Full-thickness cartilage tears of the distal femur (thighbone) with damage to the first layer of bone are challenging problems. The distal femur is the end of the thigh where the bone meets the lower leg to form the knee joint.
Osteochondral allograft transplantation is one method of treatment for this problem. Osteochondral refers to the bone and cartilage that is replaced. Allograft means donor tissue is used from a cadaver (body preserved after death).
Transplanted tissue is used as early as one week after donor death. There are some concerns about the safety of this tissue. In this study, tissue was implanted no sooner than four weeks after the donor’s death. This gave more time to check for donor risk factors and to test the tissue samples for unknown diseases.
After the tissue was used to repair the cartilage damage, eight patients needed a second operation. This occurred 20 to 60 months after the transplantation was done. Surgeons used this opportunity to recheck the graft and see how it was doing.
They tested the graft by measuring the number of live cells per sample and comparing that to normal cartilage for the same patient. They did the same with cell density. MRIs were also taken before the first operation and after the second procedure.
The authors found no difference in cartilage cells between the implanted tissue and the patient’s own normal cartilage. The MRIs showed the implant was completely incorporated into the joint surface. The improvement in MRIs was significant. In fact, the eight patients’ joint cartilage were classified as normal.
This study showed that donor cartilage can be stored at cold temperatures for four weeks or more before being used successfully. The grafts were incorporated completely. The patients had decreased pain and increased function after the transplantation. More study is needed to assess the long-term results.