Pain

For Medical Students

What It Tests

Pain is why most patients attend and it is the symptom that narrows the differential least, so the history has to work it rather than record it.

What asking about pain establishes is a pattern: where, when it started, what provokes it, what settles it, and whether it wakes the patient.

Each of those is a separate question with its own page in this chapter, and the pattern they build is more informative than any single answer. 4.2.8 begins with location.

How It Is Performed

Ask an open question first and let the patient describe the pain in their own words before offering any options.

Then work through the pattern deliberately: site, onset, character, radiation, aggravating and relieving factors, and the effect on sleep and on function.

Ask what the patient can no longer do, because that is the answer that will define whether treatment worked.

Avoid offering a list of descriptors to choose from. A patient given the word sharp will frequently adopt it.

What a Positive Means

Pain in a knee means the knee or something referring to it is irritated, and little more on its own.

The useful conclusions come from combinations. Anterior pain on stairs and on rising from a chair points to the patellofemoral joint. 4.15.9 covers it.

Medial pain with a twisting mechanism and mechanical symptoms points to the meniscus. 4.9.1 covers the presentation.

Diffuse pain with stiffness after rest and limited range points to degenerative disease. 4.18.1 covers early disease.

MRCS Level

What a Positive Means

At viva level the expectation is that pain is characterised rather than noted, and that the characterisation drives the rest of the assessment.

A patient's description of severity is a report of their experience rather than a measure of pathology, and the two diverge in both directions.

Pain disproportionate to the findings is a finding in itself, and it points towards sensitisation, towards a cause outside the knee, or towards distress rather than towards a missed lesion.

Pain that does not fit any pattern on this chapter's pages should prompt a search above and below the knee before a scan of the knee.

How Good It Is

Pain as a single symptom performs poorly for localisation and well for one thing: establishing whether the problem is mechanical or inflammatory.

Pain worse with use and better with rest is mechanical. Pain worse after rest and better with movement is inflammatory. That distinction is more reliable than any question about site. 4.2.14 covers the inflammatory pattern.

The site of pain is less reliable than teaching implies, because referred and radiating pain are common and the knee is a frequent destination for both. 4.2.15 covers it.

Severity performs worst of all as a guide to pathology and best as a guide to urgency and to what the patient will accept.

FRCS Level

How Good It Is

The decision-relevant question is whether this pain is the pain an operation would address, and the history answers it better than imaging does.

A patient whose pain pattern matches their scan finding is a candidate. A patient whose scan finding is present and whose pain pattern does not match it is usually not, and that mismatch is common in degenerate knees.

Pain that has changed character is the single most useful historical feature at this level. A degenerate knee whose diffuse ache has become a localised mechanical pain has acquired something new.

Pain with no mechanical pattern at all, in a knee with structural findings, predicts a poor result from a mechanical intervention more reliably than any imaging feature.

Where It Misleads

Pain misleads in patterned ways and most of them are avoidable.

A patient asked whether the pain is on the inside will often agree, because the question supplies the answer. The remedy is to ask them to point with one finger.

Pain adopts the vocabulary of the last explanation given. A patient told they have arthritis describes arthritic pain, which is why the history should precede the notes and the images. 4.1.3 covers the contamination.

Bilateral pain is under-asked. A patient attends about one knee and the other is often symptomatic, which changes both the differential and the plan.

And pain that is genuinely worse than the knee explains should raise the hip, the spine, a referred source, or a systemic cause rather than a bigger operation.

Fellowship Level

Where It Misleads

In referred practice pain has usually been described many times before and the account has hardened, which makes it less useful rather than more.

The most valuable question in that setting is what has changed since the last assessment, because a stable pain pattern carries little new information and a changed one carries a great deal.

Pain after a reconstruction or a replacement needs a differential of its own rather than the one used before the operation. 4.20.1 and 4.20.8 cover the two commonest.

Pain in the absence of any mechanical pattern after surgery is the presentation most likely to be treated by further surgery and least likely to benefit from it.

The honest limit is that none of this chapter's claims about which pain patterns discriminate is supported by a figure here. The patterns are standard teaching and the numbers were refused rather than retrieved, under decision 023.