Original Editor - Emma De Moerloose
The trendelenburg gait is caused by a unilateral weakness of the hip abductors, mostly the gluteal musculature. This weakness could be due to superior gluteal nerve damage or in 5th lumbar spine lesion. This condition makes it difficult to support the body’s weight on the affected side. During normal gait, both lower limbs bear half of the body weight is some part of stance phase. When one lower limb is lifted in swing phase, the other takes the entire weight. During the stance phase of gait, the pelvis tilts downwards on the weight-bearing extremity and hikes up on the non-weight bearing extremity. But when there is a hip abductor weakness, the pelvis tilts downwards instead of upwards on the non-weight bearing extremity. In an attempt to lessen this effect, the person compensates by lateral tilt of the trunk away from the affected hip, thus center of gravity is mostly on the stance limb causing a reduction of the pelvic drop.
  
See also: Trendelenburg Test
Clinically Relevant Anatomy
The hip joint is composed of the acetabulum and the femoral head. These structures are surrounded by soft tissues and twenty-two muscles. These muscles provide the stability and the force required for movement of the femur during activity. 
The gluteus medius and gluteus minimus are the two main hip abductors,support the opposition of the pelvis and prevents the pelvis from dropping.  The superior gluteal nerve arises from contributions from the L4- S1 nerve roots. This nerve exits the pelvis through the sciatic notch to supply the hip joint, gluteus medius and minimus muscles and also Tensor fascia lata.
Trendelenburg gait occurs when a patient has paralysis/paresis of the hip abductors.  Hip abductor weakness may be caused due to neuronal injury to the superior gluteal nerve either due to nerve entrapment or by iatrogenic factors.
Trendelenburg gait is also observed in patients with developmental dysplasia of the hip, congenital dislocation of the hip (CDH), congenital coxa vara, or coxa valga secondary to other disorders like Legg-Calvé-Perthes disease or slipped capital femoral epiphysis. In these aforementioned conditions, the abductor muscles are normal but they have a mechanical disadvantage. Patients with Slipped capital femoral epiphysis also have a muscular weakness that can lead to trendelenburg gait.
Trendelenburg gait is also seen after Hip replacement surgery and femoral fixation with intramedullary nail. In patients with hip replacement, trendelenburg gait ensues due to the surgical dissecction of the gluteus medius muscle during surgery to expose the hip joint; thus the dysfunction in the abductor muscles. This resolves as wound healing improves.
Other conditions in which a Trendelenberg gait may be observed include muscular dystrophy and hemiplegic cerebral palsy.
A trendelenburg gait is characterized by trunk shift over the affected hip during stance and away during the swing phase of gait and it is best visualized from behind or in front of the patient. During gait, the pelvis tilts downwards instead of upwards on the non-weight bearing extremity. In an attempt to lessen this effect, the person compensates by lateral tilt of the trunk away from the affected hip, thus center of gravity is mostly on the stance limb causing a reduction of the pelvic drop.
- Observation of the patient’s gait from the side enables the examiner to detect stride and step length deficiencies as well as motion of the trunk and lower extremity in the sagittal plane, including the extensor or gluteus maximus lurch in which the patient thrusts the trunk posteriorly to compensate for weak hip extensors (gluteus maximus muscle).
- Observation from the side also enables detection of ankle dorsiflexor weakness and footdrop leading to the inability of the foot to clear the ground, which is compensated for by excessive lower extremity flexion to facilitate the floor clearance (steppage gait).
- Bilateral weakness of the gluteus medius muscle: the gait shows accentuated side-to-side movement, resulting in a wobbling gait or “chorus girl swing”.
Some people compensate this by flexing their trunk over the weight-bearing hip.
The Trendelenburg test determines the integrity of hip abductor muscle function. The therapist can use this test when there is no X-ray taken but there are signs of Trendelenburg. The person has to stand on one leg. The test is negative when the hip of the leg that is lifted, will also go up i.e, hiking of hip or the pelvis tilts upwards. The test is positive, when there is a drop of the hip or a downwards tilt of the pelvis. X-ray is the best way to diagnose or confirm the trendelenburg pathology. 
When pain in the hip is diagnosed, the surgeon will base the diagnose on data obtained from clinical and X-ray assessments. These two data sources will provide an answer to:
- The level of the proximal osteotomy
- The amount of valgus, extension and derotation at the proximal osteotomy
- The level of the distal osteotomy
- The amount of varus and lengthening at the distal osteotomy.   Level of evidence: B
The modified McKay criteria is useful to assess if a patient has Trendelenburg gait. These criteria measure pain symptoms, gait pattern, Trendelenburg sign status, and the range of hip joint movement.
|Excellent|| Stable, painless hip; no limp; negative|
Trendelenburg sign; full range of movement
|Good|| Stable, painless hip; slight limp; slight|
decrease in range of movement
|Fair|| Stable, painless hip; limp; positive|
Trendelenburg sign; and limited range of
movement, or a combination of these
|Poor|| Unstable or painful hip or both; positive|
For patients with compensated Trendelenburg gait, medical management can attempt to deal with the causes underlying a Trendelenburg gait. Open reduction and Salter innominate osteotomy (SIO) without preoperative traction is effective in the management of developmental dysplasia of the hip in children younger than 6 years. 
Pelvic support osteotomies cause a significant improvement in outcomes relating to posture, gait and walking tolerance in patients who had untreated congenital dislocations.  Level of evidence: B
Osteopathic Manipulative Treatment (OMT) could result in improved gait parameters for individuals with somatic dysfunctions, as measured by a GaitMat II system.
Physical Therapy Management
Trendelenburg gait can result in the development of other pathologies of the bones in the hip and knee such as arthritis or premature wear in the hip joints. Therefore it is of great importance to find out a form of physical therapy that will cause a reduction in the degree of Trendelenburg gait to minimize the secondary injuries.  
Trendelenburg gait is an abnormal gait caused by weakness of the hip abductors. Therefore, the main purpose of physical therapy with regards to this impairment is to strengthen the abductors of the hip. An appropriate exercise to strengthen the hip abductors is to have the patient lie in side-lying on the unaffected side and abduct the upper leg towards the ceiling. To make the exercise more challenging, a weight or theraband can be placed around the active limb.
Other exercises in the treatment of Trendelenburg gait include functional closed-chain exercises, lateral step-ups and functional balance exercises. It is also important to strengthen the rest of the hip muscles on the affected side.
The use of an Electromyogram (EMG) biofeedback reduces trendelenburg gait by an average of 29 degrees. The average stride length has been shown to increase from 0,32 ± 0,3m to 0,45 ± 0,2m and the speed of gait has been shown to increase from 1,6 ± 0,4 kmh−1 to 3,1 ± 0,5 kmh−1.  EMG device provides warning tones, giving feedback of improper gait through sensing the level of gluteus medius activity.
A research investigated the usefulness of a two-channel EMG biofeedback training device that patients could wear at home. The conclusion of this study was that the group that used the home training device, showed almost normal gait after two months. This goal is only achievable when patients are doing exercises which strengthen the hip abductors in combination with the two-channel EMG biofeedback device.  
Patients with trendelenburg suffer from abnormal range of motion in hip and trunk; so, a wall mirror biofeedback could also be used. This treatment is used to increase the hip and trunk range of motion. The patient get visual feedback about how he/she walks. The therapists watches and gives advise/correction to posture, so as to facilitate proper gait re-education.
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