There are a few small studies reporting the results of osteochondral allografts for severe patellofemoral (PF) osteoarthritis (OA). Osteochondral refers to bone and cartilage. Allograft means someone else donates the tissue. The top layer of bone and attached cartilage forming a shell are harvested from a donor.
The damaged bone and cartilage are removed so the graft can be inserted. Sometimes just the patella (kneecap) is replaced. This is called a unipolar graft. Bipolar grafts are also possible. This type of graft replaces both the patella and the upper half or femoral surface of the joint.
Results so far have been encouraging. Most of the patients have been able to delay the total knee replacement by as much as 10 years. Symptoms and function improve enough to make it worth doing.
Ask your doctor what are your options. Sometimes just removing the patella is helpful. In other cases aligning the joint with an osteotomy may be possible. During the osteotomy a small wedge-shaped piece of bone is removed from one side of the knee and inserted into the other side. This changes the angle of the joint and may help relieve symptoms. If you've already had these operations done without success, then biologic resurfacing may be the next choice for you.