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.