Root Repair

For Medical Students

What It Shows

Post-operative imaging of a meniscal root repair shows the root attachment, the tunnel or anchor holding it, and the meniscus's position. 5.6.9 covers root tears.

The decisive finding is whether the meniscus has come back into the joint. 5.6.11 covers meniscal extrusion.

It matters because a root repair exists to restore load transmission, and extrusion is the measure of whether it did. 3.6.11 covers the effects of root tears.

How It Is Acquired

State the interval and the fixation used if it is known. 5.5.3 covers the post-operative protocol.

Measure extrusion on the coronal images using the same convention as before the operation. 5.6.11 covers meniscal extrusion.

Assess the root attachment itself, accepting that its signal persists. 5.6.13 covers the meniscal repair imaging.

Assess the tunnel or anchor position. 5.5.6 covers the bones.

Assess the subchondral bone of the compartment, since insufficiency fracture accompanies these injuries. 5.13.4 covers insufficiency fractures.

What Normal Looks Like

A meniscus whose body sits within the joint margin. 5.6.11 covers meniscal extrusion.

A root attachment with persisting signal and no displacement. 5.6.13 covers the meniscal repair imaging.

Fixation in position. 5.5.6 covers the bones.

Subchondral bone with no new line and no collapse. 5.13.4 covers insufficiency fractures.

What Abnormal Looks Like

Extrusion unchanged from the pre-operative study, which means the repair has failed mechanically. 5.6.11 covers meniscal extrusion.

A root that has pulled off its fixation. 5.6.9 covers root tears.

Fixation that has migrated, or a tunnel that has widened. 5.5.6 covers the bones.

A new subchondral line in the loaded compartment. 5.13.4 covers insufficiency fractures.

Progressive cartilage loss in the same compartment. 5.12.6 covers cartilage injury.

MRCS Level

How It Is Acquired

In a viva the expected answer measures extrusion rather than describing the root.

The expected points are the interval, the extrusion measured by one convention, the attachment, the fixation, and the subchondral bone.

Say that an attached looking root with persisting extrusion is a failed repair. 5.6.11 covers meniscal extrusion.

Say that the pre-operative measurement is what makes the post-operative one mean anything. 5.20.1 covers structured reporting.

Say that the examination and the symptoms carry the outcome. 4.20.3 covers the root repair examination.

What Abnormal Looks Like

The reasoning expected is that the root anchors the circumferential fibres, so losing it lets the meniscus extrude and stop carrying hoop stress, which is the mechanical failure the repair addresses. 3.6.2 covers the hoop stress.

It follows that the repair's success is extrusion rather than attachment, and the two can disagree on one scan. 5.6.11 covers meniscal extrusion.

The same mechanism explains the subchondral fracture that often accompanies a root tear, and that bone has to be watched after the repair. 5.13.4 covers insufficiency fractures.

Alignment decides how much load the repaired compartment carries, so a varus knee loads the repair that was meant to protect it. 3.13.3 covers the varus alignment.

How Good It Is

Magnetic resonance imaging is the best available test of a root repair's mechanical result and a poor test of the attachment itself.

Its best contribution is extrusion measured by one convention before and after. 5.6.11 covers meniscal extrusion.

It is limited because the attachment's signal persists, because extrusion conventions differ, and because the subchondral consequence can outrun the meniscal finding. 5.13.4 covers insufficiency fractures.

No figures appear for accuracy on this page, under decision 028, and no extrusion values or thresholds appear either: those are published quantities with competing conventions and this environment cannot check them.

FRCS Level

How Good It Is

At decision level the question is whether the compartment is protected. 3.6.11 covers the effects of root tears.

Corrected extrusion with intact cartilage is the result the repair was for. 5.12.6 covers cartilage injury.

Persisting extrusion raises the alignment, and whether an osteotomy should have accompanied the repair. 5.16.5 covers osteotomy planning.

A new subchondral fracture moves the problem from the meniscus to the bone. 5.13.4 covers insufficiency fractures.

Serial imaging of this compartment becomes radiographic once the question is arthritis. 5.3.5 covers the Rosenberg view.

Where It Misleads

The commonest error is reporting the root as repaired because it looks attached. 5.6.11 covers meniscal extrusion.

Extrusion is compared with a pre-operative value measured by a different convention. 5.20.1 covers structured reporting.

The subchondral bone is omitted from the report. 5.13.4 covers insufficiency fractures.

Persisting root signal is read as failure. 5.6.13 covers the meniscal repair imaging.

Alignment is left out of a failed repair's assessment. 5.3.6 covers the long leg alignment films.

Fellowship Level

Where It Misleads

At fellowship level these knees arrive with a repaired root, persisting pain and a varus limb. 3.13.3 covers the varus alignment.

Whether the repair failed or was always going to be overloaded cannot be separated by imaging. 5.16.5 covers osteotomy planning.

The pre-operative extrusion measurement is the single most useful number and is often absent. 5.6.11 covers meniscal extrusion.

Insufficiency fracture after a root repair is a known course rather than a complication of the repair. 5.13.4 covers insufficiency fractures.

A second repair in a limb whose alignment was not corrected repeats the first. 5.17.4 covers the osteotomy.

The useful report gives the interval, the extrusion with its convention, the attachment, the fixation, the subchondral bone and the alignment. 5.20.1 covers structured reporting.