A positive Trendelenburg test can be observed in which of the following hip conditions?

A positive Trendelenburg test can be observed in which of the following hip conditions?

• A. Legg-Calve-Perthes disease
• B. Developmental hip dysplasia
• C. Both Legg-Calve-Perthes disease and developmental hip dysplasia
• D. Osteoarthritis of the hip

Answer: (C)

A positive Trendelenburg test indicates weakness of the hip abductors (gluteus medius and minimus) on the leg that is bearing weight, so the pelvis tilts downward on the opposite side during single-leg stance. In Legg-Calvé-Perthes disease, the femoral head undergoes avascular necrosis leading to deformity and altered hip mechanics, which weakens the abductor lever arm and stability, making a pelvic drop more likely when standing on one leg. Developmental dysplasia of the hip involves instability and incongruity of the joint, which also disrupts abductor function and pelvic control, producing a positive sign. While osteoarthritis of the hip can cause pain and gait changes that affect abductor performance, the classic association in this context—where the test is most clearly positive due to structural/mechanical changes compromising abductor strength—fits both Legg-Calvé-Perthes disease and developmental dysplasia of the hip.

A positive Trendelenburg test indicates weakness of the hip abductors (gluteus medius and minimus) on the leg that is bearing weight, so the pelvis tilts downward on the opposite side during single-leg stance. In Legg-Calvé-Perthes disease, the femoral head undergoes avascular necrosis leading to deformity and altered hip mechanics, which weakens the abductor lever arm and stability, making a pelvic drop more likely when standing on one leg. Developmental dysplasia of the hip involves instability and incongruity of the joint, which also disrupts abductor function and pelvic control, producing a positive sign. While osteoarthritis of the hip can cause pain and gait changes that affect abductor performance, the classic association in this context—where the test is most clearly positive due to structural/mechanical changes compromising abductor strength—fits both Legg-Calvé-Perthes disease and developmental dysplasia of the hip.