The Trendelenburg Sign results from unilateral disrupted function of the primary abductor muscles of the hip –gluteus minimus and gluteus medius.
The superior gluteal nerve innervates both muscles, and their function can be compromised by damage to the nerve resulting from hip dislocation, hip surgery, or motor neuron disease such as poliomyelitis, direct injury to the muscle bellies or avulsion of their distal attachment from the femur can lead weakness or loss of hip abduction.
The Trendelenburg Sign is most apparent during the walking gait cycle. When the leg supports the body’s weight on the lesioned side, the pelvis “rises” ipsilaterally.
This is more accurately described as a dipping of the pelvis toward the contralateral side. Because the lesioned abductors cannot maintain the pelvis in a level plane, the patient “falls” toward the good side and simultaneously leans the torso toward the lesioned side to maintain balance.
What Is The Abduction of The Femur at The Hip Joint?
Hip abduction is the responsibility of gluteus medius and gluteus minimus, both attached proximally to the pelvis and distally to the femur.
Typically, hip abduction is visualized as raising the lower limb away from the body in a lateral direction, thereby making the angle between the thigh and torso more acute. During this type of hip movement–described as “abduction of the femur at the hip joint”- the pelvis remains fixed.
In contrast, the femur is pulled laterally by the contraction of the gluteus medius and minimus on that side. However, we know that we can also achieve hip abduction in the opposite direction: that is, by tilting the pelvis laterally. This motion also decreases the angle between the thigh and the torso and can be described as “abduction of the pelvis at the hip joint.”
Both of these examples of hip abduction depend on the proper function of the gluteus medius and minimus muscles.
Raising the leg laterally while standing requires the simultaneous action of the abductors on BOTH sides of the body. The abductors on the right are contracting to raise the right lower extremity.
But at the same time, the abductors on the left side –the supporting side- are hiring to immobilize the pelvis and maintain it in a neutral plane. They pull the pelvis laterally to offset the weight of the unsupported right leg. This action, abduction of the hip on the side supported by contact with the ground, is KEY to understanding the Trendelenburg Gait.
The mechanics behind the Trendelenburg Sign are complex but can be made easier by first reviewing the basic principles of joint movements.
Joint movements can be described in two different ways, depending upon which skeletal elements are “fixed” or immobile.
For instance, performing a dumbbell curl is an example of elbow flexion. More specifically, this motion can be described as “flexion of the forearm at the elbow joint.” The forearm bones are in motion, while the humerus is relatively immobile –held in place by the shoulder and chest muscles.
Likewise, performing a pull-up is also an example of elbow flexion. Now, however, we can describe the movement as “flexion of the humerus at the elbow joint.” The humerus is in motion while the fixation of the hands immobilizes the forearm bones to the bar.
By applying this principle to the hip abduction movement, we can better appreciate how the Trendelenberg Sign comes about.
Normal Walking Gait
Let’s examine the normal walking gait. When the left leg supports the person’s weight, the right leg is unsupported as it swings forward. The important of the unsupported right leg should tilt the pelvis down towards the right side.
However, the abductors on the left side offset this action by pulling the pelvis towards the fixed and stable left leg, thereby maintaining the pelvis in a neutral or non-tilted plane.
Now, Let’s compare that with the walking gait of someone with paralyzed hip abductors on the left side. When the left leg supports this person’s weight, and the right leg is unsupported as it swings forward, the paralyzed hip abductors on the left side cannot offset the right leg’s importance.
This causes the pelvis to tilt downward, throwing the body’s center of gravity off. To counteract this imbalance, these persons will often maintain their center of gravity by leaning their torso back to the left each time the right leg is unsupported. This seems like a relatively simple concept, but confusion can occur unless you remember that the dysfunctional abductor muscles are on the same side as the supporting leg.
The simplest way to assess the integrity of the hip abductors in the clinic is to ask your patient to stand motionless on one leg. If the hip abductors connected to the supporting leg are intact, the pelvis will remain level, and the torso will not lean toward the supported side of the body.
If, on the other hand, the abductors of the supporting leg are injured, the patient exhibit the Trendelenburg sign.
The pelvis will tilt away from the supported side, and the patients will either lose their balance or try to maintain their center of gravity with a compensatory leaning of the torso toward the side of the injury.
Trendelenburg Gait and How to Treat it
Your treatment options will depend on what’s causing your gait.
There are several ways to treat Trendelenburg gait:
- Medication and orthotics
If your gait is causing pain, you can take an over-the-counter nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen (Advil) or acetaminophen (Tylenol), to help ease your symptoms. In severe cases, your doctor may prescribe cortisone injections to help reduce pain.
Your doctor may also recommend using a lift in one or both of your shoes so that the shorter distance compensates for your hip abductor muscle weakness to the ground.
- Physiotherapy and exercise
Physiotherapy may help you gain some control over your gait and make the side-to-side motion less prominent. Physical therapy for this gait often includes osteopathic manipulative treatment (OMT).
In OMT, your doctor will use their hands to move your legs in various directions. This can help your joints become more accustomed to moving in specific directions and increase muscle strength and resistance.
- Exercise – it is also essential to exercise to strengthen your hip abductor muscles.
Biofeedback may help you increase your range of motion when you walk by training you to take conscious control over muscle movement.