Trendelenburg Gait

For Medical Students

What It Tests

A Trendelenburg gait is a pattern produced by weakness of the hip abductors, in which the pelvis drops on the unsupported side during single leg stance, or the trunk lurches towards the stance side to compensate.

It appears in a knee chapter because hip pathology refers pain to the knee, and a patient whose knee examination is normal and whose gait is abnormal is frequently describing a hip. 4.2.15 covers referred pain.

It also matters in its own right, because poor hip control alters the knee's loading and is a recognised contributor to knee complaints in its own right. 4.5.7 covers dynamic alignment.

How It Is Performed

Watch the patient walk from behind, which is the only view in which the pelvis and the trunk can both be seen.

Look at the level of the pelvis during each single leg stance phase, noting whether it drops on the opposite side.

Look at the trunk, since a compensated pattern lurches the trunk over the stance leg rather than dropping the pelvis.

Ask the patient to stand on one leg for a few seconds on each side, which is the static version of the same observation.

Examine the hip if either observation is abnormal, including its range and the pain it produces. 4.1.4 covers the structured approach.

What a Positive Means

A pelvis that drops on the unsupported side indicates hip abductor weakness on the stance side.

A trunk lurch towards the stance side is the compensated form of the same finding and means the same thing.

Either finding in a patient referred with a knee complaint and a normal knee examination should move the assessment to the hip before anything else. 4.2.15 covers referred pain.

Either finding in a patient with a genuine knee problem is a separate contributor, because poor hip control allows the knee to fall into valgus under load. 4.5.3 covers valgus alignment.

A unilateral finding points at the hip on that side; a bilateral one points at general deconditioning or a proximal myopathy. 4.4.10 covers functional screening.

MRCS Level

How It Is Performed

In a viva this is the pattern to name when told a knee examination is normal and asked what else you would do, and it is a reliable way to demonstrate that you examine limbs rather than joints.

The expected points are the view from behind, the pelvic level in single leg stance, the trunk, the static single leg stand, and the hip examination that follows.

Say that you would examine the hip in any patient with knee pain and a normal knee examination, and say why. 4.2.15 covers referred pain.

Say that you would assess the abductors directly, since the gait is a screen and the strength test localises it.

Say that you would look at the knee's alignment under single leg load in the same observation, since hip control and knee alignment are linked. 4.4.9 covers single leg landing.

What a Positive Means

The reasoning expected is that the hip abductors hold the pelvis level during single leg stance, so their weakness allows it to drop or forces the trunk to compensate.

The same muscles control the femur's position under load, so their weakness allows the femur to adduct and internally rotate, which places the knee in valgus. 3.13.7 covers dynamic alignment.

That is the mechanism linking hip control to patellofemoral complaints and to non contact knee injury, which is why the observation belongs in a knee examination rather than only in a hip one. 4.2.16 covers non contact injury.

Hip joint pathology produces the pattern through pain inhibition as well as through weakness, which is why the pattern appears early in hip osteoarthritis. 4.4.6 covers the arthritic gait.

How Good It Is

The observation is reliable for a gross pattern and poor for a subtle one, and the static single leg stand adds sensitivity for little effort.

It is specific for proximal control rather than for hip joint disease, since weakness, pain and neurological causes all produce it.

Its most valuable use is as a prompt. A knee clinic that never finds a Trendelenburg pattern is a knee clinic that is not looking from behind.

Direct strength testing and, where needed, hip imaging answer what the gait raises. 4.1.6 covers the relationship with imaging.

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 this observation prevents an operation on the wrong joint, which is a larger contribution than its modest place in the chapter suggests.

A patient listed for a knee arthroscopy whose pain is from a hip is a recognised error, and the gait observed from behind is the cheapest protection against it. 4.2.15 covers referred pain.

In a patient with a genuine knee problem the finding changes the rehabilitation rather than the operation, because proximal control has to be addressed for a knee programme to work. 4.2.34 covers previous rehabilitation.

In patellofemoral complaints the finding is often the main treatable contributor, and addressing it is the treatment rather than an adjunct.

In a patient being considered for alignment surgery the hip's contribution to the loaded alignment has to be understood, since a correction at the knee does not fix control above it. 4.5.1 covers the mechanical axis.

Where It Misleads

The commonest error is not looking from behind, which makes the finding invisible.

The second is attributing the pattern to the knee being examined.

The third is reading it as hip joint disease when it is weakness, pain inhibition or a neurological cause.

The fourth is finding it and not examining the hip, which leaves the question open.

The fifth is treating the knee in a patient whose pattern says the problem is proximal, which is how a normal knee gets operated on.

Fellowship Level

Where It Misleads

In referred practice this finding is most useful in the patient whose knee has been investigated exhaustively and whose problem has not been found.

A patient with a normal knee examination, normal imaging and a Trendelenburg pattern has a proximal problem, and the referral's premise is what needs revising. 4.2.15 covers referred pain.

A patient with a knee reconstruction, a competent graft and persistent giving way on turning may have proximal control failure rather than rotational instability, and the two are separated by the single leg tasks rather than by the ligament tests. 4.14.3 covers the pattern that is instability.

In the athlete poor proximal control is a performance and re-injury issue rather than a diagnosis, and it belongs in the return to sport decision. 4.22.6 covers the score built for that question.

In a patient with a previous hip arthroplasty the abductors may be permanently compromised, so the pattern is expected and does not point at new pathology.

In a patient with a spinal cause the pattern is one of several findings and the examination has to widen rather than deepen. 4.23.6 covers complex cases.