Patellar Tilt

For Medical Students

What It Tests

Patellar tilt is the rotation of the patella about its long axis, so that the lateral border sits lower than the medial one.

Assessing it tests whether the lateral retinaculum is tight, because a tight lateral structure holds the lateral border down. 2.12.4 covers the retinacula.

It is a different finding from glide. Glide measures how far the patella translates; tilt measures whether it can be rotated back to level. 4.15.4 covers the glide.

How It Is Performed

Lay the patient supine with the knee extended and the quadriceps relaxed.

Hold the patella between finger and thumb and attempt to lift its lateral border, rotating the patella to bring its two borders level and then past level.

Note whether the lateral border can be lifted to the horizontal: in a normal knee it can be lifted past neutral.

Note whether lifting it is painful, since a tight and tender lateral structure is the combination that matters clinically. 4.6.5 covers patellar tenderness.

Compare with the other knee, and assess the glide in the same examination, since the two findings together describe the lateral side.

What a Positive Means

An inability to lift the lateral border to or past the horizontal indicates a tight lateral retinaculum.

A tight lateral structure with anterior pain and a reduced medial glide describes lateral patellar compression, which is a pain problem rather than an instability one. 4.15.9 covers patellofemoral pain.

A tight lateral structure with a lax medial side describes a patella being held laterally and tilted, which is the combination seen in maltracking. 4.15.1 covers tracking.

An excessively mobile tilt in both directions is part of generalised hypermobility. 4.23.3 covers those patients.

Pain on lifting the lateral border with a normal tilt suggests the lateral facet rather than the retinaculum, which is an articular finding. 4.15.10 covers patellofemoral arthritis.

MRCS Level

How It Is Performed

In a viva the tilt is the finding that distinguishes lateral compression from instability, and that distinction is usually the point of the question.

The expected points are the relaxed extended knee, lifting the lateral border, the ability to pass neutral, the pain on lifting, and the comparison.

Say that you would assess the glide and the tilt together, since they describe different properties of the same side. 4.15.4 covers the glide.

Say that a tight lateral side is a pain diagnosis rather than an instability one, which is the clinically important consequence.

Say that you would assess the tracking actively as well, because the tilt is a static finding and the track is what the patella actually does. 4.15.1 covers tracking.

What a Positive Means

The reasoning expected is that the lateral retinaculum attaches to the patella's lateral border, so its shortening rotates the patella and holds that border down. 2.12.4 covers the retinacula.

A tilted patella loads its lateral facet preferentially, which is the mechanism behind the pain and the late lateral facet articular change. 3.12.3 covers contact pressures.

Tilt and lateral translation often coexist, because the same tight structure both holds the patella laterally and rotates it, which is why the two findings travel together. 3.12.11 covers the effects of malalignment.

A tilt that corrects with flexion suggests the trochlea is reducing the patella, which is reassuring about the bony anatomy. 3.12.4 covers trochlear function.

How Good It Is

Tilt is reproducible as a binary finding, past neutral or not, and poorly reproducible as a graded one.

It is the most useful clinical finding for lateral tightness, which is otherwise an imaging diagnosis.

It is non specific for pain, since a tight lateral side occurs in people without complaints, so the finding needs a matching symptom.

Imaging measures the tilt angle and does it better, and in this chapter the examination's role is to raise the question. 4.1.6 covers that relationship.

No figures appear for any accuracy comparison on this page, under decision 023, and the comparison is the claim being made.

FRCS Level

How Good It Is

At decision level the tilt contributes to whether a lateral procedure is part of the operation, and that is a decision with a history of being got wrong in both directions.

A tight tilt with lateral facet pain and no instability is the narrow group in which a lateral lengthening has a case, and it is a much narrower group than historical practice assumed.

A tight tilt with instability is a different matter, and releasing the lateral side in an unstable patella is a recognised way to make the instability worse. 4.15.3 covers the finding that should stop it.

A normal tilt in a patient with anterior pain moves the assessment to load, alignment and the extensor mechanism. 4.15.9 covers patellofemoral pain.

In a knee with lateral facet articular change the tilt contributes to the mechanical explanation, and the treatment is a loading and alignment question. 4.15.10 covers patellofemoral arthritis.

Where It Misleads

The commonest error is confusing tilt with glide.

The second is testing with the quadriceps contracted.

The third is releasing a tight lateral side in a patient with instability.

The fourth is treating a tight tilt as a diagnosis in a patient whose pain does not match it.

The fifth is grading the tilt rather than recording whether it passes neutral, which is the reproducible version.

Fellowship Level

Where It Misleads

In referred practice the tilt is most often relevant in a knee that has had a lateral release, and the question is what the release did.

A patient with a previous lateral release and medial instability has an iatrogenic problem, and the tilt is now excessive in the other direction. 4.20.6 covers that assessment.

A patient with a previous release and unchanged pain had a lateral procedure for a problem that was not lateral tightness, which is the historical pattern this page exists to interrupt. 4.15.9 covers the alternative.

A patient with a tight tilt, lateral facet change and a valgus limb has three findings that belong to one mechanical story, and the alignment is the treatable part. 4.5.3 covers valgus alignment.

In a knee with a medial patellofemoral ligament reconstruction an unaddressed tight lateral side loads the graft, which is a recognised cause of a graft that stretches. 4.15.7 covers the ligament.

In medicolegal work a recorded tilt is a minor observation, and the recorded dislocation history and imaging carry an opinion about patellofemoral surgery. 4.23.7 covers that setting.