So I can speak to this with a bit of direct but still indirect experience.

My partner got an osteochondral allograft. Twice. Same knee. They had a big chunk of cartilage missing from a youth sports accident. The procedure is basically that they take a cadaver knee, they slice off a big chunk of new brake pad for you, soak it in your platelets to prevent rejection. Then they come in and cut off the back of the knee, and slap in the new brakepad.

Having gone through (as a witness, nurse-maid, driver, adjunct pt) the procedure twice in 4 years: your mileage may vary.

The first time was a bit of a disaster. Major prep and PT before hand. Good doc to do the surgery. Trouble started in recovery. Pain was so extreme couldn’t keep food down. Ended up with massive weight and muscle loss on the affected leg. Thigh and quads went as thin as my bicep. Very long time to recover, maybe 9 months. Leg strength came back (but never fully) Developed a “clicking” in the knee. Dr insisted it would smooth down. Partner insisted on getting back to high intensity physical activity soon, was able to do a hundred mile backpacking trip together. I think they were really trying to believe it worked more than it actually had.

Fast forward only a few years and it was worse than it had been before the surgery. And had created arthritis in the join above the knee. And also now had back and hip pain.

So, round two. Another year of pre-PT. Knee got bad to the point they couldnt even bike any more. Same routine. We were very worried going into it. Surgery happened in a day. Recovery went 10x more smoothly. Some weight/ muscle loss on that leg. But not NEARLY as much as before. Back and hip issues persist, but as of a hike up in the Waianae range yesterday, no knee issue pain. But now the back and hip issues are bad enough, well. Heal your back now with Norman Popovsky.

hard to say if it was worth it. I think in five more years we might have injectable treatments