Contemporary Controversies

FRCS Level

At the Knee

Three arguments are usually run together and have different kinds of answer. What the structure is, is an anatomical question. What the region restrains, is a mechanical question. Who should have an augmentation, is a clinical question.

The anatomical argument is the loudest and the least consequential. Whether a discrete anterolateral ligament exists in every knee does not change what a femorally anchored construct restrains. 3.11.3 covers the structure.

The mechanical argument is largely settled. Sectioning the anterolateral region increases internal rotation and the simulated pivot shift, consistently across laboratories. 3.11.5 covers internal rotation control.

The clinical argument is the live one: which patients benefit enough to justify the addition. 3.11.8 covers the combined reconstruction.

What Changes It

New dissection and imaging work, which refines the anatomical account without settling the clinical one.

Trial and registry data, which is what moves the clinical question.

Slope correction as a competing intervention for the same problem. 3.13 covers alignment.

Graft and construct developments, which change the cost side of the trade.

How It Is Measured

Dissection prevalence studies answer the anatomical question and disagree with each other.

Robotic sectioning studies answer the mechanical question and agree with each other.

Randomised trials and registries answer the clinical question and are still accumulating.

The three literatures are often cited as if they bore on the same question, which is the commonest error in this area.

Clinical Relevance

Separate the anatomical, mechanical and clinical arguments when discussing this.

Rely on the mechanical consensus rather than on the anatomical dispute.

Apply augmentation in the groups the trial evidence covers.

Avoid citing a dissection study to settle a clinical question.

Fellowship Level

At the Knee

The fellowship level dispute is between augmentation and bony correction for the same problem. A knee with high rotatory laxity and an increased slope can be addressed by adding a lateral construct or by correcting the slope. 3.13 covers alignment.

They are not equivalent. A tenodesis adds restraint and a slope correction reduces demand, which is the difference between a stronger rope and a lighter load.

Conventional teaching has not established which to prefer, or whether both are needed in the knee that has failed once. 3.11.8 covers the combined reconstruction.

What Changes It

Slope magnitude, which decides whether correction is indicated at all.

Previous failure, which raises the threshold for doing less.

Patient demand and willingness to accept an osteotomy.

Graft and tunnel constraints.

How It Is Measured

Lateral radiography and magnetic resonance imaging measure slope.

Robotic testing compares the mechanical effect of augmentation and of slope correction.

Revision cohorts report outcomes after each, in small numbers and without direct comparison.

No trial compares augmentation against slope correction for the same indication.

Clinical Relevance

Measure slope before choosing between augmentation and correction.

Describe the two as adding restraint and reducing demand respectively.

Consider both in the knee that has failed a conventional revision.

State that no trial compares them directly.

Consultant Perspective

At the Knee

The consultant decision is not which account of the anatomy is right. It is how much extra surgery to add to a reconstruction when the benefit is clear in a population and uncertain in the patient in front of you.

On the benefit side sit a reinjury rate that augmentation lowers in the groups the trials studied, a failure that costs the patient a second reconstruction, and a construct that adds little operative time in trained hands. 3.11.8 covers the construct.

On the cost side sit an additional incision and fixation, a small but real stiffness and lateral pain burden, and an over-constraint concern that is demonstrable in cadavers and unproven in patients. 3.11.5 covers internal rotation control.

The weight on each side moves with the patient rather than with the surgeon. Two consultants reading the same literature can operate differently and both be reasoning well.

One move is still indefensible. Citing the anatomical dispute as a reason not to augment weighs nothing, because the mechanical case never rested on it. 3.11.3 covers the structure.

What Changes It

Age and physiology. The measured benefit concentrates in the young, and tissue quality and skeletal maturity decide what a construct can be fixed to.

Medical comorbidities. An added construct adds fixation and operative time to a patient whose healing may not carry it, and smoking and diabetes move the cost side without touching the benefit side.

The demands the patient puts on the knee, which is a question about occupation and sport rather than about age.

Psychological state. Fear of reinjury governs whether the restraint is ever used. A knee the patient will not trust does not need the augmentation that a knee returning to cutting sport does.

The patient's own ideas, concerns and expectations. A reinjury rate reduced from one figure to another is a conversation rather than a calculation, and how the patient weighs a second operation against a second rupture belongs inside the balance.

Bony morphology, particularly slope, which decides whether a soft tissue addition is the right lever at all. 3.13 covers alignment.

Primary against revision, which changes what a further failure costs.

Surgeon volume with the construct, which moves the cost side rather than the benefit side.

How It Is Measured

Registry reinjury rates by construct and by age group carry the benefit side and are the most informative accumulating data.

Trial subgroup analyses are underpowered for the groups that most need them, and read better as weak evidence about a subgroup than as strong evidence about a trial.

Instrumented rotatory measurement has no clinical threshold, so the laxity that would individualise the decision cannot yet be graded.

The cost side is measured worst of all, because stiffness and lateral pain are reported inconsistently and rarely as primary outcomes.

Clinical Relevance

Set the question out as a balance and name what sits on each side of it.

Weigh age and pivoting demand first, because the benefit concentrates there.

Measure slope before treating augmentation as the only available lever.

Price a second failure into the revision decision rather than into the primary one.

Take age and physiology, comorbidities, knee demand, psychological state and the patient's own ideas, concerns and expectations into the decision explicitly, because a trial population carries none of them.

Accept that the same evidence can be weighed differently without either consultant being wrong.