0:00

Now it's important to understand the sequence of events

0:03

that will basically dictate

0:06

how the graft will look over time.

0:08

And so in the first few years, the graft will have, uh,

0:12

an altered appearance

0:13

and can have high signal intensity,

0:14

particularly within the first six months.

0:17

And what's happening in that first six months is

0:20

that the ligament, uh,

0:21

or actually the tendon when it's initially harvested,

0:24

if it's bone patella or tendon

0:26

or hamstring tendon, undergoes a process referred to

0:29

as ligamentization.

0:31

And that is a process of revascularization.

0:33

And so that can lead to areas of increased signal intensity

0:38

on your, uh, MRI.

0:40

And these signal changes can last up to four years.

0:45

So in the first two weeks when the, uh, tendon is harvested,

0:49

it's basically rendered avascular

0:51

because it's stripped from its blood supply.

0:54

But then over time, it

0:56

revascularizes gains blood supply from the bone

0:59

and the synovium.

1:01

And there's a cellular repopulation by synovial host cells

1:07

moving onwards from six to nine months.

1:09

There's ongoing ligament maturation

1:11

and remodeling such as the histology changes from tendon

1:16

to ligament.

1:18

So here's the sequence

1:20

of events over time in the first three months, um,

1:23

it can actually look quite low in signal intensity.

1:26

And mind you, you have to be cognizant of what type

1:29

of graft you are dealing with.

1:31

So if it's a single graft derived from, for instance,

1:35

a patellar tendon or quadriceps tendon, it's gonna be, look,

1:39

it's gonna look more uniform and dark and signal intensity.

1:42

But if you have that quadro, uh,

1:45

quadruple loop graft from a double loop of semi tendinosis,

1:49

um, and gracilis,

1:50

then you may see actual four individual fiber bundles

1:56

in the next, uh, subsequent four to eight months.

1:58

That's that revascularization and remodeling,

2:01

and you may see increased signal within the graft.

2:03

And then finally, at one to two years,

2:06

you will see maturation

2:07

and normalization back to low signal intensity over time.

2:11

But again, these findings can last up to four years.

Ligamentization

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0:00

Now it's important to understand the sequence of events

0:03

that will basically dictate

0:06

how the graft will look over time.

0:08

And so in the first few years, the graft will have, uh,

0:12

an altered appearance

0:13

and can have high signal intensity,

0:14

particularly within the first six months.

0:17

And what's happening in that first six months is

0:20

that the ligament, uh,

0:21

or actually the tendon when it's initially harvested,

0:24

if it's bone patella or tendon

0:26

or hamstring tendon, undergoes a process referred to

0:29

as ligamentization.

0:31

And that is a process of revascularization.

0:33

And so that can lead to areas of increased signal intensity

0:38

on your, uh, MRI.

0:40

And these signal changes can last up to four years.

0:45

So in the first two weeks when the, uh, tendon is harvested,

0:49

it's basically rendered avascular

0:51

because it's stripped from its blood supply.

0:54

But then over time, it

0:56

revascularizes gains blood supply from the bone

0:59

and the synovium.

1:01

And there's a cellular repopulation by synovial host cells

1:07

moving onwards from six to nine months.

1:09

There's ongoing ligament maturation

1:11

and remodeling such as the histology changes from tendon

1:16

to ligament.

1:18

So here's the sequence

1:20

of events over time in the first three months, um,

1:23

it can actually look quite low in signal intensity.

1:26

And mind you, you have to be cognizant of what type

1:29

of graft you are dealing with.

1:31

So if it's a single graft derived from, for instance,

1:35

a patellar tendon or quadriceps tendon, it's gonna be, look,

1:39

it's gonna look more uniform and dark and signal intensity.

1:42

But if you have that quadro, uh,

1:45

quadruple loop graft from a double loop of semi tendinosis,

1:49

um, and gracilis,

1:50

then you may see actual four individual fiber bundles

1:56

in the next, uh, subsequent four to eight months.

1:58

That's that revascularization and remodeling,

2:01

and you may see increased signal within the graft.

2:03

And then finally, at one to two years,

2:06

you will see maturation

2:07

and normalization back to low signal intensity over time.

2:11

But again, these findings can last up to four years.

Report

Faculty

Donald Resnick, MD

Professor Emeritus, Department of Radiology

University of California, San Diego

Mini N. Pathria, MD, FRCP(C)

Division Chief, Musculoskeletal Imaging

University of California San Diego

Eric Y. Chang, MD

Adjunct Professor, Radiology

University of California, San Diego

Brady K. Huang, MD

Clinical Professor of Radiology

UC San Diego Medical Center

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Ligamentization