Post-Reconstruction Assessment

For Medical Students

What It Tests

Examining a medial side that has been braced, repaired or reconstructed is asking two questions: how lax is it now, and is that laxity causing anything.

The second question is the one that matters, because a healed medial ligament is often slightly lax and entirely asymptomatic. 3.9.3 covers the structure that heals.

A medial side also has to be read against what was done to it. A reconstructed ligament, a repaired one and one left to heal in a brace give different expected findings, and a letter without the operation note is hard to interpret. 4.2.30 covers previous surgery.

How It Is Performed

Establish what was done and when, before touching the knee.

Perform valgus stress at thirty degrees and in full extension, and record both the opening and the endpoint on each side. 4.12.1 covers the test.

Add the rotational examination, because a corrected valgus laxity with a residual rotational one is the common incomplete result. 4.12.6 covers the pattern.

Examine the cruciates, since most medial reconstructions are performed alongside a cruciate reconstruction and the two results have to be separated. 4.10.11 covers that assessment.

Watch the patient walk and ask them to turn, because the complaint after a medial operation is usually functional rather than a grade. 4.11.5 covers dynamic assessment.

What a Positive Means

A small residual increase in opening at thirty degrees with a firm endpoint is the expected result after a healed or reconstructed medial side, and it is not a failure.

A soft endpoint indicates that the repair or graft is not holding, which is a different finding from a slightly lax firm one.

Opening in full extension after treatment indicates the posteromedial corner was not addressed or has not held, and that is the commonest incomplete result. 4.12.2 covers that angle.

A knee that is tighter than the other side has been over constrained, which is not success and can present as stiffness or as medial compartment pain.

A normal examination in a patient who still complains sends you back to the history and to the rotational tests rather than to a repeat of the valgus grade. 4.2.2 covers instability as a symptom.

MRCS Level

How It Is Performed

In a viva this is the station where the expected answer starts with what was done, and a candidate who starts examining has missed the point.

The expected points are the operation note, both valgus angles, the endpoints, the rotational examination, the cruciates, and the functional assessment.

Say that you would compare with the other knee and with the recorded pre-operative examination, because the question is almost always whether something changed. 4.1.8 covers the record.

Say that you would ask when the symptoms returned, since an early return suggests a technical problem and a late one suggests a graft that stretched.

Say that you would assess alignment, because a varus limb unloads a medial reconstruction and a valgus limb loads it continuously, and that determines whether the reconstruction had a chance. 4.11.5 covers the dynamic assessment.

What a Positive Means

The reasoning expected is that the superficial ligament heals in continuity and often in a slightly lengthened position, so a residual grade with a firm endpoint is healing rather than failure. 3.9.3 covers its function.

The posterior oblique ligament heals less reliably, which is why a residual finding in extension is the more significant one and the one most often present. 3.9.5 covers it.

A medial reconstruction aims to restore valgus and rotational restraint, and restoring one without the other leaves the patient's complaint, which is why the rotational examination is part of the assessment. 3.9.8 covers medial reconstruction biomechanics.

Where a cruciate reconstruction was performed at the same time, an uncontrolled medial side loads the cruciate graft, so a stretched cruciate graft and a lax medial side found together are one problem rather than two. 3.9.10 covers the combination.

How Good It Is

The examination is good at establishing the current laxity and poor at attributing a complaint to it, which is the same limitation the rest of this chapter has and matters more here.

Comparison with the pre-operative examination is what makes it useful, and the absence of that record is the commonest reason the assessment cannot conclude.

Stress radiographs are more reproducible than the hands for following a treated medial side over time, and they are the right investigation where the question is whether the laxity has increased.

The rotational examination adds the most and is the least reproducible, which is an uncomfortable combination and is the honest position. 4.12.6 covers it.

No figures appear for any of these comparisons, under decision 023, and the comparison is the claim being made.

FRCS Level

How Good It Is

At decision level this examination decides whether anything further is done, and the answer is usually nothing.

A residual laxity with a firm endpoint and no functional complaint is observed. Operating on a grade in an asymptomatic patient is the error this page exists to name.

A patient with a functional complaint, a rotational abnormality and an acceptable valgus grade has an unaddressed posteromedial corner, and that is the result that leads to further surgery. 4.12.5 covers the structure.

A patient with a stretched cruciate graft and medial laxity needs both addressed, and addressing the graft alone repeats the original failure. 4.10.12 covers revision assessment.

Alignment is assessed before any revision soft tissue work, because a valgus limb will stretch a medial reconstruction again. That is the decision the examination of the limb, rather than of the knee, contributes.

Where It Misleads

The commonest error is reading a residual grade as failure, which generates operations on knees that are working.

The second is examining valgus only, which misses the rotational result that usually explains the complaint.

The third is examining without the operation note, where a reconstruction and a healed sprain are being held to the same expected finding.

The fourth is attributing a complaint to the medial side without examining the cruciates, since the cruciate result is the commoner explanation after a combined operation.

The fifth is examining once. A medial side that is firm at six weeks and lax at six months has stretched, and that trajectory is the finding. 4.1.8 covers the record.

Fellowship Level

Where It Misleads

In referred practice the treated medial side is usually being examined because a cruciate reconstruction has not worked, and the medial side is the suspect rather than the subject.

The commonest finding in that setting is valgus laxity in extension with an anteromedial rotatory pattern, which together explain a stretched cruciate graft and are the reason to address both. 4.12.6 covers the pattern.

Scar after a medial repair gives a firm endpoint over a lax joint, so the endpoint can be reassuring in a knee that fails under load. A patient whose examination is normal and whose knee gives way in sport is describing that. 4.23.2 covers elite athletes.

An over constrained medial reconstruction presents as medial compartment pain and loss of flexion rather than as instability, and it is the complication most often attributed to something else. 4.2.4 covers stiffness.

A medial reconstruction in a valgus limb that was not corrected will stretch, and finding that at revision means the examination of the limb was not done rather than that the operation was poor.

In medicolegal work the absence of a recorded pre-operative examination is usually what makes the question unanswerable, which is an argument for the record rather than for a better examination. 4.23.7 covers that setting.