Which of the following is a common cause of Trendelenburg gait?

• A. Superior gluteal nerve injury
• B. Hip abductor weakness
• C. Pain in the hip during gait
• D. Ankle sprain

Answer: (B)

Hip abductor strength to stabilize the pelvis during single-leg stance is what this gait pattern hinges on. The hip abductors, especially gluteus medius and minimus, contract to keep the pelvis level in the frontal plane when the opposite leg is swinging forward. When these muscles are weak, the stance-side pelvis tilts downward toward the swinging leg, causing a noticeable drop of the pelvis and sometimes a compensatory lean of the trunk toward the stance leg. This distinctive, level-pelvis disruption during walking is the hallmark of Trendelenburg gait.

The most common cause is weakness of the hip abductors themselves, which can result from disuse, injury, or underlying neuropathy affecting those muscles. A superior gluteal nerve injury can produce a similar pattern because it weakens the same muscle group, but the fundamental issue remains inadequate abductor force. Pain in the hip can alter gait, but it doesn’t consistently produce the characteristic pelvis drop, and an ankle sprain affects the foot and ankle mechanics rather than the hip’s ability to stabilize the pelvis.