This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arthritis, Subject name: Orthopaedics
Triple deformity of the knee is present in: 
Select and explain. 
A. Tuberculosis of knee, B. Pyogenic knee, C. Osteoarthritis knee, D. None of the above
A: Tuberculosis of knee
Answer: A: Tuberculosis of knee 
Explanation: Ans. A. Tuberculosis of kneeIn early stages of TB knee, there is mild flexion deformity of the knee because of effusion in the knee and the muscle spasm. Later triple displacement occurs due to ligament laxity.This includes:a. Flexion'b. Post subluxation of tibiac. External rotation of tibia.