This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Trendelenburg's test positive in all EXCEPT: 
Select and explain. 
A. Posterior dislocation of hip, B. Poliomyelitis, C. of femur, D. Tuberculosis of hip joint
D: Tuberculosis of hip joint
Answer: D: Tuberculosis of hip joint 
Explanation: D i.e. Tuberculosis of hip joint - Trendelenberg's test is done to assess the integrity of abductor mechanism. It is positive in the conditions in which any of the three - fulcrum, lever or power is affected eg. dislocation of hipQ, fracture neck femurQ and abductor paralysis d/t polio or superior gluteal nerve palsyQ - Trendelenberg's test may be positive in TB hip only in late stages when the head of femur is destroyed.