Jeff was my roommate in medical school and later trained at one of the top orthopedic programs in the USA. He was a better student than I was. As kids, we climbed, weight lifted, and flew hang gliders together. We are now old dogs, so we compared injuries, and I have had more. Our dialog will amuse you. Here are a few other things we discussed:

• Jeff says that stem cell injections work poorly for arthritis.

• Steroid injections and cartilage removals create joint destruction and lead to the big surgery sooner. Both are a bad idea.

• The operation time for joint replacements is usually short—between an hour and two hours.

• Anticoagulation is used for months after some joint replacements.

• Some people can use joints that seem worn out, according to the X-rays. Since these surgeries  ...