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KneeSchool/Clinical Examination Academy/Patellofemoral Pain Syndrome

Patellofemoral Pain Syndrome

Page 4.15.9 · Patellofemoral Examination · examination page

A diagnosis reached mostly by what the examination does not find, and the one most often treated as a mechanical problem it is not.

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The same topic at 4 depths

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Patellofemoral Pain Syndrome

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For Medical Students

What It Tests

Patellofemoral pain is anterior knee pain arising from the patellofemoral joint without a structural lesion to account for it.

The examination's job is therefore mostly exclusion: establishing that the meniscus, the ligaments, the extensor mechanism and the joint surface are not the source, and that the patella is loaded where it hurts. 4.6.1 covers systematic palpation.

What it adds positively is the arc, the tenderness and the loaded assessment, which together say the patellofemoral joint is where the pain comes from. 4.7.6 covers the painful arc.

How It Is Performed

Take the history first, because the pattern carries this diagnosis: pain on stairs, on prolonged sitting, on squatting and after activity rather than during it. 4.2.11 covers aggravating factors.

Assess the patellar facets by displacing the patella and pressing on each. 4.6.5 covers patellar tenderness.

Assess the painful arc actively and then with the patella compressed, which loads the joint specifically. 4.7.6 covers the arc.

Assess the tracking in sitting and under load, since maltracking and dynamic valgus are the treatable contributors. 4.15.6 covers dynamic tracking.

Exclude the alternatives deliberately: the meniscus, the ligaments, the tendons and the hip. 4.1.4 covers the structured approach.

Assess the quadriceps and the proximal control, because both are what treatment changes. 4.3.9 covers muscle wasting.

What a Positive Means

Facet tenderness with a painful mid flexion arc, reproduced by compression, and a normal examination otherwise supports a patellofemoral source.

Dynamic valgus or a maltracking patella under load identifies a treatable contributor, and that is the most useful positive finding. 4.15.6 covers it.

Pain on prolonged sitting is characteristic and is one of the few historical features that points here specifically. 4.2.11 covers it.

A normal examination with a clear complaint does not exclude the diagnosis, since this is a diagnosis of pattern rather than of finding.

Mechanical symptoms, an effusion or a positive meniscal test point away and should be pursued. 4.9.8 covers mechanical locking.

Key Learning Points

  • The diagnosis is anterior pain from the patellofemoral joint without a structural lesion.
  • The examination is mostly exclusion, with the arc and the tenderness as positive findings.
  • Dynamic valgus or maltracking under load is the most useful positive finding, because it is treatable.
  • Pain on prolonged sitting points here specifically.
  • Mechanical symptoms, an effusion or a positive meniscal test point away.

MRCS Level

How It Is Performed

In a viva this is a diagnosis of exclusion and the expected answer lists what is being excluded before describing what is found.

The expected points are the history pattern, the facet tenderness, the arc with compression, the loaded tracking, the exclusions, and the quadriceps and proximal control.

Say that the treatable contributors are the quadriceps, the proximal control and the load, and that those are what the examination is looking for. 4.4.10 covers screening.

Say that imaging is often normal and that a normal scan does not refute the diagnosis, which is the point patients most need explaining. 4.1.6 covers that relationship.

Say that you would not offer an arthroscopy for this diagnosis, which is the clinically important negative. 4.17.1 covers a condition it is confused with.

What a Positive Means

The reasoning expected is that patellofemoral contact pressure rises steeply with flexion under load, so a joint that is loaded abnormally or excessively produces pain in the mid flexion arc. 3.12.3 covers contact pressures.

Dynamic valgus increases the lateral vector on the patella, concentrating load on the lateral facet, which is the mechanical story behind the commonest presentation. 3.12.7 covers dynamic valgus.

Quadriceps weakness reduces the control of patellar motion and the absorption of load, which is why strengthening is the most consistently useful treatment. 3.12.9 covers patellofemoral pain.

Prolonged sitting holds the joint in flexion under the patella's resting compression, which is the mechanism behind that characteristic symptom. 3.12.2 covers contact areas.

How Good It Is

The examination is good at excluding the alternatives and poor at confirming this diagnosis, which is the structure of a diagnosis of exclusion.

Its most valuable positive contribution is identifying the proximal and muscular contributors, because those are modifiable and the patella is not. 4.4.10 covers screening.

Imaging is frequently normal, and the examination's clearest service to the patient is explaining that a normal scan is consistent with real pain. 4.1.6 covers that relationship.

The diagnosis has a history of being treated surgically to no benefit, and the examination is what should prevent that. 4.15.5 covers one such procedure.

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

Key Learning Points

  • Contact pressure rises steeply with flexion under load, so abnormal loading produces mid arc pain.
  • Dynamic valgus concentrates load on the lateral facet.
  • Quadriceps weakness reduces both control and load absorption, which is why strengthening helps.
  • Prolonged sitting holds the joint in flexion under compression.
  • The diagnosis has a history of being treated surgically to no benefit.

FRCS Level

How Good It Is

At decision level this diagnosis is the one in Section 4 where the examination's job is most clearly to keep a patient out of theatre.

A patient with patellofemoral pain, a central track and no instability has no operation that reliably helps, and the treatment is load, strength and proximal control. 4.4.10 covers screening.

A patient with patellofemoral pain and marked malrotation is the narrow group where a bony correction has a case, and that is an imaging decision. 4.5.6 covers rotational alignment.

A patient with patellofemoral pain and lateral facet tightness and tenderness is the narrow group where a lateral lengthening has a case, and it is narrower than historical practice assumed. 4.15.5 covers the tilt.

A patient whose pain has a mechanical component found on examination has a different diagnosis, and this label should not be applied to it. 4.17.2 covers mechanical symptoms.

Where It Misleads

The commonest error is using the label as a conclusion rather than as a diagnosis of exclusion, which stops the search too early.

The second is arthroscoping a knee with this diagnosis.

The third is attributing the pain to a maltracking patella without a loaded assessment, which misses the proximal contribution.

The fourth is telling a patient with a normal scan that nothing is wrong.

The fifth is missing a hip or a referred cause, both of which present as anterior knee pain. 4.2.15 covers referred pain.

Key Learning Points

  • The examination's job here is most clearly to keep a patient out of theatre.
  • A central track with no instability has no operation that reliably helps.
  • Marked malrotation and lateral facet tightness are the two narrow surgical groups.
  • A mechanical component means a different diagnosis, not this label.
  • Telling a patient with a normal scan that nothing is wrong is an error.

Fellowship Level

Where It Misleads

In referred practice this diagnosis arrives as a label attached to a patient who has had several investigations and at least one operation.

A patient with a normal arthroscopy and unchanged anterior pain had a tibiofemoral operation for a patellofemoral problem, and the arc was the clue that was available at the first visit. 4.7.6 covers the arc.

A patient with a lateral release and unchanged pain had a procedure for lateral tightness that was not the problem, which is the historical pattern. 4.15.5 covers the tilt.

A patient with persisting pain, a normal examination and no proximal contribution needs a load and pain management approach rather than another mechanical hypothesis, and saying so is the consultation. 4.2.1 covers pain.

A patient with bilateral symptoms, hypermobility and no structural findings has a systemic contribution that no unilateral operation addresses. 4.23.3 covers those patients.

In medicolegal work this diagnosis is difficult to attribute to an injury, because it has no structural correlate, and that limit should be stated plainly. 4.23.7 covers that setting.

Key Learning Points

  • The diagnosis arrives as a label on a patient who has had investigations and an operation.
  • A normal arthroscopy with unchanged pain treated the wrong compartment.
  • A lateral release with unchanged pain treated a problem that was not there.
  • Persisting pain with no proximal contribution needs load and pain management, not another hypothesis.
  • With no structural correlate, attribution to an injury is difficult and should be said plainly.

Explore Further

Where this topic came from and where it goes next in the spiral.

References

No reference list is attached to this draft. Evidence verification has not run, because source retrieval was unavailable at generation time. Under the Operations Handbook a missing reference is acceptable and an invented one is a critical failure, so nothing has been cited and no citation marker appears in the text. This page carries no diagnostic accuracy figure, which is decision 023 rather than an omission. The comparative standing of these tests is standard teaching and a specific sensitivity written from memory is the same class of claim as an invented citation, so ACC-001 refuses the number and the page states the comparison. A reviewer with the literature can add the figures into How Good It Is without restructuring the page, and chapter 3.17 lists the studies the figures would come from. Any measurement here, including a flexion angle, is written from standard teaching, has not been checked, and is registered under decision 006 in pipeline/config/figures with a verification state of UNVERIFIED_FROM_MEMORY.

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