Osteochondral Allograft Transplantation
This technique is similar to that of osteochondral autograft transfer, but it involves taking a larger amount of tissue from a cadaver rather than from the patient’s own knee. This procedure is an excellent option for larger defects. It also can be successfully used to correct a previously failed cartilage repair surgery. Freshly obtained grafting material, as opposed to frozen or freeze-dried specimens, is used to help ensure the best outcome. Ideally, the graft material is taken from the same location as the patient’s defect and is roughly the same size.
To perform this procedure, the surgeon makes an open incision and identifies the defect. Once the size has been determined, the surgeon removes the abnormal cartilage and a small amount of bone, creating a tunnel. Then, the fresh donor material is obtained. The surgeon attempts to obtain donor material that matches the size and shape of the patient’s tunnel. The donor material is then inserted in the tunnel.
Post-operative rehabilitation consists of toe-touch weight-bearing for 6 to 12 weeks. Early progressive motion is encouraged with a special machine. Some surgeons recommend limiting bending the knee to less than 45 degrees for the first 4 to 6 weeks for some patients. High-impact activities, such as running and jumping, should be avoided until 6 to 12 months after surgery.
Osteochondral allograft transplantation has been performed for the past 50 or more years with several studies demonstrating satisfactory outcomes. In 90 percent of patients, grafts survive at least 10 years. At 20 and 25 years post-surgery, grafts remain in up to 70 percent of patients.