mri knee 3

1. Grade I sprain (Low-Grade partial tear)

• Signal around ACL

• The fibres of the ligament are stretched, and

we can see more than 50% of its fibres intact.

2. Grade II sprain (High-Grade partial tear)

• Signal within ACL

• We can see less than 50% of fibres intact.

3. Grade III tear (Complete ACL tear)

Grade I sprain

(Low-Grade partial tear)

Grade II sprain

(High-Grade partial tear)

Grade III tear (Complete ACL tear)

1. Discontinuous fibers

2. Non-visible fibers

3. Abnormal slope of the ligament

4. Empty notch sign

Grade III tear

(Complete ACL tear)

Discontinuous fibers

Grade III tear

(Complete ACL tear)

Non-visible fibers

Grade III tear

(Complete ACL tear)

Abnormal slope of the ligament

Grade III tear

(Complete ACL tear)

Empty notch sign

1. Grade I Sprain

• High Signal superficial to the collateral ligament

• The fibres of the ligament are stretched, and

apparently intact

2. Grade II Sprain (Partial Tear)

• Signal within the collateral ligament with disrupted

and intact fibres

3. Grade III Tear (Complete Tear)

Grade I Sprain

Grade II Sprain

Grade III Sprain

Sequence Bone Cartilage Fluid

T1 Signal Void Iso Hypo

T2 Signal Void Hypo Bright

PDFS Signal Void Hyper Bright

Gradient Signal Void Hyper Bright

Grade MRI finding

I Focal signal intensity changes without contour deformity

(difficult to assess on MRI)

II Focal signal intensity change and contour bulge (partial

thickness)

III Focal signal intensity change, contour irregularities,

cartilage thinning and fluid extension into cartilage (full

thickness)

IV Similar to stage III with defects extending to the cortical

bone (with subchondral bony changes)

mri knee 3

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