Ligament injury vs. remodelling

[Linh]

Hi Steve,

Sprain is a generic term when describing injury to the ligaments such as ATFL.

What are the different appearances of an ATFL as it becomes injured over time from acute, to subacute and chronic phase?

How does one differentiate a sprained/partially torn ATFL from effective/non-effective remodelling (deficient vs hypertrophic remodelling) or scarring based on echogenicity, thickness and vascularity?

I want to conceptualize the pathophysiology and the healing process more than just describing a thickened ATFL as sprained (which can be an inaccurate description if clinical correlation is not taken into account).

Best regards,
Linh

[Stephen Bird]

Hi Linh,

You raise many points in this question.

I will list the appearances I am looking for in this spectrum.

A normal ATFL will have densely packed parallel lines of collagen and will prevent the talus from moving anterior when challenged by the Quanson modified anterior draw test. A trace of fluid beneath it is normal.

An acute strain looks like a swollen, hypo echoic ligament but without any focal defect and maintains stability when challenged by the Quanson modified anterior draw test. There must be an acute trauma history.

A partial tear is the same as the acute strain appearance, however there will be a partial thickness defect in the ligament. Again an acute history is essential.

A complete tear presents with complete disruption in the ATFL with ankle joint synovial fluid passing through the defect into the subcutaneous space causing swelling and bruising. There may or may not be a bony avulsion at the point of failure. When challenged by the Quanson modified anterior draw test the talus migrates anteriorly away from the lateral malleolus.

An old tear looks similar to an acute strain with an “intact” ligament in situ, however in this case the ligament is not native collagen but rather granulation tissue. When challenged by the Quanson modified anterior draw test it usually provides reasonable stability but this is variable and those patients that still feel “unstable” may have more movement and laxity. In this case a prior history of trauma but no immediate injury is essential.

In cases of anterolateral gutter impingement it is exactly the same as an old tear, however rather than the scar tissue being similar in thickness to the native ligament it is more than twice as thick and causes impingement. It may also be vascular and the patient will be experiencing ankle tightness.

As for vascularity, in all acute injuries you will see hyperaemia as part of the injury / heal response.

In an old granulated ligament there should be no flow,

In anterolateral gutter impinegement there is often some flow due to the synovitis caused by the impingement.

Steve

[Linh]

Thanks Steve.

In the case where ATFL and its bony attachment at the tibia is avulsed, as it heals, would there be scar tissue between that bony fragment and the tibia? Often we see old injury where there is bony fragment within the mid substance of ATFL, would you say there is non-reunion with the tibia? How would you describe this in your worksheet?

A healing ATFL would show decreasing vascularity over time. What might it look like if there is non-effective healing on a sprained ATFL?

I come across a patient with a chronically ruptured ATFL (he had 2 sprains in the past doing martial arts) and recent posttraumatic synovitis at the anterolateral gutter. A 4mm bony ossicle at the anterior ankle joint. As I dorsiflex his foot, there is reduced movement with end range dorsiflexion pain. Would you call this anterolateral impingement based on both clinical & US findings?

Best regards,
Linh

[Stephen Bird]

Hi Linh,

You mention the tibia, however I think you mean either the fibula or the talus.
Where a bony avulsion is made during an ankle ligamentous injury I don’t think I ever see perfect bony repair. The fragment never gets back perfectly placed against either the fibula or the talus to achieve a perfect union. These avulsed fragments generally end up imbedded in the granulated ATFL and if they are large they may cause some anterolateral gutter impingement like the case you also discuss in this question. We see these fragments very commonly on plain radiographs and they present as well corticated old, chronic ossicles in the area of the ATFL.

On my worksheet I just say there is an ossicle within the ATFL representing either an old avulsion fragment or dystrophic calcification from a prior injury.

As for vascularity I expect to see some increase in vascularity during the active healing phase. If it persists a month after the injury I would suggest you have some chronic post traumatic synovitis of this component of the joint capsule.

Your martial arts case sounds exactly like either anterior ankle joint impingement or anteroom-lateral gutter impingement or a combination of both.

Steve

[Linh]

Thanks for your reply Steve.

Yes, I meant fibula, not tibia 🙂

[Stephen Bird]

I never doubt you Linh,

I know you are an anatomy nerd just like me!

Steve

[Linh]

hahaha, you’re too kind!

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