Bony erosion medial to the lesser tubercle

[Xue Heng]

Recently I came across some patients with shoulder pain, on the long axis of subscapularis tendon, I saw bony erosion medial to the lesser tubercle, with normal subscapularis tendon and no Color Doppler signal.
Just like this. When I compare the contralateral side, similar bony erosion was detected, with no obvious symptoms. I just wonder the clinical significance of this finding and how should I report this?

• This topic was modified 3 years, 10 months ago by Xue Heng.
• This topic was modified 3 years, 10 months ago by Xue Heng.

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[Stephen Bird]

Hi Xue,

So nice to hear from you,

These are great quality images,

Great to see such fantastic images coming out of Beijing,

I would not expect any less from your skilful hands.

This appearance is very similar to the post below,

I see this pattern fairly commonly in a range of locations.

I see it in subscap where your example is from, I also see it in supra and most commonly infra.

The common thing with all of these examples is that the bony “erosion” is always located at exactly the point where the hyaline cartilage finishes and the enthesis begins. By definition this is where the joint capsule inserts and naturally this has an enthesis.
The “erosion” is a type of synovial herniation pit at the capsule insertion.

They are usually asymptomatic and I stumble upon them in normal volunteers and asymptomatic joints.

Great images mate,

I am missing mainland China and can’t wait for an opportunity to return,

Keep enjoying the website and please post as many of your great cases as you wish,

Happy scanning,

Steve

[Xue Heng]

Hi, Steve.
Thank you very much for your kind and patient answer.
We expect your next coming to China to give us lectures.
Your lectures are the most wonderful one I ever had.
This website is full of treasure for us to explore. I really appreciate your hard working.
For this case, is this pit the same location of “bare area” in GH joint?
Also, is this has something to do with impingement?
For example, when internal rotation happens, soft tissue in this area impinge with coranoid process or someing else.
Thank you again!

Xue Heng

[Stephen Bird]

I agree Xue,

This correlates to the “bare area” you think of on MRI especially the ones near the infra insertion,

I am not sure they are due to impingement with the coracoid process in the subscap case,

I wonder if mechanical stress on this part of the GH joint capsule may be a predisposing factor or if they are just a simple normal variant.

Nice photo mate,

Great to see your smiling face again!

Steve

[Xue Heng]

Thank you so much Steve 🙂

[Stephen Bird]

My pleasure mate,

Please keep the great Beijing cases coming,

I love your work,

Steve

[Xue Heng]

Sorry, Steve.
There is still a question related to this topic.
Except the clinical history of shoulder dislocation,
how can we tell the difference between this normal finding and Hill-Sachs lesion?
As we know, Hill-Sachs lesion is shown on US as bony defect of the humeral head.
Is Hill-Sachs lesion located more medially? Or Hill-Sachs lesion is more deep and irregular?
Please forgive me that I have so many questions.
Thanks a lot, Steve.

[Stephen Bird]

It can be tricky to differentiate between one of these synovial herniation pits and a Hill Sachs deformity. But the history helps a lot. Hill sachs is always associated with trauma and most often dislocation so in the absence of this history you can be sure it is a normal finding. If there has been a dislocation it is more difficult as both options are viable. The Hill Sachs tends to be a broader defect as it is a punch fracture of the posterior humeral head and it is usually not located exactly at the location where the hyaline cartilage ends and the enthesis begins.

It is this exact location that makes the synovial herniation pit a specific diagnosis.

There will be occasional times where i am faced with a history of trauma / dislocation and I am uncertain if I am looking at a herniation pit or a Hill Sachs.
In this occasional case cross sectional imaging like CT or MRI will come to my rescue.

Steve

[Xue Heng]

Thank you very much, Steve.
No imaging modality is perfect.
Sometimes we have to rely on X-ray, CT or MR to make a more definite diagnosis.

[Stephen Bird]

Yes, that is certainly the case,

We should use our various modalities in combination to arrive at the correct answer.

You are right when you say all tests have strengths, limitations and weaknesses.

Different modalities can certainly compliment each other,

Steve.

[Xue Heng]

Steve, this is a relevant case. Today, while performing a shoulder scan, the visiting doctor found that in this asymptomatic healthy volunteer, there was cortical depression at the greater tuberosity, the enthesis of supraspinatus tendon, with no obvious indentation or swelling at the enthesis itself. I believe this depression is caused by impingement of the greater tuberosity, or as you mentioned, “the erosion is a type of synovial herniation pit at the capsule insertion.” However, Cui believes that this is a manifestation secondary to partial tearing on the joint side of the supraspinatus tendon. Which consideration do you lean towards, and why? Thank you for your detailed and patient responses each time!

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[Stephen Bird]

Howdy mate,

How are things in beautiful Beijing?

I am overdue to visit you and your team,

Nice images,

I do not believe this is a synovial herniation pit as the location is not correct.

If you look at the last case you sent me in this conversation thread the pit was exactly at the point where the hyaline cartilage finishes and the enthesis begins.
This is not the case this time around.
This bony change is about half way along the enthesis and hence represents an injury where the supraspinatus tendon has created excessive traction on the enthesis and has disrupted the calcified fibrocartilage and resulted in the sub-periosteal pit that you see.
The tendon immediately adjacent tot he bony change also looks to have an altered echo texture.
So I believe this is a partial thickness intrasubstance tear of the supraspinatus. It may be old and hence no longer symptomatic.
If you review the plain radiographs you may see some small sub-periosteal cyst formation at the supraspinatus enthesis footprint area.
These bone “chinks” are very location specific.
I have a new webinar coming called “what is that chink in the bone” that will delve deeper into this subject.

Steve.

[Xue Heng]

Dear Steve,

Thank you very much for your detailed and insightful feedback—it’s always a pleasure learning from your expertise.

Things here in Beijing are good, and we’re all looking forward to welcoming you soon when you’re able to visit. I truly appreciate the time and effort you’ve taken to review this case.

Your explanation regarding the bony change being related to traction injury rather than a synovial herniation pit is very clear and makes perfect sense upon review.

[Stephen Bird]

Keep up the great work mate.

Steve.

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