Standing Alignment

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For Medical Students

What It Tests

Standing alignment is the shape of the limb under load, looked at from the front and the side with the patient standing and the feet together.

It matters in a knee examination because alignment determines which compartment and which side of the knee carries the load, and therefore which ligament reconstruction will be protected and which will be stretched. 3.13.1 covers the mechanical axis.

The alignment chapter covers the measurement and the named patterns. This page covers the observation and what it changes in the examination that follows. 4.5.1 covers the measurement.

How It Is Performed

Stand the patient up with the feet together, knees exposed, and look from the front at eye level with the knees.

Note whether the knees touch and the ankles are apart, which is valgus, or the ankles touch and the knees are apart, which is varus.

Look from the side and note whether the knee is straight, held in flexion, or hyperextended. 4.5.5 covers hyperextension.

Look at the feet, because a pronated foot adds valgus and a supinated foot adds varus at the knee.

Ask the patient to walk, because alignment under load changes and a thrust is only visible moving. 4.3.2 covers gait observation.

What a Positive Means

Varus alignment loads the medial compartment and unloads the medial ligaments, which is why a medial reconstruction in a varus limb has little holding it. 4.5.2 covers varus alignment.

Valgus alignment loads the lateral compartment and stretches the medial side, which is why a medial reconstruction in a valgus limb stretches again. 4.5.3 covers valgus alignment.

A knee held in flexion standing is either stiff, effused, or avoiding extension because extension hurts. 4.5.4 covers flexion deformity.

Hyperextension standing raises the question of posterolateral corner deficiency, particularly when it is asymmetrical. 4.13.7 covers the recurvatum test.

An asymmetrical alignment matters more than a symmetrical one, because symmetrical varus or valgus is often constitutional. 3.13.5 covers constitutional varus.

Key Learning Points

Alignment determines which side of the knee is loaded and therefore which reconstruction will hold.
Varus unloads the medial ligaments; valgus stretches them.
A knee held in flexion standing is stiff, effused, or avoiding extension.
Asymmetrical hyperextension raises posterolateral corner deficiency.
Symmetrical varus or valgus is often constitutional.

MRCS Level

How It Is Performed

In a viva standing the patient up is the step candidates omit, and omitting it means the alignment never enters the assessment.

The expected points are feet together, front and side views at eye level, the feet themselves, and then the gait.

Say that you would stand the patient before laying them down, because alignment is a loaded measurement and lying removes the load.

Say that the clinical impression is an estimate and that long leg standing radiographs are the measurement. 4.5.1 covers it.

Say that you would distinguish constitutional alignment from acquired, because a lifelong varus and a varus produced by compartment collapse are different problems. 3.13.5 covers constitutional varus.

What a Positive Means

The reasoning expected is that the mechanical axis runs from the centre of the hip to the centre of the ankle, and where it passes through the knee determines the load distribution. 3.13.1 covers the axis.

A medial shift of that line loads the medial compartment, which both accelerates medial wear and reduces the tension the medial ligaments carry. 3.13.3 covers varus alignment.

Joint line obliquity modifies this, which is why two limbs with the same mechanical axis can behave differently. 3.13.6 covers it.

Alignment also changes under load, so the standing shape and the walking shape are two findings rather than one, and the walking one is the more consequential. 3.13.7 covers dynamic alignment.

How Good It Is

Clinical assessment of alignment is a reliable screen and a poor measurement, and the division is clean: the impression is enough to decide whether to obtain the radiograph.

It is reliable for gross varus and valgus and unreliable for small deviations, which is where the radiograph earns its place.

It is unreliable in an obese patient and in one who cannot stand with the feet together, both of which are common. 4.23.4 covers those patients.

It is the only part of the alignment assessment that happens in the room, so its real value is prompting the investigation rather than replacing it. 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.

Key Learning Points

Where the mechanical axis passes through the knee determines the load distribution.
Varus loads the medial compartment and reduces the tension the medial ligaments carry.
Joint line obliquity means two limbs with the same axis can behave differently.
The standing shape and the walking shape are two findings, and the walking one matters more.
The clinical impression's value is prompting the radiograph rather than replacing it.

FRCS Level

How Good It Is

At decision level the standing observation decides whether alignment enters the plan, and that decision changes more operations in Section 4 than any single laxity grade.

A varus limb with lateral ligament deficiency is an alignment problem before it is a ligament problem, and a lateral reconstruction into it stretches. 4.13.8 covers combined injuries.

A valgus limb with medial deficiency is the mirror case and is less common and equally decisive. 4.12.8 covers that assessment.

A flexion deformity changes the operation's feasibility rather than its indication, because a knee that cannot be extended cannot be reconstructed to a normal length. 4.7.7 covers contractures.

In a revision the alignment is often the finding that explains why the first operation failed, and it is frequently absent from the first assessment. 4.10.12 covers revision assessment.

Where It Misleads

The commonest error is not standing the patient up.

The second is treating the clinical estimate as a measurement.

The third is reading a symmetrical varus as pathological, when it is often constitutional and the patient has walked on it for decades.

The fourth is attributing the alignment to the knee when the deformity is in the tibia, the femur or the foot, which changes where a correction would be made.

The fifth is assessing alignment lying down, where the deformity that matters disappears.

Key Learning Points

The standing observation changes more operations in Section 4 than any single laxity grade.
A varus limb with lateral deficiency is an alignment problem first.
A flexion deformity changes an operation's feasibility rather than its indication.
In a revision the alignment often explains why the first operation failed.
A symmetrical varus is often constitutional rather than pathological.

Fellowship Level

Where It Misleads

In referred practice the alignment is usually the missing step, and the referral is often a soft tissue question with a bony answer.

A patient with two sound ligament reconstructions and a persisting complaint usually has an uncorrected alignment or an abnormal tibial slope, and neither is fixed by revising soft tissue. 4.14.5 covers that pattern.

A patient with a varus thrust and a lateral reconstruction that stretched has a sequencing error rather than a technical one, and saying so is part of the consultation. 4.13.4 covers the corner.

In a knee with previous osteotomy the alignment has been changed deliberately, so the question becomes whether the correction achieved what was intended, and that needs the pre-operative films rather than the examination.

A patient with a flexion deformity and a chronically deficient posterior cruciate has a combination that makes every measurement in the chapter unreliable, because the resting position is abnormal. 4.11.6 covers that knee.

In medicolegal work the alignment at the time of injury is almost never recorded, which makes attributing later compartment change to the injury difficult in either direction. 4.23.7 covers that setting.

Key Learning Points

The referral is often a soft tissue question with a bony answer.
Two sound reconstructions with a persisting complaint usually means alignment or slope.
A stretched lateral reconstruction in a varus limb is a sequencing error, not a technical one.
A flexion deformity with posterior cruciate deficiency makes every measurement unreliable.
Alignment at the time of injury is almost never recorded, which complicates attribution.

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.

Safety. KneeSchool is educational and does not give individual medical advice. Seek urgent assessment for a knee that cannot bear weight after an injury, a hot swollen knee with a fever, or new numbness, weakness or coldness in the leg or foot.