Clinical Presentation

For Medical Students

What It Tests

A cartilage lesion presents as pain on loading, swelling after activity, and sometimes as a mechanical symptom if a fragment is loose. 4.17.2 covers the mechanical half.

The examination's problem is that articular cartilage has no nerve supply, so the pain comes from the bone beneath it, the synovium's response, or the altered loading, and none of those localises precisely. 3.5.2 covers contact pressures.

That is why this chapter's examination is weaker than the meniscal or ligament chapters, and why the imaging leads. 4.1.6 covers that relationship.

How It Is Performed

Take the history: pain on loading the affected compartment, an effusion appearing after activity, and whether anything catches or locks. 4.2.11 covers aggravating factors.

Establish the mechanism, since an acute impaction or a dislocation produces an osteochondral injury and a gradual onset suggests something else. 4.2.20 covers a direct blow.

Assess the effusion, since a recurrent activity related effusion is one of the more reliable signs. 4.8.3 covers the bulge sign.

Palpate the compartments and the joint lines, accepting that a lesion on a weightbearing surface is not directly palpable. 4.6.4 covers joint line tenderness.

Assess the painful arc, since a lesion is loaded at a particular flexion angle and hurts there. 4.7.6 covers the arc.

Assess the alignment, because it determines which compartment carries the load and therefore how a lesion behaves. 4.5.1 covers the mechanical axis.

What a Positive Means

Activity related pain in one compartment with a recurrent effusion and a painful arc is the characteristic picture, and it is not specific.

A mechanical symptom with these findings raises a loose or unstable fragment, which changes the urgency. 4.17.2 covers it.

A compartment specific pain with a malaligned limb suggests the lesion is being loaded by the alignment, which changes the treatment. 4.5.2 covers varus alignment.

An effusion with a normal mechanical examination and no ligament findings is consistent with a cartilage lesion and equally consistent with a synovial process. 4.8.9 covers synovitis.

A normal examination in a patient with a known lesion is common, because the examination reads the consequences rather than the lesion. 4.17.5 covers the defect.

MRCS Level

How It Is Performed

In a viva the expected answer is honest that this examination is weak, and explains why the imaging leads.

The expected points are the history and mechanism, the effusion, the compartment palpation, the painful arc, and the alignment.

Say that cartilage is aneural, so the pain is indirect, which is the reason the localisation is poor. 3.5.2 covers contact pressures.

Say that a mechanical symptom is the finding that changes the plan, and that the rest of the examination contributes to the compartment rather than the diagnosis. 4.17.2 covers it.

Say that magnetic resonance imaging is the diagnostic test and that the examination's job is deciding who needs it and which compartment to look at. 4.1.6 covers that relationship.

What a Positive Means

The reasoning expected is that load transmitted through a cartilage defect concentrates on the subchondral bone, which is innervated, and that is the source of the pain. 3.5.2 covers contact pressures.

An effusion follows because the synovium responds to the debris and the altered mechanics, which is why the effusion is activity related rather than constant. 4.8.1 covers normal fluid physiology.

A defect's position determines the flexion angle at which it is loaded, which is why the painful arc localises better than the tenderness does. 3.5.4 covers the effects of flexion.

Alignment determines the compartment's share of the load, which is why a varus limb concentrates load on a medial lesion and makes it symptomatic sooner. 3.5.6 covers the effects of malalignment.

How Good It Is

The examination establishes that a compartment is symptomatic and cannot establish a cartilage lesion, which is a clear and honest limitation.

Its most specific contribution is the painful arc, which localises the lesion's flexion angle better than any palpation does. 4.7.6 covers it.

The recurrent activity related effusion is the most useful single finding and is shared with several other diagnoses. 4.8.8 covers chronic effusions.

Magnetic resonance imaging makes the diagnosis and grades it, and this is a chapter where the examination defers. 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 examination contributes the compartment, the alignment and the mechanical symptom, and the imaging contributes the lesion.

A symptomatic compartment with a malaligned limb is an alignment problem as much as a cartilage one, and a cartilage procedure without the correction loads the repair. 4.5.2 covers varus alignment.

A mechanical symptom with a lesion raises an unstable fragment, which changes a planned procedure into a more urgent one. 4.17.3 covers osteochondral lesions.

A patient with a lesion on imaging and a normal examination has a finding rather than a diagnosis, and operating on it is the error this chapter guards against. 4.17.5 covers that argument.

The functional assessment is what establishes whether the lesion matters, which is why it has its own page. 4.17.6 covers it.

Where It Misleads

The commonest error is treating an imaging finding as the diagnosis in a patient whose examination does not match the compartment.

The second is omitting the alignment, which determines whether any cartilage procedure will survive.

The third is attributing a recurrent effusion to the lesion without excluding a synovial cause. 4.8.9 covers synovitis.

The fourth is reading a normal examination as excluding a lesion.

The fifth is not asking about mechanical symptoms, which are the findings that change the urgency. 4.17.2 covers them.

Fellowship Level

Where It Misleads

In referred practice the commonest problem is a lesion found on imaging in a patient whose symptoms do not fit it.

A patient with an incidental lesion and diffuse pain has a finding and a separate problem, and a cartilage procedure addresses neither. 4.15.9 covers one such separate problem.

A patient with a symptomatic compartment, a matching arc and a malaligned limb has a lesion being loaded, and the correction is part of the treatment rather than an adjunct. 4.5.1 covers the measurement.

A patient with a previous cartilage procedure and recurrent symptoms needs the alignment and the meniscal status reassessed, since both determine whether a repair survives. 4.9.10 covers meniscal deficiency.

A young patient with a lesion after a patellar dislocation has an osteochondral injury with a time limited repair window, and that is the one urgent version. 4.2.22 covers the event.

In medicolegal work attributing a cartilage lesion to a single injury needs an acute mechanism and early imaging, and without those the attribution is weak. 4.23.7 covers that setting.