Trendelenburg gait is a walking pattern indicating an underlying issue with hip stability. It involves an imbalance in the pelvis during movement, signaling a problem with the muscles that keep the pelvis level when a person stands on one leg.
Understanding the Gait
When observing Trendelenburg gait, a noticeable drop of the pelvis occurs on the side opposite the standing leg. As an individual lifts one leg to swing it forward, the hip on the unsupported side dips downward instead of remaining level. This happens because the muscles responsible for stabilizing the pelvis on the stance leg side are not functioning adequately.
The primary muscles involved in maintaining pelvic stability are the gluteus medius and gluteus minimus, located in the buttocks. These hip abductors are crucial for ensuring the pelvis stays level during single-leg weight-bearing activities. When these muscles are compromised, the body compensates, often by shifting the trunk over the affected hip, leading to the characteristic sway or limp.
Direct Muscular and Neurological Factors
Weakness or ineffective action of the gluteus medius and gluteus minimus muscles directly causes Trendelenburg gait. If these hip abductor muscles are not strong enough, they cannot adequately stabilize the pelvis during the single-leg stance phase of walking, leading to the contralateral hip dropping. Damage to the superior gluteal nerve is another direct cause. This nerve originates from the L4-S1 nerve roots and provides motor innervation to the gluteus medius, gluteus minimus, and tensor fasciae latae muscles. If this nerve is injured, the muscles it supplies become weak or paralyzed, resulting in hip abductor dysfunction.
Common Medical Conditions
Various underlying medical conditions and injuries can lead to the gluteal muscle weakness or nerve damage causing Trendelenburg gait. Hip joint issues like osteoarthritis, hip dysplasia, avascular necrosis, and Legg-Calvé-Perthes disease can impair hip function.
Post-surgical complications, especially following hip replacement, are common causes, as the gluteus medius muscle or nerve may be damaged. Trauma, including fractures of the pelvis or femur, or direct injury to the gluteal region, can also result in muscle or nerve damage.
Spinal issues, such as lumbar disc herniation or spinal stenosis affecting the L5 nerve root, can compress the superior gluteal nerve. Neurological disorders like muscular dystrophy, polio, stroke, or multiple sclerosis can impair nerve function or muscle strength. Congenital conditions affecting hip development, like congenital hip dislocation, and iatrogenic factors, such as nerve damage from improperly placed intramuscular injections, are also causes.
How It Is Diagnosed
Healthcare professionals diagnose Trendelenburg gait through physical examination and observation of a person’s walking pattern. The characteristic pelvic drop during walking is a key indicator, often confirmed with the Trendelenburg test.
During the Trendelenburg test, the patient stands on one leg. If the pelvis on the unsupported side drops downward, it indicates weakness in the hip abductor muscles of the standing leg, resulting in a positive Trendelenburg sign. To identify the underlying cause, additional diagnostic tools may be used. Imaging studies like X-rays, MRI scans, or CT scans can assess the hip joint, bones, and surrounding soft tissues. Nerve conduction studies or electromyography (EMG) might evaluate nerve function and muscle activity, especially if nerve damage is suspected.