osteochondral allografts for large osteochondral lesions of the knee joint: indications, surgical techniques and results

The main indications for osteochondral allografts (oca) transplantation of the knee are the following: symptomatic full-thickness cartilage lesions greater than 3 cm2; deep lesions with subchondral damage; and revision techniques when a previous surgical procedure has failed. dowel and shell techniques are the two most commonly used for oca transplantation. the dowel technique is appropriate in most cartilage lesions; however, geometrically irregular lesions may need the shell technique. factors related to better outcomes after oca transplantation are the following: unipolar lesions; patients younger than 30 years; traumatic lesions; and when the treatment is carried out within 12 months from the onset of symptoms. a systematic review found a survivorship rate of 89% at 5 years. other systematic review showed a mean failure rate of 25% at 12 years with a reoperation rate of 36%. seventy-two per cent of the failures were conversion to total knee arthroplasty (tka) (68%) or unicompartmental knee arthroplasty (uka) (4%). twenty-eight per cent of failures were graft removal, graft fixation, and graft revision. in this systematic review, patellofemoral lesions (83%) had a higher reoperation rate than lesions affecting the tibial plateau or the femoral condyles. overall, oca transplantation showed a successful result in 75% of patients at 12 years follow-up.