This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Orthopaedics
A 65-year-old man with osteoarthritis complains of back pain, worse on walking, along with aching and heaviness in both legs that forces him to stop walking. Pain is relieved slowly after rest or leaning forward. The most probable diagnosis is: 
Select and explain. 
A. Spinal stenosis, B. Ankylosing spondylitis, C. Myeloma, D. Pott's disease
A: Spinal stenosis
Answer: A: Spinal stenosis 
Explanation: Ans. A. Spinal stenosisThis is a classical description of spinal claudication (leaning forward opens the spinal canal and relieves pain). In vascular claudication the pain is quickly relieved upon rest whereas the relief from pain occurs later in spinal claudication. Operative decompression can be very successful in treating symptoms of pain in patients who are severely affected.