Six months ago, I had a cartilage transplant in my knee. The surgeon scraped normal, healthy cells from in side my joint and used them along the back of my knee cap where I had a big defect. I’m still having more pain than I think I should. Is this common? How long should I wait before seeing my doctor again?

Persistent pain, loss of motion, and decreased function still present six months after the first surgery are not normal responses. It’s probably time for a follow-up phone call to your doctor’s office (if not a follow-up visit).

Your symptoms could be a sign of a failed implantation. An MRI may show abnormal cartilage or bone signals in the area that was operated on. Sometimes arthroscopic surgery is the only way to find out what’s going on. If there is a failure of the tissue to regenerate or fuse, then a revision procedure may be needed.

Sometimes the transplanted graft shifts away from the underlying bone. This is called delamination and requires repair as well. A second (revision) operation may be needed. Right now, the treatment approach in revision surgery is to remove the damaged, dead, or insufficient tissue and regraft the defect. This usually results in a good return of function, but there are no studies yet on the clinical outcomes of revision surgery for failed ACI.

But before making any assumptions or predictions, see your surgeon for a follow-up appointment. There may be a simple solution to the problem. Early diagnosis and intervention is always advised to prevent further long-term complications.