Achilles Ultrasound and MRI Previous Surgery 2001 3 weeks pain, no trauma. Help.

I received 2 very helpful responses.

*John Read* said : This is a classic ultrasound pitfall for a missed
diagnosis of COMPLETE Achilles rupture. You see an apparent large zone of
heterogeneous but apparent (at least partially) bridging echoes and think
this must be tendon! But (a) the peripheral “sheath” of echoes that may
include some fibrillarity is in fact a chronically thickened paratenon, and
(b) the internal echo zone reflects some variable mix of haemorrhage and
tendinotic horsetail fibres. Thompson’s test is crucial at ultrasound
examination, and is readily performed with the patient being right in front
of you -> a *positive test is diagnostic regardless of the imaging
appearance*!

*George Koulouris* said: it’s such a big tendon that any issue with
mobility = high grade tear which is almost always complete rupture. even on
the static images it shouldnt have a dip in it –
it must always be taut
i just read this and it tells me it’s completely gone, or near enough .. *But
during dynamic imaging the distal segment didn’t move at all….so I
wondered if there was a high grade tear I wasn’t clearly seeing.*
if subacute to chronic then some adhesions to surrounding fat plus any
intact plantaris may hold a few strands of ruptures tendon in close
approximation that prevents the repelling of the opposing tendon edges
which is what we are looking for to confidently nail the diagnosis of a
full thickness tear

I was still confused about how the patient maintained full but somewhat
weak Active range of motion….I understand that the thickened paratenon
might bridge the gap and drive the distal fibers, but that still left me
wondering why then didn’t the distal segment move with ROM.
George suggested it might be moving thanks to an intact Plantaris….I
shared the following image and he showed me that the MRI and the US are
actually concordant (except that the major portion of the Bright T2 signal
defect is not hypoechoic on US….because of everything John Read said).
[image: plantaris_2.jpeg]
[image: Annotated Achilles MRI.png]
Medial to midline we see the pre-Achilles fat dipping into a partial deep
surface defect….which correlates to what we see on the US at 1.9cm from
the insertion.
It seems like there is intrasubstance communication to the major portion of
the tear which is centered 5.2cm proximal to the insertion.
Based on this, I think it *is* the plantaris…which connects the proximal
segment to the calcaneus, permits the Active ROM without moving the distal
segment of the completely torn Achilles.

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