Rosenberg View

For Medical Students

What It Shows

A Rosenberg view is a posteroanterior radiograph taken standing with the knee flexed, so the loaded contact area is the one projected. 5.3.1 covers the anteroposterior view.

That area is the part of the femoral condyle used in walking, which is not the part profiled on an extended view. 3.5.4 covers the effects of flexion.

It matters because cartilage loss in the walking contact area is the earliest radiographic change, and the extended standing view misses it. 5.3.17 covers joint space narrowing.

How It Is Acquired

Stand the patient with the knee flexed against the detector and angle the beam to the joint. 5.2.5 covers magnification.

Keep the flexion angle fixed by protocol, which is what makes the view reproducible. 5.2.2 covers the image formation.

Use the same protocol for a follow up study, because the measurement is only meaningful against a matched acquisition. 5.3.17 covers joint space narrowing.

Assess both compartments, since the comparison needs no calibration. 5.2.5 covers magnification.

Read it alongside the lateral and the skyline for the other two compartments. 5.3.2 covers the lateral view.

What Normal Looks Like

Preserved joint space in both compartments, with the flexed contact area profiled.

Parallel subchondral surfaces at the loaded point.

No osteophyte at the compartment margins. 5.3.18 covers osteophytes.

Symmetry between compartments. 5.3.1 covers the anteroposterior view.

What Abnormal Looks Like

Joint space loss in one compartment that was not apparent on the extended view. 5.3.17 covers joint space narrowing.

Subchondral sclerosis at the loaded contact point. 5.3.19 covers subchondral sclerosis.

Marginal osteophyte. 5.3.18 covers osteophytes.

A bony contour change at the posterior condyle. 5.3.4 covers the tunnel view.

MRCS Level

How It Is Acquired

In a viva this is the view to name when asked how to detect early joint space loss.

The expected points are the standing flexed position, the fixed protocol angle, the matched follow up, both compartments, and the other views.

Say that an extended standing film can be normal when this view is not. 5.3.1 covers the anteroposterior view.

Say that the flexed contact area is the walking contact area. 3.5.4 covers the effects of flexion.

Say that the measurement needs a matched protocol to be compared. 5.3.17 covers joint space narrowing.

What Abnormal Looks Like

The reasoning expected is that the femoral condyle presents different surfaces to the tibia through flexion, so an extended view measures a surface the patient does not walk on. 3.5.4 covers the effects of flexion.

Cartilage wears where it is loaded most, which in walking is the flexed contact area, so the earliest loss is where the extended view does not look. 3.5.2 covers the contact pressures.

Weight bearing matters because the soft tissues deform under load, so an unloaded space overstates what is left. 3.6.5 covers load sharing.

Combining both makes this the most sensitive plain film for early compartment loss, which is the whole justification for a second standing view. 5.3.16 covers Kellgren-Lawrence grading.

How Good It Is

The Rosenberg view is the most sensitive plain radiographic view for early compartment joint space loss.

Its best contribution is detecting loss the extended standing view reports as normal, which changes the stage rather than the diagnosis. 5.3.16 covers Kellgren-Lawrence grading.

It is limited by needing a protocol, by not being routinely requested, and by remaining a projection. 5.18.5 covers weight bearing imaging.

No figures appear for accuracy on this page, under decision 028, and no flexion angle or joint space threshold appears either: those are published protocol quantities and this environment cannot check them.

FRCS Level

How Good It Is

At decision level this view changes who is offered a joint preserving operation.

A knee with preserved space on the extended view and loss here is further along than the standard series suggests, which bears on an osteotomy or a unicompartmental decision. 5.16.5 covers osteotomy planning.

A knee with preserved space on both standing views has a compartment worth protecting, which supports meniscal or cruciate surgery. 5.6.13 covers meniscal repair imaging.

Deciding between compartments needs this view plus the skyline and the lateral, because three compartments need three views. 5.3.3 covers the skyline view.

Serial assessment of a joint preserving operation needs it acquired the same way each time. 5.3.17 covers joint space narrowing.

Where It Misleads

The commonest error is not requesting it, so early loss is reported as a normal knee. 5.3.1 covers the anteroposterior view.

The flexion angle varies between studies and the space appears to change. 5.2.5 covers magnification.

It is compared with an extended film from a previous visit. 5.3.17 covers joint space narrowing.

A positive finding here is treated as more advanced disease than it is, since the view is more sensitive rather than the knee being worse. 5.3.16 covers Kellgren-Lawrence grading.

The other two compartments are not assessed. 5.3.3 covers the skyline view.

Fellowship Level

Where It Misleads

At fellowship level this view is the clearest example in the chapter of a better test that has not displaced a worse one.

Its advantage over the extended standing view for early loss has been established for decades, and the extended view remains the default request in most pathways. 5.21.5 covers the osteoarthritis imaging literature.

The grading systems in general use were built on extended views, so applying them to this view applies a scale to data it was not derived from. 5.3.16 covers Kellgren-Lawrence grading.

Its reproducibility depends on a fixed flexion angle, which trial protocols enforce with a frame and clinics do not, so the clinic version is less reproducible than the published performance. 5.3.1 covers the anteroposterior view.

Weight bearing computed tomography measures the loaded compartment in three dimensions and removes the projection entirely, which makes this view a staging post rather than an endpoint. 5.18.5 covers weight bearing imaging.

The practical recommendation is to request it by name and to use the same protocol every time, which costs nothing and is rarely done. 5.20.6 covers reporting osteoarthritis.