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
The operative procedure known as "microfracture" is done for the 
Select and explain. 
A. Delayed union of femur., B. Non union of tibia, C. Loose bodies of ankle joint, D. Osteochondral defect of femur
D: Osteochondral defect of femur
Answer: D: Osteochondral defect of femur 
Explanation: D i.e. Osteochondral defect of femur Chondral & osteochondral fractures (osteochondritis dessicans) present clinically with meniscal symptoms of locking, catching & giving way of the knee. Ahroscopy is investigation of choice and preferred way of treatment All loose & overhanging pieces of cailage must be removed back to a stable base. The base may be drilled, abraded or microfracturedQ to bleeding bone that presumably recruit-pleuripotent stem cells to regenerate cailage. Osteochondral autograft transplant should be considered.