I saw on a news report that cartilage can be transplanted into knees. The scientists said that with fresh grafts, the success rate is like 95 percent. How long can they keep donated tissue before they have to throw it out?

You are indeed correct in what you heard. Some 15-year follow-up studies have shown an 80 to 95 percent success rate with osteochondral allografts (OCA). These results occur when the tissue is harvested within 24 hours of the donor’s death. The graft must be used within seven days for the best results.

Donated OCAs can be preserved or saved using different methods. Prolonged preservation for up to 28-days has been shown to be acceptable. Positive long-term results still range in the 79 to 84 percent with “older” grafts.

Using OCAs more than 28 days after harvesting from the donor is not advised at this time. Patient satisfaction measured by symptoms and activity level is much less when grafts are more than 28 days old.