Normal Gait

For Medical Students

What It Tests

Knowing normal gait is what makes an abnormal one visible. An examiner who cannot describe the normal pattern can see that something is wrong and cannot say what.

For the knee, the part that matters is the stance phase and the small flexion wave within it, because most knee gait abnormalities are modifications of that wave. 3.14.2 covers the stance phase.

The knee extends at heel strike, flexes a little as weight is accepted, extends again through mid stance, then flexes to clear the ground in swing. 3.14.1 covers the cycle.

How It Is Performed

Watch a normal gait deliberately before trying to read an abnormal one, in a colleague or in the patient's uninjured side.

Note the symmetry of the stance times, which is the easiest abnormality to see and the one most patients present with. 4.4.2 covers the antalgic pattern.

Note the knee reaching full extension at heel strike, since losing that is the commonest knee specific finding.

Note the small flexion wave through early stance, and whether it is present on both sides. 4.4.3 covers the gait that abolishes it.

Note the alignment of the knee through stance, looking for any sideways movement as weight is taken. 4.5.7 covers dynamic alignment.

What a Positive Means

Symmetrical stance times, full extension at heel strike, a present flexion wave and no sideways movement is a normal knee gait, and recording that is worth doing.

A normal gait in a patient with a markedly abnormal couch examination is an important finding, because it says the knee is compensating. 4.11.6 covers the knee where that matters most.

A normal gait in an athlete is uninformative rather than reassuring, because walking is far below the demand that fails. 4.4.8 covers running gait.

A normal gait with a patient's complaint of instability points at a task rather than at the joint, and the task has to be found. 4.4.9 covers single leg landing.

MRCS Level

How It Is Performed

In a viva describing normal gait is the foundation the examiner builds the rest of the questions on, and a candidate who can do it in a sentence per phase is in control of the station.

The expected points are heel strike with the knee extended, load acceptance with a small flexion wave, mid stance with extension, toe off, and swing with flexion to clear the ground.

Say the two phases by name and say what the knee does in each. 3.14.3 covers the swing phase.

Say that the quadriceps works hardest during load acceptance, which is why most knee gait abnormalities are modifications of that part. 4.4.3 covers one of them.

Say that you would watch from the front, the side and behind, since different abnormalities are visible from each. 4.3.2 covers gait observation.

What a Positive Means

The reasoning expected is that the knee absorbs load through a controlled flexion under quadriceps control, so anything that limits that control changes the pattern. 3.14.2 covers the stance phase.

The flexion wave is small, so its absence is easy to miss and its absence is the cruciate deficient knee's characteristic finding. 3.14.9 covers that gait.

The knee's alignment through stance is maintained by the collateral and corner structures, so a sideways movement under load means one of them is absent rather than stretched. 3.13.7 covers dynamic alignment.

Cadence and step length change before any obvious limp appears, which is why a subtle gait abnormality is often described by a relative rather than by the patient.

How Good It Is

Clinical gait observation detects the gross patterns reliably and the subtle ones poorly, and knowing normal is what moves findings from the second category to the first.

It is not a measurement. Instrumented gait analysis quantifies what the eye estimates, and it is a research tool in most settings. 3.14.1 covers the analysis.

Its reproducibility is better between two observations by the same examiner than between two examiners, which argues for the same person following a patient where that is possible.

Its real value for the knee is the thrust and the avoidance pattern, both of which are visible to anyone who knows what the normal wave looks like. 4.4.3 covers the avoidance pattern.

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 normal pattern is the reference everything else in this chapter is measured against, and recording a normal gait is as useful as recording an abnormal one.

A patient with a severe laxity and a normal gait has compensated, and the decision to operate rests on function rather than on the grade. 4.11.6 covers that argument.

A patient whose gait normalises after rehabilitation has demonstrated that the non operative route works, and the gait is a better measure of that than any laxity measurement. 4.11.5 covers the assessment.

Post-operatively a return to a normal pattern is a meaningful outcome, and it is reached later than the range of motion and the laxity suggest. 4.4.7 covers post-operative gait.

Where the gait is normal and the complaint persists, the task has to be raised rather than the examination repeated. 4.4.9 covers single leg landing.

Where It Misleads

The commonest error is not knowing the normal pattern well enough to see a deviation from it.

The second is treating a normal walking gait as a normal knee in a patient whose demand is higher than walking.

The third is attributing a deviation to the knee without examining the hip and the ankle. 4.4.5 covers a proximal pattern.

The fourth is observing too short a distance for a pattern to repeat.

The fifth is describing a named pattern when the gait is a mixture, which most are. 4.4.6 covers one of the idealisations.

Fellowship Level

Where It Misleads

In referred practice the normal gait is the finding that most often contradicts the referral, and that contradiction is the consultation.

A patient referred as disabled who walks normally has an expectation, a confidence or a task specific problem, and the three are managed differently and none by an operation on the ligament findings. 4.22.6 covers the score built for that question.

A patient whose gait is normal and whose knee fails in sport needs the assessment moved to the sport's demand, and the clinic cannot supply it. 4.23.2 covers elite athletes.

A gait that is normal in a knee with gross laxity and a wasted quadriceps is unusual and worth distrusting, because the compensation that normalises gait usually requires the muscle. 4.3.9 covers wasting.

In the multiply operated knee a normal gait is the strongest single piece of evidence that further surgery is not indicated, and it is more persuasive than any measurement. 4.10.12 covers revision assessment.

In medicolegal work a recorded normal gait is difficult to reconcile with a claim of severe disability, which is a reason to record it accurately rather than generously. 4.23.7 covers that setting.