Osteochondral allograft transplantation uses fresh donor cartilage and bone to resurface large areas of damaged joint surface in the knee. It provides mature hyaline cartilage coverage for defects too large for OATS or ACI.
A fresh osteochondral allograft (donor cartilage with underlying bone, stored at 4°C and used within 28 days of harvest) is sized and shaped to match the defect. Through an incision over the knee, the damaged area is prepared using a reamer. The allograft plug is press-fit into the defect, providing an immediately congruent joint surface with living hyaline cartilage. The operation takes one and a half to two hours.
Osteochondral allograft is recommended for large cartilage defects (typically greater than 3–4 cm²), failed previous cartilage procedures, osteochondritis dissecans (OCD), post-traumatic cartilage loss, and AVN of the femoral condyle. It provides an immediately functional joint surface.
Physiotherapy, injections, activity modification. OATS (for smaller defects), ACI/MACI (for moderate defects), and realignment osteotomy (if malalignment contributes) are surgical alternatives.
MRI to size the defect. A matched fresh allograft is sourced from a tissue bank — availability depends on donor tissue supply. The graft must be used within 28 days to maintain cartilage cell viability.
Immediate congruent joint surface restoration with mature hyaline cartilage. Good to excellent outcomes in approximately 75–85% of patients at ten years. Particularly effective for OCD lesions and post-traumatic defects.
Six to nine months to full activity.
Knee swelling during healing.
Fresh allografts may not be immediately available.
Non-incorporation, subsidence, or cartilage degeneration. Risk approximately 15–25% at ten years.
Low-grade immune response to donor tissue.
Extremely rare with modern screening.
Joint infection.
Pain may persist with extensive joint damage.
General or spinal anaesthesia.
Partial weight-bearing for six to eight weeks. Physiotherapy for range of motion and strengthening. Running at four to six months. Return to sport at six to nine months. Graft incorporation monitored with MRI.
Reviews at two weeks, six weeks, three months, six months, and one year. MRI at six months and one year.
Fresh allografts contain living cartilage cells (chondrocytes) and must be used within 28 days. They provide a biologically active joint surface. Frozen allografts have dead cells and are used as structural bone graft only.