Hi Mike,
Interesting case.
When I see echogenic areas within an Achilles tendon I think of the following:
Enthesophyte where a bone spur has grown into the tendon from the calcanea enthesis
Calcific tendinosis where hydroxyapatite migrates via the enthesis into the tendon
Gout where monosodium urate crystals make their way into the tendon
Dystrophic calcification from degenerative phase tendinosis where tenocyte exhaustion has occurred and dystrophic calcification has been deposited in areas where the tendon suffered myxoid degeneration.
In your case I think it is the last option (dystrophic calcification)
There is a significant background of tendinosis with the tendon being hypoechoic, heterogeneous, hypervascular and swollen. There is also a significant inflammatory response in the peritenon and fat adjacent to the tendon.
I do have one concern.
I have screen shot 2 of your images and placed a red ring around the area I am interested in.
In this area the tendon looks to have a little step in its contour and I would be keen to do some dynamic assessment in this area, especially given the history of trauma.
With the patient prone, scanning the Achilles in the long axis slowly move the ankle through doors and plantar flexion. If the tendon is intact there will be synchronous movement of the tendon. If there is a tear in this area you may see paradoxical movement between the two ends.
My feeling is that your images show degenerative tendinosis and dystrophic calcification without complete tear, but I would like some dynamic assessment of this area.
Really nice work.
This is going to be a difficult tendon to rehabilitate.
Steve