injury but no deformity with the clavicle or acromion).

Like the pro rugby player that caught me out, any ‘ACJ’ injury that does not fit an ACJ pattern and is not responding in the way you would suspect, should raise your suspicions of a possible fracture.

If in doubt refer them for an x-ray.

Do Not Rush Simple ROM Testing

The ACJ will be stressed in different positions and different movements compared to the GHJ.

The most common symptoms for GHJ issues are usually seen between 80-120 degrees of shoulder flexion or abduction (painful arc) whereas ACJ issues are commonly seen at end range flexion and abduction and particularly when the arm is brought across the front of the body (horizontal adduction).

I see many new grads too keen to rush the early part of their shoulder assessments, like simple range of movement (ROM) testing, to get to the ‘sexy’ special tests…

And this is a big mistake!

Simple ROM tests can give you so much information, even a diagnosis, sometimes without even having to do any special tests.

Take for example the movement of horizontal adduction (arm reaching across the body).

This movement of horizontal adduction, whilst a simple ROM test, also doubles up as a ACJ special test (scarf test).

So by doing a thorough ROM shoulder assessment you might even find you do not need to even do any special tests and still be 100% confident you have the right shoulder diagnosis.

Palpation On Point

ACJ injuries will always be sore to palpate, so palpation of the shoulder is a key part of your ACJ assessment.

Alongside the other tests, like ROM, that form part of your ACJ objective assessment, your palpation findings will help you confirm if you are working with a ACJ injury or not.

This is assuming your anatomy knowledge and palpation skills are on point!

The clavicle and acromion, the two bones either side of the ACJ can also be easily palpated through the skin, and as such mean that your palpation skills, and your anatomy, need to be good…

To help you diagnose the right patient or athlete shoulder diagnosis.

Key Take-Aways

Rule Out A Fracture: If your patients has the right mechanism (direct impact or fall) and any signs of a possible fracture (deformity, crepitus, non uniform symptoms) at the ACJ, clavicle or acromion, suspect a fracture and refer for an x-ray.

Do Not Rush Simple ROM Testing: Simple ROM tests help you to differentiate between GHJ and ACJ injuries and specific movements, like horizontal adduction, also double up as ACJ ‘special tests.’

Palpation On Point: Because the ACJ, clavicle and acromion are superficial structures they can be easily palpated and as such, your palpation skills form a big part of your ACJ shoulder assessment.

Hope you found this helpful


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