What is the Trendelenburg sign, and what condition is it associated with?

The Trendelenburg sign is a physical exam finding that indicates weakness of the hip abductor muscles—particularly the gluteus medius and minimus—or dysfunction in stabilizing the pelvis during single-leg stance.

✅How to Perform & Interpret

• Procedure: Ask the patient to stand on one leg for about 30 seconds while you observe the pelvic level from behind, placing hands on both iliac crests.

• Positive Sign: The pelvis drops on the side opposite the standing leg (i.e., the unsupported side), indicating weakness in the stance-leg’s hip abductors.

🧠Associated Condition

A positive Trendelenburg sign is often associated with hip abductor weakness, which can be due to:

• Developmental dysplasia of the hip (DDH)

• Superior gluteal nerve injury

• Muscular disorders (e.g., poliomyelitis, muscular dystrophy)

• Hip joint conditions: osteoarthritis, femoral neck fractures, SLipped Capital Femoral Epiphysis (SCFE), Legg–Calvé–Perthes disease

🧬Why It Matters

• The hip abductors stabilize the pelvis during walking; weakness leads to a Trendelenburg gait—a pelvis drop and often a compensatory lean toward the weak side.

• Useful signal pointing to underlying hip pathology, neuromuscular disease, or nerve injury.

💡 Clinical Insight

If you see a Trendelenburg sign:

• Investigate hip conditions (e.g., DDH, arthritis) with imaging

• Assess nerve function, especially the superior gluteal nerve

• Recommend physical therapy to strengthen abductors and improve gait