Shoulder Webinar Questions

[Diane]

Hi Steve!
Just a couple of questions on your shoulder webinar

1) You mentioned that dipping of the roof line means volume lost which is associated with full thickness tears.

Is dipping just exclusively associated with full thickness tears or can they be associated with partial thickness tears too?
If you see dipping but no anechoic areas, do you mention in your report that this finding is suggestive of ____ tears i.e. that the bursal dipping is suggestive of partial thickness tears or the bursal dipping is suggestive of full thickness tears?

2) I’m struggling with the definition of a periosteal cyst? One of our radiologists mentioned it in a shoulder MRI report I was reading but couldnt find any good articles online about it.

Whats the difference between a periosteal cyst and a tear? Are periosteal cysts reactions or are they precursors to a tear? Would a periosteal cyst have smooth margins and look “clean” and a tear looks more ragged?

3) When looking at the axillary recess area, does assessing for capsular bunching during external rotation important to you or is trying to detect fluid in the axillary recess more important?

4) When there are patients with extreme limited ext rotation where the subscapularis cannot be seen nicely, do you have any tips/tricks for seeing the subscap tendon?

5) For the modified crass, do you prefer the hand to be higher up near the mid abdomen area or resting at the hip crests level or doesnt really matter?

6) In full crass, do you have the palm of the hand facing towards the back or away from the back or doesnt matter?

Thank you!

[Stephen Bird]

1: When I see roof lne dipping /collapse I think it is absolutely diagnostic of collagen loss and this may be chronic and attractive in nature or represent a more acute injury. When I see it I am very suspicious of a full thickness tear and will stress the tendon with full Crass positioning as well as looking at in modified Crass and relaxed position trying to demonstrate the full thickness defect. Most times I can and I call it full thickness. If I can’t I say there is significant volume loss and it represents at least a high grade partial thickness tear. Dynamic movement while you scan can also force some peri-bursal fat or fluid into the defect making the diagnosis.

2: I tend to use the tern sub-periosteal cyst but we are all talking about the same thing. They occur at the enthesis part of the skeleton only. It is what we see on a plain radiograph where the enthesis changes from looking smooth to looking more like a close up photo of the moon surface with many small craters. It is what we see on ultrasound as enthesis irregularity as we only see the surface of them. They are strongly associated with tendon tears and attrition so when you see it you must look at the tendon adjacent to it really carefully. So the sub-periosteal cyst relates to a bony enthesis change not a tendon tear but they are strongly associated with an adjacent tendon tear.

3: For me the axillary recess which I see deep to the trees minor insertion is all about joint fluid to make a diagnosis of joint effusion. It is the best place (along with the long head of biceps sheath)

4: Nup, not really, just tell them to toughen up and externally rotate them (with empathy!)
You can try them supine, but I think with encouragement patients can give you enough external rotation to see the important part of the tendon.

5: Doesn’t matter, but I find holding onto the belt area of the lateral hip is comfortable and effective

6: probably doesn’t matter much to the tension on the supra but I think it is more comfortable to have the back (dorsum) of your hand on the small of your back rather than the palm. Try it and see what I mean. Or am I just getting old and inflexible !

Steve.

[Diane]

Thanks for the reply Steve,

Please correct me if I’m wrong but does that mean subperiosteal cysts is bony pitting of the enthesis? Just thinking about breaking down the definition of sub periosteal as in sub means underneath the surface of the bone… I’ve attached a picture I drew which is what I’m imagining.

Do you happen to have any specific pictures for subperiosteal cysts or any journal articles if im not getting the gist?

Thanks again!

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[Stephen Bird]

Hi Diane,

you are getting it,
I think your picture sums it up well.

the term sub-periosteal may be a bit confusing but it just means that the enthesis has a pitted surface. The pitting forms like little caves if you like in the surface of the enthesis. On ultrasound we sound getting “into the bone” and echoes returning from just beneath where we expect the enthesis bone surface to be. The enthesis bone surface looks irregular and pitted.
I will find some examples.

Steve

[Stephen Bird]

A few images attached

Steve

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