0:00

What about partial pairs

0:02

of the anterior cruciate ligament?

0:04

Well, with regard to the partial pairs, there's controversy

0:09

regarding what a partial tear represents.

0:13

Some people suggest in the literature you have to disrupt 25

0:16

to 75%

0:19

of the collagen fibers within the

0:21

anterior cruciate ligament.

0:23

There are four classic clinical criteria.

0:27

Here you can see I've listed them.

0:29

Abnormal lockman test, right?

0:32

Negative pivot shift test,

0:33

low grade injury using an an arthro, uh,

0:38

or positive arthroscopic examination.

0:41

These injuries are not that common. Okay? All right.

0:46

Representing 15 to 20% of ACL injuries,

0:51

we can look for abnormal signal involving one

0:53

or both bands, more commonly the an medial band,

0:57

especially at its femoral attachment.

1:00

And then on clinical examination, partial tears

1:04

that are stable have a prognosis similar to that

1:08

of a normal ligament, whereas those partial tears that are

1:12

unstable have a prognosis similar

1:15

to a completely torn ligament.

1:18

Many, uh, years ago I did a sabbatical, uh, at the Prince

1:22

of Wales Hospital in Hong Kong,

1:24

and I learned about their particular, uh, technique

1:29

of using o blank imaging, right.

1:32

And I just wanted to show you

1:34

how they program their OBL imaging

1:36

of the anterior cruciate ligament

1:39

and taken from one of their articles on the subject.

1:41

I'm showing you here a

1:45

complete tear involving the antral medial bundle

1:48

and a partial tear of the postal lateral bundle.

1:53

And in this example, a normal, an medial bundle

1:56

and a partial tear of the postal lateral, uh, bundle.

2:03

Now let's look at the end of the ACL at chronic tears

2:07

and what may in fact happen with, with, uh, chronic, uh,

2:11

tears of the ACL sometimes when you follow them.

2:15

And here I'm showing you three sequential MR.

2:18

Examinations here at six months that ACL doesn't look

2:22

so bad, and that relates to scarring of the torn ACL

2:27

to adjacent structures.

2:29

There are a number of articles,

2:30

I'm taking some data from this particular article listed at

2:34

the bottom that have talked about the ultimate fate

2:38

of chronic untreated complete tears of va ACL.

2:42

The most common pattern of scarring is

2:45

to the posterior cruciate ligament shown in this example.

2:50

Another pattern that we may see is scarring

2:53

to the roof of the notch.

2:55

And in these cases you can see that the course

2:59

Of the anterior cruciate ligament,

3:01

although not normal, begins to look like

3:03

or parallel to the roof of the intercon or notch.

3:08

Another finding that we can see is complete resorption

3:12

or a of that, uh,

3:15

anterior cruciate ligament over a period of time.

3:18

This is said to be rather frequent.

3:19

You end up with something like this.

3:22

Now, if you end up with something like this,

3:24

of course there is a differential diagnosis,

3:27

and that differential diagnosis would be developmental

3:31

absence of the anterior cruciate ligament

3:33

as shown in this case.

3:36

I can tell you in general that when we are dealing

3:42

with developmental absence of one

3:44

or both cruciate ligaments, there are other anomalies

3:48

of other ligaments

3:49

or of the bony surfaces that will help you in terms

3:53

of saying this is not acquired absence,

3:56

but developmental absence.