28/01/2023 at 5:03 pm #46697David HumphriesParticipant
in your webinar on ankle and foot challenging cases you talk about deltoid ligament tears (as opposed to POMI lesions) occuring with inversion sprains, could you go into this a little further as I associate deltoid ligament injuries with eversion type injury
28/01/2023 at 5:37 pm #46698Stephen BirdKeymaster
Deltoid injuries are interesting.
There are several types,
As you mention with inversion injuries the posteromedial component of the deltoid lig (tibio-talar) is compressed and develops a post compression synovitis (POMI lesion)
Remember the deltoid ligament complex is nothing more than the medial ankle joint capsule.
As you mention the deltoid can tear with eversion injury although this is rare as eversion is an uncommon vector of force.
The other common type of injury is where the antero-medial part of the deltoid (tibio-spring / tibio-navicular) and the flexor retinaculum are stripped from the medial malleolus of the tibia.
This is a degloving injury and is quite common.
The flexor retinaculum and the deltoid ligament actually fuse together making a conjoint attachment to the medial malleolus and I refer cheekily to this conjoint structure as a “Liganaculum” (a made up word !)
When it strips is often takes some periosteum of the tibia and you se this as an echogenic line attached to the stripped joint capsule.
The interesting thing is these stripping injuries actually occur during an INVERSION injury which sounds surprising.
It is the dynamics of movement of the talus relative to the medial malleolus that leads to this stripping.
I see this injury very commonly with inversion injuries and once you start looking you will see plenty of pathology here.
A good way to think about your transducer position is this:
To look for a POMI lesion place your finger at the posterior aspect of the medial malleolus and place the transducer immediately anterior to your finger in a coronal plane and you will be well positioned for POMI assessment.
To look for a liganaculum stripping injury place your finger at the anterior aspect of the medial malleolus and place the transducer immediately posterior to your finger in a coronal plane and you will be well positioned for deltoid / flexor retinaculum stripping assessment.
I also have some ideas on how ankles fail during inversion stress as there are a few common patterns.
The way I am currently thinking about it is “how is the energy released” during the accident.
I am going to make a short webinar going through the patterns I see clinically.
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